1 files changed, 144 insertions, 134 deletions

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index cce9ace651a2..fac918ccb305 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -1,7 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- *  linux/fs/9p/vfs_addr.c
- *
  * This file contians vfs address (mmap) ops for 9P2000.
  *
  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
@@ -19,7 +17,7 @@
 #include <linux/idr.h>
 #include <linux/sched.h>
 #include <linux/uio.h>
-#include <linux/bvec.h>
+#include <linux/netfs.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -29,196 +27,215 @@
 #include "fid.h"
 
 /**
- * v9fs_fid_readpage - read an entire page in from 9P
- *
- * @fid: fid being read
- * @page: structure to page
- *
+ * v9fs_req_issue_op - Issue a read from 9P
+ * @subreq: The read to make
  */
-static int v9fs_fid_readpage(void *data, struct page *page)
+static void v9fs_req_issue_op(struct netfs_read_subrequest *subreq)
 {
-	struct p9_fid *fid = data;
-	struct inode *inode = page->mapping->host;
-	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
+	struct netfs_read_request *rreq = subreq->rreq;
+	struct p9_fid *fid = rreq->netfs_priv;
 	struct iov_iter to;
-	int retval, err;
+	loff_t pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len   - subreq->transferred;
+	int total, err;
 
-	p9_debug(P9_DEBUG_VFS, "\n");
+	iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len);
 
-	BUG_ON(!PageLocked(page));
+	total = p9_client_read(fid, pos, &to, &err);
+	netfs_subreq_terminated(subreq, err ?: total, false);
+}
 
-	retval = v9fs_readpage_from_fscache(inode, page);
-	if (retval == 0)
-		return retval;
+/**
+ * v9fs_init_rreq - Initialise a read request
+ * @rreq: The read request
+ * @file: The file being read from
+ */
+static void v9fs_init_rreq(struct netfs_read_request *rreq, struct file *file)
+{
+	struct p9_fid *fid = file->private_data;
 
-	iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
+	refcount_inc(&fid->count);
+	rreq->netfs_priv = fid;
+}
 
-	retval = p9_client_read(fid, page_offset(page), &to, &err);
-	if (err) {
-		v9fs_uncache_page(inode, page);
-		retval = err;
-		goto done;
-	}
+/**
+ * v9fs_req_cleanup - Cleanup request initialized by v9fs_init_rreq
+ * @mapping: unused mapping of request to cleanup
+ * @priv: private data to cleanup, a fid, guaranted non-null.
+ */
+static void v9fs_req_cleanup(struct address_space *mapping, void *priv)
+{
+	struct p9_fid *fid = priv;
 
-	zero_user(page, retval, PAGE_SIZE - retval);
-	flush_dcache_page(page);
-	SetPageUptodate(page);
+	p9_client_clunk(fid);
+}
 
-	v9fs_readpage_to_fscache(inode, page);
-	retval = 0;
+/**
+ * v9fs_is_cache_enabled - Determine if caching is enabled for an inode
+ * @inode: The inode to check
+ */
+static bool v9fs_is_cache_enabled(struct inode *inode)
+{
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(inode));
 
-done:
-	unlock_page(page);
-	return retval;
+	return fscache_cookie_enabled(cookie) && !hlist_empty(&cookie->backing_objects);
 }
 
 /**
- * v9fs_vfs_readpage - read an entire page in from 9P
- *
- * @filp: file being read
- * @page: structure to page
- *
+ * v9fs_begin_cache_operation - Begin a cache operation for a read
+ * @rreq: The read request
  */
-
-static int v9fs_vfs_readpage(struct file *filp, struct page *page)
+static int v9fs_begin_cache_operation(struct netfs_read_request *rreq)
 {
-	return v9fs_fid_readpage(filp->private_data, page);
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
+
+	return fscache_begin_read_operation(rreq, cookie);
 }
 
+static const struct netfs_read_request_ops v9fs_req_ops = {
+	.init_rreq		= v9fs_init_rreq,
+	.is_cache_enabled	= v9fs_is_cache_enabled,
+	.begin_cache_operation	= v9fs_begin_cache_operation,
+	.issue_op		= v9fs_req_issue_op,
+	.cleanup		= v9fs_req_cleanup,
+};
+
 /**
- * v9fs_vfs_readpages - read a set of pages from 9P
- *
- * @filp: file being read
- * @mapping: the address space
- * @pages: list of pages to read
- * @nr_pages: count of pages to read
+ * v9fs_vfs_readpage - read an entire page in from 9P
+ * @file: file being read
+ * @page: structure to page
  *
  */
-
-static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
-			     struct list_head *pages, unsigned nr_pages)
+static int v9fs_vfs_readpage(struct file *file, struct page *page)
 {
-	int ret = 0;
-	struct inode *inode;
+	struct folio *folio = page_folio(page);
 
-	inode = mapping->host;
-	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
-
-	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
-	if (ret == 0)
-		return ret;
+	return netfs_readpage(file, folio, &v9fs_req_ops, NULL);
+}
 
-	ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
-			filp->private_data);
-	p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
-	return ret;
+/**
+ * v9fs_vfs_readahead - read a set of pages from 9P
+ * @ractl: The readahead parameters
+ */
+static void v9fs_vfs_readahead(struct readahead_control *ractl)
+{
+	netfs_readahead(ractl, &v9fs_req_ops, NULL);
 }
 
 /**
  * v9fs_release_page - release the private state associated with a page
+ * @page: The page to be released
+ * @gfp: The caller's allocation restrictions
  *
  * Returns 1 if the page can be released, false otherwise.
  */
 
 static int v9fs_release_page(struct page *page, gfp_t gfp)
 {
-	if (PagePrivate(page))
+	struct folio *folio = page_folio(page);
+
+	if (folio_test_private(folio))
 		return 0;
-	return v9fs_fscache_release_page(page, gfp);
+#ifdef CONFIG_9P_FSCACHE
+	if (folio_test_fscache(folio)) {
+		if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS))
+			return 0;
+		folio_wait_fscache(folio);
+	}
+#endif
+	return 1;
 }
 
 /**
  * v9fs_invalidate_page - Invalidate a page completely or partially
- *
- * @page: structure to page
- * @offset: offset in the page
+ * @page: The page to be invalidated
+ * @offset: offset of the invalidated region
+ * @length: length of the invalidated region
  */
 
 static void v9fs_invalidate_page(struct page *page, unsigned int offset,
 				 unsigned int length)
 {
-	/*
-	 * If called with zero offset, we should release
-	 * the private state assocated with the page
-	 */
-	if (offset == 0 && length == PAGE_SIZE)
-		v9fs_fscache_invalidate_page(page);
+	struct folio *folio = page_folio(page);
+
+	folio_wait_fscache(folio);
 }
 
-static int v9fs_vfs_writepage_locked(struct page *page)
+static int v9fs_vfs_write_folio_locked(struct folio *folio)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio_inode(folio);
 	struct v9fs_inode *v9inode = V9FS_I(inode);
-	loff_t size = i_size_read(inode);
+	loff_t start = folio_pos(folio);
+	loff_t i_size = i_size_read(inode);
 	struct iov_iter from;
-	struct bio_vec bvec;
-	int err, len;
+	size_t len = folio_size(folio);
+	int err;
 
-	if (page->index == size >> PAGE_SHIFT)
-		len = size & ~PAGE_MASK;
-	else
-		len = PAGE_SIZE;
+	if (start >= i_size)
+		return 0; /* Simultaneous truncation occurred */
 
-	bvec.bv_page = page;
-	bvec.bv_offset = 0;
-	bvec.bv_len = len;
-	iov_iter_bvec(&from, WRITE, &bvec, 1, len);
+	len = min_t(loff_t, i_size - start, len);
+
+	iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);
 
-	set_page_writeback(page);
+	folio_start_writeback(folio);
 
-	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
+	p9_client_write(v9inode->writeback_fid, start, &from, &err);
 
-	end_page_writeback(page);
+	folio_end_writeback(folio);
 	return err;
 }
 
 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 {
+	struct folio *folio = page_folio(page);
 	int retval;
 
-	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
+	p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
 
-	retval = v9fs_vfs_writepage_locked(page);
+	retval = v9fs_vfs_write_folio_locked(folio);
 	if (retval < 0) {
 		if (retval == -EAGAIN) {
-			redirty_page_for_writepage(wbc, page);
+			folio_redirty_for_writepage(wbc, folio);
 			retval = 0;
 		} else {
-			SetPageError(page);
-			mapping_set_error(page->mapping, retval);
+			mapping_set_error(folio_mapping(folio), retval);
 		}
 	} else
 		retval = 0;
 
-	unlock_page(page);
+	folio_unlock(folio);
 	return retval;
 }
 
 /**
  * v9fs_launder_page - Writeback a dirty page
+ * @page: The page to be cleaned up
+ *
  * Returns 0 on success.
  */
 
 static int v9fs_launder_page(struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	int retval;
-	struct inode *inode = page->mapping->host;
 
-	v9fs_fscache_wait_on_page_write(inode, page);
-	if (clear_page_dirty_for_io(page)) {
-		retval = v9fs_vfs_writepage_locked(page);
+	if (folio_clear_dirty_for_io(folio)) {
+		retval = v9fs_vfs_write_folio_locked(folio);
 		if (retval)
 			return retval;
 	}
+	folio_wait_fscache(folio);
 	return 0;
 }
 
 /**
  * v9fs_direct_IO - 9P address space operation for direct I/O
  * @iocb: target I/O control block
+ * @iter: The data/buffer to use
  *
  * The presence of v9fs_direct_IO() in the address space ops vector
  * allowes open() O_DIRECT flags which would have failed otherwise.
@@ -238,11 +255,13 @@ v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	loff_t pos = iocb->ki_pos;
 	ssize_t n;
 	int err = 0;
+
 	if (iov_iter_rw(iter) == WRITE) {
 		n = p9_client_write(file->private_data, pos, iter, &err);
 		if (n) {
 			struct inode *inode = file_inode(file);
 			loff_t i_size = i_size_read(inode);
+
 			if (pos + n > i_size)
 				inode_add_bytes(inode, pos + n - i_size);
 		}
@@ -253,58 +272,49 @@ v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 }
 
 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
-			    loff_t pos, unsigned len, unsigned flags,
-			    struct page **pagep, void **fsdata)
+			    loff_t pos, unsigned int len, unsigned int flags,
+			    struct page **subpagep, void **fsdata)
 {
-	int retval = 0;
-	struct page *page;
-	struct v9fs_inode *v9inode;
-	pgoff_t index = pos >> PAGE_SHIFT;
-	struct inode *inode = mapping->host;
-
+	int retval;
+	struct folio *folio;
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	v9inode = V9FS_I(inode);
-start:
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page) {
-		retval = -ENOMEM;
-		goto out;
-	}
 	BUG_ON(!v9inode->writeback_fid);
-	if (PageUptodate(page))
-		goto out;
 
-	if (len == PAGE_SIZE)
-		goto out;
+	/* Prefetch area to be written into the cache if we're caching this
+	 * file.  We need to do this before we get a lock on the page in case
+	 * there's more than one writer competing for the same cache block.
+	 */
+	retval = netfs_write_begin(filp, mapping, pos, len, flags, &folio, fsdata,
+				   &v9fs_req_ops, NULL);
+	if (retval < 0)
+		return retval;
 
-	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
-	put_page(page);
-	if (!retval)
-		goto start;
-out:
-	*pagep = page;
+	*subpagep = &folio->page;
 	return retval;
 }
 
 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
-			  loff_t pos, unsigned len, unsigned copied,
-			  struct page *page, void *fsdata)
+			  loff_t pos, unsigned int len, unsigned int copied,
+			  struct page *subpage, void *fsdata)
 {
 	loff_t last_pos = pos + copied;
-	struct inode *inode = page->mapping->host;
+	struct folio *folio = page_folio(subpage);
+	struct inode *inode = mapping->host;
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		if (unlikely(copied < len)) {
 			copied = 0;
 			goto out;
-		} else if (len == PAGE_SIZE) {
-			SetPageUptodate(page);
 		}
+
+		folio_mark_uptodate(folio);
 	}
+
 	/*
 	 * No need to use i_size_read() here, the i_size
 	 * cannot change under us because we hold the i_mutex.
@@ -313,10 +323,10 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 		inode_add_bytes(inode, last_pos - inode->i_size);
 		i_size_write(inode, last_pos);
 	}
-	set_page_dirty(page);
+	folio_mark_dirty(folio);
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return copied;
 }
@@ -324,7 +334,7 @@ out:
 
 const struct address_space_operations v9fs_addr_operations = {
 	.readpage = v9fs_vfs_readpage,
-	.readpages = v9fs_vfs_readpages,
+	.readahead = v9fs_vfs_readahead,
 	.set_page_dirty = __set_page_dirty_nobuffers,
 	.writepage = v9fs_vfs_writepage,
 	.write_begin = v9fs_write_begin,