This is a note to let you know that I've just added the patch titled
shmem: Fix shmem_rename2()
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
shmem-fix-shmem_rename2.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2a19b5907894edf435a9aa7f4638f1d321730eb4
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Mon Apr 15 11:20:56 2024 -0400
shmem: Fix shmem_rename2()
[ Upstream commit ad191eb6d6942bb835a0b20b647f7c53c1d99ca4 ]
When renaming onto an existing directory entry, user space expects
the replacement entry to have the same directory offset as the
original one.
Link: https://gitlab.alpinelinux.org/alpine/aports/-/issues/15966
Fixes: a2e459555c5f ("shmem: stable directory offsets")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240415152057.4605-4-cel@xxxxxxxxxx
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/libfs.c b/fs/libfs.c
index c392a6edd3930..b635ee5adbcce 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -366,6 +366,9 @@ int simple_offset_empty(struct dentry *dentry)
*
* Caller provides appropriate serialization.
*
+ * User space expects the directory offset value of the replaced
+ * (new) directory entry to be unchanged after a rename.
+ *
* Returns zero on success, a negative errno value on failure.
*/
int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -373,8 +376,14 @@ int simple_offset_rename(struct inode *old_dir, struct dentry *old_dentry,
{
struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir);
struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir);
+ long new_offset = dentry2offset(new_dentry);
simple_offset_remove(old_ctx, old_dentry);
+
+ if (new_offset) {
+ offset_set(new_dentry, 0);
+ return simple_offset_replace(new_ctx, old_dentry, new_offset);
+ }
return simple_offset_add(new_ctx, old_dentry);
}
