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Diffstat (limited to 'fs/libfs.c')
-rw-r--r--fs/libfs.c153
1 files changed, 91 insertions, 62 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index 0ca80b2af420..74dc8b9e7f53 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -25,7 +25,7 @@ int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
{
struct inode *inode = d_inode(dentry);
generic_fillattr(inode, stat);
- stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
+ stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9);
return 0;
}
EXPORT_SYMBOL(simple_getattr);
@@ -33,7 +33,7 @@ EXPORT_SYMBOL(simple_getattr);
int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
{
buf->f_type = dentry->d_sb->s_magic;
- buf->f_bsize = PAGE_CACHE_SIZE;
+ buf->f_bsize = PAGE_SIZE;
buf->f_namelen = NAME_MAX;
return 0;
}
@@ -71,9 +71,7 @@ EXPORT_SYMBOL(simple_lookup);
int dcache_dir_open(struct inode *inode, struct file *file)
{
- static struct qstr cursor_name = QSTR_INIT(".", 1);
-
- file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
+ file->private_data = d_alloc_cursor(file->f_path.dentry);
return file->private_data ? 0 : -ENOMEM;
}
@@ -86,10 +84,64 @@ int dcache_dir_close(struct inode *inode, struct file *file)
}
EXPORT_SYMBOL(dcache_dir_close);
+/* parent is locked at least shared */
+static struct dentry *next_positive(struct dentry *parent,
+ struct list_head *from,
+ int count)
+{
+ unsigned *seq = &parent->d_inode->i_dir_seq, n;
+ struct dentry *res;
+ struct list_head *p;
+ bool skipped;
+ int i;
+
+retry:
+ i = count;
+ skipped = false;
+ n = smp_load_acquire(seq) & ~1;
+ res = NULL;
+ rcu_read_lock();
+ for (p = from->next; p != &parent->d_subdirs; p = p->next) {
+ struct dentry *d = list_entry(p, struct dentry, d_child);
+ if (!simple_positive(d)) {
+ skipped = true;
+ } else if (!--i) {
+ res = d;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ if (skipped) {
+ smp_rmb();
+ if (unlikely(*seq != n))
+ goto retry;
+ }
+ return res;
+}
+
+static void move_cursor(struct dentry *cursor, struct list_head *after)
+{
+ struct dentry *parent = cursor->d_parent;
+ unsigned n, *seq = &parent->d_inode->i_dir_seq;
+ spin_lock(&parent->d_lock);
+ for (;;) {
+ n = *seq;
+ if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
+ break;
+ cpu_relax();
+ }
+ __list_del(cursor->d_child.prev, cursor->d_child.next);
+ if (after)
+ list_add(&cursor->d_child, after);
+ else
+ list_add_tail(&cursor->d_child, &parent->d_subdirs);
+ smp_store_release(seq, n + 2);
+ spin_unlock(&parent->d_lock);
+}
+
loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
{
struct dentry *dentry = file->f_path.dentry;
- inode_lock(d_inode(dentry));
switch (whence) {
case 1:
offset += file->f_pos;
@@ -97,34 +149,21 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
if (offset >= 0)
break;
default:
- inode_unlock(d_inode(dentry));
return -EINVAL;
}
if (offset != file->f_pos) {
file->f_pos = offset;
if (file->f_pos >= 2) {
- struct list_head *p;
struct dentry *cursor = file->private_data;
+ struct dentry *to;
loff_t n = file->f_pos - 2;
- spin_lock(&dentry->d_lock);
- /* d_lock not required for cursor */
- list_del(&cursor->d_child);
- p = dentry->d_subdirs.next;
- while (n && p != &dentry->d_subdirs) {
- struct dentry *next;
- next = list_entry(p, struct dentry, d_child);
- spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
- if (simple_positive(next))
- n--;
- spin_unlock(&next->d_lock);
- p = p->next;
- }
- list_add_tail(&cursor->d_child, p);
- spin_unlock(&dentry->d_lock);
+ inode_lock_shared(dentry->d_inode);
+ to = next_positive(dentry, &dentry->d_subdirs, n);
+ move_cursor(cursor, to ? &to->d_child : NULL);
+ inode_unlock_shared(dentry->d_inode);
}
}
- inode_unlock(d_inode(dentry));
return offset;
}
EXPORT_SYMBOL(dcache_dir_lseek);
@@ -145,36 +184,25 @@ int dcache_readdir(struct file *file, struct dir_context *ctx)
{
struct dentry *dentry = file->f_path.dentry;
struct dentry *cursor = file->private_data;
- struct list_head *p, *q = &cursor->d_child;
+ struct list_head *p = &cursor->d_child;
+ struct dentry *next;
+ bool moved = false;
if (!dir_emit_dots(file, ctx))
return 0;
- spin_lock(&dentry->d_lock);
- if (ctx->pos == 2)
- list_move(q, &dentry->d_subdirs);
- for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
- struct dentry *next = list_entry(p, struct dentry, d_child);
- spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
- if (!simple_positive(next)) {
- spin_unlock(&next->d_lock);
- continue;
- }
-
- spin_unlock(&next->d_lock);
- spin_unlock(&dentry->d_lock);
+ if (ctx->pos == 2)
+ p = &dentry->d_subdirs;
+ while ((next = next_positive(dentry, p, 1)) != NULL) {
if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
d_inode(next)->i_ino, dt_type(d_inode(next))))
- return 0;
- spin_lock(&dentry->d_lock);
- spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
- /* next is still alive */
- list_move(q, p);
- spin_unlock(&next->d_lock);
- p = q;
+ break;
+ moved = true;
+ p = &next->d_child;
ctx->pos++;
}
- spin_unlock(&dentry->d_lock);
+ if (moved)
+ move_cursor(cursor, p);
return 0;
}
EXPORT_SYMBOL(dcache_readdir);
@@ -190,7 +218,7 @@ const struct file_operations simple_dir_operations = {
.release = dcache_dir_close,
.llseek = dcache_dir_lseek,
.read = generic_read_dir,
- .iterate = dcache_readdir,
+ .iterate_shared = dcache_readdir,
.fsync = noop_fsync,
};
EXPORT_SYMBOL(simple_dir_operations);
@@ -395,7 +423,7 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
struct page *page;
pgoff_t index;
- index = pos >> PAGE_CACHE_SHIFT;
+ index = pos >> PAGE_SHIFT;
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
@@ -403,10 +431,10 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
*pagep = page;
- if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
- unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ if (!PageUptodate(page) && (len != PAGE_SIZE)) {
+ unsigned from = pos & (PAGE_SIZE - 1);
- zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
+ zero_user_segments(page, 0, from, from + len, PAGE_SIZE);
}
return 0;
}
@@ -442,7 +470,7 @@ int simple_write_end(struct file *file, struct address_space *mapping,
/* zero the stale part of the page if we did a short copy */
if (copied < len) {
- unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ unsigned from = pos & (PAGE_SIZE - 1);
zero_user(page, from + copied, len - copied);
}
@@ -458,7 +486,7 @@ int simple_write_end(struct file *file, struct address_space *mapping,
set_page_dirty(page);
unlock_page(page);
- page_cache_release(page);
+ put_page(page);
return copied;
}
@@ -477,8 +505,8 @@ int simple_fill_super(struct super_block *s, unsigned long magic,
struct dentry *dentry;
int i;
- s->s_blocksize = PAGE_CACHE_SIZE;
- s->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ s->s_blocksize = PAGE_SIZE;
+ s->s_blocksize_bits = PAGE_SHIFT;
s->s_magic = magic;
s->s_op = &simple_super_operations;
s->s_time_gran = 1;
@@ -994,12 +1022,12 @@ int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
{
u64 last_fs_block = num_blocks - 1;
u64 last_fs_page =
- last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
+ last_fs_block >> (PAGE_SHIFT - blocksize_bits);
if (unlikely(num_blocks == 0))
return 0;
- if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
+ if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT))
return -EINVAL;
if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
@@ -1121,14 +1149,15 @@ static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr)
return -EPERM;
}
-static int empty_dir_setxattr(struct dentry *dentry, const char *name,
- const void *value, size_t size, int flags)
+static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode,
+ const char *name, const void *value,
+ size_t size, int flags)
{
return -EOPNOTSUPP;
}
-static ssize_t empty_dir_getxattr(struct dentry *dentry, const char *name,
- void *value, size_t size)
+static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode,
+ const char *name, void *value, size_t size)
{
return -EOPNOTSUPP;
}
@@ -1169,7 +1198,7 @@ static int empty_dir_readdir(struct file *file, struct dir_context *ctx)
static const struct file_operations empty_dir_operations = {
.llseek = empty_dir_llseek,
.read = generic_read_dir,
- .iterate = empty_dir_readdir,
+ .iterate_shared = empty_dir_readdir,
.fsync = noop_fsync,
};
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