diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2025-01-24 14:19:38 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-01 18:37:53 +0100 |
| commit | 307f68e49ddafa89f8d0c3fdbdb396cb01ee8373 (patch) | |
| tree | ff792b11cf35d9f2712c92af34fc8ce5a8e3ac97 /fs/libfs.c | |
| parent | fc90bbcc08da47a4635455b4e946717d5c26258b (diff) | |
libfs: Add simple_offset_empty()
[ Upstream commit ecba88a3b32d733d41e27973e25b2bc580f64281 ]
For simple filesystems that use directory offset mapping, rely
strictly on the directory offset map to tell when a directory has
no children.
After this patch is applied, the emptiness test holds only the RCU
read lock when the directory being tested has no children.
In addition, this adds another layer of confirmation that
simple_offset_add/remove() are working as expected.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/170820143463.6328.7872919188371286951.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 5a1a25be995e ("libfs: Add simple_offset_rename() API")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/libfs.c')
| -rw-r--r-- | fs/libfs.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index c3dc58e776f9..d7b901cb9af4 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -313,6 +313,38 @@ void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) } /** + * simple_offset_empty - Check if a dentry can be unlinked + * @dentry: dentry to be tested + * + * Returns 0 if @dentry is a non-empty directory; otherwise returns 1. + */ +int simple_offset_empty(struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + struct offset_ctx *octx; + struct dentry *child; + unsigned long index; + int ret = 1; + + if (!inode || !S_ISDIR(inode->i_mode)) + return ret; + + index = DIR_OFFSET_MIN; + octx = inode->i_op->get_offset_ctx(inode); + xa_for_each(&octx->xa, index, child) { + spin_lock(&child->d_lock); + if (simple_positive(child)) { + spin_unlock(&child->d_lock); + ret = 0; + break; + } + spin_unlock(&child->d_lock); + } + + return ret; +} + +/** * simple_offset_rename_exchange - exchange rename with directory offsets * @old_dir: parent of dentry being moved * @old_dentry: dentry being moved |