Patch "shmem: Fix shmem_rename2()" has been added to the 6.6-stable tree

gregkh
2025-01-30T09:00:03Z

This is a note to let you know that I've just added the patch titled

shmem: Fix shmem_rename2()

to the 6.6-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-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.

From stable+bounces-110406-greg=kroah.com@vger.kernel.org Fri Jan 24 20:22:02 2025
From: cel@kernel.org
Date: Fri, 24 Jan 2025 14:19:41 -0500
Subject: shmem: Fix shmem_rename2()
To: Hugh Dickins <hughd@google.com>, Andrew Morten <akpm@linux-foundation.org>, Christian Brauner <brauner@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Sasha Levin <sashal@kernel.org>
Cc: <linux-fsdevel@vger.kernel.org>, <stable@vger.kernel.org>, <linux-mm@kvack.org>, yukuai3@huawei.com, yangerkun@huawei.com, Chuck Lever <chuck.lever@oracle.com>
Message-ID: <20250124191946.22308-7-cel@kernel.org>

From: Chuck Lever <chuck.lever@oracle.com>

[ 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@oracle.com>
Link: https://lore.kernel.org/r/20240415152057.4605-4-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/libfs.c | 9 +++++++++
1 file changed, 9 insertions(+)

--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -365,6 +365,9 @@ int simple_offset_empty(struct dentry *d
*
* 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,
@@ -372,8 +375,14 @@ int simple_offset_rename(struct inode *o
{
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);
}

Patches currently in stable-queue which might be from cel@kernel.org are

queue-6.6/libfs-replace-simple_offset-end-of-directory-detection.patch
queue-6.6/libfs-re-arrange-locking-in-offset_iterate_dir.patch
queue-6.6/libfs-add-simple_offset_empty.patch
queue-6.6/shmem-fix-shmem_rename2.patch
queue-6.6/revert-libfs-add-simple_offset_empty.patch
queue-6.6/libfs-use-d_children-list-to-iterate-simple_offset-directories.patch
queue-6.6/libfs-define-a-minimum-directory-offset.patch
queue-6.6/libfs-return-enospc-when-the-directory-offset-range-is-exhausted.patch
queue-6.6/libfs-fix-simple_offset_rename_exchange.patch
queue-6.6/libfs-add-simple_offset_rename-api.patch