aboutsummaryrefslogtreecommitdiff
path: root/fs/netfs
diff options
context:
space:
mode:
Diffstat (limited to 'fs/netfs')
-rw-r--r--fs/netfs/Kconfig39
-rw-r--r--fs/netfs/Makefile23
-rw-r--r--fs/netfs/buffered_read.c273
-rw-r--r--fs/netfs/buffered_write.c581
-rw-r--r--fs/netfs/direct_read.c126
-rw-r--r--fs/netfs/direct_write.c196
-rw-r--r--fs/netfs/fscache_cache.c429
-rw-r--r--fs/netfs/fscache_cookie.c1180
-rw-r--r--fs/netfs/fscache_internal.h14
-rw-r--r--fs/netfs/fscache_io.c293
-rw-r--r--fs/netfs/fscache_main.c108
-rw-r--r--fs/netfs/fscache_proc.c47
-rw-r--r--fs/netfs/fscache_stats.c103
-rw-r--r--fs/netfs/fscache_volume.c520
-rw-r--r--fs/netfs/internal.h313
-rw-r--r--fs/netfs/io.c361
-rw-r--r--fs/netfs/iterator.c97
-rw-r--r--fs/netfs/locking.c216
-rw-r--r--fs/netfs/main.c148
-rw-r--r--fs/netfs/misc.c252
-rw-r--r--fs/netfs/objects.c124
-rw-r--r--fs/netfs/stats.c53
-rw-r--r--fs/netfs/write_collect.c808
-rw-r--r--fs/netfs/write_issue.c684
24 files changed, 6727 insertions, 261 deletions
diff --git a/fs/netfs/Kconfig b/fs/netfs/Kconfig
index b4db21022cb4..bec805e0c44c 100644
--- a/fs/netfs/Kconfig
+++ b/fs/netfs/Kconfig
@@ -21,3 +21,42 @@ config NETFS_STATS
multi-CPU system these may be on cachelines that keep bouncing
between CPUs. On the other hand, the stats are very useful for
debugging purposes. Saying 'Y' here is recommended.
+
+config FSCACHE
+ bool "General filesystem local caching manager"
+ depends on NETFS_SUPPORT
+ help
+ This option enables a generic filesystem caching manager that can be
+ used by various network and other filesystems to cache data locally.
+ Different sorts of caches can be plugged in, depending on the
+ resources available.
+
+ See Documentation/filesystems/caching/fscache.rst for more information.
+
+config FSCACHE_STATS
+ bool "Gather statistical information on local caching"
+ depends on FSCACHE && PROC_FS
+ select NETFS_STATS
+ help
+ This option causes statistical information to be gathered on local
+ caching and exported through file:
+
+ /proc/fs/fscache/stats
+
+ The gathering of statistics adds a certain amount of overhead to
+ execution as there are a quite a few stats gathered, and on a
+ multi-CPU system these may be on cachelines that keep bouncing
+ between CPUs. On the other hand, the stats are very useful for
+ debugging purposes. Saying 'Y' here is recommended.
+
+ See Documentation/filesystems/caching/fscache.rst for more information.
+
+config FSCACHE_DEBUG
+ bool "Debug FS-Cache"
+ depends on FSCACHE
+ help
+ This permits debugging to be dynamically enabled in the local caching
+ management module. If this is set, the debugging output may be
+ enabled by setting bits in /sys/modules/fscache/parameter/debug.
+
+ See Documentation/filesystems/caching/fscache.rst for more information.
diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile
index 386d6fb92793..8e6781e0b10b 100644
--- a/fs/netfs/Makefile
+++ b/fs/netfs/Makefile
@@ -2,11 +2,30 @@
netfs-y := \
buffered_read.o \
+ buffered_write.o \
+ direct_read.o \
+ direct_write.o \
io.o \
iterator.o \
+ locking.o \
main.o \
- objects.o
+ misc.o \
+ objects.o \
+ write_collect.o \
+ write_issue.o
netfs-$(CONFIG_NETFS_STATS) += stats.o
-obj-$(CONFIG_NETFS_SUPPORT) := netfs.o
+netfs-$(CONFIG_FSCACHE) += \
+ fscache_cache.o \
+ fscache_cookie.o \
+ fscache_io.o \
+ fscache_main.o \
+ fscache_volume.o
+
+ifeq ($(CONFIG_PROC_FS),y)
+netfs-$(CONFIG_FSCACHE) += fscache_proc.o
+endif
+netfs-$(CONFIG_FSCACHE_STATS) += fscache_stats.o
+
+obj-$(CONFIG_NETFS_SUPPORT) += netfs.o
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 2cd3ccf4c439..a6bb03bea920 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -10,12 +10,16 @@
#include "internal.h"
/*
- * Unlock the folios in a read operation. We need to set PG_fscache on any
+ * Unlock the folios in a read operation. We need to set PG_writeback on any
* folios we're going to write back before we unlock them.
+ *
+ * Note that if the deprecated NETFS_RREQ_USE_PGPRIV2 is set then we use
+ * PG_private_2 and do a direct write to the cache from here instead.
*/
void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
{
struct netfs_io_subrequest *subreq;
+ struct netfs_folio *finfo;
struct folio *folio;
pgoff_t start_page = rreq->start / PAGE_SIZE;
pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;
@@ -47,14 +51,14 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
xas_for_each(&xas, folio, last_page) {
loff_t pg_end;
bool pg_failed = false;
- bool folio_started;
+ bool wback_to_cache = false;
+ bool folio_started = false;
if (xas_retry(&xas, folio))
continue;
pg_end = folio_pos(folio) + folio_size(folio) - 1;
- folio_started = false;
for (;;) {
loff_t sreq_end;
@@ -62,9 +66,16 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
pg_failed = true;
break;
}
- if (!folio_started && test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) {
- folio_start_fscache(folio);
- folio_started = true;
+ if (test_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags)) {
+ if (!folio_started && test_bit(NETFS_SREQ_COPY_TO_CACHE,
+ &subreq->flags)) {
+ trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache);
+ folio_start_private_2(folio);
+ folio_started = true;
+ }
+ } else {
+ wback_to_cache |=
+ test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);
}
pg_failed |= subreq_failed;
sreq_end = subreq->start + subreq->len - 1;
@@ -86,11 +97,25 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
if (!pg_failed) {
flush_dcache_folio(folio);
+ finfo = netfs_folio_info(folio);
+ if (finfo) {
+ trace_netfs_folio(folio, netfs_folio_trace_filled_gaps);
+ if (finfo->netfs_group)
+ folio_change_private(folio, finfo->netfs_group);
+ else
+ folio_detach_private(folio);
+ kfree(finfo);
+ }
folio_mark_uptodate(folio);
+ if (wback_to_cache && !WARN_ON_ONCE(folio_get_private(folio) != NULL)) {
+ trace_netfs_folio(folio, netfs_folio_trace_copy_to_cache);
+ folio_attach_private(folio, NETFS_FOLIO_COPY_TO_CACHE);
+ filemap_dirty_folio(folio->mapping, folio);
+ }
}
if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {
- if (folio_index(folio) == rreq->no_unlock_folio &&
+ if (folio->index == rreq->no_unlock_folio &&
test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags))
_debug("no unlock");
else
@@ -105,7 +130,9 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
}
static void netfs_cache_expand_readahead(struct netfs_io_request *rreq,
- loff_t *_start, size_t *_len, loff_t i_size)
+ unsigned long long *_start,
+ unsigned long long *_len,
+ unsigned long long i_size)
{
struct netfs_cache_resources *cres = &rreq->cache_resources;
@@ -147,6 +174,15 @@ static void netfs_rreq_expand(struct netfs_io_request *rreq,
}
}
+/*
+ * Begin an operation, and fetch the stored zero point value from the cookie if
+ * available.
+ */
+static int netfs_begin_cache_read(struct netfs_io_request *rreq, struct netfs_inode *ctx)
+{
+ return fscache_begin_read_operation(&rreq->cache_resources, netfs_i_cookie(ctx));
+}
+
/**
* netfs_readahead - Helper to manage a read request
* @ractl: The description of the readahead request
@@ -180,11 +216,9 @@ void netfs_readahead(struct readahead_control *ractl)
if (IS_ERR(rreq))
return;
- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
- goto cleanup_free;
- }
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto cleanup_free;
netfs_stat(&netfs_n_rh_readahead);
trace_netfs_read(rreq, readahead_pos(ractl), readahead_length(ractl),
@@ -192,6 +226,10 @@ void netfs_readahead(struct readahead_control *ractl)
netfs_rreq_expand(rreq, ractl);
+ /* Set up the output buffer */
+ iov_iter_xarray(&rreq->iter, ITER_DEST, &ractl->mapping->i_pages,
+ rreq->start, rreq->len);
+
/* Drop the refs on the folios here rather than in the cache or
* filesystem. The locks will be dropped in netfs_rreq_unlock().
*/
@@ -199,6 +237,7 @@ void netfs_readahead(struct readahead_control *ractl)
;
netfs_begin_read(rreq, false);
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
return;
cleanup_free:
@@ -223,12 +262,13 @@ EXPORT_SYMBOL(netfs_readahead);
*/
int netfs_read_folio(struct file *file, struct folio *folio)
{
- struct address_space *mapping = folio_file_mapping(folio);
+ struct address_space *mapping = folio->mapping;
struct netfs_io_request *rreq;
struct netfs_inode *ctx = netfs_inode(mapping->host);
+ struct folio *sink = NULL;
int ret;
- _enter("%lx", folio_index(folio));
+ _enter("%lx", folio->index);
rreq = netfs_alloc_request(mapping, file,
folio_file_pos(folio), folio_size(folio),
@@ -238,15 +278,64 @@ int netfs_read_folio(struct file *file, struct folio *folio)
goto alloc_error;
}
- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto discard;
+
+ netfs_stat(&netfs_n_rh_read_folio);
+ trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
+
+ /* Set up the output buffer */
+ if (folio_test_dirty(folio)) {
+ /* Handle someone trying to read from an unflushed streaming
+ * write. We fiddle the buffer so that a gap at the beginning
+ * and/or a gap at the end get copied to, but the middle is
+ * discarded.
+ */
+ struct netfs_folio *finfo = netfs_folio_info(folio);
+ struct bio_vec *bvec;
+ unsigned int from = finfo->dirty_offset;
+ unsigned int to = from + finfo->dirty_len;
+ unsigned int off = 0, i = 0;
+ size_t flen = folio_size(folio);
+ size_t nr_bvec = flen / PAGE_SIZE + 2;
+ size_t part;
+
+ ret = -ENOMEM;
+ bvec = kmalloc_array(nr_bvec, sizeof(*bvec), GFP_KERNEL);
+ if (!bvec)
+ goto discard;
+
+ sink = folio_alloc(GFP_KERNEL, 0);
+ if (!sink)
goto discard;
+
+ trace_netfs_folio(folio, netfs_folio_trace_read_gaps);
+
+ rreq->direct_bv = bvec;
+ rreq->direct_bv_count = nr_bvec;
+ if (from > 0) {
+ bvec_set_folio(&bvec[i++], folio, from, 0);
+ off = from;
+ }
+ while (off < to) {
+ part = min_t(size_t, to - off, PAGE_SIZE);
+ bvec_set_folio(&bvec[i++], sink, part, 0);
+ off += part;
+ }
+ if (to < flen)
+ bvec_set_folio(&bvec[i++], folio, flen - to, to);
+ iov_iter_bvec(&rreq->iter, ITER_DEST, bvec, i, rreq->len);
+ } else {
+ iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,
+ rreq->start, rreq->len);
}
- netfs_stat(&netfs_n_rh_readpage);
- trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_readpage);
- return netfs_begin_read(rreq, true);
+ ret = netfs_begin_read(rreq, true);
+ if (sink)
+ folio_put(sink);
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
+ return ret < 0 ? ret : 0;
discard:
netfs_put_request(rreq, false, netfs_rreq_trace_put_discard);
@@ -377,7 +466,7 @@ retry:
if (!netfs_is_cache_enabled(ctx) &&
netfs_skip_folio_read(folio, pos, len, false)) {
netfs_stat(&netfs_n_rh_write_zskip);
- goto have_folio_no_wait;
+ goto have_folio;
}
rreq = netfs_alloc_request(mapping, file,
@@ -387,14 +476,12 @@ retry:
ret = PTR_ERR(rreq);
goto error;
}
- rreq->no_unlock_folio = folio_index(folio);
+ rreq->no_unlock_folio = folio->index;
__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
- if (ctx->ops->begin_cache_operation) {
- ret = ctx->ops->begin_cache_operation(rreq);
- if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
- goto error_put;
- }
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto error_put;
netfs_stat(&netfs_n_rh_write_begin);
trace_netfs_read(rreq, pos, len, netfs_read_trace_write_begin);
@@ -405,6 +492,10 @@ retry:
ractl._nr_pages = folio_nr_pages(folio);
netfs_rreq_expand(rreq, &ractl);
+ /* Set up the output buffer */
+ iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,
+ rreq->start, rreq->len);
+
/* We hold the folio locks, so we can drop the references */
folio_get(folio);
while (readahead_folio(&ractl))
@@ -413,12 +504,9 @@ retry:
ret = netfs_begin_read(rreq, true);
if (ret < 0)
goto error;
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
have_folio:
- ret = folio_wait_fscache_killable(folio);
- if (ret < 0)
- goto error;
-have_folio_no_wait:
*_folio = folio;
_leave(" = 0");
return 0;
@@ -434,3 +522,124 @@ error:
return ret;
}
EXPORT_SYMBOL(netfs_write_begin);
+
+/*
+ * Preload the data into a page we're proposing to write into.
+ */
+int netfs_prefetch_for_write(struct file *file, struct folio *folio,
+ size_t offset, size_t len)
+{
+ struct netfs_io_request *rreq;
+ struct address_space *mapping = folio->mapping;
+ struct netfs_inode *ctx = netfs_inode(mapping->host);
+ unsigned long long start = folio_pos(folio);
+ size_t flen = folio_size(folio);
+ int ret;
+
+ _enter("%zx @%llx", flen, start);
+
+ ret = -ENOMEM;
+
+ rreq = netfs_alloc_request(mapping, file, start, flen,
+ NETFS_READ_FOR_WRITE);
+ if (IS_ERR(rreq)) {
+ ret = PTR_ERR(rreq);
+ goto error;
+ }
+
+ rreq->no_unlock_folio = folio->index;
+ __set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);
+ ret = netfs_begin_cache_read(rreq, ctx);
+ if (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)
+ goto error_put;
+
+ netfs_stat(&netfs_n_rh_write_begin);
+ trace_netfs_read(rreq, start, flen, netfs_read_trace_prefetch_for_write);
+
+ /* Set up the output buffer */
+ iov_iter_xarray(&rreq->iter, ITER_DEST, &mapping->i_pages,
+ rreq->start, rreq->len);
+
+ ret = netfs_begin_read(rreq, true);
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
+ return ret;
+
+error_put:
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_discard);
+error:
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/**
+ * netfs_buffered_read_iter - Filesystem buffered I/O read routine
+ * @iocb: kernel I/O control block
+ * @iter: destination for the data read
+ *
+ * This is the ->read_iter() routine for all filesystems that can use the page
+ * cache directly.
+ *
+ * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be
+ * returned when no data can be read without waiting for I/O requests to
+ * complete; it doesn't prevent readahead.
+ *
+ * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests
+ * shall be made for the read or for readahead. When no data can be read,
+ * -EAGAIN shall be returned. When readahead would be triggered, a partial,
+ * possibly empty read shall be returned.
+ *
+ * Return:
+ * * number of bytes copied, even for partial reads
+ * * negative error code (or 0 if IOCB_NOIO) if nothing was read
+ */
+ssize_t netfs_buffered_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct netfs_inode *ictx = netfs_inode(inode);
+ ssize_t ret;
+
+ if (WARN_ON_ONCE((iocb->ki_flags & IOCB_DIRECT) ||
+ test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags)))
+ return -EINVAL;
+
+ ret = netfs_start_io_read(inode);
+ if (ret == 0) {
+ ret = filemap_read(iocb, iter, 0);
+ netfs_end_io_read(inode);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(netfs_buffered_read_iter);
+
+/**
+ * netfs_file_read_iter - Generic filesystem read routine
+ * @iocb: kernel I/O control block
+ * @iter: destination for the data read
+ *
+ * This is the ->read_iter() routine for all filesystems that can use the page
+ * cache directly.
+ *
+ * The IOCB_NOWAIT flag in iocb->ki_flags indicates that -EAGAIN shall be
+ * returned when no data can be read without waiting for I/O requests to
+ * complete; it doesn't prevent readahead.
+ *
+ * The IOCB_NOIO flag in iocb->ki_flags indicates that no new I/O requests
+ * shall be made for the read or for readahead. When no data can be read,
+ * -EAGAIN shall be returned. When readahead would be triggered, a partial,
+ * possibly empty read shall be returned.
+ *
+ * Return:
+ * * number of bytes copied, even for partial reads
+ * * negative error code (or 0 if IOCB_NOIO) if nothing was read
+ */
+ssize_t netfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct netfs_inode *ictx = netfs_inode(iocb->ki_filp->f_mapping->host);
+
+ if ((iocb->ki_flags & IOCB_DIRECT) ||
+ test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags))
+ return netfs_unbuffered_read_iter(iocb, iter);
+
+ return netfs_buffered_read_iter(iocb, iter);
+}
+EXPORT_SYMBOL(netfs_file_read_iter);
diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c
new file mode 100644
index 000000000000..1121601536d1
--- /dev/null
+++ b/fs/netfs/buffered_write.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Network filesystem high-level buffered write support.
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/pagevec.h>
+#include "internal.h"
+
+/*
+ * Determined write method. Adjust netfs_folio_traces if this is changed.
+ */
+enum netfs_how_to_modify {
+ NETFS_FOLIO_IS_UPTODATE, /* Folio is uptodate already */
+ NETFS_JUST_PREFETCH, /* We have to read the folio anyway */
+ NETFS_WHOLE_FOLIO_MODIFY, /* We're going to overwrite the whole folio */
+ NETFS_MODIFY_AND_CLEAR, /* We can assume there is no data to be downloaded. */
+ NETFS_STREAMING_WRITE, /* Store incomplete data in non-uptodate page. */
+ NETFS_STREAMING_WRITE_CONT, /* Continue streaming write. */
+ NETFS_FLUSH_CONTENT, /* Flush incompatible content. */
+};
+
+static void netfs_set_group(struct folio *folio, struct netfs_group *netfs_group)
+{
+ void *priv = folio_get_private(folio);
+
+ if (netfs_group && (!priv || priv == NETFS_FOLIO_COPY_TO_CACHE))
+ folio_attach_private(folio, netfs_get_group(netfs_group));
+ else if (!netfs_group && priv == NETFS_FOLIO_COPY_TO_CACHE)
+ folio_detach_private(folio);
+}
+
+/*
+ * Decide how we should modify a folio. We might be attempting to do
+ * write-streaming, in which case we don't want to a local RMW cycle if we can
+ * avoid it. If we're doing local caching or content crypto, we award that
+ * priority over avoiding RMW. If the file is open readably, then we also
+ * assume that we may want to read what we wrote.
+ */
+static enum netfs_how_to_modify netfs_how_to_modify(struct netfs_inode *ctx,
+ struct file *file,
+ struct folio *folio,
+ void *netfs_group,
+ size_t flen,
+ size_t offset,
+ size_t len,
+ bool maybe_trouble)
+{
+ struct netfs_folio *finfo = netfs_folio_info(folio);
+ struct netfs_group *group = netfs_folio_group(folio);
+ loff_t pos = folio_file_pos(folio);
+
+ _enter("");
+
+ if (group != netfs_group && group != NETFS_FOLIO_COPY_TO_CACHE)
+ return NETFS_FLUSH_CONTENT;
+
+ if (folio_test_uptodate(folio))
+ return NETFS_FOLIO_IS_UPTODATE;
+
+ if (pos >= ctx->zero_point)
+ return NETFS_MODIFY_AND_CLEAR;
+
+ if (!maybe_trouble && offset == 0 && len >= flen)
+ return NETFS_WHOLE_FOLIO_MODIFY;
+
+ if (file->f_mode & FMODE_READ)
+ goto no_write_streaming;
+
+ if (netfs_is_cache_enabled(ctx)) {
+ /* We don't want to get a streaming write on a file that loses
+ * caching service temporarily because the backing store got
+ * culled.
+ */
+ goto no_write_streaming;
+ }
+
+ if (!finfo)
+ return NETFS_STREAMING_WRITE;
+
+ /* We can continue a streaming write only if it continues on from the
+ * previous. If it overlaps, we must flush lest we suffer a partial
+ * copy and disjoint dirty regions.
+ */
+ if (offset == finfo->dirty_offset + finfo->dirty_len)
+ return NETFS_STREAMING_WRITE_CONT;
+ return NETFS_FLUSH_CONTENT;
+
+no_write_streaming:
+ if (finfo) {
+ netfs_stat(&netfs_n_wh_wstream_conflict);
+ return NETFS_FLUSH_CONTENT;
+ }
+ return NETFS_JUST_PREFETCH;
+}
+
+/*
+ * Grab a folio for writing and lock it. Attempt to allocate as large a folio
+ * as possible to hold as much of the remaining length as possible in one go.
+ */
+static struct folio *netfs_grab_folio_for_write(struct address_space *mapping,
+ loff_t pos, size_t part)
+{
+ pgoff_t index = pos / PAGE_SIZE;
+ fgf_t fgp_flags = FGP_WRITEBEGIN;
+
+ if (mapping_large_folio_support(mapping))
+ fgp_flags |= fgf_set_order(pos % PAGE_SIZE + part);
+
+ return __filemap_get_folio(mapping, index, fgp_flags,
+ mapping_gfp_mask(mapping));
+}
+
+/*
+ * Update i_size and estimate the update to i_blocks to reflect the additional
+ * data written into the pagecache until we can find out from the server what
+ * the values actually are.
+ */
+static void netfs_update_i_size(struct netfs_inode *ctx, struct inode *inode,
+ loff_t i_size, loff_t pos, size_t copied)
+{
+ blkcnt_t add;
+ size_t gap;
+
+ if (ctx->ops->update_i_size) {
+ ctx->ops->update_i_size(inode, pos);
+ return;
+ }
+
+ i_size_write(inode, pos);
+#if IS_ENABLED(CONFIG_FSCACHE)
+ fscache_update_cookie(ctx->cache, NULL, &pos);
+#endif
+
+ gap = SECTOR_SIZE - (i_size & (SECTOR_SIZE - 1));
+ if (copied > gap) {
+ add = DIV_ROUND_UP(copied - gap, SECTOR_SIZE);
+
+ inode->i_blocks = min_t(blkcnt_t,
+ DIV_ROUND_UP(pos, SECTOR_SIZE),
+ inode->i_blocks + add);
+ }
+}
+
+/**
+ * netfs_perform_write - Copy data into the pagecache.
+ * @iocb: The operation parameters
+ * @iter: The source buffer
+ * @netfs_group: Grouping for dirty pages (eg. ceph snaps).
+ *
+ * Copy data into pagecache pages attached to the inode specified by @iocb.
+ * The caller must hold appropriate inode locks.
+ *
+ * Dirty pages are tagged with a netfs_folio struct if they're not up to date
+ * to indicate the range modified. Dirty pages may also be tagged with a
+ * netfs-specific grouping such that data from an old group gets flushed before
+ * a new one is started.
+ */
+ssize_t netfs_perform_write(struct kiocb *iocb, struct iov_iter *iter,
+ struct netfs_group *netfs_group)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file_inode(file);
+ struct address_space *mapping = inode->i_mapping;
+ struct netfs_inode *ctx = netfs_inode(inode);
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_NONE,
+ .for_sync = true,
+ .nr_to_write = LONG_MAX,
+ .range_start = iocb->ki_pos,
+ .range_end = iocb->ki_pos + iter->count,
+ };
+ struct netfs_io_request *wreq = NULL;
+ struct netfs_folio *finfo;
+ struct folio *folio, *writethrough = NULL;
+ enum netfs_how_to_modify howto;
+ enum netfs_folio_trace trace;
+ unsigned int bdp_flags = (iocb->ki_flags & IOCB_SYNC) ? 0: BDP_ASYNC;
+ ssize_t written = 0, ret, ret2;
+ loff_t i_size, pos = iocb->ki_pos, from, to;
+ size_t max_chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;
+ bool maybe_trouble = false;
+
+ if (unlikely(test_bit(NETFS_ICTX_WRITETHROUGH, &ctx->flags) ||
+ iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC))
+ ) {
+ wbc_attach_fdatawrite_inode(&wbc, mapping->host);
+
+ ret = filemap_write_and_wait_range(mapping, pos, pos + iter->count);
+ if (ret < 0) {
+ wbc_detach_inode(&wbc);
+ goto out;
+ }
+
+ wreq = netfs_begin_writethrough(iocb, iter->count);
+ if (IS_ERR(wreq)) {
+ wbc_detach_inode(&wbc);
+ ret = PTR_ERR(wreq);
+ wreq = NULL;
+ goto out;
+ }
+ if (!is_sync_kiocb(iocb))
+ wreq->iocb = iocb;
+ netfs_stat(&netfs_n_wh_writethrough);
+ } else {
+ netfs_stat(&netfs_n_wh_buffered_write);
+ }
+
+ do {
+ size_t flen;
+ size_t offset; /* Offset into pagecache folio */
+ size_t part; /* Bytes to write to folio */
+ size_t copied; /* Bytes copied from user */
+
+ ret = balance_dirty_pages_ratelimited_flags(mapping, bdp_flags);
+ if (unlikely(ret < 0))
+ break;
+
+ offset = pos & (max_chunk - 1);
+ part = min(max_chunk - offset, iov_iter_count(iter));
+
+ /* Bring in the user pages that we will copy from _first_ lest
+ * we hit a nasty deadlock on copying from the same page as
+ * we're writing to, without it being marked uptodate.
+ *
+ * Not only is this an optimisation, but it is also required to
+ * check that the address is actually valid, when atomic
+ * usercopies are used below.
+ *
+ * We rely on the page being held onto long enough by the LRU
+ * that we can grab it below if this causes it to be read.
+ */
+ ret = -EFAULT;
+ if (unlikely(fault_in_iov_iter_readable(iter, part) == part))
+ break;
+
+ folio = netfs_grab_folio_for_write(mapping, pos, part);
+ if (IS_ERR(folio)) {
+ ret = PTR_ERR(folio);
+ break;
+ }
+
+ flen = folio_size(folio);
+ offset = pos & (flen - 1);
+ part = min_t(size_t, flen - offset, part);
+
+ /* Wait for writeback to complete. The writeback engine owns
+ * the info in folio->private and may change it until it
+ * removes the WB mark.
+ */
+ if (folio_get_private(folio) &&
+ folio_wait_writeback_killable(folio)) {
+ ret = written ? -EINTR : -ERESTARTSYS;
+ goto error_folio_unlock;
+ }
+
+ if (signal_pending(current)) {
+ ret = written ? -EINTR : -ERESTARTSYS;
+ goto error_folio_unlock;
+ }
+
+ /* See if we need to prefetch the area we're going to modify.
+ * We need to do this before we get a lock on the folio in case
+ * there's more than one writer competing for the same cache
+ * block.
+ */
+ howto = netfs_how_to_modify(ctx, file, folio, netfs_group,
+ flen, offset, part, maybe_trouble);
+ _debug("howto %u", howto);
+ switch (howto) {
+ case NETFS_JUST_PREFETCH:
+ ret = netfs_prefetch_for_write(file, folio, offset, part);
+ if (ret < 0) {
+ _debug("prefetch = %zd", ret);
+ goto error_folio_unlock;
+ }
+ break;
+ case NETFS_FOLIO_IS_UPTODATE:
+ case NETFS_WHOLE_FOLIO_MODIFY:
+ case NETFS_STREAMING_WRITE_CONT:
+ break;
+ case NETFS_MODIFY_AND_CLEAR:
+ zero_user_segment(&folio->page, 0, offset);
+ break;
+ case NETFS_STREAMING_WRITE:
+ ret = -EIO;
+ if (WARN_ON(folio_get_private(folio)))
+ goto error_folio_unlock;
+ break;
+ case NETFS_FLUSH_CONTENT:
+ trace_netfs_folio(folio, netfs_flush_content);
+ from = folio_pos(folio);
+ to = from + folio_size(folio) - 1;
+ folio_unlock(folio);
+ folio_put(folio);
+ ret = filemap_write_and_wait_range(mapping, from, to);
+ if (ret < 0)
+ goto error_folio_unlock;
+ continue;
+ }
+
+ if (mapping_writably_mapped(mapping))
+ flush_dcache_folio(folio);
+
+ copied = copy_folio_from_iter_atomic(folio, offset, part, iter);
+
+ flush_dcache_folio(folio);
+
+ /* Deal with a (partially) failed copy */
+ if (copied == 0) {
+ ret = -EFAULT;
+ goto error_folio_unlock;
+ }
+
+ trace = (enum netfs_folio_trace)howto;
+ switch (howto) {
+ case NETFS_FOLIO_IS_UPTODATE:
+ case NETFS_JUST_PREFETCH:
+ netfs_set_group(folio, netfs_group);
+ break;
+ case NETFS_MODIFY_AND_CLEAR:
+ zero_user_segment(&folio->page, offset + copied, flen);
+ netfs_set_group(folio, netfs_group);
+ folio_mark_uptodate(folio);
+ break;
+ case NETFS_WHOLE_FOLIO_MODIFY:
+ if (unlikely(copied < part)) {
+ maybe_trouble = true;
+ iov_iter_revert(iter, copied);
+ copied = 0;
+ folio_unlock(folio);
+ goto retry;
+ }
+ netfs_set_group(folio, netfs_group);
+ folio_mark_uptodate(folio);
+ break;
+ case NETFS_STREAMING_WRITE:
+ if (offset == 0 && copied == flen) {
+ netfs_set_group(folio, netfs_group);
+ folio_mark_uptodate(folio);
+ trace = netfs_streaming_filled_page;
+ break;
+ }
+ finfo = kzalloc(sizeof(*finfo), GFP_KERNEL);
+ if (!finfo) {
+ iov_iter_revert(iter, copied);
+ ret = -ENOMEM;
+ goto error_folio_unlock;
+ }
+ finfo->netfs_group = netfs_get_group(netfs_group);
+ finfo->dirty_offset = offset;
+ finfo->dirty_len = copied;
+ folio_attach_private(folio, (void *)((unsigned long)finfo |
+ NETFS_FOLIO_INFO));
+ break;
+ case NETFS_STREAMING_WRITE_CONT:
+ finfo = netfs_folio_info(folio);
+ finfo->dirty_len += copied;
+ if (finfo->dirty_offset == 0 && finfo->dirty_len == flen) {
+ if (finfo->netfs_group)
+ folio_change_private(folio, finfo->netfs_group);
+ else
+ folio_detach_private(folio);
+ folio_mark_uptodate(folio);
+ kfree(finfo);
+ trace = netfs_streaming_cont_filled_page;
+ }
+ break;
+ default:
+ WARN(true, "Unexpected modify type %u ix=%lx\n",
+ howto, folio->index);
+ ret = -EIO;
+ goto error_folio_unlock;
+ }
+
+ trace_netfs_folio(folio, trace);
+
+ /* Update the inode size if we moved the EOF marker */
+ pos += copied;
+ i_size = i_size_read(inode);
+ if (pos > i_size)
+ netfs_update_i_size(ctx, inode, i_size, pos, copied);
+ written += copied;
+
+ if (likely(!wreq)) {
+ folio_mark_dirty(folio);
+ folio_unlock(folio);
+ } else {
+ netfs_advance_writethrough(wreq, &wbc, folio, copied,
+ offset + copied == flen,
+ &writethrough);
+ /* Folio unlocked */
+ }
+ retry:
+ folio_put(folio);
+ folio = NULL;
+
+ cond_resched();
+ } while (iov_iter_count(iter));
+
+out:
+ if (likely(written) && ctx->ops->post_modify)
+ ctx->ops->post_modify(inode);
+
+ if (unlikely(wreq)) {
+ ret2 = netfs_end_writethrough(wreq, &wbc, writethrough);
+ wbc_detach_inode(&wbc);
+ if (ret2 == -EIOCBQUEUED)
+ return ret2;
+ if (ret == 0)
+ ret = ret2;
+ }
+
+ iocb->ki_pos += written;
+ _leave(" = %zd [%zd]", written, ret);
+ return written ? written : ret;
+
+error_folio_unlock:
+ folio_unlock(folio);
+ folio_put(folio);
+ goto out;
+}
+EXPORT_SYMBOL(netfs_perform_write);
+
+/**
+ * netfs_buffered_write_iter_locked - write data to a file
+ * @iocb: IO state structure (file, offset, etc.)
+ * @from: iov_iter with data to write
+ * @netfs_group: Grouping for dirty pages (eg. ceph snaps).
+ *
+ * This function does all the work needed for actually writing data to a
+ * file. It does all basic checks, removes SUID from the file, updates
+ * modification times and calls proper subroutines depending on whether we
+ * do direct IO or a standard buffered write.
+ *
+ * The caller must hold appropriate locks around this function and have called
+ * generic_write_checks() already. The caller is also responsible for doing
+ * any necessary syncing afterwards.
+ *
+ * This function does *not* take care of syncing data in case of O_SYNC write.
+ * A caller has to handle it. This is mainly due to the fact that we want to
+ * avoid syncing under i_rwsem.
+ *
+ * Return:
+ * * number of bytes written, even for truncated writes
+ * * negative error code if no data has been written at all
+ */
+ssize_t netfs_buffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *from,
+ struct netfs_group *netfs_group)
+{
+ struct file *file = iocb->ki_filp;
+ ssize_t ret;
+
+ trace_netfs_write_iter(iocb, from);
+
+ ret = file_remove_privs(file);
+ if (ret)
+ return ret;
+
+ ret = file_update_time(file);
+ if (ret)
+ return ret;
+
+ return netfs_perform_write(iocb, from, netfs_group);
+}
+EXPORT_SYMBOL(netfs_buffered_write_iter_locked);
+
+/**
+ * netfs_file_write_iter - write data to a file
+ * @iocb: IO state structure
+ * @from: iov_iter with data to write
+ *
+ * Perform a write to a file, writing into the pagecache if possible and doing
+ * an unbuffered write instead if not.
+ *
+ * Return:
+ * * Negative error code if no data has been written at all of
+ * vfs_fsync_range() failed for a synchronous write
+ * * Number of bytes written, even for truncated writes
+ */
+ssize_t netfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ struct netfs_inode *ictx = netfs_inode(inode);
+ ssize_t ret;
+
+ _enter("%llx,%zx,%llx", iocb->ki_pos, iov_iter_count(from), i_size_read(inode));
+
+ if (!iov_iter_count(from))
+ return 0;
+
+ if ((iocb->ki_flags & IOCB_DIRECT) ||
+ test_bit(NETFS_ICTX_UNBUFFERED, &ictx->flags))
+ return netfs_unbuffered_write_iter(iocb, from);
+
+ ret = netfs_start_io_write(inode);
+ if (ret < 0)
+ return ret;
+
+ ret = generic_write_checks(iocb, from);
+ if (ret > 0)
+ ret = netfs_buffered_write_iter_locked(iocb, from, NULL);
+ netfs_end_io_write(inode);
+ if (ret > 0)
+ ret = generic_write_sync(iocb, ret);
+ return ret;
+}
+EXPORT_SYMBOL(netfs_file_write_iter);
+
+/*
+ * Notification that a previously read-only page is about to become writable.
+ * Note that the caller indicates a single page of a multipage folio.
+ */
+vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group)
+{
+ struct netfs_group *group;
+ struct folio *folio = page_folio(vmf->page);
+ struct file *file = vmf->vma->vm_file;
+ struct inode *inode = file_inode(file);
+ struct netfs_inode *ictx = netfs_inode(inode);
+ vm_fault_t ret = VM_FAULT_RETRY;
+ int err;
+
+ _enter("%lx", folio->index);
+
+ sb_start_pagefault(inode->i_sb);
+
+ if (folio_lock_killable(folio) < 0)
+ goto out;
+
+ if (folio_wait_writeback_killable(folio)) {
+ ret = VM_FAULT_LOCKED;
+ goto out;
+ }
+
+ /* Can we see a streaming write here? */
+ if (WARN_ON(!folio_test_uptodate(folio))) {
+ ret = VM_FAULT_SIGBUS | VM_FAULT_LOCKED;
+ goto out;
+ }
+
+ group = netfs_folio_group(folio);
+ if (group != netfs_group && group != NETFS_FOLIO_COPY_TO_CACHE) {
+ folio_unlock(folio);
+ err = filemap_fdatawait_range(inode->i_mapping,
+ folio_pos(folio),
+ folio_pos(folio) + folio_size(folio));
+ switch (err) {
+ case 0:
+ ret = VM_FAULT_RETRY;
+ goto out;
+ case -ENOMEM:
+ ret = VM_FAULT_OOM;
+ goto out;
+ default:
+ ret = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ }
+
+ if (folio_test_dirty(folio))
+ trace_netfs_folio(folio, netfs_folio_trace_mkwrite_plus);
+ else
+ trace_netfs_folio(folio, netfs_folio_trace_mkwrite);
+ netfs_set_group(folio, netfs_group);
+ file_update_time(file);
+ if (ictx->ops->post_modify)
+ ictx->ops->post_modify(inode);
+ ret = VM_FAULT_LOCKED;
+out:
+ sb_end_pagefault(inode->i_sb);
+ return ret;
+}
+EXPORT_SYMBOL(netfs_page_mkwrite);
diff --git a/fs/netfs/direct_read.c b/fs/netfs/direct_read.c
new file mode 100644
index 000000000000..10a1e4da6bda
--- /dev/null
+++ b/fs/netfs/direct_read.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Direct I/O support.
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/sched/mm.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+/**
+ * netfs_unbuffered_read_iter_locked - Perform an unbuffered or direct I/O read
+ * @iocb: The I/O control descriptor describing the read
+ * @iter: The output buffer (also specifies read length)
+ *
+ * Perform an unbuffered I/O or direct I/O from the file in @iocb to the
+ * output buffer. No use is made of the pagecache.
+ *
+ * The caller must hold any appropriate locks.
+ */
+ssize_t netfs_unbuffered_read_iter_locked(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct netfs_io_request *rreq;
+ ssize_t ret;
+ size_t orig_count = iov_iter_count(iter);
+ bool async = !is_sync_kiocb(iocb);
+
+ _enter("");
+
+ if (!orig_count)
+ return 0; /* Don't update atime */
+
+ ret = kiocb_write_and_wait(iocb, orig_count);
+ if (ret < 0)
+ return ret;
+ file_accessed(iocb->ki_filp);
+
+ rreq = netfs_alloc_request(iocb->ki_filp->f_mapping, iocb->ki_filp,
+ iocb->ki_pos, orig_count,
+ NETFS_DIO_READ);
+ if (IS_ERR(rreq))
+ return PTR_ERR(rreq);
+
+ netfs_stat(&netfs_n_rh_dio_read);
+ trace_netfs_read(rreq, rreq->start, rreq->len, netfs_read_trace_dio_read);
+
+ /* If this is an async op, we have to keep track of the destination
+ * buffer for ourselves as the caller's iterator will be trashed when
+ * we return.
+ *
+ * In such a case, extract an iterator to represent as much of the the
+ * output buffer as we can manage. Note that the extraction might not
+ * be able to allocate a sufficiently large bvec array and may shorten
+ * the request.
+ */
+ if (user_backed_iter(iter)) {
+ ret = netfs_extract_user_iter(iter, rreq->len, &rreq->iter, 0);
+ if (ret < 0)
+ goto out;
+ rreq->direct_bv = (struct bio_vec *)rreq->iter.bvec;
+ rreq->direct_bv_count = ret;
+ rreq->direct_bv_unpin = iov_iter_extract_will_pin(iter);
+ rreq->len = iov_iter_count(&rreq->iter);
+ } else {
+ rreq->iter = *iter;
+ rreq->len = orig_count;
+ rreq->direct_bv_unpin = false;
+ iov_iter_advance(iter, orig_count);
+ }
+
+ // TODO: Set up bounce buffer if needed
+
+ if (async)
+ rreq->iocb = iocb;
+
+ ret = netfs_begin_read(rreq, is_sync_kiocb(iocb));
+ if (ret < 0)
+ goto out; /* May be -EIOCBQUEUED */
+ if (!async) {
+ // TODO: Copy from bounce buffer
+ iocb->ki_pos += rreq->transferred;
+ ret = rreq->transferred;
+ }
+
+out:
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
+ if (ret > 0)
+ orig_count -= ret;
+ if (ret != -EIOCBQUEUED)
+ iov_iter_revert(iter, orig_count - iov_iter_count(iter));
+ return ret;
+}
+EXPORT_SYMBOL(netfs_unbuffered_read_iter_locked);
+
+/**
+ * netfs_unbuffered_read_iter - Perform an unbuffered or direct I/O read
+ * @iocb: The I/O control descriptor describing the read
+ * @iter: The output buffer (also specifies read length)
+ *
+ * Perform an unbuffered I/O or direct I/O from the file in @iocb to the
+ * output buffer. No use is made of the pagecache.
+ */
+ssize_t netfs_unbuffered_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ ssize_t ret;
+
+ if (!iter->count)
+ return 0; /* Don't update atime */
+
+ ret = netfs_start_io_direct(inode);
+ if (ret == 0) {
+ ret = netfs_unbuffered_read_iter_locked(iocb, iter);
+ netfs_end_io_direct(inode);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(netfs_unbuffered_read_iter);
diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c
new file mode 100644
index 000000000000..608ba6416919
--- /dev/null
+++ b/fs/netfs/direct_write.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Unbuffered and direct write support.
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/uio.h>
+#include "internal.h"
+
+static void netfs_cleanup_dio_write(struct netfs_io_request *wreq)
+{
+ struct inode *inode = wreq->inode;
+ unsigned long long end = wreq->start + wreq->len;
+
+ if (!wreq->error &&
+ i_size_read(inode) < end) {
+ if (wreq->netfs_ops->update_i_size)
+ wreq->netfs_ops->update_i_size(inode, end);
+ else
+ i_size_write(inode, end);
+ }
+}
+
+/*
+ * Perform an unbuffered write where we may have to do an RMW operation on an
+ * encrypted file. This can also be used for direct I/O writes.
+ */
+static ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *iter,
+ struct netfs_group *netfs_group)
+{
+ struct netfs_io_request *wreq;
+ unsigned long long start = iocb->ki_pos;
+ unsigned long long end = start + iov_iter_count(iter);
+ ssize_t ret, n;
+ size_t len = iov_iter_count(iter);
+ bool async = !is_sync_kiocb(iocb);
+
+ _enter("");
+
+ /* We're going to need a bounce buffer if what we transmit is going to
+ * be different in some way to the source buffer, e.g. because it gets
+ * encrypted/compressed or because it needs expanding to a block size.
+ */
+ // TODO
+
+ _debug("uw %llx-%llx", start, end);
+
+ wreq = netfs_create_write_req(iocb->ki_filp->f_mapping, iocb->ki_filp, start,
+ iocb->ki_flags & IOCB_DIRECT ?
+ NETFS_DIO_WRITE : NETFS_UNBUFFERED_WRITE);
+ if (IS_ERR(wreq))
+ return PTR_ERR(wreq);
+
+ wreq->io_streams[0].avail = true;
+ trace_netfs_write(wreq, (iocb->ki_flags & IOCB_DIRECT ?
+ netfs_write_trace_dio_write :
+ netfs_write_trace_unbuffered_write));
+
+ {
+ /* If this is an async op and we're not using a bounce buffer,
+ * we have to save the source buffer as the iterator is only
+ * good until we return. In such a case, extract an iterator
+ * to represent as much of the the output buffer as we can
+ * manage. Note that the extraction might not be able to
+ * allocate a sufficiently large bvec array and may shorten the
+ * request.
+ */
+ if (async || user_backed_iter(iter)) {
+ n = netfs_extract_user_iter(iter, len, &wreq->iter, 0);
+ if (n < 0) {
+ ret = n;
+ goto out;
+ }
+ wreq->direct_bv = (struct bio_vec *)wreq->iter.bvec;
+ wreq->direct_bv_count = n;
+ wreq->direct_bv_unpin = iov_iter_extract_will_pin(iter);
+ } else {
+ wreq->iter = *iter;
+ }
+
+ wreq->io_iter = wreq->iter;
+ }
+
+ __set_bit(NETFS_RREQ_USE_IO_ITER, &wreq->flags);
+
+ /* Copy the data into the bounce buffer and encrypt it. */
+ // TODO
+
+ /* Dispatch the write. */
+ __set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags);
+ if (async)
+ wreq->iocb = iocb;
+ wreq->cleanup = netfs_cleanup_dio_write;
+ ret = netfs_unbuffered_write(wreq, is_sync_kiocb(iocb), iov_iter_count(&wreq->io_iter));
+ if (ret < 0) {
+ _debug("begin = %zd", ret);
+ goto out;
+ }
+
+ if (!async) {
+ trace_netfs_rreq(wreq, netfs_rreq_trace_wait_ip);
+ wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE);
+ smp_rmb(); /* Read error/transferred after RIP flag */
+ ret = wreq->error;
+ if (ret == 0) {
+ ret = wreq->transferred;
+ iocb->ki_pos += ret;
+ }
+ } else {
+ ret = -EIOCBQUEUED;
+ }
+
+out:
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
+ return ret;
+}
+
+/**
+ * netfs_unbuffered_write_iter - Unbuffered write to a file
+ * @iocb: IO state structure
+ * @from: iov_iter with data to write
+ *
+ * Do an unbuffered write to a file, writing the data directly to the server
+ * and not lodging the data in the pagecache.
+ *
+ * Return:
+ * * Negative error code if no data has been written at all of
+ * vfs_fsync_range() failed for a synchronous write
+ * * Number of bytes written, even for truncated writes
+ */
+ssize_t netfs_unbuffered_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ struct netfs_inode *ictx = netfs_inode(inode);
+ ssize_t ret;
+ loff_t pos = iocb->ki_pos;
+ unsigned long long end = pos + iov_iter_count(from) - 1;
+
+ _enter("%llx,%zx,%llx", pos, iov_iter_count(from), i_size_read(inode));
+
+ if (!iov_iter_count(from))
+ return 0;
+
+ trace_netfs_write_iter(iocb, from);
+ netfs_stat(&netfs_n_wh_dio_write);
+
+ ret = netfs_start_io_direct(inode);
+ if (ret < 0)
+ return ret;
+ ret = generic_write_checks(iocb, from);
+ if (ret <= 0)
+ goto out;
+ ret = file_remove_privs(file);
+ if (ret < 0)
+ goto out;
+ ret = file_update_time(file);
+ if (ret < 0)
+ goto out;
+ if (iocb->ki_flags & IOCB_NOWAIT) {
+ /* We could block if there are any pages in the range. */
+ ret = -EAGAIN;
+ if (filemap_range_has_page(mapping, pos, end))
+ if (filemap_invalidate_inode(inode, true, pos, end))
+ goto out;
+ } else {
+ ret = filemap_write_and_wait_range(mapping, pos, end);
+ if (ret < 0)
+ goto out;
+ }
+
+ /*
+ * After a write we want buffered reads to be sure to go to disk to get
+ * the new data. We invalidate clean cached page from the region we're
+ * about to write. We do this *before* the write so that we can return
+ * without clobbering -EIOCBQUEUED from ->direct_IO().
+ */
+ ret = filemap_invalidate_inode(inode, true, pos, end);
+ if (ret < 0)
+ goto out;
+ end = iocb->ki_pos + iov_iter_count(from);
+ if (end > ictx->zero_point)
+ ictx->zero_point = end;
+
+ fscache_invalidate(netfs_i_cookie(ictx), NULL, i_size_read(inode),
+ FSCACHE_INVAL_DIO_WRITE);
+ ret = netfs_unbuffered_write_iter_locked(iocb, from, NULL);
+out:
+ netfs_end_io_direct(inode);
+ return ret;
+}
+EXPORT_SYMBOL(netfs_unbuffered_write_iter);
diff --git a/fs/netfs/fscache_cache.c b/fs/netfs/fscache_cache.c
new file mode 100644
index 000000000000..9397ed39b0b4
--- /dev/null
+++ b/fs/netfs/fscache_cache.c
@@ -0,0 +1,429 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* FS-Cache cache handling
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define FSCACHE_DEBUG_LEVEL CACHE
+#include <linux/export.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+static LIST_HEAD(fscache_caches);
+DECLARE_RWSEM(fscache_addremove_sem);
+EXPORT_SYMBOL(fscache_addremove_sem);
+DECLARE_WAIT_QUEUE_HEAD(fscache_clearance_waiters);
+EXPORT_SYMBOL(fscache_clearance_waiters);
+
+static atomic_t fscache_cache_debug_id;
+
+/*
+ * Allocate a cache cookie.
+ */
+static struct fscache_cache *fscache_alloc_cache(const char *name)
+{
+ struct fscache_cache *cache;
+
+ cache = kzalloc(sizeof(*cache), GFP_KERNEL);
+ if (cache) {
+ if (name) {
+ cache->name = kstrdup(name, GFP_KERNEL);
+ if (!cache->name) {
+ kfree(cache);
+ return NULL;
+ }
+ }
+ refcount_set(&cache->ref, 1);
+ INIT_LIST_HEAD(&cache->cache_link);
+ cache->debug_id = atomic_inc_return(&fscache_cache_debug_id);
+ }
+ return cache;
+}
+
+static bool fscache_get_cache_maybe(struct fscache_cache *cache,
+ enum fscache_cache_trace where)
+{
+ bool success;
+ int ref;
+
+ success = __refcount_inc_not_zero(&cache->ref, &ref);
+ if (success)
+ trace_fscache_cache(cache->debug_id, ref + 1, where);
+ return success;
+}
+
+/*
+ * Look up a cache cookie.
+ */
+struct fscache_cache *fscache_lookup_cache(const char *name, bool is_cache)
+{
+ struct fscache_cache *candidate, *cache, *unnamed = NULL;
+
+ /* firstly check for the existence of the cache under read lock */
+ down_read(&fscache_addremove_sem);
+
+ list_for_each_entry(cache, &fscache_caches, cache_link) {
+ if (cache->name && name && strcmp(cache->name, name) == 0 &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_r;
+ if (!cache->name && !name &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_r;
+ }
+
+ if (!name) {
+ list_for_each_entry(cache, &fscache_caches, cache_link) {
+ if (cache->name &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_r;
+ }
+ }
+
+ up_read(&fscache_addremove_sem);
+
+ /* the cache does not exist - create a candidate */
+ candidate = fscache_alloc_cache(name);
+ if (!candidate)
+ return ERR_PTR(-ENOMEM);
+
+ /* write lock, search again and add if still not present */
+ down_write(&fscache_addremove_sem);
+
+ list_for_each_entry(cache, &fscache_caches, cache_link) {
+ if (cache->name && name && strcmp(cache->name, name) == 0 &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_w;
+ if (!cache->name) {
+ unnamed = cache;
+ if (!name &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_w;
+ }
+ }
+
+ if (unnamed && is_cache &&
+ fscache_get_cache_maybe(unnamed, fscache_cache_get_acquire))
+ goto use_unnamed_cache;
+
+ if (!name) {
+ list_for_each_entry(cache, &fscache_caches, cache_link) {
+ if (cache->name &&
+ fscache_get_cache_maybe(cache, fscache_cache_get_acquire))
+ goto got_cache_w;
+ }
+ }
+
+ list_add_tail(&candidate->cache_link, &fscache_caches);
+ trace_fscache_cache(candidate->debug_id,
+ refcount_read(&candidate->ref),
+ fscache_cache_new_acquire);
+ up_write(&fscache_addremove_sem);
+ return candidate;
+
+got_cache_r:
+ up_read(&fscache_addremove_sem);
+ return cache;
+use_unnamed_cache:
+ cache = unnamed;
+ cache->name = candidate->name;
+ candidate->name = NULL;
+got_cache_w:
+ up_write(&fscache_addremove_sem);
+ kfree(candidate->name);
+ kfree(candidate);
+ return cache;
+}
+
+/**
+ * fscache_acquire_cache - Acquire a cache-level cookie.
+ * @name: The name of the cache.
+ *
+ * Get a cookie to represent an actual cache. If a name is given and there is
+ * a nameless cache record available, this will acquire that and set its name,
+ * directing all the volumes using it to this cache.
+ *
+ * The cache will be switched over to the preparing state if not currently in
+ * use, otherwise -EBUSY will be returned.
+ */
+struct fscache_cache *fscache_acquire_cache(const char *name)
+{
+ struct fscache_cache *cache;
+
+ ASSERT(name);
+ cache = fscache_lookup_cache(name, true);
+ if (IS_ERR(cache))
+ return cache;
+
+ if (!fscache_set_cache_state_maybe(cache,
+ FSCACHE_CACHE_IS_NOT_PRESENT,
+ FSCACHE_CACHE_IS_PREPARING)) {
+ pr_warn("Cache tag %s in use\n", name);
+ fscache_put_cache(cache, fscache_cache_put_cache);
+ return ERR_PTR(-EBUSY);
+ }
+
+ return cache;
+}
+EXPORT_SYMBOL(fscache_acquire_cache);
+
+/**
+ * fscache_put_cache - Release a cache-level cookie.
+ * @cache: The cache cookie to be released
+ * @where: An indication of where the release happened
+ *
+ * Release the caller's reference on a cache-level cookie. The @where
+ * indication should give information about the circumstances in which the call
+ * occurs and will be logged through a tracepoint.
+ */
+void fscache_put_cache(struct fscache_cache *cache,
+ enum fscache_cache_trace where)
+{
+ unsigned int debug_id;
+ bool zero;
+ int ref;
+
+ if (IS_ERR_OR_NULL(cache))
+ return;
+
+ debug_id = cache->debug_id;
+ zero = __refcount_dec_and_test(&cache->ref, &ref);
+ trace_fscache_cache(debug_id, ref - 1, where);
+
+ if (zero) {
+ down_write(&fscache_addremove_sem);
+ list_del_init(&cache->cache_link);
+ up_write(&fscache_addremove_sem);
+ kfree(cache->name);
+ kfree(cache);
+ }
+}
+
+/**
+ * fscache_relinquish_cache - Reset cache state and release cookie
+ * @cache: The cache cookie to be released
+ *
+ * Reset the state of a cache and release the caller's reference on a cache
+ * cookie.
+ */
+void fscache_relinquish_cache(struct fscache_cache *cache)
+{
+ enum fscache_cache_trace where =
+ (cache->state == FSCACHE_CACHE_IS_PREPARING) ?
+ fscache_cache_put_prep_failed :
+ fscache_cache_put_relinquish;
+
+ cache->ops = NULL;
+ cache->cache_priv = NULL;
+ fscache_set_cache_state(cache, FSCACHE_CACHE_IS_NOT_PRESENT);
+ fscache_put_cache(cache, where);
+}
+EXPORT_SYMBOL(fscache_relinquish_cache);
+
+/**
+ * fscache_add_cache - Declare a cache as being open for business
+ * @cache: The cache-level cookie representing the cache
+ * @ops: Table of cache operations to use
+ * @cache_priv: Private data for the cache record
+ *
+ * Add a cache to the system, making it available for netfs's to use.
+ *
+ * See Documentation/filesystems/caching/backend-api.rst for a complete
+ * description.
+ */
+int fscache_add_cache(struct fscache_cache *cache,
+ const struct fscache_cache_ops *ops,
+ void *cache_priv)
+{
+ int n_accesses;
+
+ _enter("{%s,%s}", ops->name, cache->name);
+
+ BUG_ON(fscache_cache_state(cache) != FSCACHE_CACHE_IS_PREPARING);
+
+ /* Get a ref on the cache cookie and keep its n_accesses counter raised
+ * by 1 to prevent wakeups from transitioning it to 0 until we're
+ * withdrawing caching services from it.
+ */
+ n_accesses = atomic_inc_return(&cache->n_accesses);
+ trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref),
+ n_accesses, fscache_access_cache_pin);
+
+ down_write(&fscache_addremove_sem);
+
+ cache->ops = ops;
+ cache->cache_priv = cache_priv;
+ fscache_set_cache_state(cache, FSCACHE_CACHE_IS_ACTIVE);
+
+ up_write(&fscache_addremove_sem);
+ pr_notice("Cache \"%s\" added (type %s)\n", cache->name, ops->name);
+ _leave(" = 0 [%s]", cache->name);
+ return 0;
+}
+EXPORT_SYMBOL(fscache_add_cache);
+
+/**
+ * fscache_begin_cache_access - Pin a cache so it can be accessed
+ * @cache: The cache-level cookie
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Attempt to pin the cache to prevent it from going away whilst we're
+ * accessing it and returns true if successful. This works as follows:
+ *
+ * (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE),
+ * then we return false to indicate access was not permitted.
+ *
+ * (2) If the cache tests as live, then we increment the n_accesses count and
+ * then recheck the liveness, ending the access if it ceased to be live.
+ *
+ * (3) When we end the access, we decrement n_accesses and wake up the any
+ * waiters if it reaches 0.
+ *
+ * (4) Whilst the cache is caching, n_accesses is kept artificially
+ * incremented to prevent wakeups from happening.
+ *
+ * (5) When the cache is taken offline, the state is changed to prevent new
+ * accesses, n_accesses is decremented and we wait for n_accesses to
+ * become 0.
+ */
+bool fscache_begin_cache_access(struct fscache_cache *cache, enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ if (!fscache_cache_is_live(cache))
+ return false;
+
+ n_accesses = atomic_inc_return(&cache->n_accesses);
+ smp_mb__after_atomic(); /* Reread live flag after n_accesses */
+ trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref),
+ n_accesses, why);
+ if (!fscache_cache_is_live(cache)) {
+ fscache_end_cache_access(cache, fscache_access_unlive);
+ return false;
+ }
+ return true;
+}
+
+/**
+ * fscache_end_cache_access - Unpin a cache at the end of an access.
+ * @cache: The cache-level cookie
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Unpin a cache after we've accessed it. The @why indicator is merely
+ * provided for tracing purposes.
+ */
+void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ smp_mb__before_atomic();
+ n_accesses = atomic_dec_return(&cache->n_accesses);
+ trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref),
+ n_accesses, why);
+ if (n_accesses == 0)
+ wake_up_var(&cache->n_accesses);
+}
+
+/**
+ * fscache_io_error - Note a cache I/O error
+ * @cache: The record describing the cache
+ *
+ * Note that an I/O error occurred in a cache and that it should no longer be
+ * used for anything. This also reports the error into the kernel log.
+ *
+ * See Documentation/filesystems/caching/backend-api.rst for a complete
+ * description.
+ */
+void fscache_io_error(struct fscache_cache *cache)
+{
+ if (fscache_set_cache_state_maybe(cache,
+ FSCACHE_CACHE_IS_ACTIVE,
+ FSCACHE_CACHE_GOT_IOERROR))
+ pr_err("Cache '%s' stopped due to I/O error\n",
+ cache->name);
+}
+EXPORT_SYMBOL(fscache_io_error);
+
+/**
+ * fscache_withdraw_cache - Withdraw a cache from the active service
+ * @cache: The cache cookie
+ *
+ * Begin the process of withdrawing a cache from service. This stops new
+ * cache-level and volume-level accesses from taking place and waits for
+ * currently ongoing cache-level accesses to end.
+ */
+void fscache_withdraw_cache(struct fscache_cache *cache)
+{
+ int n_accesses;
+
+ pr_notice("Withdrawing cache \"%s\" (%u objs)\n",
+ cache->name, atomic_read(&cache->object_count));
+
+ fscache_set_cache_state(cache, FSCACHE_CACHE_IS_WITHDRAWN);
+
+ /* Allow wakeups on dec-to-0 */
+ n_accesses = atomic_dec_return(&cache->n_accesses);
+ trace_fscache_access_cache(cache->debug_id, refcount_read(&cache->ref),
+ n_accesses, fscache_access_cache_unpin);
+
+ wait_var_event(&cache->n_accesses,
+ atomic_read(&cache->n_accesses) == 0);
+}
+EXPORT_SYMBOL(fscache_withdraw_cache);
+
+#ifdef CONFIG_PROC_FS
+static const char fscache_cache_states[NR__FSCACHE_CACHE_STATE] = "-PAEW";
+
+/*
+ * Generate a list of caches in /proc/fs/fscache/caches
+ */
+static int fscache_caches_seq_show(struct seq_file *m, void *v)
+{
+ struct fscache_cache *cache;
+
+ if (v == &fscache_caches) {
+ seq_puts(m,
+ "CACHE REF VOLS OBJS ACCES S NAME\n"
+ "======== ===== ===== ===== ===== = ===============\n"
+ );
+ return 0;
+ }
+
+ cache = list_entry(v, struct fscache_cache, cache_link);
+ seq_printf(m,
+ "%08x %5d %5d %5d %5d %c %s\n",
+ cache->debug_id,
+ refcount_read(&cache->ref),
+ atomic_read(&cache->n_volumes),
+ atomic_read(&cache->object_count),
+ atomic_read(&cache->n_accesses),
+ fscache_cache_states[cache->state],
+ cache->name ?: "-");
+ return 0;
+}
+
+static void *fscache_caches_seq_start(struct seq_file *m, loff_t *_pos)
+ __acquires(fscache_addremove_sem)
+{
+ down_read(&fscache_addremove_sem);
+ return seq_list_start_head(&fscache_caches, *_pos);
+}
+
+static void *fscache_caches_seq_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+ return seq_list_next(v, &fscache_caches, _pos);
+}
+
+static void fscache_caches_seq_stop(struct seq_file *m, void *v)
+ __releases(fscache_addremove_sem)
+{
+ up_read(&fscache_addremove_sem);
+}
+
+const struct seq_operations fscache_caches_seq_ops = {
+ .start = fscache_caches_seq_start,
+ .next = fscache_caches_seq_next,
+ .stop = fscache_caches_seq_stop,
+ .show = fscache_caches_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
diff --git a/fs/netfs/fscache_cookie.c b/fs/netfs/fscache_cookie.c
new file mode 100644
index 000000000000..bce2492186d0
--- /dev/null
+++ b/fs/netfs/fscache_cookie.c
@@ -0,0 +1,1180 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* netfs cookie management
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * See Documentation/filesystems/caching/netfs-api.rst for more information on
+ * the netfs API.
+ */
+
+#define FSCACHE_DEBUG_LEVEL COOKIE
+#include <linux/module.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+struct kmem_cache *fscache_cookie_jar;
+
+static void fscache_cookie_lru_timed_out(struct timer_list *timer);
+static void fscache_cookie_lru_worker(struct work_struct *work);
+static void fscache_cookie_worker(struct work_struct *work);
+static void fscache_unhash_cookie(struct fscache_cookie *cookie);
+static void fscache_perform_invalidation(struct fscache_cookie *cookie);
+
+#define fscache_cookie_hash_shift 15
+static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
+static LIST_HEAD(fscache_cookies);
+static DEFINE_RWLOCK(fscache_cookies_lock);
+static LIST_HEAD(fscache_cookie_lru);
+static DEFINE_SPINLOCK(fscache_cookie_lru_lock);
+DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out);
+static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker);
+static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAIFUWRD";
+static unsigned int fscache_lru_cookie_timeout = 10 * HZ;
+
+void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
+{
+ const u8 *k;
+
+ pr_err("%c-cookie c=%08x [fl=%lx na=%u nA=%u s=%c]\n",
+ prefix,
+ cookie->debug_id,
+ cookie->flags,
+ atomic_read(&cookie->n_active),
+ atomic_read(&cookie->n_accesses),
+ fscache_cookie_states[cookie->state]);
+ pr_err("%c-cookie V=%08x [%s]\n",
+ prefix,
+ cookie->volume->debug_id,
+ cookie->volume->key);
+
+ k = (cookie->key_len <= sizeof(cookie->inline_key)) ?
+ cookie->inline_key : cookie->key;
+ pr_err("%c-key=[%u] '%*phN'\n", prefix, cookie->key_len, cookie->key_len, k);
+}
+
+static void fscache_free_cookie(struct fscache_cookie *cookie)
+{
+ if (WARN_ON_ONCE(!list_empty(&cookie->commit_link))) {
+ spin_lock(&fscache_cookie_lru_lock);
+ list_del_init(&cookie->commit_link);
+ spin_unlock(&fscache_cookie_lru_lock);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ fscache_stat(&fscache_n_cookies_lru_removed);
+ }
+
+ if (WARN_ON_ONCE(test_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags))) {
+ fscache_print_cookie(cookie, 'F');
+ return;
+ }
+
+ write_lock(&fscache_cookies_lock);
+ list_del(&cookie->proc_link);
+ write_unlock(&fscache_cookies_lock);
+ if (cookie->aux_len > sizeof(cookie->inline_aux))
+ kfree(cookie->aux);
+ if (cookie->key_len > sizeof(cookie->inline_key))
+ kfree(cookie->key);
+ fscache_stat_d(&fscache_n_cookies);
+ kmem_cache_free(fscache_cookie_jar, cookie);
+}
+
+static void __fscache_queue_cookie(struct fscache_cookie *cookie)
+{
+ if (!queue_work(fscache_wq, &cookie->work))
+ fscache_put_cookie(cookie, fscache_cookie_put_over_queued);
+}
+
+static void fscache_queue_cookie(struct fscache_cookie *cookie,
+ enum fscache_cookie_trace where)
+{
+ fscache_get_cookie(cookie, where);
+ __fscache_queue_cookie(cookie);
+}
+
+/*
+ * Initialise the access gate on a cookie by setting a flag to prevent the
+ * state machine from being queued when the access counter transitions to 0.
+ * We're only interested in this when we withdraw caching services from the
+ * cookie.
+ */
+static void fscache_init_access_gate(struct fscache_cookie *cookie)
+{
+ int n_accesses;
+
+ n_accesses = atomic_read(&cookie->n_accesses);
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ n_accesses, fscache_access_cache_pin);
+ set_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags);
+}
+
+/**
+ * fscache_end_cookie_access - Unpin a cache at the end of an access.
+ * @cookie: A data file cookie
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Unpin a cache cookie after we've accessed it and bring a deferred
+ * relinquishment or withdrawal state into effect.
+ *
+ * The @why indicator is provided for tracing purposes.
+ */
+void fscache_end_cookie_access(struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ smp_mb__before_atomic();
+ n_accesses = atomic_dec_return(&cookie->n_accesses);
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ n_accesses, why);
+ if (n_accesses == 0 &&
+ !test_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags))
+ fscache_queue_cookie(cookie, fscache_cookie_get_end_access);
+}
+EXPORT_SYMBOL(fscache_end_cookie_access);
+
+/*
+ * Pin the cache behind a cookie so that we can access it.
+ */
+static void __fscache_begin_cookie_access(struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ n_accesses = atomic_inc_return(&cookie->n_accesses);
+ smp_mb__after_atomic(); /* (Future) read state after is-caching.
+ * Reread n_accesses after is-caching
+ */
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ n_accesses, why);
+}
+
+/**
+ * fscache_begin_cookie_access - Pin a cache so data can be accessed
+ * @cookie: A data file cookie
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Attempt to pin the cache to prevent it from going away whilst we're
+ * accessing data and returns true if successful. This works as follows:
+ *
+ * (1) If the cookie is not being cached (ie. FSCACHE_COOKIE_IS_CACHING is not
+ * set), we return false to indicate access was not permitted.
+ *
+ * (2) If the cookie is being cached, we increment its n_accesses count and
+ * then recheck the IS_CACHING flag, ending the access if it got cleared.
+ *
+ * (3) When we end the access, we decrement the cookie's n_accesses and wake
+ * up the any waiters if it reaches 0.
+ *
+ * (4) Whilst the cookie is actively being cached, its n_accesses is kept
+ * artificially incremented to prevent wakeups from happening.
+ *
+ * (5) When the cache is taken offline or if the cookie is culled, the flag is
+ * cleared to prevent new accesses, the cookie's n_accesses is decremented
+ * and we wait for it to become 0.
+ *
+ * The @why indicator are merely provided for tracing purposes.
+ */
+bool fscache_begin_cookie_access(struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
+ return false;
+ __fscache_begin_cookie_access(cookie, why);
+ if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags) ||
+ !fscache_cache_is_live(cookie->volume->cache)) {
+ fscache_end_cookie_access(cookie, fscache_access_unlive);
+ return false;
+ }
+ return true;
+}
+
+static inline void wake_up_cookie_state(struct fscache_cookie *cookie)
+{
+ /* Use a barrier to ensure that waiters see the state variable
+ * change, as spin_unlock doesn't guarantee a barrier.
+ *
+ * See comments over wake_up_bit() and waitqueue_active().
+ */
+ smp_mb();
+ wake_up_var(&cookie->state);
+}
+
+/*
+ * Change the state a cookie is at and wake up anyone waiting for that. Impose
+ * an ordering between the stuff stored in the cookie and the state member.
+ * Paired with fscache_cookie_state().
+ */
+static void __fscache_set_cookie_state(struct fscache_cookie *cookie,
+ enum fscache_cookie_state state)
+{
+ smp_store_release(&cookie->state, state);
+}
+
+static void fscache_set_cookie_state(struct fscache_cookie *cookie,
+ enum fscache_cookie_state state)
+{
+ spin_lock(&cookie->lock);
+ __fscache_set_cookie_state(cookie, state);
+ spin_unlock(&cookie->lock);
+ wake_up_cookie_state(cookie);
+}
+
+/**
+ * fscache_cookie_lookup_negative - Note negative lookup
+ * @cookie: The cookie that was being looked up
+ *
+ * Note that some part of the metadata path in the cache doesn't exist and so
+ * we can release any waiting readers in the certain knowledge that there's
+ * nothing for them to actually read.
+ *
+ * This function uses no locking and must only be called from the state machine.
+ */
+void fscache_cookie_lookup_negative(struct fscache_cookie *cookie)
+{
+ set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_CREATING);
+}
+EXPORT_SYMBOL(fscache_cookie_lookup_negative);
+
+/**
+ * fscache_resume_after_invalidation - Allow I/O to resume after invalidation
+ * @cookie: The cookie that was invalidated
+ *
+ * Tell fscache that invalidation is sufficiently complete that I/O can be
+ * allowed again.
+ */
+void fscache_resume_after_invalidation(struct fscache_cookie *cookie)
+{
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE);
+}
+EXPORT_SYMBOL(fscache_resume_after_invalidation);
+
+/**
+ * fscache_caching_failed - Report that a failure stopped caching on a cookie
+ * @cookie: The cookie that was affected
+ *
+ * Tell fscache that caching on a cookie needs to be stopped due to some sort
+ * of failure.
+ *
+ * This function uses no locking and must only be called from the state machine.
+ */
+void fscache_caching_failed(struct fscache_cookie *cookie)
+{
+ clear_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags);
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_FAILED);
+ trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref),
+ fscache_cookie_failed);
+}
+EXPORT_SYMBOL(fscache_caching_failed);
+
+/*
+ * Set the index key in a cookie. The cookie struct has space for a 16-byte
+ * key plus length and hash, but if that's not big enough, it's instead a
+ * pointer to a buffer containing 3 bytes of hash, 1 byte of length and then
+ * the key data.
+ */
+static int fscache_set_key(struct fscache_cookie *cookie,
+ const void *index_key, size_t index_key_len)
+{
+ void *buf;
+ size_t buf_size;
+
+ buf_size = round_up(index_key_len, sizeof(__le32));
+
+ if (index_key_len > sizeof(cookie->inline_key)) {
+ buf = kzalloc(buf_size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ cookie->key = buf;
+ } else {
+ buf = cookie->inline_key;
+ }
+
+ memcpy(buf, index_key, index_key_len);
+ cookie->key_hash = fscache_hash(cookie->volume->key_hash,
+ buf, buf_size);
+ return 0;
+}
+
+static bool fscache_cookie_same(const struct fscache_cookie *a,
+ const struct fscache_cookie *b)
+{
+ const void *ka, *kb;
+
+ if (a->key_hash != b->key_hash ||
+ a->volume != b->volume ||
+ a->key_len != b->key_len)
+ return false;
+
+ if (a->key_len <= sizeof(a->inline_key)) {
+ ka = &a->inline_key;
+ kb = &b->inline_key;
+ } else {
+ ka = a->key;
+ kb = b->key;
+ }
+ return memcmp(ka, kb, a->key_len) == 0;
+}
+
+static atomic_t fscache_cookie_debug_id = ATOMIC_INIT(1);
+
+/*
+ * Allocate a cookie.
+ */
+static struct fscache_cookie *fscache_alloc_cookie(
+ struct fscache_volume *volume,
+ u8 advice,
+ const void *index_key, size_t index_key_len,
+ const void *aux_data, size_t aux_data_len,
+ loff_t object_size)
+{
+ struct fscache_cookie *cookie;
+
+ /* allocate and initialise a cookie */
+ cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+ if (!cookie)
+ return NULL;
+ fscache_stat(&fscache_n_cookies);
+
+ cookie->volume = volume;
+ cookie->advice = advice;
+ cookie->key_len = index_key_len;
+ cookie->aux_len = aux_data_len;
+ cookie->object_size = object_size;
+ if (object_size == 0)
+ __set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
+
+ if (fscache_set_key(cookie, index_key, index_key_len) < 0)
+ goto nomem;
+
+ if (cookie->aux_len <= sizeof(cookie->inline_aux)) {
+ memcpy(cookie->inline_aux, aux_data, cookie->aux_len);
+ } else {
+ cookie->aux = kmemdup(aux_data, cookie->aux_len, GFP_KERNEL);
+ if (!cookie->aux)
+ goto nomem;
+ }
+
+ refcount_set(&cookie->ref, 1);
+ cookie->debug_id = atomic_inc_return(&fscache_cookie_debug_id);
+ spin_lock_init(&cookie->lock);
+ INIT_LIST_HEAD(&cookie->commit_link);
+ INIT_WORK(&cookie->work, fscache_cookie_worker);
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
+
+ write_lock(&fscache_cookies_lock);
+ list_add_tail(&cookie->proc_link, &fscache_cookies);
+ write_unlock(&fscache_cookies_lock);
+ fscache_see_cookie(cookie, fscache_cookie_new_acquire);
+ return cookie;
+
+nomem:
+ fscache_free_cookie(cookie);
+ return NULL;
+}
+
+static inline bool fscache_cookie_is_dropped(struct fscache_cookie *cookie)
+{
+ return READ_ONCE(cookie->state) == FSCACHE_COOKIE_STATE_DROPPED;
+}
+
+static void fscache_wait_on_collision(struct fscache_cookie *candidate,
+ struct fscache_cookie *wait_for)
+{
+ enum fscache_cookie_state *statep = &wait_for->state;
+
+ wait_var_event_timeout(statep, fscache_cookie_is_dropped(wait_for),
+ 20 * HZ);
+ if (!fscache_cookie_is_dropped(wait_for)) {
+ pr_notice("Potential collision c=%08x old: c=%08x",
+ candidate->debug_id, wait_for->debug_id);
+ wait_var_event(statep, fscache_cookie_is_dropped(wait_for));
+ }
+}
+
+/*
+ * Attempt to insert the new cookie into the hash. If there's a collision, we
+ * wait for the old cookie to complete if it's being relinquished and an error
+ * otherwise.
+ */
+static bool fscache_hash_cookie(struct fscache_cookie *candidate)
+{
+ struct fscache_cookie *cursor, *wait_for = NULL;
+ struct hlist_bl_head *h;
+ struct hlist_bl_node *p;
+ unsigned int bucket;
+
+ bucket = candidate->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
+ h = &fscache_cookie_hash[bucket];
+
+ hlist_bl_lock(h);
+ hlist_bl_for_each_entry(cursor, p, h, hash_link) {
+ if (fscache_cookie_same(candidate, cursor)) {
+ if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cursor->flags))
+ goto collision;
+ wait_for = fscache_get_cookie(cursor,
+ fscache_cookie_get_hash_collision);
+ break;
+ }
+ }
+
+ fscache_get_volume(candidate->volume, fscache_volume_get_cookie);
+ atomic_inc(&candidate->volume->n_cookies);
+ hlist_bl_add_head(&candidate->hash_link, h);
+ set_bit(FSCACHE_COOKIE_IS_HASHED, &candidate->flags);
+ hlist_bl_unlock(h);
+
+ if (wait_for) {
+ fscache_wait_on_collision(candidate, wait_for);
+ fscache_put_cookie(wait_for, fscache_cookie_put_hash_collision);
+ }
+ return true;
+
+collision:
+ trace_fscache_cookie(cursor->debug_id, refcount_read(&cursor->ref),
+ fscache_cookie_collision);
+ pr_err("Duplicate cookie detected\n");
+ fscache_print_cookie(cursor, 'O');
+ fscache_print_cookie(candidate, 'N');
+ hlist_bl_unlock(h);
+ return false;
+}
+
+/*
+ * Request a cookie to represent a data storage object within a volume.
+ *
+ * We never let on to the netfs about errors. We may set a negative cookie
+ * pointer, but that's okay
+ */
+struct fscache_cookie *__fscache_acquire_cookie(
+ struct fscache_volume *volume,
+ u8 advice,
+ const void *index_key, size_t index_key_len,
+ const void *aux_data, size_t aux_data_len,
+ loff_t object_size)
+{
+ struct fscache_cookie *cookie;
+
+ _enter("V=%x", volume->debug_id);
+
+ if (!index_key || !index_key_len || index_key_len > 255 || aux_data_len > 255)
+ return NULL;
+ if (!aux_data || !aux_data_len) {
+ aux_data = NULL;
+ aux_data_len = 0;
+ }
+
+ fscache_stat(&fscache_n_acquires);
+
+ cookie = fscache_alloc_cookie(volume, advice,
+ index_key, index_key_len,
+ aux_data, aux_data_len,
+ object_size);
+ if (!cookie) {
+ fscache_stat(&fscache_n_acquires_oom);
+ return NULL;
+ }
+
+ if (!fscache_hash_cookie(cookie)) {
+ fscache_see_cookie(cookie, fscache_cookie_discard);
+ fscache_free_cookie(cookie);
+ return NULL;
+ }
+
+ trace_fscache_acquire(cookie);
+ fscache_stat(&fscache_n_acquires_ok);
+ _leave(" = c=%08x", cookie->debug_id);
+ return cookie;
+}
+EXPORT_SYMBOL(__fscache_acquire_cookie);
+
+/*
+ * Prepare a cache object to be written to.
+ */
+static void fscache_prepare_to_write(struct fscache_cookie *cookie)
+{
+ cookie->volume->cache->ops->prepare_to_write(cookie);
+}
+
+/*
+ * Look up a cookie in the cache.
+ */
+static void fscache_perform_lookup(struct fscache_cookie *cookie)
+{
+ enum fscache_access_trace trace = fscache_access_lookup_cookie_end_failed;
+ bool need_withdraw = false;
+
+ _enter("");
+
+ if (!cookie->volume->cache_priv) {
+ fscache_create_volume(cookie->volume, true);
+ if (!cookie->volume->cache_priv) {
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
+ goto out;
+ }
+ }
+
+ if (!cookie->volume->cache->ops->lookup_cookie(cookie)) {
+ if (cookie->state != FSCACHE_COOKIE_STATE_FAILED)
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
+ need_withdraw = true;
+ _leave(" [fail]");
+ goto out;
+ }
+
+ fscache_see_cookie(cookie, fscache_cookie_see_active);
+ spin_lock(&cookie->lock);
+ if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_INVALIDATING);
+ else
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_ACTIVE);
+ spin_unlock(&cookie->lock);
+ wake_up_cookie_state(cookie);
+ trace = fscache_access_lookup_cookie_end;
+
+out:
+ fscache_end_cookie_access(cookie, trace);
+ if (need_withdraw)
+ fscache_withdraw_cookie(cookie);
+ fscache_end_volume_access(cookie->volume, cookie, trace);
+}
+
+/*
+ * Begin the process of looking up a cookie. We offload the actual process to
+ * a worker thread.
+ */
+static bool fscache_begin_lookup(struct fscache_cookie *cookie, bool will_modify)
+{
+ if (will_modify) {
+ set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
+ set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
+ }
+ if (!fscache_begin_volume_access(cookie->volume, cookie,
+ fscache_access_lookup_cookie))
+ return false;
+
+ __fscache_begin_cookie_access(cookie, fscache_access_lookup_cookie);
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_LOOKING_UP);
+ set_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags);
+ set_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags);
+ return true;
+}
+
+/*
+ * Start using the cookie for I/O. This prevents the backing object from being
+ * reaped by VM pressure.
+ */
+void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify)
+{
+ enum fscache_cookie_state state;
+ bool queue = false;
+ int n_active;
+
+ _enter("c=%08x", cookie->debug_id);
+
+ if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
+ "Trying to use relinquished cookie\n"))
+ return;
+
+ spin_lock(&cookie->lock);
+
+ n_active = atomic_inc_return(&cookie->n_active);
+ trace_fscache_active(cookie->debug_id, refcount_read(&cookie->ref),
+ n_active, atomic_read(&cookie->n_accesses),
+ will_modify ?
+ fscache_active_use_modify : fscache_active_use);
+
+again:
+ state = fscache_cookie_state(cookie);
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_QUIESCENT:
+ queue = fscache_begin_lookup(cookie, will_modify);
+ break;
+
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_CREATING:
+ if (will_modify)
+ set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
+ break;
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ if (will_modify &&
+ !test_and_set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags)) {
+ set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
+ queue = true;
+ }
+ /*
+ * We could race with cookie_lru which may set LRU_DISCARD bit
+ * but has yet to run the cookie state machine. If this happens
+ * and another thread tries to use the cookie, clear LRU_DISCARD
+ * so we don't end up withdrawing the cookie while in use.
+ */
+ if (test_and_clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags))
+ fscache_see_cookie(cookie, fscache_cookie_see_lru_discard_clear);
+ break;
+
+ case FSCACHE_COOKIE_STATE_FAILED:
+ case FSCACHE_COOKIE_STATE_WITHDRAWING:
+ break;
+
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ spin_unlock(&cookie->lock);
+ wait_var_event(&cookie->state,
+ fscache_cookie_state(cookie) !=
+ FSCACHE_COOKIE_STATE_LRU_DISCARDING);
+ spin_lock(&cookie->lock);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ WARN(1, "Can't use cookie in state %u\n", state);
+ break;
+ }
+
+ spin_unlock(&cookie->lock);
+ if (queue)
+ fscache_queue_cookie(cookie, fscache_cookie_get_use_work);
+ _leave("");
+}
+EXPORT_SYMBOL(__fscache_use_cookie);
+
+static void fscache_unuse_cookie_locked(struct fscache_cookie *cookie)
+{
+ clear_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags);
+ if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
+ return;
+
+ cookie->unused_at = jiffies;
+ spin_lock(&fscache_cookie_lru_lock);
+ if (list_empty(&cookie->commit_link)) {
+ fscache_get_cookie(cookie, fscache_cookie_get_lru);
+ fscache_stat(&fscache_n_cookies_lru);
+ }
+ list_move_tail(&cookie->commit_link, &fscache_cookie_lru);
+
+ spin_unlock(&fscache_cookie_lru_lock);
+ timer_reduce(&fscache_cookie_lru_timer,
+ jiffies + fscache_lru_cookie_timeout);
+}
+
+/*
+ * Stop using the cookie for I/O.
+ */
+void __fscache_unuse_cookie(struct fscache_cookie *cookie,
+ const void *aux_data, const loff_t *object_size)
+{
+ unsigned int debug_id = cookie->debug_id;
+ unsigned int r = refcount_read(&cookie->ref);
+ unsigned int a = atomic_read(&cookie->n_accesses);
+ unsigned int c;
+
+ if (aux_data || object_size)
+ __fscache_update_cookie(cookie, aux_data, object_size);
+
+ /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */
+ c = atomic_fetch_add_unless(&cookie->n_active, -1, 1);
+ if (c != 1) {
+ trace_fscache_active(debug_id, r, c - 1, a, fscache_active_unuse);
+ return;
+ }
+
+ spin_lock(&cookie->lock);
+ r = refcount_read(&cookie->ref);
+ a = atomic_read(&cookie->n_accesses);
+ c = atomic_dec_return(&cookie->n_active);
+ trace_fscache_active(debug_id, r, c, a, fscache_active_unuse);
+ if (c == 0)
+ fscache_unuse_cookie_locked(cookie);
+ spin_unlock(&cookie->lock);
+}
+EXPORT_SYMBOL(__fscache_unuse_cookie);
+
+/*
+ * Perform work upon the cookie, such as committing its cache state,
+ * relinquishing it or withdrawing the backing cache. We're protected from the
+ * cache going away under us as object withdrawal must come through this
+ * non-reentrant work item.
+ */
+static void fscache_cookie_state_machine(struct fscache_cookie *cookie)
+{
+ enum fscache_cookie_state state;
+ bool wake = false;
+
+ _enter("c=%x", cookie->debug_id);
+
+again:
+ spin_lock(&cookie->lock);
+again_locked:
+ state = cookie->state;
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_QUIESCENT:
+ /* The QUIESCENT state is jumped to the LOOKING_UP state by
+ * fscache_use_cookie().
+ */
+
+ if (atomic_read(&cookie->n_accesses) == 0 &&
+ test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) {
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_RELINQUISHING);
+ wake = true;
+ goto again_locked;
+ }
+ break;
+
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ spin_unlock(&cookie->lock);
+ fscache_init_access_gate(cookie);
+ fscache_perform_lookup(cookie);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ spin_unlock(&cookie->lock);
+ fscache_perform_invalidation(cookie);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ if (test_and_clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags)) {
+ spin_unlock(&cookie->lock);
+ fscache_prepare_to_write(cookie);
+ spin_lock(&cookie->lock);
+ }
+ if (test_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) {
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_LRU_DISCARDING);
+ wake = true;
+ goto again_locked;
+ }
+ fallthrough;
+
+ case FSCACHE_COOKIE_STATE_FAILED:
+ if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
+ fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
+
+ if (atomic_read(&cookie->n_accesses) != 0)
+ break;
+ if (test_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags)) {
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_RELINQUISHING);
+ wake = true;
+ goto again_locked;
+ }
+ if (test_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags)) {
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_WITHDRAWING);
+ wake = true;
+ goto again_locked;
+ }
+ break;
+
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ case FSCACHE_COOKIE_STATE_WITHDRAWING:
+ if (cookie->cache_priv) {
+ spin_unlock(&cookie->lock);
+ cookie->volume->cache->ops->withdraw_cookie(cookie);
+ spin_lock(&cookie->lock);
+ }
+
+ if (test_and_clear_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
+ fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
+
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ fscache_see_cookie(cookie, fscache_cookie_see_relinquish);
+ fscache_unhash_cookie(cookie);
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_DROPPED);
+ wake = true;
+ goto out;
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ fscache_see_cookie(cookie, fscache_cookie_see_lru_discard);
+ break;
+ case FSCACHE_COOKIE_STATE_WITHDRAWING:
+ fscache_see_cookie(cookie, fscache_cookie_see_withdraw);
+ break;
+ default:
+ BUG();
+ }
+
+ clear_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
+ clear_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags);
+ clear_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags);
+ clear_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
+ set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_QUIESCENT);
+ wake = true;
+ goto again_locked;
+
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ break;
+
+ default:
+ WARN_ONCE(1, "Cookie %x in unexpected state %u\n",
+ cookie->debug_id, state);
+ break;
+ }
+
+out:
+ spin_unlock(&cookie->lock);
+ if (wake)
+ wake_up_cookie_state(cookie);
+ _leave("");
+}
+
+static void fscache_cookie_worker(struct work_struct *work)
+{
+ struct fscache_cookie *cookie = container_of(work, struct fscache_cookie, work);
+
+ fscache_see_cookie(cookie, fscache_cookie_see_work);
+ fscache_cookie_state_machine(cookie);
+ fscache_put_cookie(cookie, fscache_cookie_put_work);
+}
+
+/*
+ * Wait for the object to become inactive. The cookie's work item will be
+ * scheduled when someone transitions n_accesses to 0 - but if someone's
+ * already done that, schedule it anyway.
+ */
+static void __fscache_withdraw_cookie(struct fscache_cookie *cookie)
+{
+ int n_accesses;
+ bool unpinned;
+
+ unpinned = test_and_clear_bit(FSCACHE_COOKIE_NO_ACCESS_WAKE, &cookie->flags);
+
+ /* Need to read the access count after unpinning */
+ n_accesses = atomic_read(&cookie->n_accesses);
+ if (unpinned)
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ n_accesses, fscache_access_cache_unpin);
+ if (n_accesses == 0)
+ fscache_queue_cookie(cookie, fscache_cookie_get_end_access);
+}
+
+static void fscache_cookie_lru_do_one(struct fscache_cookie *cookie)
+{
+ fscache_see_cookie(cookie, fscache_cookie_see_lru_do_one);
+
+ spin_lock(&cookie->lock);
+ if (cookie->state != FSCACHE_COOKIE_STATE_ACTIVE ||
+ time_before(jiffies, cookie->unused_at + fscache_lru_cookie_timeout) ||
+ atomic_read(&cookie->n_active) > 0) {
+ spin_unlock(&cookie->lock);
+ fscache_stat(&fscache_n_cookies_lru_removed);
+ } else {
+ set_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags);
+ spin_unlock(&cookie->lock);
+ fscache_stat(&fscache_n_cookies_lru_expired);
+ _debug("lru c=%x", cookie->debug_id);
+ __fscache_withdraw_cookie(cookie);
+ }
+
+ fscache_put_cookie(cookie, fscache_cookie_put_lru);
+}
+
+static void fscache_cookie_lru_worker(struct work_struct *work)
+{
+ struct fscache_cookie *cookie;
+ unsigned long unused_at;
+
+ spin_lock(&fscache_cookie_lru_lock);
+
+ while (!list_empty(&fscache_cookie_lru)) {
+ cookie = list_first_entry(&fscache_cookie_lru,
+ struct fscache_cookie, commit_link);
+ unused_at = cookie->unused_at + fscache_lru_cookie_timeout;
+ if (time_before(jiffies, unused_at)) {
+ timer_reduce(&fscache_cookie_lru_timer, unused_at);
+ break;
+ }
+
+ list_del_init(&cookie->commit_link);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ spin_unlock(&fscache_cookie_lru_lock);
+ fscache_cookie_lru_do_one(cookie);
+ spin_lock(&fscache_cookie_lru_lock);
+ }
+
+ spin_unlock(&fscache_cookie_lru_lock);
+}
+
+static void fscache_cookie_lru_timed_out(struct timer_list *timer)
+{
+ queue_work(fscache_wq, &fscache_cookie_lru_work);
+}
+
+static void fscache_cookie_drop_from_lru(struct fscache_cookie *cookie)
+{
+ bool need_put = false;
+
+ if (!list_empty(&cookie->commit_link)) {
+ spin_lock(&fscache_cookie_lru_lock);
+ if (!list_empty(&cookie->commit_link)) {
+ list_del_init(&cookie->commit_link);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ fscache_stat(&fscache_n_cookies_lru_dropped);
+ need_put = true;
+ }
+ spin_unlock(&fscache_cookie_lru_lock);
+ if (need_put)
+ fscache_put_cookie(cookie, fscache_cookie_put_lru);
+ }
+}
+
+/*
+ * Remove a cookie from the hash table.
+ */
+static void fscache_unhash_cookie(struct fscache_cookie *cookie)
+{
+ struct hlist_bl_head *h;
+ unsigned int bucket;
+
+ bucket = cookie->key_hash & (ARRAY_SIZE(fscache_cookie_hash) - 1);
+ h = &fscache_cookie_hash[bucket];
+
+ hlist_bl_lock(h);
+ hlist_bl_del(&cookie->hash_link);
+ clear_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags);
+ hlist_bl_unlock(h);
+ fscache_stat(&fscache_n_relinquishes_dropped);
+}
+
+static void fscache_drop_withdraw_cookie(struct fscache_cookie *cookie)
+{
+ fscache_cookie_drop_from_lru(cookie);
+ __fscache_withdraw_cookie(cookie);
+}
+
+/**
+ * fscache_withdraw_cookie - Mark a cookie for withdrawal
+ * @cookie: The cookie to be withdrawn.
+ *
+ * Allow the cache backend to withdraw the backing for a cookie for its own
+ * reasons, even if that cookie is in active use.
+ */
+void fscache_withdraw_cookie(struct fscache_cookie *cookie)
+{
+ set_bit(FSCACHE_COOKIE_DO_WITHDRAW, &cookie->flags);
+ fscache_drop_withdraw_cookie(cookie);
+}
+EXPORT_SYMBOL(fscache_withdraw_cookie);
+
+/*
+ * Allow the netfs to release a cookie back to the cache.
+ * - the object will be marked as recyclable on disk if retire is true
+ */
+void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
+{
+ fscache_stat(&fscache_n_relinquishes);
+ if (retire)
+ fscache_stat(&fscache_n_relinquishes_retire);
+
+ _enter("c=%08x{%d},%d",
+ cookie->debug_id, atomic_read(&cookie->n_active), retire);
+
+ if (WARN(test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
+ "Cookie c=%x already relinquished\n", cookie->debug_id))
+ return;
+
+ if (retire)
+ set_bit(FSCACHE_COOKIE_RETIRED, &cookie->flags);
+ trace_fscache_relinquish(cookie, retire);
+
+ ASSERTCMP(atomic_read(&cookie->n_active), ==, 0);
+ ASSERTCMP(atomic_read(&cookie->volume->n_cookies), >, 0);
+ atomic_dec(&cookie->volume->n_cookies);
+
+ if (test_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags)) {
+ set_bit(FSCACHE_COOKIE_DO_RELINQUISH, &cookie->flags);
+ fscache_drop_withdraw_cookie(cookie);
+ } else {
+ fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_DROPPED);
+ fscache_unhash_cookie(cookie);
+ }
+ fscache_put_cookie(cookie, fscache_cookie_put_relinquish);
+}
+EXPORT_SYMBOL(__fscache_relinquish_cookie);
+
+/*
+ * Drop a reference to a cookie.
+ */
+void fscache_put_cookie(struct fscache_cookie *cookie,
+ enum fscache_cookie_trace where)
+{
+ struct fscache_volume *volume = cookie->volume;
+ unsigned int cookie_debug_id = cookie->debug_id;
+ bool zero;
+ int ref;
+
+ zero = __refcount_dec_and_test(&cookie->ref, &ref);
+ trace_fscache_cookie(cookie_debug_id, ref - 1, where);
+ if (zero) {
+ fscache_free_cookie(cookie);
+ fscache_put_volume(volume, fscache_volume_put_cookie);
+ }
+}
+EXPORT_SYMBOL(fscache_put_cookie);
+
+/*
+ * Get a reference to a cookie.
+ */
+struct fscache_cookie *fscache_get_cookie(struct fscache_cookie *cookie,
+ enum fscache_cookie_trace where)
+{
+ int ref;
+
+ __refcount_inc(&cookie->ref, &ref);
+ trace_fscache_cookie(cookie->debug_id, ref + 1, where);
+ return cookie;
+}
+EXPORT_SYMBOL(fscache_get_cookie);
+
+/*
+ * Ask the cache to effect invalidation of a cookie.
+ */
+static void fscache_perform_invalidation(struct fscache_cookie *cookie)
+{
+ if (!cookie->volume->cache->ops->invalidate_cookie(cookie))
+ fscache_caching_failed(cookie);
+ fscache_end_cookie_access(cookie, fscache_access_invalidate_cookie_end);
+}
+
+/*
+ * Invalidate an object.
+ */
+void __fscache_invalidate(struct fscache_cookie *cookie,
+ const void *aux_data, loff_t new_size,
+ unsigned int flags)
+{
+ bool is_caching;
+
+ _enter("c=%x", cookie->debug_id);
+
+ fscache_stat(&fscache_n_invalidates);
+
+ if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
+ "Trying to invalidate relinquished cookie\n"))
+ return;
+
+ if ((flags & FSCACHE_INVAL_DIO_WRITE) &&
+ test_and_set_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags))
+ return;
+
+ spin_lock(&cookie->lock);
+ set_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
+ fscache_update_aux(cookie, aux_data, &new_size);
+ cookie->inval_counter++;
+ trace_fscache_invalidate(cookie, new_size);
+
+ switch (cookie->state) {
+ case FSCACHE_COOKIE_STATE_INVALIDATING: /* is_still_valid will catch it */
+ default:
+ spin_unlock(&cookie->lock);
+ _leave(" [no %u]", cookie->state);
+ return;
+
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ if (!test_and_set_bit(FSCACHE_COOKIE_DO_INVALIDATE, &cookie->flags))
+ __fscache_begin_cookie_access(cookie, fscache_access_invalidate_cookie);
+ fallthrough;
+ case FSCACHE_COOKIE_STATE_CREATING:
+ spin_unlock(&cookie->lock);
+ _leave(" [look %x]", cookie->inval_counter);
+ return;
+
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ is_caching = fscache_begin_cookie_access(
+ cookie, fscache_access_invalidate_cookie);
+ if (is_caching)
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_INVALIDATING);
+ spin_unlock(&cookie->lock);
+ wake_up_cookie_state(cookie);
+
+ if (is_caching)
+ fscache_queue_cookie(cookie, fscache_cookie_get_inval_work);
+ _leave(" [inv]");
+ return;
+ }
+}
+EXPORT_SYMBOL(__fscache_invalidate);
+
+#ifdef CONFIG_PROC_FS
+/*
+ * Generate a list of extant cookies in /proc/fs/fscache/cookies
+ */
+static int fscache_cookies_seq_show(struct seq_file *m, void *v)
+{
+ struct fscache_cookie *cookie;
+ unsigned int keylen = 0, auxlen = 0;
+ u8 *p;
+
+ if (v == &fscache_cookies) {
+ seq_puts(m,
+ "COOKIE VOLUME REF ACT ACC S FL DEF \n"
+ "======== ======== === === === = == ================\n"
+ );
+ return 0;
+ }
+
+ cookie = list_entry(v, struct fscache_cookie, proc_link);
+
+ seq_printf(m,
+ "%08x %08x %3d %3d %3d %c %02lx",
+ cookie->debug_id,
+ cookie->volume->debug_id,
+ refcount_read(&cookie->ref),
+ atomic_read(&cookie->n_active),
+ atomic_read(&cookie->n_accesses),
+ fscache_cookie_states[cookie->state],
+ cookie->flags);
+
+ keylen = cookie->key_len;
+ auxlen = cookie->aux_len;
+
+ if (keylen > 0 || auxlen > 0) {
+ seq_puts(m, " ");
+ p = keylen <= sizeof(cookie->inline_key) ?
+ cookie->inline_key : cookie->key;
+ for (; keylen > 0; keylen--)
+ seq_printf(m, "%02x", *p++);
+ if (auxlen > 0) {
+ seq_puts(m, ", ");
+ p = auxlen <= sizeof(cookie->inline_aux) ?
+ cookie->inline_aux : cookie->aux;
+ for (; auxlen > 0; auxlen--)
+ seq_printf(m, "%02x", *p++);
+ }
+ }
+
+ seq_puts(m, "\n");
+ return 0;
+}
+
+static void *fscache_cookies_seq_start(struct seq_file *m, loff_t *_pos)
+ __acquires(fscache_cookies_lock)
+{
+ read_lock(&fscache_cookies_lock);
+ return seq_list_start_head(&fscache_cookies, *_pos);
+}
+
+static void *fscache_cookies_seq_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+ return seq_list_next(v, &fscache_cookies, _pos);
+}
+
+static void fscache_cookies_seq_stop(struct seq_file *m, void *v)
+ __releases(rcu)
+{
+ read_unlock(&fscache_cookies_lock);
+}
+
+
+const struct seq_operations fscache_cookies_seq_ops = {
+ .start = fscache_cookies_seq_start,
+ .next = fscache_cookies_seq_next,
+ .stop = fscache_cookies_seq_stop,
+ .show = fscache_cookies_seq_show,
+};
+#endif
diff --git a/fs/netfs/fscache_internal.h b/fs/netfs/fscache_internal.h
new file mode 100644
index 000000000000..a09b948fcef2
--- /dev/null
+++ b/fs/netfs/fscache_internal.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Internal definitions for FS-Cache
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include "internal.h"
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+
+#define pr_fmt(fmt) "FS-Cache: " fmt
diff --git a/fs/netfs/fscache_io.c b/fs/netfs/fscache_io.c
new file mode 100644
index 000000000000..38637e5c9b57
--- /dev/null
+++ b/fs/netfs/fscache_io.c
@@ -0,0 +1,293 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Cache data I/O routines
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#define FSCACHE_DEBUG_LEVEL OPERATION
+#include <linux/fscache-cache.h>
+#include <linux/uio.h>
+#include <linux/bvec.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include "internal.h"
+
+/**
+ * fscache_wait_for_operation - Wait for an object become accessible
+ * @cres: The cache resources for the operation being performed
+ * @want_state: The minimum state the object must be at
+ *
+ * See if the target cache object is at the specified minimum state of
+ * accessibility yet, and if not, wait for it.
+ */
+bool fscache_wait_for_operation(struct netfs_cache_resources *cres,
+ enum fscache_want_state want_state)
+{
+ struct fscache_cookie *cookie = fscache_cres_cookie(cres);
+ enum fscache_cookie_state state;
+
+again:
+ if (!fscache_cache_is_live(cookie->volume->cache)) {
+ _leave(" [broken]");
+ return false;
+ }
+
+ state = fscache_cookie_state(cookie);
+ _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state);
+
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_CREATING:
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ if (want_state == FSCACHE_WANT_PARAMS)
+ goto ready; /* There can be no content */
+ fallthrough;
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ wait_var_event(&cookie->state,
+ fscache_cookie_state(cookie) != state);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ goto ready;
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ default:
+ _leave(" [not live]");
+ return false;
+ }
+
+ready:
+ if (!cres->cache_priv2)
+ return cookie->volume->cache->ops->begin_operation(cres, want_state);
+ return true;
+}
+EXPORT_SYMBOL(fscache_wait_for_operation);
+
+/*
+ * Begin an I/O operation on the cache, waiting till we reach the right state.
+ *
+ * Attaches the resources required to the operation resources record.
+ */
+static int fscache_begin_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie,
+ enum fscache_want_state want_state,
+ enum fscache_access_trace why)
+{
+ enum fscache_cookie_state state;
+ long timeo;
+ bool once_only = false;
+
+ cres->ops = NULL;
+ cres->cache_priv = cookie;
+ cres->cache_priv2 = NULL;
+ cres->debug_id = cookie->debug_id;
+ cres->inval_counter = cookie->inval_counter;
+
+ if (!fscache_begin_cookie_access(cookie, why)) {
+ cres->cache_priv = NULL;
+ return -ENOBUFS;
+ }
+
+again:
+ spin_lock(&cookie->lock);
+
+ state = fscache_cookie_state(cookie);
+ _enter("c=%08x{%u},%x", cookie->debug_id, state, want_state);
+
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ case FSCACHE_COOKIE_STATE_INVALIDATING:
+ goto wait_for_file_wrangling;
+ case FSCACHE_COOKIE_STATE_CREATING:
+ if (want_state == FSCACHE_WANT_PARAMS)
+ goto ready; /* There can be no content */
+ goto wait_for_file_wrangling;
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ goto ready;
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ WARN(1, "Can't use cookie in state %u\n", cookie->state);
+ goto not_live;
+ default:
+ goto not_live;
+ }
+
+ready:
+ spin_unlock(&cookie->lock);
+ if (!cookie->volume->cache->ops->begin_operation(cres, want_state))
+ goto failed;
+ return 0;
+
+wait_for_file_wrangling:
+ spin_unlock(&cookie->lock);
+ trace_fscache_access(cookie->debug_id, refcount_read(&cookie->ref),
+ atomic_read(&cookie->n_accesses),
+ fscache_access_io_wait);
+ timeo = wait_var_event_timeout(&cookie->state,
+ fscache_cookie_state(cookie) != state, 20 * HZ);
+ if (timeo <= 1 && !once_only) {
+ pr_warn("%s: cookie state change wait timed out: cookie->state=%u state=%u",
+ __func__, fscache_cookie_state(cookie), state);
+ fscache_print_cookie(cookie, 'O');
+ once_only = true;
+ }
+ goto again;
+
+not_live:
+ spin_unlock(&cookie->lock);
+failed:
+ cres->cache_priv = NULL;
+ cres->ops = NULL;
+ fscache_end_cookie_access(cookie, fscache_access_io_not_live);
+ _leave(" = -ENOBUFS");
+ return -ENOBUFS;
+}
+
+int __fscache_begin_read_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie)
+{
+ return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS,
+ fscache_access_io_read);
+}
+EXPORT_SYMBOL(__fscache_begin_read_operation);
+
+int __fscache_begin_write_operation(struct netfs_cache_resources *cres,
+ struct fscache_cookie *cookie)
+{
+ return fscache_begin_operation(cres, cookie, FSCACHE_WANT_PARAMS,
+ fscache_access_io_write);
+}
+EXPORT_SYMBOL(__fscache_begin_write_operation);
+
+struct fscache_write_request {
+ struct netfs_cache_resources cache_resources;
+ struct address_space *mapping;
+ loff_t start;
+ size_t len;
+ bool set_bits;
+ bool using_pgpriv2;
+ netfs_io_terminated_t term_func;
+ void *term_func_priv;
+};
+
+void __fscache_clear_page_bits(struct address_space *mapping,
+ loff_t start, size_t len)
+{
+ pgoff_t first = start / PAGE_SIZE;
+ pgoff_t last = (start + len - 1) / PAGE_SIZE;
+ struct page *page;
+
+ if (len) {
+ XA_STATE(xas, &mapping->i_pages, first);
+
+ rcu_read_lock();
+ xas_for_each(&xas, page, last) {
+ folio_end_private_2(page_folio(page));
+ }
+ rcu_read_unlock();
+ }
+}
+EXPORT_SYMBOL(__fscache_clear_page_bits);
+
+/*
+ * Deal with the completion of writing the data to the cache.
+ */
+static void fscache_wreq_done(void *priv, ssize_t transferred_or_error,
+ bool was_async)
+{
+ struct fscache_write_request *wreq = priv;
+
+ if (wreq->using_pgpriv2)
+ fscache_clear_page_bits(wreq->mapping, wreq->start, wreq->len,
+ wreq->set_bits);
+
+ if (wreq->term_func)
+ wreq->term_func(wreq->term_func_priv, transferred_or_error,
+ was_async);
+ fscache_end_operation(&wreq->cache_resources);
+ kfree(wreq);
+}
+
+void __fscache_write_to_cache(struct fscache_cookie *cookie,
+ struct address_space *mapping,
+ loff_t start, size_t len, loff_t i_size,
+ netfs_io_terminated_t term_func,
+ void *term_func_priv,
+ bool using_pgpriv2, bool cond)
+{
+ struct fscache_write_request *wreq;
+ struct netfs_cache_resources *cres;
+ struct iov_iter iter;
+ int ret = -ENOBUFS;
+
+ if (len == 0)
+ goto abandon;
+
+ _enter("%llx,%zx", start, len);
+
+ wreq = kzalloc(sizeof(struct fscache_write_request), GFP_NOFS);
+ if (!wreq)
+ goto abandon;
+ wreq->mapping = mapping;
+ wreq->start = start;
+ wreq->len = len;
+ wreq->using_pgpriv2 = using_pgpriv2;
+ wreq->set_bits = cond;
+ wreq->term_func = term_func;
+ wreq->term_func_priv = term_func_priv;
+
+ cres = &wreq->cache_resources;
+ if (fscache_begin_operation(cres, cookie, FSCACHE_WANT_WRITE,
+ fscache_access_io_write) < 0)
+ goto abandon_free;
+
+ ret = cres->ops->prepare_write(cres, &start, &len, len, i_size, false);
+ if (ret < 0)
+ goto abandon_end;
+
+ /* TODO: Consider clearing page bits now for space the write isn't
+ * covering. This is more complicated than it appears when THPs are
+ * taken into account.
+ */
+
+ iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len);
+ fscache_write(cres, start, &iter, fscache_wreq_done, wreq);
+ return;
+
+abandon_end:
+ return fscache_wreq_done(wreq, ret, false);
+abandon_free:
+ kfree(wreq);
+abandon:
+ if (using_pgpriv2)
+ fscache_clear_page_bits(mapping, start, len, cond);
+ if (term_func)
+ term_func(term_func_priv, ret, false);
+}
+EXPORT_SYMBOL(__fscache_write_to_cache);
+
+/*
+ * Change the size of a backing object.
+ */
+void __fscache_resize_cookie(struct fscache_cookie *cookie, loff_t new_size)
+{
+ struct netfs_cache_resources cres;
+
+ trace_fscache_resize(cookie, new_size);
+ if (fscache_begin_operation(&cres, cookie, FSCACHE_WANT_WRITE,
+ fscache_access_io_resize) == 0) {
+ fscache_stat(&fscache_n_resizes);
+ set_bit(FSCACHE_COOKIE_NEEDS_UPDATE, &cookie->flags);
+
+ /* We cannot defer a resize as we need to do it inside the
+ * netfs's inode lock so that we're serialised with respect to
+ * writes.
+ */
+ cookie->volume->cache->ops->resize_cookie(&cres, new_size);
+ fscache_end_operation(&cres);
+ } else {
+ fscache_stat(&fscache_n_resizes_null);
+ }
+}
+EXPORT_SYMBOL(__fscache_resize_cookie);
diff --git a/fs/netfs/fscache_main.c b/fs/netfs/fscache_main.c
new file mode 100644
index 000000000000..42e98bb523e3
--- /dev/null
+++ b/fs/netfs/fscache_main.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* General filesystem local caching manager
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define FSCACHE_DEBUG_LEVEL CACHE
+#include <linux/module.h>
+#include <linux/init.h>
+#include "internal.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/fscache.h>
+
+EXPORT_TRACEPOINT_SYMBOL(fscache_access_cache);
+EXPORT_TRACEPOINT_SYMBOL(fscache_access_volume);
+EXPORT_TRACEPOINT_SYMBOL(fscache_access);
+
+struct workqueue_struct *fscache_wq;
+EXPORT_SYMBOL(fscache_wq);
+
+/*
+ * Mixing scores (in bits) for (7,20):
+ * Input delta: 1-bit 2-bit
+ * 1 round: 330.3 9201.6
+ * 2 rounds: 1246.4 25475.4
+ * 3 rounds: 1907.1 31295.1
+ * 4 rounds: 2042.3 31718.6
+ * Perfect: 2048 31744
+ * (32*64) (32*31/2 * 64)
+ */
+#define HASH_MIX(x, y, a) \
+ ( x ^= (a), \
+ y ^= x, x = rol32(x, 7),\
+ x += y, y = rol32(y,20),\
+ y *= 9 )
+
+static inline unsigned int fold_hash(unsigned long x, unsigned long y)
+{
+ /* Use arch-optimized multiply if one exists */
+ return __hash_32(y ^ __hash_32(x));
+}
+
+/*
+ * Generate a hash. This is derived from full_name_hash(), but we want to be
+ * sure it is arch independent and that it doesn't change as bits of the
+ * computed hash value might appear on disk. The caller must guarantee that
+ * the source data is a multiple of four bytes in size.
+ */
+unsigned int fscache_hash(unsigned int salt, const void *data, size_t len)
+{
+ const __le32 *p = data;
+ unsigned int a, x = 0, y = salt, n = len / sizeof(__le32);
+
+ for (; n; n--) {
+ a = le32_to_cpu(*p++);
+ HASH_MIX(x, y, a);
+ }
+ return fold_hash(x, y);
+}
+
+/*
+ * initialise the fs caching module
+ */
+int __init fscache_init(void)
+{
+ int ret = -ENOMEM;
+
+ fscache_wq = alloc_workqueue("fscache", WQ_UNBOUND | WQ_FREEZABLE, 0);
+ if (!fscache_wq)
+ goto error_wq;
+
+ ret = fscache_proc_init();
+ if (ret < 0)
+ goto error_proc;
+
+ fscache_cookie_jar = kmem_cache_create("fscache_cookie_jar",
+ sizeof(struct fscache_cookie),
+ 0, 0, NULL);
+ if (!fscache_cookie_jar) {
+ pr_notice("Failed to allocate a cookie jar\n");
+ ret = -ENOMEM;
+ goto error_cookie_jar;
+ }
+
+ pr_notice("FS-Cache loaded\n");
+ return 0;
+
+error_cookie_jar:
+ fscache_proc_cleanup();
+error_proc:
+ destroy_workqueue(fscache_wq);
+error_wq:
+ return ret;
+}
+
+/*
+ * clean up on module removal
+ */
+void __exit fscache_exit(void)
+{
+ _enter("");
+
+ kmem_cache_destroy(fscache_cookie_jar);
+ fscache_proc_cleanup();
+ destroy_workqueue(fscache_wq);
+ pr_notice("FS-Cache unloaded\n");
+}
diff --git a/fs/netfs/fscache_proc.c b/fs/netfs/fscache_proc.c
new file mode 100644
index 000000000000..874d951bc390
--- /dev/null
+++ b/fs/netfs/fscache_proc.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* FS-Cache statistics viewing interface
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define FSCACHE_DEBUG_LEVEL CACHE
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+/*
+ * Add files to /proc/fs/netfs/.
+ */
+int __init fscache_proc_init(void)
+{
+ if (!proc_symlink("fs/fscache", NULL, "netfs"))
+ goto error_sym;
+
+ if (!proc_create_seq("fs/netfs/caches", S_IFREG | 0444, NULL,
+ &fscache_caches_seq_ops))
+ goto error;
+
+ if (!proc_create_seq("fs/netfs/volumes", S_IFREG | 0444, NULL,
+ &fscache_volumes_seq_ops))
+ goto error;
+
+ if (!proc_create_seq("fs/netfs/cookies", S_IFREG | 0444, NULL,
+ &fscache_cookies_seq_ops))
+ goto error;
+ return 0;
+
+error:
+ remove_proc_entry("fs/fscache", NULL);
+error_sym:
+ return -ENOMEM;
+}
+
+/*
+ * Clean up the /proc/fs/fscache symlink.
+ */
+void fscache_proc_cleanup(void)
+{
+ remove_proc_subtree("fs/fscache", NULL);
+}
diff --git a/fs/netfs/fscache_stats.c b/fs/netfs/fscache_stats.c
new file mode 100644
index 000000000000..add21abdf713
--- /dev/null
+++ b/fs/netfs/fscache_stats.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* FS-Cache statistics
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define FSCACHE_DEBUG_LEVEL CACHE
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+/*
+ * operation counters
+ */
+atomic_t fscache_n_volumes;
+atomic_t fscache_n_volumes_collision;
+atomic_t fscache_n_volumes_nomem;
+atomic_t fscache_n_cookies;
+atomic_t fscache_n_cookies_lru;
+atomic_t fscache_n_cookies_lru_expired;
+atomic_t fscache_n_cookies_lru_removed;
+atomic_t fscache_n_cookies_lru_dropped;
+
+atomic_t fscache_n_acquires;
+atomic_t fscache_n_acquires_ok;
+atomic_t fscache_n_acquires_oom;
+
+atomic_t fscache_n_invalidates;
+
+atomic_t fscache_n_updates;
+EXPORT_SYMBOL(fscache_n_updates);
+
+atomic_t fscache_n_relinquishes;
+atomic_t fscache_n_relinquishes_retire;
+atomic_t fscache_n_relinquishes_dropped;
+
+atomic_t fscache_n_resizes;
+atomic_t fscache_n_resizes_null;
+
+atomic_t fscache_n_read;
+EXPORT_SYMBOL(fscache_n_read);
+atomic_t fscache_n_write;
+EXPORT_SYMBOL(fscache_n_write);
+atomic_t fscache_n_no_write_space;
+EXPORT_SYMBOL(fscache_n_no_write_space);
+atomic_t fscache_n_no_create_space;
+EXPORT_SYMBOL(fscache_n_no_create_space);
+atomic_t fscache_n_culled;
+EXPORT_SYMBOL(fscache_n_culled);
+atomic_t fscache_n_dio_misfit;
+EXPORT_SYMBOL(fscache_n_dio_misfit);
+
+/*
+ * display the general statistics
+ */
+int fscache_stats_show(struct seq_file *m)
+{
+ seq_puts(m, "-- FS-Cache statistics --\n");
+ seq_printf(m, "Cookies: n=%d v=%d vcol=%u voom=%u\n",
+ atomic_read(&fscache_n_cookies),
+ atomic_read(&fscache_n_volumes),
+ atomic_read(&fscache_n_volumes_collision),
+ atomic_read(&fscache_n_volumes_nomem)
+ );
+
+ seq_printf(m, "Acquire: n=%u ok=%u oom=%u\n",
+ atomic_read(&fscache_n_acquires),
+ atomic_read(&fscache_n_acquires_ok),
+ atomic_read(&fscache_n_acquires_oom));
+
+ seq_printf(m, "LRU : n=%u exp=%u rmv=%u drp=%u at=%ld\n",
+ atomic_read(&fscache_n_cookies_lru),
+ atomic_read(&fscache_n_cookies_lru_expired),
+ atomic_read(&fscache_n_cookies_lru_removed),
+ atomic_read(&fscache_n_cookies_lru_dropped),
+ timer_pending(&fscache_cookie_lru_timer) ?
+ fscache_cookie_lru_timer.expires - jiffies : 0);
+
+ seq_printf(m, "Invals : n=%u\n",
+ atomic_read(&fscache_n_invalidates));
+
+ seq_printf(m, "Updates: n=%u rsz=%u rsn=%u\n",
+ atomic_read(&fscache_n_updates),
+ atomic_read(&fscache_n_resizes),
+ atomic_read(&fscache_n_resizes_null));
+
+ seq_printf(m, "Relinqs: n=%u rtr=%u drop=%u\n",
+ atomic_read(&fscache_n_relinquishes),
+ atomic_read(&fscache_n_relinquishes_retire),
+ atomic_read(&fscache_n_relinquishes_dropped));
+
+ seq_printf(m, "NoSpace: nwr=%u ncr=%u cull=%u\n",
+ atomic_read(&fscache_n_no_write_space),
+ atomic_read(&fscache_n_no_create_space),
+ atomic_read(&fscache_n_culled));
+
+ seq_printf(m, "IO : rd=%u wr=%u mis=%u\n",
+ atomic_read(&fscache_n_read),
+ atomic_read(&fscache_n_write),
+ atomic_read(&fscache_n_dio_misfit));
+ return 0;
+}
diff --git a/fs/netfs/fscache_volume.c b/fs/netfs/fscache_volume.c
new file mode 100644
index 000000000000..cdf991bdd9de
--- /dev/null
+++ b/fs/netfs/fscache_volume.c
@@ -0,0 +1,520 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Volume-level cache cookie handling.
+ *
+ * Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define FSCACHE_DEBUG_LEVEL COOKIE
+#include <linux/export.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+#define fscache_volume_hash_shift 10
+static struct hlist_bl_head fscache_volume_hash[1 << fscache_volume_hash_shift];
+static atomic_t fscache_volume_debug_id;
+static LIST_HEAD(fscache_volumes);
+
+static void fscache_create_volume_work(struct work_struct *work);
+
+struct fscache_volume *fscache_get_volume(struct fscache_volume *volume,
+ enum fscache_volume_trace where)
+{
+ int ref;
+
+ __refcount_inc(&volume->ref, &ref);
+ trace_fscache_volume(volume->debug_id, ref + 1, where);
+ return volume;
+}
+
+static void fscache_see_volume(struct fscache_volume *volume,
+ enum fscache_volume_trace where)
+{
+ int ref = refcount_read(&volume->ref);
+
+ trace_fscache_volume(volume->debug_id, ref, where);
+}
+
+/*
+ * Pin the cache behind a volume so that we can access it.
+ */
+static void __fscache_begin_volume_access(struct fscache_volume *volume,
+ struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ n_accesses = atomic_inc_return(&volume->n_accesses);
+ smp_mb__after_atomic();
+ trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0,
+ refcount_read(&volume->ref),
+ n_accesses, why);
+}
+
+/**
+ * fscache_begin_volume_access - Pin a cache so a volume can be accessed
+ * @volume: The volume cookie
+ * @cookie: A datafile cookie for a tracing reference (or NULL)
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Attempt to pin the cache to prevent it from going away whilst we're
+ * accessing a volume and returns true if successful. This works as follows:
+ *
+ * (1) If the cache tests as not live (state is not FSCACHE_CACHE_IS_ACTIVE),
+ * then we return false to indicate access was not permitted.
+ *
+ * (2) If the cache tests as live, then we increment the volume's n_accesses
+ * count and then recheck the cache liveness, ending the access if it
+ * ceased to be live.
+ *
+ * (3) When we end the access, we decrement the volume's n_accesses and wake
+ * up the any waiters if it reaches 0.
+ *
+ * (4) Whilst the cache is caching, the volume's n_accesses is kept
+ * artificially incremented to prevent wakeups from happening.
+ *
+ * (5) When the cache is taken offline, the state is changed to prevent new
+ * accesses, the volume's n_accesses is decremented and we wait for it to
+ * become 0.
+ *
+ * The datafile @cookie and the @why indicator are merely provided for tracing
+ * purposes.
+ */
+bool fscache_begin_volume_access(struct fscache_volume *volume,
+ struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ if (!fscache_cache_is_live(volume->cache))
+ return false;
+ __fscache_begin_volume_access(volume, cookie, why);
+ if (!fscache_cache_is_live(volume->cache)) {
+ fscache_end_volume_access(volume, cookie, fscache_access_unlive);
+ return false;
+ }
+ return true;
+}
+
+/**
+ * fscache_end_volume_access - Unpin a cache at the end of an access.
+ * @volume: The volume cookie
+ * @cookie: A datafile cookie for a tracing reference (or NULL)
+ * @why: An indication of the circumstances of the access for tracing
+ *
+ * Unpin a cache volume after we've accessed it. The datafile @cookie and the
+ * @why indicator are merely provided for tracing purposes.
+ */
+void fscache_end_volume_access(struct fscache_volume *volume,
+ struct fscache_cookie *cookie,
+ enum fscache_access_trace why)
+{
+ int n_accesses;
+
+ smp_mb__before_atomic();
+ n_accesses = atomic_dec_return(&volume->n_accesses);
+ trace_fscache_access_volume(volume->debug_id, cookie ? cookie->debug_id : 0,
+ refcount_read(&volume->ref),
+ n_accesses, why);
+ if (n_accesses == 0)
+ wake_up_var(&volume->n_accesses);
+}
+EXPORT_SYMBOL(fscache_end_volume_access);
+
+static bool fscache_volume_same(const struct fscache_volume *a,
+ const struct fscache_volume *b)
+{
+ size_t klen;
+
+ if (a->key_hash != b->key_hash ||
+ a->cache != b->cache ||
+ a->key[0] != b->key[0])
+ return false;
+
+ klen = round_up(a->key[0] + 1, sizeof(__le32));
+ return memcmp(a->key, b->key, klen) == 0;
+}
+
+static bool fscache_is_acquire_pending(struct fscache_volume *volume)
+{
+ return test_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &volume->flags);
+}
+
+static void fscache_wait_on_volume_collision(struct fscache_volume *candidate,
+ unsigned int collidee_debug_id)
+{
+ wait_on_bit_timeout(&candidate->flags, FSCACHE_VOLUME_ACQUIRE_PENDING,
+ TASK_UNINTERRUPTIBLE, 20 * HZ);
+ if (fscache_is_acquire_pending(candidate)) {
+ pr_notice("Potential volume collision new=%08x old=%08x",
+ candidate->debug_id, collidee_debug_id);
+ fscache_stat(&fscache_n_volumes_collision);
+ wait_on_bit(&candidate->flags, FSCACHE_VOLUME_ACQUIRE_PENDING,
+ TASK_UNINTERRUPTIBLE);
+ }
+}
+
+/*
+ * Attempt to insert the new volume into the hash. If there's a collision, we
+ * wait for the old volume to complete if it's being relinquished and an error
+ * otherwise.
+ */
+static bool fscache_hash_volume(struct fscache_volume *candidate)
+{
+ struct fscache_volume *cursor;
+ struct hlist_bl_head *h;
+ struct hlist_bl_node *p;
+ unsigned int bucket, collidee_debug_id = 0;
+
+ bucket = candidate->key_hash & (ARRAY_SIZE(fscache_volume_hash) - 1);
+ h = &fscache_volume_hash[bucket];
+
+ hlist_bl_lock(h);
+ hlist_bl_for_each_entry(cursor, p, h, hash_link) {
+ if (fscache_volume_same(candidate, cursor)) {
+ if (!test_bit(FSCACHE_VOLUME_RELINQUISHED, &cursor->flags))
+ goto collision;
+ fscache_see_volume(cursor, fscache_volume_get_hash_collision);
+ set_bit(FSCACHE_VOLUME_COLLIDED_WITH, &cursor->flags);
+ set_bit(FSCACHE_VOLUME_ACQUIRE_PENDING, &candidate->flags);
+ collidee_debug_id = cursor->debug_id;
+ break;
+ }
+ }
+
+ hlist_bl_add_head(&candidate->hash_link, h);
+ hlist_bl_unlock(h);
+
+ if (fscache_is_acquire_pending(candidate))
+ fscache_wait_on_volume_collision(candidate, collidee_debug_id);
+ return true;
+
+collision:
+ fscache_see_volume(cursor, fscache_volume_collision);
+ hlist_bl_unlock(h);
+ return false;
+}
+
+/*
+ * Allocate and initialise a volume representation cookie.
+ */
+static struct fscache_volume *fscache_alloc_volume(const char *volume_key,
+ const char *cache_name,
+ const void *coherency_data,
+ size_t coherency_len)
+{
+ struct fscache_volume *volume;
+ struct fscache_cache *cache;
+ size_t klen, hlen;
+ u8 *key;
+
+ klen = strlen(volume_key);
+ if (klen > NAME_MAX)
+ return NULL;
+
+ if (!coherency_data)
+ coherency_len = 0;
+
+ cache = fscache_lookup_cache(cache_name, false);
+ if (IS_ERR(cache))
+ return NULL;
+
+ volume = kzalloc(struct_size(volume, coherency, coherency_len),
+ GFP_KERNEL);
+ if (!volume)
+ goto err_cache;
+
+ volume->cache = cache;
+ volume->coherency_len = coherency_len;
+ if (coherency_data)
+ memcpy(volume->coherency, coherency_data, coherency_len);
+ INIT_LIST_HEAD(&volume->proc_link);
+ INIT_WORK(&volume->work, fscache_create_volume_work);
+ refcount_set(&volume->ref, 1);
+ spin_lock_init(&volume->lock);
+
+ /* Stick the length on the front of the key and pad it out to make
+ * hashing easier.
+ */
+ hlen = round_up(1 + klen + 1, sizeof(__le32));
+ key = kzalloc(hlen, GFP_KERNEL);
+ if (!key)
+ goto err_vol;
+ key[0] = klen;
+ memcpy(key + 1, volume_key, klen);
+
+ volume->key = key;
+ volume->key_hash = fscache_hash(0, key, hlen);
+
+ volume->debug_id = atomic_inc_return(&fscache_volume_debug_id);
+ down_write(&fscache_addremove_sem);
+ atomic_inc(&cache->n_volumes);
+ list_add_tail(&volume->proc_link, &fscache_volumes);
+ fscache_see_volume(volume, fscache_volume_new_acquire);
+ fscache_stat(&fscache_n_volumes);
+ up_write(&fscache_addremove_sem);
+ _leave(" = v=%x", volume->debug_id);
+ return volume;
+
+err_vol:
+ kfree(volume);
+err_cache:
+ fscache_put_cache(cache, fscache_cache_put_alloc_volume);
+ fscache_stat(&fscache_n_volumes_nomem);
+ return NULL;
+}
+
+/*
+ * Create a volume's representation on disk. Have a volume ref and a cache
+ * access we have to release.
+ */
+static void fscache_create_volume_work(struct work_struct *work)
+{
+ const struct fscache_cache_ops *ops;
+ struct fscache_volume *volume =
+ container_of(work, struct fscache_volume, work);
+
+ fscache_see_volume(volume, fscache_volume_see_create_work);
+
+ ops = volume->cache->ops;
+ if (ops->acquire_volume)
+ ops->acquire_volume(volume);
+ fscache_end_cache_access(volume->cache,
+ fscache_access_acquire_volume_end);
+
+ clear_and_wake_up_bit(FSCACHE_VOLUME_CREATING, &volume->flags);
+ fscache_put_volume(volume, fscache_volume_put_create_work);
+}
+
+/*
+ * Dispatch a worker thread to create a volume's representation on disk.
+ */
+void fscache_create_volume(struct fscache_volume *volume, bool wait)
+{
+ if (test_and_set_bit(FSCACHE_VOLUME_CREATING, &volume->flags))
+ goto maybe_wait;
+ if (volume->cache_priv)
+ goto no_wait; /* We raced */
+ if (!fscache_begin_cache_access(volume->cache,
+ fscache_access_acquire_volume))
+ goto no_wait;
+
+ fscache_get_volume(volume, fscache_volume_get_create_work);
+ if (!schedule_work(&volume->work))
+ fscache_put_volume(volume, fscache_volume_put_create_work);
+
+maybe_wait:
+ if (wait) {
+ fscache_see_volume(volume, fscache_volume_wait_create_work);
+ wait_on_bit(&volume->flags, FSCACHE_VOLUME_CREATING,
+ TASK_UNINTERRUPTIBLE);
+ }
+ return;
+no_wait:
+ clear_bit_unlock(FSCACHE_VOLUME_CREATING, &volume->flags);
+ wake_up_bit(&volume->flags, FSCACHE_VOLUME_CREATING);
+}
+
+/*
+ * Acquire a volume representation cookie and link it to a (proposed) cache.
+ */
+struct fscache_volume *__fscache_acquire_volume(const char *volume_key,
+ const char *cache_name,
+ const void *coherency_data,
+ size_t coherency_len)
+{
+ struct fscache_volume *volume;
+
+ volume = fscache_alloc_volume(volume_key, cache_name,
+ coherency_data, coherency_len);
+ if (!volume)
+ return ERR_PTR(-ENOMEM);
+
+ if (!fscache_hash_volume(volume)) {
+ fscache_put_volume(volume, fscache_volume_put_hash_collision);
+ return ERR_PTR(-EBUSY);
+ }
+
+ fscache_create_volume(volume, false);
+ return volume;
+}
+EXPORT_SYMBOL(__fscache_acquire_volume);
+
+static void fscache_wake_pending_volume(struct fscache_volume *volume,
+ struct hlist_bl_head *h)
+{
+ struct fscache_volume *cursor;
+ struct hlist_bl_node *p;
+
+ hlist_bl_for_each_entry(cursor, p, h, hash_link) {
+ if (fscache_volume_same(cursor, volume)) {
+ fscache_see_volume(cursor, fscache_volume_see_hash_wake);
+ clear_and_wake_up_bit(FSCACHE_VOLUME_ACQUIRE_PENDING,
+ &cursor->flags);
+ return;
+ }
+ }
+}
+
+/*
+ * Remove a volume cookie from the hash table.
+ */
+static void fscache_unhash_volume(struct fscache_volume *volume)
+{
+ struct hlist_bl_head *h;
+ unsigned int bucket;
+
+ bucket = volume->key_hash & (ARRAY_SIZE(fscache_volume_hash) - 1);
+ h = &fscache_volume_hash[bucket];
+
+ hlist_bl_lock(h);
+ hlist_bl_del(&volume->hash_link);
+ if (test_bit(FSCACHE_VOLUME_COLLIDED_WITH, &volume->flags))
+ fscache_wake_pending_volume(volume, h);
+ hlist_bl_unlock(h);
+}
+
+/*
+ * Drop a cache's volume attachments.
+ */
+static void fscache_free_volume(struct fscache_volume *volume)
+{
+ struct fscache_cache *cache = volume->cache;
+
+ if (volume->cache_priv) {
+ __fscache_begin_volume_access(volume, NULL,
+ fscache_access_relinquish_volume);
+ if (volume->cache_priv)
+ cache->ops->free_volume(volume);
+ fscache_end_volume_access(volume, NULL,
+ fscache_access_relinquish_volume_end);
+ }
+
+ down_write(&fscache_addremove_sem);
+ list_del_init(&volume->proc_link);
+ atomic_dec(&volume->cache->n_volumes);
+ up_write(&fscache_addremove_sem);
+
+ if (!hlist_bl_unhashed(&volume->hash_link))
+ fscache_unhash_volume(volume);
+
+ trace_fscache_volume(volume->debug_id, 0, fscache_volume_free);
+ kfree(volume->key);
+ kfree(volume);
+ fscache_stat_d(&fscache_n_volumes);
+ fscache_put_cache(cache, fscache_cache_put_volume);
+}
+
+/*
+ * Drop a reference to a volume cookie.
+ */
+void fscache_put_volume(struct fscache_volume *volume,
+ enum fscache_volume_trace where)
+{
+ if (volume) {
+ unsigned int debug_id = volume->debug_id;
+ bool zero;
+ int ref;
+
+ zero = __refcount_dec_and_test(&volume->ref, &ref);
+ trace_fscache_volume(debug_id, ref - 1, where);
+ if (zero)
+ fscache_free_volume(volume);
+ }
+}
+
+/*
+ * Relinquish a volume representation cookie.
+ */
+void __fscache_relinquish_volume(struct fscache_volume *volume,
+ const void *coherency_data,
+ bool invalidate)
+{
+ if (WARN_ON(test_and_set_bit(FSCACHE_VOLUME_RELINQUISHED, &volume->flags)))
+ return;
+
+ if (invalidate) {
+ set_bit(FSCACHE_VOLUME_INVALIDATE, &volume->flags);
+ } else if (coherency_data) {
+ memcpy(volume->coherency, coherency_data, volume->coherency_len);
+ }
+
+ fscache_put_volume(volume, fscache_volume_put_relinquish);
+}
+EXPORT_SYMBOL(__fscache_relinquish_volume);
+
+/**
+ * fscache_withdraw_volume - Withdraw a volume from being cached
+ * @volume: Volume cookie
+ *
+ * Withdraw a cache volume from service, waiting for all accesses to complete
+ * before returning.
+ */
+void fscache_withdraw_volume(struct fscache_volume *volume)
+{
+ int n_accesses;
+
+ _debug("withdraw V=%x", volume->debug_id);
+
+ /* Allow wakeups on dec-to-0 */
+ n_accesses = atomic_dec_return(&volume->n_accesses);
+ trace_fscache_access_volume(volume->debug_id, 0,
+ refcount_read(&volume->ref),
+ n_accesses, fscache_access_cache_unpin);
+
+ wait_var_event(&volume->n_accesses,
+ atomic_read(&volume->n_accesses) == 0);
+}
+EXPORT_SYMBOL(fscache_withdraw_volume);
+
+#ifdef CONFIG_PROC_FS
+/*
+ * Generate a list of volumes in /proc/fs/fscache/volumes
+ */
+static int fscache_volumes_seq_show(struct seq_file *m, void *v)
+{
+ struct fscache_volume *volume;
+
+ if (v == &fscache_volumes) {
+ seq_puts(m,
+ "VOLUME REF nCOOK ACC FL CACHE KEY\n"
+ "======== ===== ===== === == =============== ================\n");
+ return 0;
+ }
+
+ volume = list_entry(v, struct fscache_volume, proc_link);
+ seq_printf(m,
+ "%08x %5d %5d %3d %02lx %-15.15s %s\n",
+ volume->debug_id,
+ refcount_read(&volume->ref),
+ atomic_read(&volume->n_cookies),
+ atomic_read(&volume->n_accesses),
+ volume->flags,
+ volume->cache->name ?: "-",
+ volume->key + 1);
+ return 0;
+}
+
+static void *fscache_volumes_seq_start(struct seq_file *m, loff_t *_pos)
+ __acquires(&fscache_addremove_sem)
+{
+ down_read(&fscache_addremove_sem);
+ return seq_list_start_head(&fscache_volumes, *_pos);
+}
+
+static void *fscache_volumes_seq_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+ return seq_list_next(v, &fscache_volumes, _pos);
+}
+
+static void fscache_volumes_seq_stop(struct seq_file *m, void *v)
+ __releases(&fscache_addremove_sem)
+{
+ up_read(&fscache_addremove_sem);
+}
+
+const struct seq_operations fscache_volumes_seq_ops = {
+ .start = fscache_volumes_seq_start,
+ .next = fscache_volumes_seq_next,
+ .stop = fscache_volumes_seq_stop,
+ .show = fscache_volumes_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
diff --git a/fs/netfs/internal.h b/fs/netfs/internal.h
index 43fac1b14e40..95e281a8af78 100644
--- a/fs/netfs/internal.h
+++ b/fs/netfs/internal.h
@@ -5,9 +5,13 @@
* Written by David Howells (dhowells@redhat.com)
*/
+#include <linux/slab.h>
+#include <linux/seq_file.h>
#include <linux/netfs.h>
#include <linux/fscache.h>
+#include <linux/fscache-cache.h>
#include <trace/events/netfs.h>
+#include <trace/events/fscache.h>
#ifdef pr_fmt
#undef pr_fmt
@@ -19,6 +23,8 @@
* buffered_read.c
*/
void netfs_rreq_unlock_folios(struct netfs_io_request *rreq);
+int netfs_prefetch_for_write(struct file *file, struct folio *folio,
+ size_t offset, size_t len);
/*
* io.c
@@ -29,6 +35,43 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync);
* main.c
*/
extern unsigned int netfs_debug;
+extern struct list_head netfs_io_requests;
+extern spinlock_t netfs_proc_lock;
+extern mempool_t netfs_request_pool;
+extern mempool_t netfs_subrequest_pool;
+
+#ifdef CONFIG_PROC_FS
+static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq)
+{
+ spin_lock(&netfs_proc_lock);
+ list_add_tail_rcu(&rreq->proc_link, &netfs_io_requests);
+ spin_unlock(&netfs_proc_lock);
+}
+static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq)
+{
+ if (!list_empty(&rreq->proc_link)) {
+ spin_lock(&netfs_proc_lock);
+ list_del_rcu(&rreq->proc_link);
+ spin_unlock(&netfs_proc_lock);
+ }
+}
+#else
+static inline void netfs_proc_add_rreq(struct netfs_io_request *rreq) {}
+static inline void netfs_proc_del_rreq(struct netfs_io_request *rreq) {}
+#endif
+
+/*
+ * misc.c
+ */
+#define NETFS_FLAG_PUT_MARK BIT(0)
+#define NETFS_FLAG_PAGECACHE_MARK BIT(1)
+int netfs_xa_store_and_mark(struct xarray *xa, unsigned long index,
+ struct folio *folio, unsigned int flags,
+ gfp_t gfp_mask);
+int netfs_add_folios_to_buffer(struct xarray *buffer,
+ struct address_space *mapping,
+ pgoff_t index, pgoff_t to, gfp_t gfp_mask);
+void netfs_clear_buffer(struct xarray *buffer);
/*
* objects.c
@@ -53,8 +96,9 @@ static inline void netfs_see_request(struct netfs_io_request *rreq,
* stats.c
*/
#ifdef CONFIG_NETFS_STATS
+extern atomic_t netfs_n_rh_dio_read;
extern atomic_t netfs_n_rh_readahead;
-extern atomic_t netfs_n_rh_readpage;
+extern atomic_t netfs_n_rh_read_folio;
extern atomic_t netfs_n_rh_rreq;
extern atomic_t netfs_n_rh_sreq;
extern atomic_t netfs_n_rh_download;
@@ -71,7 +115,19 @@ extern atomic_t netfs_n_rh_write_begin;
extern atomic_t netfs_n_rh_write_done;
extern atomic_t netfs_n_rh_write_failed;
extern atomic_t netfs_n_rh_write_zskip;
+extern atomic_t netfs_n_wh_buffered_write;
+extern atomic_t netfs_n_wh_writethrough;
+extern atomic_t netfs_n_wh_dio_write;
+extern atomic_t netfs_n_wh_writepages;
+extern atomic_t netfs_n_wh_wstream_conflict;
+extern atomic_t netfs_n_wh_upload;
+extern atomic_t netfs_n_wh_upload_done;
+extern atomic_t netfs_n_wh_upload_failed;
+extern atomic_t netfs_n_wh_write;
+extern atomic_t netfs_n_wh_write_done;
+extern atomic_t netfs_n_wh_write_failed;
+int netfs_stats_show(struct seq_file *m, void *v);
static inline void netfs_stat(atomic_t *stat)
{
@@ -89,6 +145,33 @@ static inline void netfs_stat_d(atomic_t *stat)
#endif
/*
+ * write_collect.c
+ */
+int netfs_folio_written_back(struct folio *folio);
+void netfs_write_collection_worker(struct work_struct *work);
+void netfs_wake_write_collector(struct netfs_io_request *wreq, bool was_async);
+
+/*
+ * write_issue.c
+ */
+struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
+ struct file *file,
+ loff_t start,
+ enum netfs_io_origin origin);
+void netfs_reissue_write(struct netfs_io_stream *stream,
+ struct netfs_io_subrequest *subreq);
+int netfs_advance_write(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream,
+ loff_t start, size_t len, bool to_eof);
+struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len);
+int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
+ struct folio *folio, size_t copied, bool to_page_end,
+ struct folio **writethrough_cache);
+int netfs_end_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
+ struct folio *writethrough_cache);
+int netfs_unbuffered_write(struct netfs_io_request *wreq, bool may_wait, size_t len);
+
+/*
* Miscellaneous functions.
*/
static inline bool netfs_is_cache_enabled(struct netfs_inode *ctx)
@@ -103,6 +186,180 @@ static inline bool netfs_is_cache_enabled(struct netfs_inode *ctx)
#endif
}
+/*
+ * Get a ref on a netfs group attached to a dirty page (e.g. a ceph snap).
+ */
+static inline struct netfs_group *netfs_get_group(struct netfs_group *netfs_group)
+{
+ if (netfs_group && netfs_group != NETFS_FOLIO_COPY_TO_CACHE)
+ refcount_inc(&netfs_group->ref);
+ return netfs_group;
+}
+
+/*
+ * Dispose of a netfs group attached to a dirty page (e.g. a ceph snap).
+ */
+static inline void netfs_put_group(struct netfs_group *netfs_group)
+{
+ if (netfs_group &&
+ netfs_group != NETFS_FOLIO_COPY_TO_CACHE &&
+ refcount_dec_and_test(&netfs_group->ref))
+ netfs_group->free(netfs_group);
+}
+
+/*
+ * Dispose of a netfs group attached to a dirty page (e.g. a ceph snap).
+ */
+static inline void netfs_put_group_many(struct netfs_group *netfs_group, int nr)
+{
+ if (netfs_group &&
+ netfs_group != NETFS_FOLIO_COPY_TO_CACHE &&
+ refcount_sub_and_test(nr, &netfs_group->ref))
+ netfs_group->free(netfs_group);
+}
+
+/*
+ * fscache-cache.c
+ */
+#ifdef CONFIG_PROC_FS
+extern const struct seq_operations fscache_caches_seq_ops;
+#endif
+bool fscache_begin_cache_access(struct fscache_cache *cache, enum fscache_access_trace why);
+void fscache_end_cache_access(struct fscache_cache *cache, enum fscache_access_trace why);
+struct fscache_cache *fscache_lookup_cache(const char *name, bool is_cache);
+void fscache_put_cache(struct fscache_cache *cache, enum fscache_cache_trace where);
+
+static inline enum fscache_cache_state fscache_cache_state(const struct fscache_cache *cache)
+{
+ return smp_load_acquire(&cache->state);
+}
+
+static inline bool fscache_cache_is_live(const struct fscache_cache *cache)
+{
+ return fscache_cache_state(cache) == FSCACHE_CACHE_IS_ACTIVE;
+}
+
+static inline void fscache_set_cache_state(struct fscache_cache *cache,
+ enum fscache_cache_state new_state)
+{
+ smp_store_release(&cache->state, new_state);
+
+}
+
+static inline bool fscache_set_cache_state_maybe(struct fscache_cache *cache,
+ enum fscache_cache_state old_state,
+ enum fscache_cache_state new_state)
+{
+ return try_cmpxchg_release(&cache->state, &old_state, new_state);
+}
+
+/*
+ * fscache-cookie.c
+ */
+extern struct kmem_cache *fscache_cookie_jar;
+#ifdef CONFIG_PROC_FS
+extern const struct seq_operations fscache_cookies_seq_ops;
+#endif
+extern struct timer_list fscache_cookie_lru_timer;
+
+extern void fscache_print_cookie(struct fscache_cookie *cookie, char prefix);
+extern bool fscache_begin_cookie_access(struct fscache_cookie *cookie,
+ enum fscache_access_trace why);
+
+static inline void fscache_see_cookie(struct fscache_cookie *cookie,
+ enum fscache_cookie_trace where)
+{
+ trace_fscache_cookie(cookie->debug_id, refcount_read(&cookie->ref),
+ where);
+}
+
+/*
+ * fscache-main.c
+ */
+extern unsigned int fscache_hash(unsigned int salt, const void *data, size_t len);
+#ifdef CONFIG_FSCACHE
+int __init fscache_init(void);
+void __exit fscache_exit(void);
+#else
+static inline int fscache_init(void) { return 0; }
+static inline void fscache_exit(void) {}
+#endif
+
+/*
+ * fscache-proc.c
+ */
+#ifdef CONFIG_PROC_FS
+extern int __init fscache_proc_init(void);
+extern void fscache_proc_cleanup(void);
+#else
+#define fscache_proc_init() (0)
+#define fscache_proc_cleanup() do {} while (0)
+#endif
+
+/*
+ * fscache-stats.c
+ */
+#ifdef CONFIG_FSCACHE_STATS
+extern atomic_t fscache_n_volumes;
+extern atomic_t fscache_n_volumes_collision;
+extern atomic_t fscache_n_volumes_nomem;
+extern atomic_t fscache_n_cookies;
+extern atomic_t fscache_n_cookies_lru;
+extern atomic_t fscache_n_cookies_lru_expired;
+extern atomic_t fscache_n_cookies_lru_removed;
+extern atomic_t fscache_n_cookies_lru_dropped;
+
+extern atomic_t fscache_n_acquires;
+extern atomic_t fscache_n_acquires_ok;
+extern atomic_t fscache_n_acquires_oom;
+
+extern atomic_t fscache_n_invalidates;
+
+extern atomic_t fscache_n_relinquishes;
+extern atomic_t fscache_n_relinquishes_retire;
+extern atomic_t fscache_n_relinquishes_dropped;
+
+extern atomic_t fscache_n_resizes;
+extern atomic_t fscache_n_resizes_null;
+
+static inline void fscache_stat(atomic_t *stat)
+{
+ atomic_inc(stat);
+}
+
+static inline void fscache_stat_d(atomic_t *stat)
+{
+ atomic_dec(stat);
+}
+
+#define __fscache_stat(stat) (stat)
+
+int fscache_stats_show(struct seq_file *m);
+#else
+
+#define __fscache_stat(stat) (NULL)
+#define fscache_stat(stat) do {} while (0)
+#define fscache_stat_d(stat) do {} while (0)
+
+static inline int fscache_stats_show(struct seq_file *m) { return 0; }
+#endif
+
+/*
+ * fscache-volume.c
+ */
+#ifdef CONFIG_PROC_FS
+extern const struct seq_operations fscache_volumes_seq_ops;
+#endif
+
+struct fscache_volume *fscache_get_volume(struct fscache_volume *volume,
+ enum fscache_volume_trace where);
+void fscache_put_volume(struct fscache_volume *volume,
+ enum fscache_volume_trace where);
+bool fscache_begin_volume_access(struct fscache_volume *volume,
+ struct fscache_cookie *cookie,
+ enum fscache_access_trace why);
+void fscache_create_volume(struct fscache_volume *volume, bool wait);
+
/*****************************************************************************/
/*
* debug tracing
@@ -143,3 +400,57 @@ do { \
#define _leave(FMT, ...) no_printk("<== %s()"FMT"", __func__, ##__VA_ARGS__)
#define _debug(FMT, ...) no_printk(FMT, ##__VA_ARGS__)
#endif
+
+/*
+ * assertions
+ */
+#if 1 /* defined(__KDEBUGALL) */
+
+#define ASSERT(X) \
+do { \
+ if (unlikely(!(X))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTCMP(X, OP, Y) \
+do { \
+ if (unlikely(!((X) OP (Y)))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ pr_err("%lx " #OP " %lx is false\n", \
+ (unsigned long)(X), (unsigned long)(Y)); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTIF(C, X) \
+do { \
+ if (unlikely((C) && !(X))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ BUG(); \
+ } \
+} while (0)
+
+#define ASSERTIFCMP(C, X, OP, Y) \
+do { \
+ if (unlikely((C) && !((X) OP (Y)))) { \
+ pr_err("\n"); \
+ pr_err("Assertion failed\n"); \
+ pr_err("%lx " #OP " %lx is false\n", \
+ (unsigned long)(X), (unsigned long)(Y)); \
+ BUG(); \
+ } \
+} while (0)
+
+#else
+
+#define ASSERT(X) do {} while (0)
+#define ASSERTCMP(X, OP, Y) do {} while (0)
+#define ASSERTIF(C, X) do {} while (0)
+#define ASSERTIFCMP(C, X, OP, Y) do {} while (0)
+
+#endif /* assert or not */
diff --git a/fs/netfs/io.c b/fs/netfs/io.c
index 7f753380e047..c93851b98368 100644
--- a/fs/netfs/io.c
+++ b/fs/netfs/io.c
@@ -21,12 +21,7 @@
*/
static void netfs_clear_unread(struct netfs_io_subrequest *subreq)
{
- struct iov_iter iter;
-
- iov_iter_xarray(&iter, ITER_DEST, &subreq->rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
- iov_iter_zero(iov_iter_count(&iter), &iter);
+ iov_iter_zero(iov_iter_count(&subreq->io_iter), &subreq->io_iter);
}
static void netfs_cache_read_terminated(void *priv, ssize_t transferred_or_error,
@@ -46,14 +41,9 @@ static void netfs_read_from_cache(struct netfs_io_request *rreq,
enum netfs_read_from_hole read_hole)
{
struct netfs_cache_resources *cres = &rreq->cache_resources;
- struct iov_iter iter;
netfs_stat(&netfs_n_rh_read);
- iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages,
- subreq->start + subreq->transferred,
- subreq->len - subreq->transferred);
-
- cres->ops->read(cres, subreq->start, &iter, read_hole,
+ cres->ops->read(cres, subreq->start, &subreq->io_iter, read_hole,
netfs_cache_read_terminated, subreq);
}
@@ -88,6 +78,13 @@ static void netfs_read_from_server(struct netfs_io_request *rreq,
struct netfs_io_subrequest *subreq)
{
netfs_stat(&netfs_n_rh_download);
+
+ if (rreq->origin != NETFS_DIO_READ &&
+ iov_iter_count(&subreq->io_iter) != subreq->len - subreq->transferred)
+ pr_warn("R=%08x[%u] ITER PRE-MISMATCH %zx != %zx-%zx %lx\n",
+ rreq->debug_id, subreq->debug_index,
+ iov_iter_count(&subreq->io_iter), subreq->len,
+ subreq->transferred, subreq->flags);
rreq->netfs_ops->issue_read(subreq);
}
@@ -102,144 +99,6 @@ static void netfs_rreq_completed(struct netfs_io_request *rreq, bool was_async)
}
/*
- * Deal with the completion of writing the data to the cache. We have to clear
- * the PG_fscache bits on the folios involved and release the caller's ref.
- *
- * May be called in softirq mode and we inherit a ref from the caller.
- */
-static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq,
- bool was_async)
-{
- struct netfs_io_subrequest *subreq;
- struct folio *folio;
- pgoff_t unlocked = 0;
- bool have_unlocked = false;
-
- rcu_read_lock();
-
- list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
- XA_STATE(xas, &rreq->mapping->i_pages, subreq->start / PAGE_SIZE);
-
- xas_for_each(&xas, folio, (subreq->start + subreq->len - 1) / PAGE_SIZE) {
- if (xas_retry(&xas, folio))
- continue;
-
- /* We might have multiple writes from the same huge
- * folio, but we mustn't unlock a folio more than once.
- */
- if (have_unlocked && folio_index(folio) <= unlocked)
- continue;
- unlocked = folio_index(folio);
- folio_end_fscache(folio);
- have_unlocked = true;
- }
- }
-
- rcu_read_unlock();
- netfs_rreq_completed(rreq, was_async);
-}
-
-static void netfs_rreq_copy_terminated(void *priv, ssize_t transferred_or_error,
- bool was_async)
-{
- struct netfs_io_subrequest *subreq = priv;
- struct netfs_io_request *rreq = subreq->rreq;
-
- if (IS_ERR_VALUE(transferred_or_error)) {
- netfs_stat(&netfs_n_rh_write_failed);
- trace_netfs_failure(rreq, subreq, transferred_or_error,
- netfs_fail_copy_to_cache);
- } else {
- netfs_stat(&netfs_n_rh_write_done);
- }
-
- trace_netfs_sreq(subreq, netfs_sreq_trace_write_term);
-
- /* If we decrement nr_copy_ops to 0, the ref belongs to us. */
- if (atomic_dec_and_test(&rreq->nr_copy_ops))
- netfs_rreq_unmark_after_write(rreq, was_async);
-
- netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
-}
-
-/*
- * Perform any outstanding writes to the cache. We inherit a ref from the
- * caller.
- */
-static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq)
-{
- struct netfs_cache_resources *cres = &rreq->cache_resources;
- struct netfs_io_subrequest *subreq, *next, *p;
- struct iov_iter iter;
- int ret;
-
- trace_netfs_rreq(rreq, netfs_rreq_trace_copy);
-
- /* We don't want terminating writes trying to wake us up whilst we're
- * still going through the list.
- */
- atomic_inc(&rreq->nr_copy_ops);
-
- list_for_each_entry_safe(subreq, p, &rreq->subrequests, rreq_link) {
- if (!test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) {
- list_del_init(&subreq->rreq_link);
- netfs_put_subrequest(subreq, false,
- netfs_sreq_trace_put_no_copy);
- }
- }
-
- list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
- /* Amalgamate adjacent writes */
- while (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) {
- next = list_next_entry(subreq, rreq_link);
- if (next->start != subreq->start + subreq->len)
- break;
- subreq->len += next->len;
- list_del_init(&next->rreq_link);
- netfs_put_subrequest(next, false,
- netfs_sreq_trace_put_merged);
- }
-
- ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len,
- rreq->i_size, true);
- if (ret < 0) {
- trace_netfs_failure(rreq, subreq, ret, netfs_fail_prepare_write);
- trace_netfs_sreq(subreq, netfs_sreq_trace_write_skip);
- continue;
- }
-
- iov_iter_xarray(&iter, ITER_SOURCE, &rreq->mapping->i_pages,
- subreq->start, subreq->len);
-
- atomic_inc(&rreq->nr_copy_ops);
- netfs_stat(&netfs_n_rh_write);
- netfs_get_subrequest(subreq, netfs_sreq_trace_get_copy_to_cache);
- trace_netfs_sreq(subreq, netfs_sreq_trace_write);
- cres->ops->write(cres, subreq->start, &iter,
- netfs_rreq_copy_terminated, subreq);
- }
-
- /* If we decrement nr_copy_ops to 0, the usage ref belongs to us. */
- if (atomic_dec_and_test(&rreq->nr_copy_ops))
- netfs_rreq_unmark_after_write(rreq, false);
-}
-
-static void netfs_rreq_write_to_cache_work(struct work_struct *work)
-{
- struct netfs_io_request *rreq =
- container_of(work, struct netfs_io_request, work);
-
- netfs_rreq_do_write_to_cache(rreq);
-}
-
-static void netfs_rreq_write_to_cache(struct netfs_io_request *rreq)
-{
- rreq->work.func = netfs_rreq_write_to_cache_work;
- if (!queue_work(system_unbound_wq, &rreq->work))
- BUG();
-}
-
-/*
* Handle a short read.
*/
static void netfs_rreq_short_read(struct netfs_io_request *rreq,
@@ -260,6 +119,30 @@ static void netfs_rreq_short_read(struct netfs_io_request *rreq,
}
/*
+ * Reset the subrequest iterator prior to resubmission.
+ */
+static void netfs_reset_subreq_iter(struct netfs_io_request *rreq,
+ struct netfs_io_subrequest *subreq)
+{
+ size_t remaining = subreq->len - subreq->transferred;
+ size_t count = iov_iter_count(&subreq->io_iter);
+
+ if (count == remaining)
+ return;
+
+ _debug("R=%08x[%u] ITER RESUB-MISMATCH %zx != %zx-%zx-%llx %x\n",
+ rreq->debug_id, subreq->debug_index,
+ iov_iter_count(&subreq->io_iter), subreq->transferred,
+ subreq->len, rreq->i_size,
+ subreq->io_iter.iter_type);
+
+ if (count < remaining)
+ iov_iter_revert(&subreq->io_iter, remaining - count);
+ else
+ iov_iter_advance(&subreq->io_iter, count - remaining);
+}
+
+/*
* Resubmit any short or failed operations. Returns true if we got the rreq
* ref back.
*/
@@ -287,6 +170,7 @@ static bool netfs_rreq_perform_resubmissions(struct netfs_io_request *rreq)
trace_netfs_sreq(subreq, netfs_sreq_trace_download_instead);
netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
atomic_inc(&rreq->nr_outstanding);
+ netfs_reset_subreq_iter(rreq, subreq);
netfs_read_from_server(rreq, subreq);
} else if (test_bit(NETFS_SREQ_SHORT_IO, &subreq->flags)) {
netfs_rreq_short_read(rreq, subreq);
@@ -321,6 +205,48 @@ static void netfs_rreq_is_still_valid(struct netfs_io_request *rreq)
}
/*
+ * Determine how much we can admit to having read from a DIO read.
+ */
+static void netfs_rreq_assess_dio(struct netfs_io_request *rreq)
+{
+ struct netfs_io_subrequest *subreq;
+ unsigned int i;
+ size_t transferred = 0;
+
+ for (i = 0; i < rreq->direct_bv_count; i++) {
+ flush_dcache_page(rreq->direct_bv[i].bv_page);
+ // TODO: cifs marks pages in the destination buffer
+ // dirty under some circumstances after a read. Do we
+ // need to do that too?
+ set_page_dirty(rreq->direct_bv[i].bv_page);
+ }
+
+ list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
+ if (subreq->error || subreq->transferred == 0)
+ break;
+ transferred += subreq->transferred;
+ if (subreq->transferred < subreq->len)
+ break;
+ }
+
+ for (i = 0; i < rreq->direct_bv_count; i++)
+ flush_dcache_page(rreq->direct_bv[i].bv_page);
+
+ rreq->transferred = transferred;
+ task_io_account_read(transferred);
+
+ if (rreq->iocb) {
+ rreq->iocb->ki_pos += transferred;
+ if (rreq->iocb->ki_complete)
+ rreq->iocb->ki_complete(
+ rreq->iocb, rreq->error ? rreq->error : transferred);
+ }
+ if (rreq->netfs_ops->done)
+ rreq->netfs_ops->done(rreq);
+ inode_dio_end(rreq->inode);
+}
+
+/*
* Assess the state of a read request and decide what to do next.
*
* Note that we could be in an ordinary kernel thread, on a workqueue or in
@@ -340,14 +266,15 @@ again:
return;
}
- netfs_rreq_unlock_folios(rreq);
+ if (rreq->origin != NETFS_DIO_READ)
+ netfs_rreq_unlock_folios(rreq);
+ else
+ netfs_rreq_assess_dio(rreq);
+ trace_netfs_rreq(rreq, netfs_rreq_trace_wake_ip);
clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);
- if (test_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags))
- return netfs_rreq_write_to_cache(rreq);
-
netfs_rreq_completed(rreq, was_async);
}
@@ -399,9 +326,9 @@ void netfs_subreq_terminated(struct netfs_io_subrequest *subreq,
struct netfs_io_request *rreq = subreq->rreq;
int u;
- _enter("[%u]{%llx,%lx},%zd",
- subreq->debug_index, subreq->start, subreq->flags,
- transferred_or_error);
+ _enter("R=%x[%x]{%llx,%lx},%zd",
+ rreq->debug_id, subreq->debug_index,
+ subreq->start, subreq->flags, transferred_or_error);
switch (subreq->source) {
case NETFS_READ_FROM_CACHE:
@@ -501,15 +428,20 @@ static enum netfs_io_source netfs_cache_prepare_read(struct netfs_io_subrequest
*/
static enum netfs_io_source
netfs_rreq_prepare_read(struct netfs_io_request *rreq,
- struct netfs_io_subrequest *subreq)
+ struct netfs_io_subrequest *subreq,
+ struct iov_iter *io_iter)
{
- enum netfs_io_source source;
+ enum netfs_io_source source = NETFS_DOWNLOAD_FROM_SERVER;
+ struct netfs_inode *ictx = netfs_inode(rreq->inode);
+ size_t lsize;
_enter("%llx-%llx,%llx", subreq->start, subreq->start + subreq->len, rreq->i_size);
- source = netfs_cache_prepare_read(subreq, rreq->i_size);
- if (source == NETFS_INVALID_READ)
- goto out;
+ if (rreq->origin != NETFS_DIO_READ) {
+ source = netfs_cache_prepare_read(subreq, rreq->i_size);
+ if (source == NETFS_INVALID_READ)
+ goto out;
+ }
if (source == NETFS_DOWNLOAD_FROM_SERVER) {
/* Call out to the netfs to let it shrink the request to fit
@@ -518,19 +450,52 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq,
* to make serial calls, it can indicate a short read and then
* we will call it again.
*/
+ if (rreq->origin != NETFS_DIO_READ) {
+ if (subreq->start >= ictx->zero_point) {
+ source = NETFS_FILL_WITH_ZEROES;
+ goto set;
+ }
+ if (subreq->len > ictx->zero_point - subreq->start)
+ subreq->len = ictx->zero_point - subreq->start;
+ }
if (subreq->len > rreq->i_size - subreq->start)
subreq->len = rreq->i_size - subreq->start;
+ if (rreq->rsize && subreq->len > rreq->rsize)
+ subreq->len = rreq->rsize;
if (rreq->netfs_ops->clamp_length &&
!rreq->netfs_ops->clamp_length(subreq)) {
source = NETFS_INVALID_READ;
goto out;
}
+
+ if (subreq->max_nr_segs) {
+ lsize = netfs_limit_iter(io_iter, 0, subreq->len,
+ subreq->max_nr_segs);
+ if (subreq->len > lsize) {
+ subreq->len = lsize;
+ trace_netfs_sreq(subreq, netfs_sreq_trace_limited);
+ }
+ }
}
- if (WARN_ON(subreq->len == 0))
+set:
+ if (subreq->len > rreq->len)
+ pr_warn("R=%08x[%u] SREQ>RREQ %zx > %llx\n",
+ rreq->debug_id, subreq->debug_index,
+ subreq->len, rreq->len);
+
+ if (WARN_ON(subreq->len == 0)) {
source = NETFS_INVALID_READ;
+ goto out;
+ }
+ subreq->source = source;
+ trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
+
+ subreq->io_iter = *io_iter;
+ iov_iter_truncate(&subreq->io_iter, subreq->len);
+ iov_iter_advance(io_iter, subreq->len);
out:
subreq->source = source;
trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
@@ -541,7 +506,7 @@ out:
* Slice off a piece of a read request and submit an I/O request for it.
*/
static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
- unsigned int *_debug_index)
+ struct iov_iter *io_iter)
{
struct netfs_io_subrequest *subreq;
enum netfs_io_source source;
@@ -550,11 +515,10 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
if (!subreq)
return false;
- subreq->debug_index = (*_debug_index)++;
subreq->start = rreq->start + rreq->submitted;
- subreq->len = rreq->len - rreq->submitted;
+ subreq->len = io_iter->count;
- _debug("slice %llx,%zx,%zx", subreq->start, subreq->len, rreq->submitted);
+ _debug("slice %llx,%zx,%llx", subreq->start, subreq->len, rreq->submitted);
list_add_tail(&subreq->rreq_link, &rreq->subrequests);
/* Call out to the cache to find out what it can do with the remaining
@@ -565,7 +529,7 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
* (the starts must coincide), in which case, we go around the loop
* again and ask it to download the next piece.
*/
- source = netfs_rreq_prepare_read(rreq, subreq);
+ source = netfs_rreq_prepare_read(rreq, subreq, io_iter);
if (source == NETFS_INVALID_READ)
goto subreq_failed;
@@ -603,7 +567,7 @@ subreq_failed:
*/
int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
{
- unsigned int debug_index = 0;
+ struct iov_iter io_iter;
int ret;
_enter("R=%x %llx-%llx",
@@ -611,50 +575,73 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
if (rreq->len == 0) {
pr_err("Zero-sized read [R=%x]\n", rreq->debug_id);
- netfs_put_request(rreq, false, netfs_rreq_trace_put_zero_len);
return -EIO;
}
- INIT_WORK(&rreq->work, netfs_rreq_work);
+ if (rreq->origin == NETFS_DIO_READ)
+ inode_dio_begin(rreq->inode);
- if (sync)
- netfs_get_request(rreq, netfs_rreq_trace_get_hold);
+ // TODO: Use bounce buffer if requested
+ rreq->io_iter = rreq->iter;
+
+ INIT_WORK(&rreq->work, netfs_rreq_work);
/* Chop the read into slices according to what the cache and the netfs
* want and submit each one.
*/
+ netfs_get_request(rreq, netfs_rreq_trace_get_for_outstanding);
atomic_set(&rreq->nr_outstanding, 1);
+ io_iter = rreq->io_iter;
do {
- if (!netfs_rreq_submit_slice(rreq, &debug_index))
+ _debug("submit %llx + %llx >= %llx",
+ rreq->start, rreq->submitted, rreq->i_size);
+ if (rreq->origin == NETFS_DIO_READ &&
+ rreq->start + rreq->submitted >= rreq->i_size)
+ break;
+ if (!netfs_rreq_submit_slice(rreq, &io_iter))
+ break;
+ if (test_bit(NETFS_RREQ_BLOCKED, &rreq->flags) &&
+ test_bit(NETFS_RREQ_NONBLOCK, &rreq->flags))
break;
} while (rreq->submitted < rreq->len);
+ if (!rreq->submitted) {
+ netfs_put_request(rreq, false, netfs_rreq_trace_put_no_submit);
+ if (rreq->origin == NETFS_DIO_READ)
+ inode_dio_end(rreq->inode);
+ ret = 0;
+ goto out;
+ }
+
if (sync) {
- /* Keep nr_outstanding incremented so that the ref always belongs to
- * us, and the service code isn't punted off to a random thread pool to
- * process.
+ /* Keep nr_outstanding incremented so that the ref always
+ * belongs to us, and the service code isn't punted off to a
+ * random thread pool to process. Note that this might start
+ * further work, such as writing to the cache.
*/
- for (;;) {
- wait_var_event(&rreq->nr_outstanding,
- atomic_read(&rreq->nr_outstanding) == 1);
+ wait_var_event(&rreq->nr_outstanding,
+ atomic_read(&rreq->nr_outstanding) == 1);
+ if (atomic_dec_and_test(&rreq->nr_outstanding))
netfs_rreq_assess(rreq, false);
- if (!test_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags))
- break;
- cond_resched();
- }
+
+ trace_netfs_rreq(rreq, netfs_rreq_trace_wait_ip);
+ wait_on_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE);
ret = rreq->error;
- if (ret == 0 && rreq->submitted < rreq->len) {
+ if (ret == 0 && rreq->submitted < rreq->len &&
+ rreq->origin != NETFS_DIO_READ) {
trace_netfs_failure(rreq, NULL, ret, netfs_fail_short_read);
ret = -EIO;
}
- netfs_put_request(rreq, false, netfs_rreq_trace_put_hold);
} else {
/* If we decrement nr_outstanding to 0, the ref belongs to us. */
if (atomic_dec_and_test(&rreq->nr_outstanding))
netfs_rreq_assess(rreq, false);
- ret = 0;
+ ret = -EIOCBQUEUED;
}
+
+out:
return ret;
}
diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 2ff07ba655a0..b781bbbf1d8d 100644
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -101,3 +101,100 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
return npages;
}
EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
+
+/*
+ * Select the span of a bvec iterator we're going to use. Limit it by both maximum
+ * size and maximum number of segments. Returns the size of the span in bytes.
+ */
+static size_t netfs_limit_bvec(const struct iov_iter *iter, size_t start_offset,
+ size_t max_size, size_t max_segs)
+{
+ const struct bio_vec *bvecs = iter->bvec;
+ unsigned int nbv = iter->nr_segs, ix = 0, nsegs = 0;
+ size_t len, span = 0, n = iter->count;
+ size_t skip = iter->iov_offset + start_offset;
+
+ if (WARN_ON(!iov_iter_is_bvec(iter)) ||
+ WARN_ON(start_offset > n) ||
+ n == 0)
+ return 0;
+
+ while (n && ix < nbv && skip) {
+ len = bvecs[ix].bv_len;
+ if (skip < len)
+ break;
+ skip -= len;
+ n -= len;
+ ix++;
+ }
+
+ while (n && ix < nbv) {
+ len = min3(n, bvecs[ix].bv_len - skip, max_size);
+ span += len;
+ nsegs++;
+ ix++;
+ if (span >= max_size || nsegs >= max_segs)
+ break;
+ skip = 0;
+ n -= len;
+ }
+
+ return min(span, max_size);
+}
+
+/*
+ * Select the span of an xarray iterator we're going to use. Limit it by both
+ * maximum size and maximum number of segments. It is assumed that segments
+ * can be larger than a page in size, provided they're physically contiguous.
+ * Returns the size of the span in bytes.
+ */
+static size_t netfs_limit_xarray(const struct iov_iter *iter, size_t start_offset,
+ size_t max_size, size_t max_segs)
+{
+ struct folio *folio;
+ unsigned int nsegs = 0;
+ loff_t pos = iter->xarray_start + iter->iov_offset;
+ pgoff_t index = pos / PAGE_SIZE;
+ size_t span = 0, n = iter->count;
+
+ XA_STATE(xas, iter->xarray, index);
+
+ if (WARN_ON(!iov_iter_is_xarray(iter)) ||
+ WARN_ON(start_offset > n) ||
+ n == 0)
+ return 0;
+ max_size = min(max_size, n - start_offset);
+
+ rcu_read_lock();
+ xas_for_each(&xas, folio, ULONG_MAX) {
+ size_t offset, flen, len;
+ if (xas_retry(&xas, folio))
+ continue;
+ if (WARN_ON(xa_is_value(folio)))
+ break;
+ if (WARN_ON(folio_test_hugetlb(folio)))
+ break;
+
+ flen = folio_size(folio);
+ offset = offset_in_folio(folio, pos);
+ len = min(max_size, flen - offset);
+ span += len;
+ nsegs++;
+ if (span >= max_size || nsegs >= max_segs)
+ break;
+ }
+
+ rcu_read_unlock();
+ return min(span, max_size);
+}
+
+size_t netfs_limit_iter(const struct iov_iter *iter, size_t start_offset,
+ size_t max_size, size_t max_segs)
+{
+ if (iov_iter_is_bvec(iter))
+ return netfs_limit_bvec(iter, start_offset, max_size, max_segs);
+ if (iov_iter_is_xarray(iter))
+ return netfs_limit_xarray(iter, start_offset, max_size, max_segs);
+ BUG();
+}
+EXPORT_SYMBOL(netfs_limit_iter);
diff --git a/fs/netfs/locking.c b/fs/netfs/locking.c
new file mode 100644
index 000000000000..75dc52a49b3a
--- /dev/null
+++ b/fs/netfs/locking.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * I/O and data path helper functionality.
+ *
+ * Borrowed from NFS Copyright (c) 2016 Trond Myklebust
+ */
+
+#include <linux/kernel.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+/*
+ * inode_dio_wait_interruptible - wait for outstanding DIO requests to finish
+ * @inode: inode to wait for
+ *
+ * Waits for all pending direct I/O requests to finish so that we can
+ * proceed with a truncate or equivalent operation.
+ *
+ * Must be called under a lock that serializes taking new references
+ * to i_dio_count, usually by inode->i_mutex.
+ */
+static int inode_dio_wait_interruptible(struct inode *inode)
+{
+ if (!atomic_read(&inode->i_dio_count))
+ return 0;
+
+ wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
+ DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
+
+ for (;;) {
+ prepare_to_wait(wq, &q.wq_entry, TASK_INTERRUPTIBLE);
+ if (!atomic_read(&inode->i_dio_count))
+ break;
+ if (signal_pending(current))
+ break;
+ schedule();
+ }
+ finish_wait(wq, &q.wq_entry);
+
+ return atomic_read(&inode->i_dio_count) ? -ERESTARTSYS : 0;
+}
+
+/* Call with exclusively locked inode->i_rwsem */
+static int netfs_block_o_direct(struct netfs_inode *ictx)
+{
+ if (!test_bit(NETFS_ICTX_ODIRECT, &ictx->flags))
+ return 0;
+ clear_bit(NETFS_ICTX_ODIRECT, &ictx->flags);
+ return inode_dio_wait_interruptible(&ictx->inode);
+}
+
+/**
+ * netfs_start_io_read - declare the file is being used for buffered reads
+ * @inode: file inode
+ *
+ * Declare that a buffered read operation is about to start, and ensure
+ * that we block all direct I/O.
+ * On exit, the function ensures that the NETFS_ICTX_ODIRECT flag is unset,
+ * and holds a shared lock on inode->i_rwsem to ensure that the flag
+ * cannot be changed.
+ * In practice, this means that buffered read operations are allowed to
+ * execute in parallel, thanks to the shared lock, whereas direct I/O
+ * operations need to wait to grab an exclusive lock in order to set
+ * NETFS_ICTX_ODIRECT.
+ * Note that buffered writes and truncates both take a write lock on
+ * inode->i_rwsem, meaning that those are serialised w.r.t. the reads.
+ */
+int netfs_start_io_read(struct inode *inode)
+ __acquires(inode->i_rwsem)
+{
+ struct netfs_inode *ictx = netfs_inode(inode);
+
+ /* Be an optimist! */
+ if (down_read_interruptible(&inode->i_rwsem) < 0)
+ return -ERESTARTSYS;
+ if (test_bit(NETFS_ICTX_ODIRECT, &ictx->flags) == 0)
+ return 0;
+ up_read(&inode->i_rwsem);
+
+ /* Slow path.... */
+ if (down_write_killable(&inode->i_rwsem) < 0)
+ return -ERESTARTSYS;
+ if (netfs_block_o_direct(ictx) < 0) {
+ up_write(&inode->i_rwsem);
+ return -ERESTARTSYS;
+ }
+ downgrade_write(&inode->i_rwsem);
+ return 0;
+}
+EXPORT_SYMBOL(netfs_start_io_read);
+
+/**
+ * netfs_end_io_read - declare that the buffered read operation is done
+ * @inode: file inode
+ *
+ * Declare that a buffered read operation is done, and release the shared
+ * lock on inode->i_rwsem.
+ */
+void netfs_end_io_read(struct inode *inode)
+ __releases(inode->i_rwsem)
+{
+ up_read(&inode->i_rwsem);
+}
+EXPORT_SYMBOL(netfs_end_io_read);
+
+/**
+ * netfs_start_io_write - declare the file is being used for buffered writes
+ * @inode: file inode
+ *
+ * Declare that a buffered read operation is about to start, and ensure
+ * that we block all direct I/O.
+ */
+int netfs_start_io_write(struct inode *inode)
+ __acquires(inode->i_rwsem)
+{
+ struct netfs_inode *ictx = netfs_inode(inode);
+
+ if (down_write_killable(&inode->i_rwsem) < 0)
+ return -ERESTARTSYS;
+ if (netfs_block_o_direct(ictx) < 0) {
+ up_write(&inode->i_rwsem);
+ return -ERESTARTSYS;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(netfs_start_io_write);
+
+/**
+ * netfs_end_io_write - declare that the buffered write operation is done
+ * @inode: file inode
+ *
+ * Declare that a buffered write operation is done, and release the
+ * lock on inode->i_rwsem.
+ */
+void netfs_end_io_write(struct inode *inode)
+ __releases(inode->i_rwsem)
+{
+ up_write(&inode->i_rwsem);
+}
+EXPORT_SYMBOL(netfs_end_io_write);
+
+/* Call with exclusively locked inode->i_rwsem */
+static int netfs_block_buffered(struct inode *inode)
+{
+ struct netfs_inode *ictx = netfs_inode(inode);
+ int ret;
+
+ if (!test_bit(NETFS_ICTX_ODIRECT, &ictx->flags)) {
+ set_bit(NETFS_ICTX_ODIRECT, &ictx->flags);
+ if (inode->i_mapping->nrpages != 0) {
+ unmap_mapping_range(inode->i_mapping, 0, 0, 0);
+ ret = filemap_fdatawait(inode->i_mapping);
+ if (ret < 0) {
+ clear_bit(NETFS_ICTX_ODIRECT, &ictx->flags);
+ return ret;
+ }
+ }
+ }
+ return 0;
+}
+
+/**
+ * netfs_start_io_direct - declare the file is being used for direct i/o
+ * @inode: file inode
+ *
+ * Declare that a direct I/O operation is about to start, and ensure
+ * that we block all buffered I/O.
+ * On exit, the function ensures that the NETFS_ICTX_ODIRECT flag is set,
+ * and holds a shared lock on inode->i_rwsem to ensure that the flag
+ * cannot be changed.
+ * In practice, this means that direct I/O operations are allowed to
+ * execute in parallel, thanks to the shared lock, whereas buffered I/O
+ * operations need to wait to grab an exclusive lock in order to clear
+ * NETFS_ICTX_ODIRECT.
+ * Note that buffered writes and truncates both take a write lock on
+ * inode->i_rwsem, meaning that those are serialised w.r.t. O_DIRECT.
+ */
+int netfs_start_io_direct(struct inode *inode)
+ __acquires(inode->i_rwsem)
+{
+ struct netfs_inode *ictx = netfs_inode(inode);
+ int ret;
+
+ /* Be an optimist! */
+ if (down_read_interruptible(&inode->i_rwsem) < 0)
+ return -ERESTARTSYS;
+ if (test_bit(NETFS_ICTX_ODIRECT, &ictx->flags) != 0)
+ return 0;
+ up_read(&inode->i_rwsem);
+
+ /* Slow path.... */
+ if (down_write_killable(&inode->i_rwsem) < 0)
+ return -ERESTARTSYS;
+ ret = netfs_block_buffered(inode);
+ if (ret < 0) {
+ up_write(&inode->i_rwsem);
+ return ret;
+ }
+ downgrade_write(&inode->i_rwsem);
+ return 0;
+}
+EXPORT_SYMBOL(netfs_start_io_direct);
+
+/**
+ * netfs_end_io_direct - declare that the direct i/o operation is done
+ * @inode: file inode
+ *
+ * Declare that a direct I/O operation is done, and release the shared
+ * lock on inode->i_rwsem.
+ */
+void netfs_end_io_direct(struct inode *inode)
+ __releases(inode->i_rwsem)
+{
+ up_read(&inode->i_rwsem);
+}
+EXPORT_SYMBOL(netfs_end_io_direct);
diff --git a/fs/netfs/main.c b/fs/netfs/main.c
index 068568702957..5f0f438e5d21 100644
--- a/fs/netfs/main.c
+++ b/fs/netfs/main.c
@@ -7,6 +7,9 @@
#include <linux/module.h>
#include <linux/export.h>
+#include <linux/mempool.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/netfs.h>
@@ -15,6 +18,151 @@ MODULE_DESCRIPTION("Network fs support");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
+EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
+
unsigned netfs_debug;
module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
+
+static struct kmem_cache *netfs_request_slab;
+static struct kmem_cache *netfs_subrequest_slab;
+mempool_t netfs_request_pool;
+mempool_t netfs_subrequest_pool;
+
+#ifdef CONFIG_PROC_FS
+LIST_HEAD(netfs_io_requests);
+DEFINE_SPINLOCK(netfs_proc_lock);
+
+static const char *netfs_origins[nr__netfs_io_origin] = {
+ [NETFS_READAHEAD] = "RA",
+ [NETFS_READPAGE] = "RP",
+ [NETFS_READ_FOR_WRITE] = "RW",
+ [NETFS_COPY_TO_CACHE] = "CC",
+ [NETFS_WRITEBACK] = "WB",
+ [NETFS_WRITETHROUGH] = "WT",
+ [NETFS_UNBUFFERED_WRITE] = "UW",
+ [NETFS_DIO_READ] = "DR",
+ [NETFS_DIO_WRITE] = "DW",
+};
+
+/*
+ * Generate a list of I/O requests in /proc/fs/netfs/requests
+ */
+static int netfs_requests_seq_show(struct seq_file *m, void *v)
+{
+ struct netfs_io_request *rreq;
+
+ if (v == &netfs_io_requests) {
+ seq_puts(m,
+ "REQUEST OR REF FL ERR OPS COVERAGE\n"
+ "======== == === == ==== === =========\n"
+ );
+ return 0;
+ }
+
+ rreq = list_entry(v, struct netfs_io_request, proc_link);
+ seq_printf(m,
+ "%08x %s %3d %2lx %4d %3d @%04llx %llx/%llx",
+ rreq->debug_id,
+ netfs_origins[rreq->origin],
+ refcount_read(&rreq->ref),
+ rreq->flags,
+ rreq->error,
+ atomic_read(&rreq->nr_outstanding),
+ rreq->start, rreq->submitted, rreq->len);
+ seq_putc(m, '\n');
+ return 0;
+}
+
+static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
+ __acquires(rcu)
+{
+ rcu_read_lock();
+ return seq_list_start_head(&netfs_io_requests, *_pos);
+}
+
+static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
+{
+ return seq_list_next(v, &netfs_io_requests, _pos);
+}
+
+static void netfs_requests_seq_stop(struct seq_file *m, void *v)
+ __releases(rcu)
+{
+ rcu_read_unlock();
+}
+
+static const struct seq_operations netfs_requests_seq_ops = {
+ .start = netfs_requests_seq_start,
+ .next = netfs_requests_seq_next,
+ .stop = netfs_requests_seq_stop,
+ .show = netfs_requests_seq_show,
+};
+#endif /* CONFIG_PROC_FS */
+
+static int __init netfs_init(void)
+{
+ int ret = -ENOMEM;
+
+ netfs_request_slab = kmem_cache_create("netfs_request",
+ sizeof(struct netfs_io_request), 0,
+ SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
+ NULL);
+ if (!netfs_request_slab)
+ goto error_req;
+
+ if (mempool_init_slab_pool(&netfs_request_pool, 100, netfs_request_slab) < 0)
+ goto error_reqpool;
+
+ netfs_subrequest_slab = kmem_cache_create("netfs_subrequest",
+ sizeof(struct netfs_io_subrequest), 0,
+ SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
+ NULL);
+ if (!netfs_subrequest_slab)
+ goto error_subreq;
+
+ if (mempool_init_slab_pool(&netfs_subrequest_pool, 100, netfs_subrequest_slab) < 0)
+ goto error_subreqpool;
+
+ if (!proc_mkdir("fs/netfs", NULL))
+ goto error_proc;
+ if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
+ &netfs_requests_seq_ops))
+ goto error_procfile;
+#ifdef CONFIG_FSCACHE_STATS
+ if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
+ netfs_stats_show))
+ goto error_procfile;
+#endif
+
+ ret = fscache_init();
+ if (ret < 0)
+ goto error_fscache;
+ return 0;
+
+error_fscache:
+error_procfile:
+ remove_proc_entry("fs/netfs", NULL);
+error_proc:
+ mempool_exit(&netfs_subrequest_pool);
+error_subreqpool:
+ kmem_cache_destroy(netfs_subrequest_slab);
+error_subreq:
+ mempool_exit(&netfs_request_pool);
+error_reqpool:
+ kmem_cache_destroy(netfs_request_slab);
+error_req:
+ return ret;
+}
+fs_initcall(netfs_init);
+
+static void __exit netfs_exit(void)
+{
+ fscache_exit();
+ remove_proc_entry("fs/netfs", NULL);
+ mempool_exit(&netfs_subrequest_pool);
+ kmem_cache_destroy(netfs_subrequest_slab);
+ mempool_exit(&netfs_request_pool);
+ kmem_cache_destroy(netfs_request_slab);
+}
+module_exit(netfs_exit);
diff --git a/fs/netfs/misc.c b/fs/netfs/misc.c
new file mode 100644
index 000000000000..bc1fc54fb724
--- /dev/null
+++ b/fs/netfs/misc.c
@@ -0,0 +1,252 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Miscellaneous routines.
+ *
+ * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/swap.h>
+#include "internal.h"
+
+/*
+ * Attach a folio to the buffer and maybe set marks on it to say that we need
+ * to put the folio later and twiddle the pagecache flags.
+ */
+int netfs_xa_store_and_mark(struct xarray *xa, unsigned long index,
+ struct folio *folio, unsigned int flags,
+ gfp_t gfp_mask)
+{
+ XA_STATE_ORDER(xas, xa, index, folio_order(folio));
+
+retry:
+ xas_lock(&xas);
+ for (;;) {
+ xas_store(&xas, folio);
+ if (!xas_error(&xas))
+ break;
+ xas_unlock(&xas);
+ if (!xas_nomem(&xas, gfp_mask))
+ return xas_error(&xas);
+ goto retry;
+ }
+
+ if (flags & NETFS_FLAG_PUT_MARK)
+ xas_set_mark(&xas, NETFS_BUF_PUT_MARK);
+ if (flags & NETFS_FLAG_PAGECACHE_MARK)
+ xas_set_mark(&xas, NETFS_BUF_PAGECACHE_MARK);
+ xas_unlock(&xas);
+ return xas_error(&xas);
+}
+
+/*
+ * Create the specified range of folios in the buffer attached to the read
+ * request. The folios are marked with NETFS_BUF_PUT_MARK so that we know that
+ * these need freeing later.
+ */
+int netfs_add_folios_to_buffer(struct xarray *buffer,
+ struct address_space *mapping,
+ pgoff_t index, pgoff_t to, gfp_t gfp_mask)
+{
+ struct folio *folio;
+ int ret;
+
+ if (to + 1 == index) /* Page range is inclusive */
+ return 0;
+
+ do {
+ /* TODO: Figure out what order folio can be allocated here */
+ folio = filemap_alloc_folio(readahead_gfp_mask(mapping), 0);
+ if (!folio)
+ return -ENOMEM;
+ folio->index = index;
+ ret = netfs_xa_store_and_mark(buffer, index, folio,
+ NETFS_FLAG_PUT_MARK, gfp_mask);
+ if (ret < 0) {
+ folio_put(folio);
+ return ret;
+ }
+
+ index += folio_nr_pages(folio);
+ } while (index <= to && index != 0);
+
+ return 0;
+}
+
+/*
+ * Clear an xarray buffer, putting a ref on the folios that have
+ * NETFS_BUF_PUT_MARK set.
+ */
+void netfs_clear_buffer(struct xarray *buffer)
+{
+ struct folio *folio;
+ XA_STATE(xas, buffer, 0);
+
+ rcu_read_lock();
+ xas_for_each_marked(&xas, folio, ULONG_MAX, NETFS_BUF_PUT_MARK) {
+ folio_put(folio);
+ }
+ rcu_read_unlock();
+ xa_destroy(buffer);
+}
+
+/**
+ * netfs_dirty_folio - Mark folio dirty and pin a cache object for writeback
+ * @mapping: The mapping the folio belongs to.
+ * @folio: The folio being dirtied.
+ *
+ * Set the dirty flag on a folio and pin an in-use cache object in memory so
+ * that writeback can later write to it. This is intended to be called from
+ * the filesystem's ->dirty_folio() method.
+ *
+ * Return: true if the dirty flag was set on the folio, false otherwise.
+ */
+bool netfs_dirty_folio(struct address_space *mapping, struct folio *folio)
+{
+ struct inode *inode = mapping->host;
+ struct netfs_inode *ictx = netfs_inode(inode);
+ struct fscache_cookie *cookie = netfs_i_cookie(ictx);
+ bool need_use = false;
+
+ _enter("");
+
+ if (!filemap_dirty_folio(mapping, folio))
+ return false;
+ if (!fscache_cookie_valid(cookie))
+ return true;
+
+ if (!(inode->i_state & I_PINNING_NETFS_WB)) {
+ spin_lock(&inode->i_lock);
+ if (!(inode->i_state & I_PINNING_NETFS_WB)) {
+ inode->i_state |= I_PINNING_NETFS_WB;
+ need_use = true;
+ }
+ spin_unlock(&inode->i_lock);
+
+ if (need_use)
+ fscache_use_cookie(cookie, true);
+ }
+ return true;
+}
+EXPORT_SYMBOL(netfs_dirty_folio);
+
+/**
+ * netfs_unpin_writeback - Unpin writeback resources
+ * @inode: The inode on which the cookie resides
+ * @wbc: The writeback control
+ *
+ * Unpin the writeback resources pinned by netfs_dirty_folio(). This is
+ * intended to be called as/by the netfs's ->write_inode() method.
+ */
+int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc)
+{
+ struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
+
+ if (wbc->unpinned_netfs_wb)
+ fscache_unuse_cookie(cookie, NULL, NULL);
+ return 0;
+}
+EXPORT_SYMBOL(netfs_unpin_writeback);
+
+/**
+ * netfs_clear_inode_writeback - Clear writeback resources pinned by an inode
+ * @inode: The inode to clean up
+ * @aux: Auxiliary data to apply to the inode
+ *
+ * Clear any writeback resources held by an inode when the inode is evicted.
+ * This must be called before clear_inode() is called.
+ */
+void netfs_clear_inode_writeback(struct inode *inode, const void *aux)
+{
+ struct fscache_cookie *cookie = netfs_i_cookie(netfs_inode(inode));
+
+ if (inode->i_state & I_PINNING_NETFS_WB) {
+ loff_t i_size = i_size_read(inode);
+ fscache_unuse_cookie(cookie, aux, &i_size);
+ }
+}
+EXPORT_SYMBOL(netfs_clear_inode_writeback);
+
+/**
+ * netfs_invalidate_folio - Invalidate or partially invalidate a folio
+ * @folio: Folio proposed for release
+ * @offset: Offset of the invalidated region
+ * @length: Length of the invalidated region
+ *
+ * Invalidate part or all of a folio for a network filesystem. The folio will
+ * be removed afterwards if the invalidated region covers the entire folio.
+ */
+void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
+{
+ struct netfs_folio *finfo;
+ size_t flen = folio_size(folio);
+
+ _enter("{%lx},%zx,%zx", folio->index, offset, length);
+
+ if (!folio_test_private(folio))
+ return;
+
+ finfo = netfs_folio_info(folio);
+
+ if (offset == 0 && length >= flen)
+ goto erase_completely;
+
+ if (finfo) {
+ /* We have a partially uptodate page from a streaming write. */
+ unsigned int fstart = finfo->dirty_offset;
+ unsigned int fend = fstart + finfo->dirty_len;
+ unsigned int end = offset + length;
+
+ if (offset >= fend)
+ return;
+ if (end <= fstart)
+ return;
+ if (offset <= fstart && end >= fend)
+ goto erase_completely;
+ if (offset <= fstart && end > fstart)
+ goto reduce_len;
+ if (offset > fstart && end >= fend)
+ goto move_start;
+ /* A partial write was split. The caller has already zeroed
+ * it, so just absorb the hole.
+ */
+ }
+ return;
+
+erase_completely:
+ netfs_put_group(netfs_folio_group(folio));
+ folio_detach_private(folio);
+ folio_clear_uptodate(folio);
+ kfree(finfo);
+ return;
+reduce_len:
+ finfo->dirty_len = offset + length - finfo->dirty_offset;
+ return;
+move_start:
+ finfo->dirty_len -= offset - finfo->dirty_offset;
+ finfo->dirty_offset = offset;
+}
+EXPORT_SYMBOL(netfs_invalidate_folio);
+
+/**
+ * netfs_release_folio - Try to release a folio
+ * @folio: Folio proposed for release
+ * @gfp: Flags qualifying the release
+ *
+ * Request release of a folio and clean up its private state if it's not busy.
+ * Returns true if the folio can now be released, false if not
+ */
+bool netfs_release_folio(struct folio *folio, gfp_t gfp)
+{
+ struct netfs_inode *ctx = netfs_inode(folio_inode(folio));
+ unsigned long long end;
+
+ end = folio_pos(folio) + folio_size(folio);
+ if (end > ctx->zero_point)
+ ctx->zero_point = end;
+
+ if (folio_test_private(folio))
+ return false;
+ fscache_note_page_release(netfs_i_cookie(ctx));
+ return true;
+}
+EXPORT_SYMBOL(netfs_release_folio);
diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
index e17cdf53f6a7..c90d482b1650 100644
--- a/fs/netfs/objects.c
+++ b/fs/netfs/objects.c
@@ -6,6 +6,8 @@
*/
#include <linux/slab.h>
+#include <linux/mempool.h>
+#include <linux/delay.h>
#include "internal.h"
/*
@@ -20,31 +22,58 @@ struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
struct inode *inode = file ? file_inode(file) : mapping->host;
struct netfs_inode *ctx = netfs_inode(inode);
struct netfs_io_request *rreq;
+ mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
+ struct kmem_cache *cache = mempool->pool_data;
+ bool is_unbuffered = (origin == NETFS_UNBUFFERED_WRITE ||
+ origin == NETFS_DIO_READ ||
+ origin == NETFS_DIO_WRITE);
+ bool cached = !is_unbuffered && netfs_is_cache_enabled(ctx);
int ret;
- rreq = kzalloc(sizeof(struct netfs_io_request), GFP_KERNEL);
- if (!rreq)
- return ERR_PTR(-ENOMEM);
+ for (;;) {
+ rreq = mempool_alloc(mempool, GFP_KERNEL);
+ if (rreq)
+ break;
+ msleep(10);
+ }
+ memset(rreq, 0, kmem_cache_size(cache));
rreq->start = start;
rreq->len = len;
+ rreq->upper_len = len;
rreq->origin = origin;
rreq->netfs_ops = ctx->ops;
rreq->mapping = mapping;
rreq->inode = inode;
rreq->i_size = i_size_read(inode);
rreq->debug_id = atomic_inc_return(&debug_ids);
+ rreq->wsize = INT_MAX;
+ spin_lock_init(&rreq->lock);
+ INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
+ INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
INIT_LIST_HEAD(&rreq->subrequests);
+ INIT_WORK(&rreq->work, NULL);
refcount_set(&rreq->ref, 1);
+
__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
+ if (cached) {
+ __set_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags);
+ if (test_bit(NETFS_ICTX_USE_PGPRIV2, &ctx->flags))
+ /* Filesystem uses deprecated PG_private_2 marking. */
+ __set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
+ }
+ if (file && file->f_flags & O_NONBLOCK)
+ __set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
if (rreq->netfs_ops->init_request) {
ret = rreq->netfs_ops->init_request(rreq, file);
if (ret < 0) {
- kfree(rreq);
+ mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
return ERR_PTR(ret);
}
}
+ trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
+ netfs_proc_add_rreq(rreq);
netfs_stat(&netfs_n_rh_rreq);
return rreq;
}
@@ -60,6 +89,8 @@ void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace
void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
{
struct netfs_io_subrequest *subreq;
+ struct netfs_io_stream *stream;
+ int s;
while (!list_empty(&rreq->subrequests)) {
subreq = list_first_entry(&rreq->subrequests,
@@ -68,39 +99,71 @@ void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
netfs_put_subrequest(subreq, was_async,
netfs_sreq_trace_put_clear);
}
+
+ for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
+ stream = &rreq->io_streams[s];
+ while (!list_empty(&stream->subrequests)) {
+ subreq = list_first_entry(&stream->subrequests,
+ struct netfs_io_subrequest, rreq_link);
+ list_del(&subreq->rreq_link);
+ netfs_put_subrequest(subreq, was_async,
+ netfs_sreq_trace_put_clear);
+ }
+ }
+}
+
+static void netfs_free_request_rcu(struct rcu_head *rcu)
+{
+ struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
+
+ mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
+ netfs_stat_d(&netfs_n_rh_rreq);
}
static void netfs_free_request(struct work_struct *work)
{
struct netfs_io_request *rreq =
container_of(work, struct netfs_io_request, work);
+ unsigned int i;
trace_netfs_rreq(rreq, netfs_rreq_trace_free);
+ netfs_proc_del_rreq(rreq);
netfs_clear_subrequests(rreq, false);
if (rreq->netfs_ops->free_request)
rreq->netfs_ops->free_request(rreq);
if (rreq->cache_resources.ops)
rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
- kfree(rreq);
- netfs_stat_d(&netfs_n_rh_rreq);
+ if (rreq->direct_bv) {
+ for (i = 0; i < rreq->direct_bv_count; i++) {
+ if (rreq->direct_bv[i].bv_page) {
+ if (rreq->direct_bv_unpin)
+ unpin_user_page(rreq->direct_bv[i].bv_page);
+ }
+ }
+ kvfree(rreq->direct_bv);
+ }
+ call_rcu(&rreq->rcu, netfs_free_request_rcu);
}
void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
enum netfs_rreq_ref_trace what)
{
- unsigned int debug_id = rreq->debug_id;
+ unsigned int debug_id;
bool dead;
int r;
- dead = __refcount_dec_and_test(&rreq->ref, &r);
- trace_netfs_rreq_ref(debug_id, r - 1, what);
- if (dead) {
- if (was_async) {
- rreq->work.func = netfs_free_request;
- if (!queue_work(system_unbound_wq, &rreq->work))
- BUG();
- } else {
- netfs_free_request(&rreq->work);
+ if (rreq) {
+ debug_id = rreq->debug_id;
+ dead = __refcount_dec_and_test(&rreq->ref, &r);
+ trace_netfs_rreq_ref(debug_id, r - 1, what);
+ if (dead) {
+ if (was_async) {
+ rreq->work.func = netfs_free_request;
+ if (!queue_work(system_unbound_wq, &rreq->work))
+ BUG();
+ } else {
+ netfs_free_request(&rreq->work);
+ }
}
}
}
@@ -111,16 +174,25 @@ void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
{
struct netfs_io_subrequest *subreq;
-
- subreq = kzalloc(sizeof(struct netfs_io_subrequest), GFP_KERNEL);
- if (subreq) {
- INIT_LIST_HEAD(&subreq->rreq_link);
- refcount_set(&subreq->ref, 2);
- subreq->rreq = rreq;
- netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
- netfs_stat(&netfs_n_rh_sreq);
+ mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
+ struct kmem_cache *cache = mempool->pool_data;
+
+ for (;;) {
+ subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
+ GFP_KERNEL);
+ if (subreq)
+ break;
+ msleep(10);
}
+ memset(subreq, 0, kmem_cache_size(cache));
+ INIT_WORK(&subreq->work, NULL);
+ INIT_LIST_HEAD(&subreq->rreq_link);
+ refcount_set(&subreq->ref, 2);
+ subreq->rreq = rreq;
+ subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
+ netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
+ netfs_stat(&netfs_n_rh_sreq);
return subreq;
}
@@ -140,7 +212,9 @@ static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
struct netfs_io_request *rreq = subreq->rreq;
trace_netfs_sreq(subreq, netfs_sreq_trace_free);
- kfree(subreq);
+ if (rreq->netfs_ops->free_subrequest)
+ rreq->netfs_ops->free_subrequest(subreq);
+ mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
netfs_stat_d(&netfs_n_rh_sreq);
netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
}
diff --git a/fs/netfs/stats.c b/fs/netfs/stats.c
index 5510a7a14a40..0892768eea32 100644
--- a/fs/netfs/stats.c
+++ b/fs/netfs/stats.c
@@ -9,8 +9,9 @@
#include <linux/seq_file.h>
#include "internal.h"
+atomic_t netfs_n_rh_dio_read;
atomic_t netfs_n_rh_readahead;
-atomic_t netfs_n_rh_readpage;
+atomic_t netfs_n_rh_read_folio;
atomic_t netfs_n_rh_rreq;
atomic_t netfs_n_rh_sreq;
atomic_t netfs_n_rh_download;
@@ -27,32 +28,56 @@ atomic_t netfs_n_rh_write_begin;
atomic_t netfs_n_rh_write_done;
atomic_t netfs_n_rh_write_failed;
atomic_t netfs_n_rh_write_zskip;
+atomic_t netfs_n_wh_buffered_write;
+atomic_t netfs_n_wh_writethrough;
+atomic_t netfs_n_wh_dio_write;
+atomic_t netfs_n_wh_writepages;
+atomic_t netfs_n_wh_wstream_conflict;
+atomic_t netfs_n_wh_upload;
+atomic_t netfs_n_wh_upload_done;
+atomic_t netfs_n_wh_upload_failed;
+atomic_t netfs_n_wh_write;
+atomic_t netfs_n_wh_write_done;
+atomic_t netfs_n_wh_write_failed;
-void netfs_stats_show(struct seq_file *m)
+int netfs_stats_show(struct seq_file *m, void *v)
{
- seq_printf(m, "RdHelp : RA=%u RP=%u WB=%u WBZ=%u rr=%u sr=%u\n",
+ seq_printf(m, "Netfs : DR=%u RA=%u RF=%u WB=%u WBZ=%u\n",
+ atomic_read(&netfs_n_rh_dio_read),
atomic_read(&netfs_n_rh_readahead),
- atomic_read(&netfs_n_rh_readpage),
+ atomic_read(&netfs_n_rh_read_folio),
atomic_read(&netfs_n_rh_write_begin),
- atomic_read(&netfs_n_rh_write_zskip),
- atomic_read(&netfs_n_rh_rreq),
- atomic_read(&netfs_n_rh_sreq));
- seq_printf(m, "RdHelp : ZR=%u sh=%u sk=%u\n",
+ atomic_read(&netfs_n_rh_write_zskip));
+ seq_printf(m, "Netfs : BW=%u WT=%u DW=%u WP=%u\n",
+ atomic_read(&netfs_n_wh_buffered_write),
+ atomic_read(&netfs_n_wh_writethrough),
+ atomic_read(&netfs_n_wh_dio_write),
+ atomic_read(&netfs_n_wh_writepages));
+ seq_printf(m, "Netfs : ZR=%u sh=%u sk=%u\n",
atomic_read(&netfs_n_rh_zero),
atomic_read(&netfs_n_rh_short_read),
atomic_read(&netfs_n_rh_write_zskip));
- seq_printf(m, "RdHelp : DL=%u ds=%u df=%u di=%u\n",
+ seq_printf(m, "Netfs : DL=%u ds=%u df=%u di=%u\n",
atomic_read(&netfs_n_rh_download),
atomic_read(&netfs_n_rh_download_done),
atomic_read(&netfs_n_rh_download_failed),
atomic_read(&netfs_n_rh_download_instead));
- seq_printf(m, "RdHelp : RD=%u rs=%u rf=%u\n",
+ seq_printf(m, "Netfs : RD=%u rs=%u rf=%u\n",
atomic_read(&netfs_n_rh_read),
atomic_read(&netfs_n_rh_read_done),
atomic_read(&netfs_n_rh_read_failed));
- seq_printf(m, "RdHelp : WR=%u ws=%u wf=%u\n",
- atomic_read(&netfs_n_rh_write),
- atomic_read(&netfs_n_rh_write_done),
- atomic_read(&netfs_n_rh_write_failed));
+ seq_printf(m, "Netfs : UL=%u us=%u uf=%u\n",
+ atomic_read(&netfs_n_wh_upload),
+ atomic_read(&netfs_n_wh_upload_done),
+ atomic_read(&netfs_n_wh_upload_failed));
+ seq_printf(m, "Netfs : WR=%u ws=%u wf=%u\n",
+ atomic_read(&netfs_n_wh_write),
+ atomic_read(&netfs_n_wh_write_done),
+ atomic_read(&netfs_n_wh_write_failed));
+ seq_printf(m, "Netfs : rr=%u sr=%u wsc=%u\n",
+ atomic_read(&netfs_n_rh_rreq),
+ atomic_read(&netfs_n_rh_sreq),
+ atomic_read(&netfs_n_wh_wstream_conflict));
+ return fscache_stats_show(m);
}
EXPORT_SYMBOL(netfs_stats_show);
diff --git a/fs/netfs/write_collect.c b/fs/netfs/write_collect.c
new file mode 100644
index 000000000000..60112e4b2c5e
--- /dev/null
+++ b/fs/netfs/write_collect.c
@@ -0,0 +1,808 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Network filesystem write subrequest result collection, assessment
+ * and retrying.
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include "internal.h"
+
+/* Notes made in the collector */
+#define HIT_PENDING 0x01 /* A front op was still pending */
+#define SOME_EMPTY 0x02 /* One of more streams are empty */
+#define ALL_EMPTY 0x04 /* All streams are empty */
+#define MAYBE_DISCONTIG 0x08 /* A front op may be discontiguous (rounded to PAGE_SIZE) */
+#define NEED_REASSESS 0x10 /* Need to loop round and reassess */
+#define REASSESS_DISCONTIG 0x20 /* Reassess discontiguity if contiguity advances */
+#define MADE_PROGRESS 0x40 /* Made progress cleaning up a stream or the folio set */
+#define BUFFERED 0x80 /* The pagecache needs cleaning up */
+#define NEED_RETRY 0x100 /* A front op requests retrying */
+#define SAW_FAILURE 0x200 /* One stream or hit a permanent failure */
+
+/*
+ * Successful completion of write of a folio to the server and/or cache. Note
+ * that we are not allowed to lock the folio here on pain of deadlocking with
+ * truncate.
+ */
+int netfs_folio_written_back(struct folio *folio)
+{
+ enum netfs_folio_trace why = netfs_folio_trace_clear;
+ struct netfs_folio *finfo;
+ struct netfs_group *group = NULL;
+ int gcount = 0;
+
+ if ((finfo = netfs_folio_info(folio))) {
+ /* Streaming writes cannot be redirtied whilst under writeback,
+ * so discard the streaming record.
+ */
+ folio_detach_private(folio);
+ group = finfo->netfs_group;
+ gcount++;
+ kfree(finfo);
+ why = netfs_folio_trace_clear_s;
+ goto end_wb;
+ }
+
+ if ((group = netfs_folio_group(folio))) {
+ if (group == NETFS_FOLIO_COPY_TO_CACHE) {
+ why = netfs_folio_trace_clear_cc;
+ folio_detach_private(folio);
+ goto end_wb;
+ }
+
+ /* Need to detach the group pointer if the page didn't get
+ * redirtied. If it has been redirtied, then it must be within
+ * the same group.
+ */
+ why = netfs_folio_trace_redirtied;
+ if (!folio_test_dirty(folio)) {
+ folio_detach_private(folio);
+ gcount++;
+ why = netfs_folio_trace_clear_g;
+ }
+ }
+
+end_wb:
+ trace_netfs_folio(folio, why);
+ folio_end_writeback(folio);
+ return gcount;
+}
+
+/*
+ * Get hold of a folio we have under writeback. We don't want to get the
+ * refcount on it.
+ */
+static struct folio *netfs_writeback_lookup_folio(struct netfs_io_request *wreq, loff_t pos)
+{
+ XA_STATE(xas, &wreq->mapping->i_pages, pos / PAGE_SIZE);
+ struct folio *folio;
+
+ rcu_read_lock();
+
+ for (;;) {
+ xas_reset(&xas);
+ folio = xas_load(&xas);
+ if (xas_retry(&xas, folio))
+ continue;
+
+ if (!folio || xa_is_value(folio))
+ kdebug("R=%08x: folio %lx (%llx) not present",
+ wreq->debug_id, xas.xa_index, pos / PAGE_SIZE);
+ BUG_ON(!folio || xa_is_value(folio));
+
+ if (folio == xas_reload(&xas))
+ break;
+ }
+
+ rcu_read_unlock();
+
+ if (WARN_ONCE(!folio_test_writeback(folio),
+ "R=%08x: folio %lx is not under writeback\n",
+ wreq->debug_id, folio->index)) {
+ trace_netfs_folio(folio, netfs_folio_trace_not_under_wback);
+ }
+ return folio;
+}
+
+/*
+ * Unlock any folios we've finished with.
+ */
+static void netfs_writeback_unlock_folios(struct netfs_io_request *wreq,
+ unsigned long long collected_to,
+ unsigned int *notes)
+{
+ for (;;) {
+ struct folio *folio;
+ struct netfs_folio *finfo;
+ unsigned long long fpos, fend;
+ size_t fsize, flen;
+
+ folio = netfs_writeback_lookup_folio(wreq, wreq->cleaned_to);
+
+ fpos = folio_pos(folio);
+ fsize = folio_size(folio);
+ finfo = netfs_folio_info(folio);
+ flen = finfo ? finfo->dirty_offset + finfo->dirty_len : fsize;
+
+ fend = min_t(unsigned long long, fpos + flen, wreq->i_size);
+
+ trace_netfs_collect_folio(wreq, folio, fend, collected_to);
+
+ if (fpos + fsize > wreq->contiguity) {
+ trace_netfs_collect_contig(wreq, fpos + fsize,
+ netfs_contig_trace_unlock);
+ wreq->contiguity = fpos + fsize;
+ }
+
+ /* Unlock any folio we've transferred all of. */
+ if (collected_to < fend)
+ break;
+
+ wreq->nr_group_rel += netfs_folio_written_back(folio);
+ wreq->cleaned_to = fpos + fsize;
+ *notes |= MADE_PROGRESS;
+
+ if (fpos + fsize >= collected_to)
+ break;
+ }
+}
+
+/*
+ * Perform retries on the streams that need it.
+ */
+static void netfs_retry_write_stream(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream)
+{
+ struct list_head *next;
+
+ _enter("R=%x[%x:]", wreq->debug_id, stream->stream_nr);
+
+ if (list_empty(&stream->subrequests))
+ return;
+
+ if (stream->source == NETFS_UPLOAD_TO_SERVER &&
+ wreq->netfs_ops->retry_request)
+ wreq->netfs_ops->retry_request(wreq, stream);
+
+ if (unlikely(stream->failed))
+ return;
+
+ /* If there's no renegotiation to do, just resend each failed subreq. */
+ if (!stream->prepare_write) {
+ struct netfs_io_subrequest *subreq;
+
+ list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
+ if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
+ break;
+ if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) {
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+ netfs_reissue_write(stream, subreq);
+ }
+ }
+ return;
+ }
+
+ next = stream->subrequests.next;
+
+ do {
+ struct netfs_io_subrequest *subreq = NULL, *from, *to, *tmp;
+ unsigned long long start, len;
+ size_t part;
+ bool boundary = false;
+
+ /* Go through the stream and find the next span of contiguous
+ * data that we then rejig (cifs, for example, needs the wsize
+ * renegotiating) and reissue.
+ */
+ from = list_entry(next, struct netfs_io_subrequest, rreq_link);
+ to = from;
+ start = from->start + from->transferred;
+ len = from->len - from->transferred;
+
+ if (test_bit(NETFS_SREQ_FAILED, &from->flags) ||
+ !test_bit(NETFS_SREQ_NEED_RETRY, &from->flags))
+ return;
+
+ list_for_each_continue(next, &stream->subrequests) {
+ subreq = list_entry(next, struct netfs_io_subrequest, rreq_link);
+ if (subreq->start + subreq->transferred != start + len ||
+ test_bit(NETFS_SREQ_BOUNDARY, &subreq->flags) ||
+ !test_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags))
+ break;
+ to = subreq;
+ len += to->len;
+ }
+
+ /* Work through the sublist. */
+ subreq = from;
+ list_for_each_entry_from(subreq, &stream->subrequests, rreq_link) {
+ if (!len)
+ break;
+ /* Renegotiate max_len (wsize) */
+ trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
+ __clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+ stream->prepare_write(subreq);
+
+ part = min(len, subreq->max_len);
+ subreq->len = part;
+ subreq->start = start;
+ subreq->transferred = 0;
+ len -= part;
+ start += part;
+ if (len && subreq == to &&
+ __test_and_clear_bit(NETFS_SREQ_BOUNDARY, &to->flags))
+ boundary = true;
+
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+ netfs_reissue_write(stream, subreq);
+ if (subreq == to)
+ break;
+ }
+
+ /* If we managed to use fewer subreqs, we can discard the
+ * excess; if we used the same number, then we're done.
+ */
+ if (!len) {
+ if (subreq == to)
+ continue;
+ list_for_each_entry_safe_from(subreq, tmp,
+ &stream->subrequests, rreq_link) {
+ trace_netfs_sreq(subreq, netfs_sreq_trace_discard);
+ list_del(&subreq->rreq_link);
+ netfs_put_subrequest(subreq, false, netfs_sreq_trace_put_done);
+ if (subreq == to)
+ break;
+ }
+ continue;
+ }
+
+ /* We ran out of subrequests, so we need to allocate some more
+ * and insert them after.
+ */
+ do {
+ subreq = netfs_alloc_subrequest(wreq);
+ subreq->source = to->source;
+ subreq->start = start;
+ subreq->max_len = len;
+ subreq->max_nr_segs = INT_MAX;
+ subreq->debug_index = atomic_inc_return(&wreq->subreq_counter);
+ subreq->stream_nr = to->stream_nr;
+ __set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
+
+ trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index,
+ refcount_read(&subreq->ref),
+ netfs_sreq_trace_new);
+ netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
+
+ list_add(&subreq->rreq_link, &to->rreq_link);
+ to = list_next_entry(to, rreq_link);
+ trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
+
+ switch (stream->source) {
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload);
+ subreq->max_len = min(len, wreq->wsize);
+ break;
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+
+ stream->prepare_write(subreq);
+
+ part = min(len, subreq->max_len);
+ subreq->len = subreq->transferred + part;
+ len -= part;
+ start += part;
+ if (!len && boundary) {
+ __set_bit(NETFS_SREQ_BOUNDARY, &to->flags);
+ boundary = false;
+ }
+
+ netfs_reissue_write(stream, subreq);
+ if (!len)
+ break;
+
+ } while (len);
+
+ } while (!list_is_head(next, &stream->subrequests));
+}
+
+/*
+ * Perform retries on the streams that need it. If we're doing content
+ * encryption and the server copy changed due to a third-party write, we may
+ * need to do an RMW cycle and also rewrite the data to the cache.
+ */
+static void netfs_retry_writes(struct netfs_io_request *wreq)
+{
+ struct netfs_io_subrequest *subreq;
+ struct netfs_io_stream *stream;
+ int s;
+
+ /* Wait for all outstanding I/O to quiesce before performing retries as
+ * we may need to renegotiate the I/O sizes.
+ */
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (!stream->active)
+ continue;
+
+ list_for_each_entry(subreq, &stream->subrequests, rreq_link) {
+ wait_on_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS,
+ TASK_UNINTERRUPTIBLE);
+ }
+ }
+
+ // TODO: Enc: Fetch changed partial pages
+ // TODO: Enc: Reencrypt content if needed.
+ // TODO: Enc: Wind back transferred point.
+ // TODO: Enc: Mark cache pages for retry.
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->need_retry) {
+ stream->need_retry = false;
+ netfs_retry_write_stream(wreq, stream);
+ }
+ }
+}
+
+/*
+ * Collect and assess the results of various write subrequests. We may need to
+ * retry some of the results - or even do an RMW cycle for content crypto.
+ *
+ * Note that we have a number of parallel, overlapping lists of subrequests,
+ * one to the server and one to the local cache for example, which may not be
+ * the same size or starting position and may not even correspond in boundary
+ * alignment.
+ */
+static void netfs_collect_write_results(struct netfs_io_request *wreq)
+{
+ struct netfs_io_subrequest *front, *remove;
+ struct netfs_io_stream *stream;
+ unsigned long long collected_to;
+ unsigned int notes;
+ int s;
+
+ _enter("%llx-%llx", wreq->start, wreq->start + wreq->len);
+ trace_netfs_collect(wreq);
+ trace_netfs_rreq(wreq, netfs_rreq_trace_collect);
+
+reassess_streams:
+ smp_rmb();
+ collected_to = ULLONG_MAX;
+ if (wreq->origin == NETFS_WRITEBACK)
+ notes = ALL_EMPTY | BUFFERED | MAYBE_DISCONTIG;
+ else if (wreq->origin == NETFS_WRITETHROUGH)
+ notes = ALL_EMPTY | BUFFERED;
+ else
+ notes = ALL_EMPTY;
+
+ /* Remove completed subrequests from the front of the streams and
+ * advance the completion point on each stream. We stop when we hit
+ * something that's in progress. The issuer thread may be adding stuff
+ * to the tail whilst we're doing this.
+ *
+ * We must not, however, merge in discontiguities that span whole
+ * folios that aren't under writeback. This is made more complicated
+ * by the folios in the gap being of unpredictable sizes - if they even
+ * exist - but we don't want to look them up.
+ */
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ loff_t rstart, rend;
+
+ stream = &wreq->io_streams[s];
+ /* Read active flag before list pointers */
+ if (!smp_load_acquire(&stream->active))
+ continue;
+
+ front = stream->front;
+ while (front) {
+ trace_netfs_collect_sreq(wreq, front);
+ //_debug("sreq [%x] %llx %zx/%zx",
+ // front->debug_index, front->start, front->transferred, front->len);
+
+ /* Stall if there may be a discontinuity. */
+ rstart = round_down(front->start, PAGE_SIZE);
+ if (rstart > wreq->contiguity) {
+ if (wreq->contiguity > stream->collected_to) {
+ trace_netfs_collect_gap(wreq, stream,
+ wreq->contiguity, 'D');
+ stream->collected_to = wreq->contiguity;
+ }
+ notes |= REASSESS_DISCONTIG;
+ break;
+ }
+ rend = round_up(front->start + front->len, PAGE_SIZE);
+ if (rend > wreq->contiguity) {
+ trace_netfs_collect_contig(wreq, rend,
+ netfs_contig_trace_collect);
+ wreq->contiguity = rend;
+ if (notes & REASSESS_DISCONTIG)
+ notes |= NEED_REASSESS;
+ }
+ notes &= ~MAYBE_DISCONTIG;
+
+ /* Stall if the front is still undergoing I/O. */
+ if (test_bit(NETFS_SREQ_IN_PROGRESS, &front->flags)) {
+ notes |= HIT_PENDING;
+ break;
+ }
+ smp_rmb(); /* Read counters after I-P flag. */
+
+ if (stream->failed) {
+ stream->collected_to = front->start + front->len;
+ notes |= MADE_PROGRESS | SAW_FAILURE;
+ goto cancel;
+ }
+ if (front->start + front->transferred > stream->collected_to) {
+ stream->collected_to = front->start + front->transferred;
+ stream->transferred = stream->collected_to - wreq->start;
+ notes |= MADE_PROGRESS;
+ }
+ if (test_bit(NETFS_SREQ_FAILED, &front->flags)) {
+ stream->failed = true;
+ stream->error = front->error;
+ if (stream->source == NETFS_UPLOAD_TO_SERVER)
+ mapping_set_error(wreq->mapping, front->error);
+ notes |= NEED_REASSESS | SAW_FAILURE;
+ break;
+ }
+ if (front->transferred < front->len) {
+ stream->need_retry = true;
+ notes |= NEED_RETRY | MADE_PROGRESS;
+ break;
+ }
+
+ cancel:
+ /* Remove if completely consumed. */
+ spin_lock(&wreq->lock);
+
+ remove = front;
+ list_del_init(&front->rreq_link);
+ front = list_first_entry_or_null(&stream->subrequests,
+ struct netfs_io_subrequest, rreq_link);
+ stream->front = front;
+ if (!front) {
+ unsigned long long jump_to = atomic64_read(&wreq->issued_to);
+
+ if (stream->collected_to < jump_to) {
+ trace_netfs_collect_gap(wreq, stream, jump_to, 'A');
+ stream->collected_to = jump_to;
+ }
+ }
+
+ spin_unlock(&wreq->lock);
+ netfs_put_subrequest(remove, false,
+ notes & SAW_FAILURE ?
+ netfs_sreq_trace_put_cancel :
+ netfs_sreq_trace_put_done);
+ }
+
+ if (front)
+ notes &= ~ALL_EMPTY;
+ else
+ notes |= SOME_EMPTY;
+
+ if (stream->collected_to < collected_to)
+ collected_to = stream->collected_to;
+ }
+
+ if (collected_to != ULLONG_MAX && collected_to > wreq->collected_to)
+ wreq->collected_to = collected_to;
+
+ /* If we have an empty stream, we need to jump it forward over any gap
+ * otherwise the collection point will never advance.
+ *
+ * Note that the issuer always adds to the stream with the lowest
+ * so-far submitted start, so if we see two consecutive subreqs in one
+ * stream with nothing between then in another stream, then the second
+ * stream has a gap that can be jumped.
+ */
+ if (notes & SOME_EMPTY) {
+ unsigned long long jump_to = wreq->start + wreq->len;
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active &&
+ stream->front &&
+ stream->front->start < jump_to)
+ jump_to = stream->front->start;
+ }
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active &&
+ !stream->front &&
+ stream->collected_to < jump_to) {
+ trace_netfs_collect_gap(wreq, stream, jump_to, 'B');
+ stream->collected_to = jump_to;
+ }
+ }
+ }
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active)
+ trace_netfs_collect_stream(wreq, stream);
+ }
+
+ trace_netfs_collect_state(wreq, wreq->collected_to, notes);
+
+ /* Unlock any folios that we have now finished with. */
+ if (notes & BUFFERED) {
+ unsigned long long clean_to = min(wreq->collected_to, wreq->contiguity);
+
+ if (wreq->cleaned_to < clean_to)
+ netfs_writeback_unlock_folios(wreq, clean_to, &notes);
+ } else {
+ wreq->cleaned_to = wreq->collected_to;
+ }
+
+ // TODO: Discard encryption buffers
+
+ /* If all streams are discontiguous with the last folio we cleared, we
+ * may need to skip a set of folios.
+ */
+ if ((notes & (MAYBE_DISCONTIG | ALL_EMPTY)) == MAYBE_DISCONTIG) {
+ unsigned long long jump_to = ULLONG_MAX;
+
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->active && stream->front &&
+ stream->front->start < jump_to)
+ jump_to = stream->front->start;
+ }
+
+ trace_netfs_collect_contig(wreq, jump_to, netfs_contig_trace_jump);
+ wreq->contiguity = jump_to;
+ wreq->cleaned_to = jump_to;
+ wreq->collected_to = jump_to;
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->collected_to < jump_to)
+ stream->collected_to = jump_to;
+ }
+ //cond_resched();
+ notes |= MADE_PROGRESS;
+ goto reassess_streams;
+ }
+
+ if (notes & NEED_RETRY)
+ goto need_retry;
+ if ((notes & MADE_PROGRESS) && test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
+ trace_netfs_rreq(wreq, netfs_rreq_trace_unpause);
+ clear_bit_unlock(NETFS_RREQ_PAUSE, &wreq->flags);
+ wake_up_bit(&wreq->flags, NETFS_RREQ_PAUSE);
+ }
+
+ if (notes & NEED_REASSESS) {
+ //cond_resched();
+ goto reassess_streams;
+ }
+ if (notes & MADE_PROGRESS) {
+ //cond_resched();
+ goto reassess_streams;
+ }
+
+out:
+ netfs_put_group_many(wreq->group, wreq->nr_group_rel);
+ wreq->nr_group_rel = 0;
+ _leave(" = %x", notes);
+ return;
+
+need_retry:
+ /* Okay... We're going to have to retry one or both streams. Note
+ * that any partially completed op will have had any wholly transferred
+ * folios removed from it.
+ */
+ _debug("retry");
+ netfs_retry_writes(wreq);
+ goto out;
+}
+
+/*
+ * Perform the collection of subrequests, folios and encryption buffers.
+ */
+void netfs_write_collection_worker(struct work_struct *work)
+{
+ struct netfs_io_request *wreq = container_of(work, struct netfs_io_request, work);
+ struct netfs_inode *ictx = netfs_inode(wreq->inode);
+ size_t transferred;
+ int s;
+
+ _enter("R=%x", wreq->debug_id);
+
+ netfs_see_request(wreq, netfs_rreq_trace_see_work);
+ if (!test_bit(NETFS_RREQ_IN_PROGRESS, &wreq->flags)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+
+ netfs_collect_write_results(wreq);
+
+ /* We're done when the app thread has finished posting subreqs and all
+ * the queues in all the streams are empty.
+ */
+ if (!test_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+ smp_rmb(); /* Read ALL_QUEUED before lists. */
+
+ transferred = LONG_MAX;
+ for (s = 0; s < NR_IO_STREAMS; s++) {
+ struct netfs_io_stream *stream = &wreq->io_streams[s];
+ if (!stream->active)
+ continue;
+ if (!list_empty(&stream->subrequests)) {
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work);
+ return;
+ }
+ if (stream->transferred < transferred)
+ transferred = stream->transferred;
+ }
+
+ /* Okay, declare that all I/O is complete. */
+ wreq->transferred = transferred;
+ trace_netfs_rreq(wreq, netfs_rreq_trace_write_done);
+
+ if (wreq->io_streams[1].active &&
+ wreq->io_streams[1].failed) {
+ /* Cache write failure doesn't prevent writeback completion
+ * unless we're in disconnected mode.
+ */
+ ictx->ops->invalidate_cache(wreq);
+ }
+
+ if (wreq->cleanup)
+ wreq->cleanup(wreq);
+
+ if (wreq->origin == NETFS_DIO_WRITE &&
+ wreq->mapping->nrpages) {
+ /* mmap may have got underfoot and we may now have folios
+ * locally covering the region we just wrote. Attempt to
+ * discard the folios, but leave in place any modified locally.
+ * ->write_iter() is prevented from interfering by the DIO
+ * counter.
+ */
+ pgoff_t first = wreq->start >> PAGE_SHIFT;
+ pgoff_t last = (wreq->start + wreq->transferred - 1) >> PAGE_SHIFT;
+ invalidate_inode_pages2_range(wreq->mapping, first, last);
+ }
+
+ if (wreq->origin == NETFS_DIO_WRITE)
+ inode_dio_end(wreq->inode);
+
+ _debug("finished");
+ trace_netfs_rreq(wreq, netfs_rreq_trace_wake_ip);
+ clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &wreq->flags);
+ wake_up_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS);
+
+ if (wreq->iocb) {
+ wreq->iocb->ki_pos += wreq->transferred;
+ if (wreq->iocb->ki_complete)
+ wreq->iocb->ki_complete(
+ wreq->iocb, wreq->error ? wreq->error : wreq->transferred);
+ wreq->iocb = VFS_PTR_POISON;
+ }
+
+ netfs_clear_subrequests(wreq, false);
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_work_complete);
+}
+
+/*
+ * Wake the collection work item.
+ */
+void netfs_wake_write_collector(struct netfs_io_request *wreq, bool was_async)
+{
+ if (!work_pending(&wreq->work)) {
+ netfs_get_request(wreq, netfs_rreq_trace_get_work);
+ if (!queue_work(system_unbound_wq, &wreq->work))
+ netfs_put_request(wreq, was_async, netfs_rreq_trace_put_work_nq);
+ }
+}
+
+/**
+ * netfs_write_subrequest_terminated - Note the termination of a write operation.
+ * @_op: The I/O request that has terminated.
+ * @transferred_or_error: The amount of data transferred or an error code.
+ * @was_async: The termination was asynchronous
+ *
+ * This tells the library that a contributory write I/O operation has
+ * terminated, one way or another, and that it should collect the results.
+ *
+ * The caller indicates in @transferred_or_error the outcome of the operation,
+ * supplying a positive value to indicate the number of bytes transferred or a
+ * negative error code. The library will look after reissuing I/O operations
+ * as appropriate and writing downloaded data to the cache.
+ *
+ * If @was_async is true, the caller might be running in softirq or interrupt
+ * context and we can't sleep.
+ *
+ * When this is called, ownership of the subrequest is transferred back to the
+ * library, along with a ref.
+ *
+ * Note that %_op is a void* so that the function can be passed to
+ * kiocb::term_func without the need for a casting wrapper.
+ */
+void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,
+ bool was_async)
+{
+ struct netfs_io_subrequest *subreq = _op;
+ struct netfs_io_request *wreq = subreq->rreq;
+ struct netfs_io_stream *stream = &wreq->io_streams[subreq->stream_nr];
+
+ _enter("%x[%x] %zd", wreq->debug_id, subreq->debug_index, transferred_or_error);
+
+ switch (subreq->source) {
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload_done);
+ break;
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write_done);
+ break;
+ case NETFS_INVALID_WRITE:
+ break;
+ default:
+ BUG();
+ }
+
+ if (IS_ERR_VALUE(transferred_or_error)) {
+ subreq->error = transferred_or_error;
+ if (subreq->error == -EAGAIN)
+ set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ else
+ set_bit(NETFS_SREQ_FAILED, &subreq->flags);
+ trace_netfs_failure(wreq, subreq, transferred_or_error, netfs_fail_write);
+
+ switch (subreq->source) {
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write_failed);
+ break;
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload_failed);
+ break;
+ default:
+ break;
+ }
+ trace_netfs_rreq(wreq, netfs_rreq_trace_set_pause);
+ set_bit(NETFS_RREQ_PAUSE, &wreq->flags);
+ } else {
+ if (WARN(transferred_or_error > subreq->len - subreq->transferred,
+ "Subreq excess write: R=%x[%x] %zd > %zu - %zu",
+ wreq->debug_id, subreq->debug_index,
+ transferred_or_error, subreq->len, subreq->transferred))
+ transferred_or_error = subreq->len - subreq->transferred;
+
+ subreq->error = 0;
+ subreq->transferred += transferred_or_error;
+
+ if (subreq->transferred < subreq->len)
+ set_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags);
+ }
+
+ trace_netfs_sreq(subreq, netfs_sreq_trace_terminated);
+
+ clear_bit_unlock(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+ wake_up_bit(&subreq->flags, NETFS_SREQ_IN_PROGRESS);
+
+ /* If we are at the head of the queue, wake up the collector,
+ * transferring a ref to it if we were the ones to do so.
+ */
+ if (list_is_first(&subreq->rreq_link, &stream->subrequests))
+ netfs_wake_write_collector(wreq, was_async);
+
+ netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
+}
+EXPORT_SYMBOL(netfs_write_subrequest_terminated);
diff --git a/fs/netfs/write_issue.c b/fs/netfs/write_issue.c
new file mode 100644
index 000000000000..e190043bc0da
--- /dev/null
+++ b/fs/netfs/write_issue.c
@@ -0,0 +1,684 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Network filesystem high-level (buffered) writeback.
+ *
+ * Copyright (C) 2024 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ *
+ * To support network filesystems with local caching, we manage a situation
+ * that can be envisioned like the following:
+ *
+ * +---+---+-----+-----+---+----------+
+ * Folios: | | | | | | |
+ * +---+---+-----+-----+---+----------+
+ *
+ * +------+------+ +----+----+
+ * Upload: | | |.....| | |
+ * (Stream 0) +------+------+ +----+----+
+ *
+ * +------+------+------+------+------+
+ * Cache: | | | | | |
+ * (Stream 1) +------+------+------+------+------+
+ *
+ * Where we have a sequence of folios of varying sizes that we need to overlay
+ * with multiple parallel streams of I/O requests, where the I/O requests in a
+ * stream may also be of various sizes (in cifs, for example, the sizes are
+ * negotiated with the server; in something like ceph, they may represent the
+ * sizes of storage objects).
+ *
+ * The sequence in each stream may contain gaps and noncontiguous subrequests
+ * may be glued together into single vectored write RPCs.
+ */
+
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include "internal.h"
+
+/*
+ * Kill all dirty folios in the event of an unrecoverable error, starting with
+ * a locked folio we've already obtained from writeback_iter().
+ */
+static void netfs_kill_dirty_pages(struct address_space *mapping,
+ struct writeback_control *wbc,
+ struct folio *folio)
+{
+ int error = 0;
+
+ do {
+ enum netfs_folio_trace why = netfs_folio_trace_kill;
+ struct netfs_group *group = NULL;
+ struct netfs_folio *finfo = NULL;
+ void *priv;
+
+ priv = folio_detach_private(folio);
+ if (priv) {
+ finfo = __netfs_folio_info(priv);
+ if (finfo) {
+ /* Kill folio from streaming write. */
+ group = finfo->netfs_group;
+ why = netfs_folio_trace_kill_s;
+ } else {
+ group = priv;
+ if (group == NETFS_FOLIO_COPY_TO_CACHE) {
+ /* Kill copy-to-cache folio */
+ why = netfs_folio_trace_kill_cc;
+ group = NULL;
+ } else {
+ /* Kill folio with group */
+ why = netfs_folio_trace_kill_g;
+ }
+ }
+ }
+
+ trace_netfs_folio(folio, why);
+
+ folio_start_writeback(folio);
+ folio_unlock(folio);
+ folio_end_writeback(folio);
+
+ netfs_put_group(group);
+ kfree(finfo);
+
+ } while ((folio = writeback_iter(mapping, wbc, folio, &error)));
+}
+
+/*
+ * Create a write request and set it up appropriately for the origin type.
+ */
+struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
+ struct file *file,
+ loff_t start,
+ enum netfs_io_origin origin)
+{
+ struct netfs_io_request *wreq;
+ struct netfs_inode *ictx;
+
+ wreq = netfs_alloc_request(mapping, file, start, 0, origin);
+ if (IS_ERR(wreq))
+ return wreq;
+
+ _enter("R=%x", wreq->debug_id);
+
+ ictx = netfs_inode(wreq->inode);
+ if (test_bit(NETFS_RREQ_WRITE_TO_CACHE, &wreq->flags))
+ fscache_begin_write_operation(&wreq->cache_resources, netfs_i_cookie(ictx));
+
+ wreq->contiguity = wreq->start;
+ wreq->cleaned_to = wreq->start;
+ INIT_WORK(&wreq->work, netfs_write_collection_worker);
+
+ wreq->io_streams[0].stream_nr = 0;
+ wreq->io_streams[0].source = NETFS_UPLOAD_TO_SERVER;
+ wreq->io_streams[0].prepare_write = ictx->ops->prepare_write;
+ wreq->io_streams[0].issue_write = ictx->ops->issue_write;
+ wreq->io_streams[0].collected_to = start;
+ wreq->io_streams[0].transferred = LONG_MAX;
+
+ wreq->io_streams[1].stream_nr = 1;
+ wreq->io_streams[1].source = NETFS_WRITE_TO_CACHE;
+ wreq->io_streams[1].collected_to = start;
+ wreq->io_streams[1].transferred = LONG_MAX;
+ if (fscache_resources_valid(&wreq->cache_resources)) {
+ wreq->io_streams[1].avail = true;
+ wreq->io_streams[1].prepare_write = wreq->cache_resources.ops->prepare_write_subreq;
+ wreq->io_streams[1].issue_write = wreq->cache_resources.ops->issue_write;
+ }
+
+ return wreq;
+}
+
+/**
+ * netfs_prepare_write_failed - Note write preparation failed
+ * @subreq: The subrequest to mark
+ *
+ * Mark a subrequest to note that preparation for write failed.
+ */
+void netfs_prepare_write_failed(struct netfs_io_subrequest *subreq)
+{
+ __set_bit(NETFS_SREQ_FAILED, &subreq->flags);
+ trace_netfs_sreq(subreq, netfs_sreq_trace_prep_failed);
+}
+EXPORT_SYMBOL(netfs_prepare_write_failed);
+
+/*
+ * Prepare a write subrequest. We need to allocate a new subrequest
+ * if we don't have one.
+ */
+static void netfs_prepare_write(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream,
+ loff_t start)
+{
+ struct netfs_io_subrequest *subreq;
+
+ subreq = netfs_alloc_subrequest(wreq);
+ subreq->source = stream->source;
+ subreq->start = start;
+ subreq->max_len = ULONG_MAX;
+ subreq->max_nr_segs = INT_MAX;
+ subreq->stream_nr = stream->stream_nr;
+
+ _enter("R=%x[%x]", wreq->debug_id, subreq->debug_index);
+
+ trace_netfs_sreq_ref(wreq->debug_id, subreq->debug_index,
+ refcount_read(&subreq->ref),
+ netfs_sreq_trace_new);
+
+ trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
+
+ switch (stream->source) {
+ case NETFS_UPLOAD_TO_SERVER:
+ netfs_stat(&netfs_n_wh_upload);
+ subreq->max_len = wreq->wsize;
+ break;
+ case NETFS_WRITE_TO_CACHE:
+ netfs_stat(&netfs_n_wh_write);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ if (stream->prepare_write)
+ stream->prepare_write(subreq);
+
+ __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+
+ /* We add to the end of the list whilst the collector may be walking
+ * the list. The collector only goes nextwards and uses the lock to
+ * remove entries off of the front.
+ */
+ spin_lock(&wreq->lock);
+ list_add_tail(&subreq->rreq_link, &stream->subrequests);
+ if (list_is_first(&subreq->rreq_link, &stream->subrequests)) {
+ stream->front = subreq;
+ if (!stream->active) {
+ stream->collected_to = stream->front->start;
+ /* Write list pointers before active flag */
+ smp_store_release(&stream->active, true);
+ }
+ }
+
+ spin_unlock(&wreq->lock);
+
+ stream->construct = subreq;
+}
+
+/*
+ * Set the I/O iterator for the filesystem/cache to use and dispatch the I/O
+ * operation. The operation may be asynchronous and should call
+ * netfs_write_subrequest_terminated() when complete.
+ */
+static void netfs_do_issue_write(struct netfs_io_stream *stream,
+ struct netfs_io_subrequest *subreq)
+{
+ struct netfs_io_request *wreq = subreq->rreq;
+
+ _enter("R=%x[%x],%zx", wreq->debug_id, subreq->debug_index, subreq->len);
+
+ if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
+ return netfs_write_subrequest_terminated(subreq, subreq->error, false);
+
+ // TODO: Use encrypted buffer
+ if (test_bit(NETFS_RREQ_USE_IO_ITER, &wreq->flags)) {
+ subreq->io_iter = wreq->io_iter;
+ iov_iter_advance(&subreq->io_iter,
+ subreq->start + subreq->transferred - wreq->start);
+ iov_iter_truncate(&subreq->io_iter,
+ subreq->len - subreq->transferred);
+ } else {
+ iov_iter_xarray(&subreq->io_iter, ITER_SOURCE, &wreq->mapping->i_pages,
+ subreq->start + subreq->transferred,
+ subreq->len - subreq->transferred);
+ }
+
+ trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
+ stream->issue_write(subreq);
+}
+
+void netfs_reissue_write(struct netfs_io_stream *stream,
+ struct netfs_io_subrequest *subreq)
+{
+ __set_bit(NETFS_SREQ_IN_PROGRESS, &subreq->flags);
+ netfs_do_issue_write(stream, subreq);
+}
+
+static void netfs_issue_write(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream)
+{
+ struct netfs_io_subrequest *subreq = stream->construct;
+
+ if (!subreq)
+ return;
+ stream->construct = NULL;
+
+ if (subreq->start + subreq->len > wreq->start + wreq->submitted)
+ wreq->len = wreq->submitted = subreq->start + subreq->len - wreq->start;
+ netfs_do_issue_write(stream, subreq);
+}
+
+/*
+ * Add data to the write subrequest, dispatching each as we fill it up or if it
+ * is discontiguous with the previous. We only fill one part at a time so that
+ * we can avoid overrunning the credits obtained (cifs) and try to parallelise
+ * content-crypto preparation with network writes.
+ */
+int netfs_advance_write(struct netfs_io_request *wreq,
+ struct netfs_io_stream *stream,
+ loff_t start, size_t len, bool to_eof)
+{
+ struct netfs_io_subrequest *subreq = stream->construct;
+ size_t part;
+
+ if (!stream->avail) {
+ _leave("no write");
+ return len;
+ }
+
+ _enter("R=%x[%x]", wreq->debug_id, subreq ? subreq->debug_index : 0);
+
+ if (subreq && start != subreq->start + subreq->len) {
+ netfs_issue_write(wreq, stream);
+ subreq = NULL;
+ }
+
+ if (!stream->construct)
+ netfs_prepare_write(wreq, stream, start);
+ subreq = stream->construct;
+
+ part = min(subreq->max_len - subreq->len, len);
+ _debug("part %zx/%zx %zx/%zx", subreq->len, subreq->max_len, part, len);
+ subreq->len += part;
+ subreq->nr_segs++;
+
+ if (subreq->len >= subreq->max_len ||
+ subreq->nr_segs >= subreq->max_nr_segs ||
+ to_eof) {
+ netfs_issue_write(wreq, stream);
+ subreq = NULL;
+ }
+
+ return part;
+}
+
+/*
+ * Write some of a pending folio data back to the server.
+ */
+static int netfs_write_folio(struct netfs_io_request *wreq,
+ struct writeback_control *wbc,
+ struct folio *folio)
+{
+ struct netfs_io_stream *upload = &wreq->io_streams[0];
+ struct netfs_io_stream *cache = &wreq->io_streams[1];
+ struct netfs_io_stream *stream;
+ struct netfs_group *fgroup; /* TODO: Use this with ceph */
+ struct netfs_folio *finfo;
+ size_t fsize = folio_size(folio), flen = fsize, foff = 0;
+ loff_t fpos = folio_pos(folio), i_size;
+ bool to_eof = false, streamw = false;
+ bool debug = false;
+
+ _enter("");
+
+ /* netfs_perform_write() may shift i_size around the page or from out
+ * of the page to beyond it, but cannot move i_size into or through the
+ * page since we have it locked.
+ */
+ i_size = i_size_read(wreq->inode);
+
+ if (fpos >= i_size) {
+ /* mmap beyond eof. */
+ _debug("beyond eof");
+ folio_start_writeback(folio);
+ folio_unlock(folio);
+ wreq->nr_group_rel += netfs_folio_written_back(folio);
+ netfs_put_group_many(wreq->group, wreq->nr_group_rel);
+ wreq->nr_group_rel = 0;
+ return 0;
+ }
+
+ if (fpos + fsize > wreq->i_size)
+ wreq->i_size = i_size;
+
+ fgroup = netfs_folio_group(folio);
+ finfo = netfs_folio_info(folio);
+ if (finfo) {
+ foff = finfo->dirty_offset;
+ flen = foff + finfo->dirty_len;
+ streamw = true;
+ }
+
+ if (wreq->origin == NETFS_WRITETHROUGH) {
+ to_eof = false;
+ if (flen > i_size - fpos)
+ flen = i_size - fpos;
+ } else if (flen > i_size - fpos) {
+ flen = i_size - fpos;
+ if (!streamw)
+ folio_zero_segment(folio, flen, fsize);
+ to_eof = true;
+ } else if (flen == i_size - fpos) {
+ to_eof = true;
+ }
+ flen -= foff;
+
+ _debug("folio %zx %zx %zx", foff, flen, fsize);
+
+ /* Deal with discontinuities in the stream of dirty pages. These can
+ * arise from a number of sources:
+ *
+ * (1) Intervening non-dirty pages from random-access writes, multiple
+ * flushers writing back different parts simultaneously and manual
+ * syncing.
+ *
+ * (2) Partially-written pages from write-streaming.
+ *
+ * (3) Pages that belong to a different write-back group (eg. Ceph
+ * snapshots).
+ *
+ * (4) Actually-clean pages that were marked for write to the cache
+ * when they were read. Note that these appear as a special
+ * write-back group.
+ */
+ if (fgroup == NETFS_FOLIO_COPY_TO_CACHE) {
+ netfs_issue_write(wreq, upload);
+ } else if (fgroup != wreq->group) {
+ /* We can't write this page to the server yet. */
+ kdebug("wrong group");
+ folio_redirty_for_writepage(wbc, folio);
+ folio_unlock(folio);
+ netfs_issue_write(wreq, upload);
+ netfs_issue_write(wreq, cache);
+ return 0;
+ }
+
+ if (foff > 0)
+ netfs_issue_write(wreq, upload);
+ if (streamw)
+ netfs_issue_write(wreq, cache);
+
+ /* Flip the page to the writeback state and unlock. If we're called
+ * from write-through, then the page has already been put into the wb
+ * state.
+ */
+ if (wreq->origin == NETFS_WRITEBACK)
+ folio_start_writeback(folio);
+ folio_unlock(folio);
+
+ if (fgroup == NETFS_FOLIO_COPY_TO_CACHE) {
+ if (!fscache_resources_valid(&wreq->cache_resources)) {
+ trace_netfs_folio(folio, netfs_folio_trace_cancel_copy);
+ netfs_issue_write(wreq, upload);
+ netfs_folio_written_back(folio);
+ return 0;
+ }
+ trace_netfs_folio(folio, netfs_folio_trace_store_copy);
+ } else if (!upload->construct) {
+ trace_netfs_folio(folio, netfs_folio_trace_store);
+ } else {
+ trace_netfs_folio(folio, netfs_folio_trace_store_plus);
+ }
+
+ /* Move the submission point forward to allow for write-streaming data
+ * not starting at the front of the page. We don't do write-streaming
+ * with the cache as the cache requires DIO alignment.
+ *
+ * Also skip uploading for data that's been read and just needs copying
+ * to the cache.
+ */
+ for (int s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ stream->submit_max_len = fsize;
+ stream->submit_off = foff;
+ stream->submit_len = flen;
+ if ((stream->source == NETFS_WRITE_TO_CACHE && streamw) ||
+ (stream->source == NETFS_UPLOAD_TO_SERVER &&
+ fgroup == NETFS_FOLIO_COPY_TO_CACHE)) {
+ stream->submit_off = UINT_MAX;
+ stream->submit_len = 0;
+ stream->submit_max_len = 0;
+ }
+ }
+
+ /* Attach the folio to one or more subrequests. For a big folio, we
+ * could end up with thousands of subrequests if the wsize is small -
+ * but we might need to wait during the creation of subrequests for
+ * network resources (eg. SMB credits).
+ */
+ for (;;) {
+ ssize_t part;
+ size_t lowest_off = ULONG_MAX;
+ int choose_s = -1;
+
+ /* Always add to the lowest-submitted stream first. */
+ for (int s = 0; s < NR_IO_STREAMS; s++) {
+ stream = &wreq->io_streams[s];
+ if (stream->submit_len > 0 &&
+ stream->submit_off < lowest_off) {
+ lowest_off = stream->submit_off;
+ choose_s = s;
+ }
+ }
+
+ if (choose_s < 0)
+ break;
+ stream = &wreq->io_streams[choose_s];
+
+ part = netfs_advance_write(wreq, stream, fpos + stream->submit_off,
+ stream->submit_len, to_eof);
+ atomic64_set(&wreq->issued_to, fpos + stream->submit_off);
+ stream->submit_off += part;
+ stream->submit_max_len -= part;
+ if (part > stream->submit_len)
+ stream->submit_len = 0;
+ else
+ stream->submit_len -= part;
+ if (part > 0)
+ debug = true;
+ }
+
+ atomic64_set(&wreq->issued_to, fpos + fsize);
+
+ if (!debug)
+ kdebug("R=%x: No submit", wreq->debug_id);
+
+ if (flen < fsize)
+ for (int s = 0; s < NR_IO_STREAMS; s++)
+ netfs_issue_write(wreq, &wreq->io_streams[s]);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * Write some of the pending data back to the server
+ */
+int netfs_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct netfs_inode *ictx = netfs_inode(mapping->host);
+ struct netfs_io_request *wreq = NULL;
+ struct folio *folio;
+ int error = 0;
+
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ mutex_lock(&ictx->wb_lock);
+ else if (!mutex_trylock(&ictx->wb_lock))
+ return 0;
+
+ /* Need the first folio to be able to set up the op. */
+ folio = writeback_iter(mapping, wbc, NULL, &error);
+ if (!folio)
+ goto out;
+
+ wreq = netfs_create_write_req(mapping, NULL, folio_pos(folio), NETFS_WRITEBACK);
+ if (IS_ERR(wreq)) {
+ error = PTR_ERR(wreq);
+ goto couldnt_start;
+ }
+
+ trace_netfs_write(wreq, netfs_write_trace_writeback);
+ netfs_stat(&netfs_n_wh_writepages);
+
+ do {
+ _debug("wbiter %lx %llx", folio->index, wreq->start + wreq->submitted);
+
+ /* It appears we don't have to handle cyclic writeback wrapping. */
+ WARN_ON_ONCE(wreq && folio_pos(folio) < wreq->start + wreq->submitted);
+
+ if (netfs_folio_group(folio) != NETFS_FOLIO_COPY_TO_CACHE &&
+ unlikely(!test_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags))) {
+ set_bit(NETFS_RREQ_UPLOAD_TO_SERVER, &wreq->flags);
+ wreq->netfs_ops->begin_writeback(wreq);
+ }
+
+ error = netfs_write_folio(wreq, wbc, folio);
+ if (error < 0)
+ break;
+ } while ((folio = writeback_iter(mapping, wbc, folio, &error)));
+
+ for (int s = 0; s < NR_IO_STREAMS; s++)
+ netfs_issue_write(wreq, &wreq->io_streams[s]);
+ smp_wmb(); /* Write lists before ALL_QUEUED. */
+ set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
+
+ mutex_unlock(&ictx->wb_lock);
+
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
+ _leave(" = %d", error);
+ return error;
+
+couldnt_start:
+ netfs_kill_dirty_pages(mapping, wbc, folio);
+out:
+ mutex_unlock(&ictx->wb_lock);
+ _leave(" = %d", error);
+ return error;
+}
+EXPORT_SYMBOL(netfs_writepages);
+
+/*
+ * Begin a write operation for writing through the pagecache.
+ */
+struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len)
+{
+ struct netfs_io_request *wreq = NULL;
+ struct netfs_inode *ictx = netfs_inode(file_inode(iocb->ki_filp));
+
+ mutex_lock(&ictx->wb_lock);
+
+ wreq = netfs_create_write_req(iocb->ki_filp->f_mapping, iocb->ki_filp,
+ iocb->ki_pos, NETFS_WRITETHROUGH);
+ if (IS_ERR(wreq)) {
+ mutex_unlock(&ictx->wb_lock);
+ return wreq;
+ }
+
+ wreq->io_streams[0].avail = true;
+ trace_netfs_write(wreq, netfs_write_trace_writethrough);
+ return wreq;
+}
+
+/*
+ * Advance the state of the write operation used when writing through the
+ * pagecache. Data has been copied into the pagecache that we need to append
+ * to the request. If we've added more than wsize then we need to create a new
+ * subrequest.
+ */
+int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
+ struct folio *folio, size_t copied, bool to_page_end,
+ struct folio **writethrough_cache)
+{
+ _enter("R=%x ic=%zu ws=%u cp=%zu tp=%u",
+ wreq->debug_id, wreq->iter.count, wreq->wsize, copied, to_page_end);
+
+ if (!*writethrough_cache) {
+ if (folio_test_dirty(folio))
+ /* Sigh. mmap. */
+ folio_clear_dirty_for_io(folio);
+
+ /* We can make multiple writes to the folio... */
+ folio_start_writeback(folio);
+ if (wreq->len == 0)
+ trace_netfs_folio(folio, netfs_folio_trace_wthru);
+ else
+ trace_netfs_folio(folio, netfs_folio_trace_wthru_plus);
+ *writethrough_cache = folio;
+ }
+
+ wreq->len += copied;
+ if (!to_page_end)
+ return 0;
+
+ *writethrough_cache = NULL;
+ return netfs_write_folio(wreq, wbc, folio);
+}
+
+/*
+ * End a write operation used when writing through the pagecache.
+ */
+int netfs_end_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
+ struct folio *writethrough_cache)
+{
+ struct netfs_inode *ictx = netfs_inode(wreq->inode);
+ int ret;
+
+ _enter("R=%x", wreq->debug_id);
+
+ if (writethrough_cache)
+ netfs_write_folio(wreq, wbc, writethrough_cache);
+
+ netfs_issue_write(wreq, &wreq->io_streams[0]);
+ netfs_issue_write(wreq, &wreq->io_streams[1]);
+ smp_wmb(); /* Write lists before ALL_QUEUED. */
+ set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
+
+ mutex_unlock(&ictx->wb_lock);
+
+ ret = wreq->error;
+ netfs_put_request(wreq, false, netfs_rreq_trace_put_return);
+ return ret;
+}
+
+/*
+ * Write data to the server without going through the pagecache and without
+ * writing it to the local cache.
+ */
+int netfs_unbuffered_write(struct netfs_io_request *wreq, bool may_wait, size_t len)
+{
+ struct netfs_io_stream *upload = &wreq->io_streams[0];
+ ssize_t part;
+ loff_t start = wreq->start;
+ int error = 0;
+
+ _enter("%zx", len);
+
+ if (wreq->origin == NETFS_DIO_WRITE)
+ inode_dio_begin(wreq->inode);
+
+ while (len) {
+ // TODO: Prepare content encryption
+
+ _debug("unbuffered %zx", len);
+ part = netfs_advance_write(wreq, upload, start, len, false);
+ start += part;
+ len -= part;
+ if (test_bit(NETFS_RREQ_PAUSE, &wreq->flags)) {
+ trace_netfs_rreq(wreq, netfs_rreq_trace_wait_pause);
+ wait_on_bit(&wreq->flags, NETFS_RREQ_PAUSE, TASK_UNINTERRUPTIBLE);
+ }
+ if (test_bit(NETFS_RREQ_FAILED, &wreq->flags))
+ break;
+ }
+
+ netfs_issue_write(wreq, upload);
+
+ smp_wmb(); /* Write lists before ALL_QUEUED. */
+ set_bit(NETFS_RREQ_ALL_QUEUED, &wreq->flags);
+ if (list_empty(&upload->subrequests))
+ netfs_wake_write_collector(wreq, false);
+
+ _leave(" = %d", error);
+ return error;
+}
Powered by cgit, Gruvboxed by Blaster4385.