Patch "libfs: Return ENOSPC when the directory offset range is exhausted" has been added to the 6.6-stable tree

[<gregkh@linuxfoundation.org>]

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

    libfs: Return ENOSPC when the directory offset range is exhausted

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:
     libfs-return-enospc-when-the-directory-offset-range-is-exhausted.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-110407-greg=kroah.com@vger.kernel.org Fri Jan 24 20:20:27 2025
From: cel@kernel.org
Date: Fri, 24 Jan 2025 14:19:42 -0500
Subject: libfs: Return ENOSPC when the directory offset range is exhausted
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>, Jeff Layton <jlayton@kernel.org>
Message-ID: <20250124191946.22308-8-cel@kernel.org>

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

[ Upstream commit 903dc9c43a155e0893280c7472d4a9a3a83d75a6 ]

Testing shows that the EBUSY error return from mtree_alloc_cyclic()
leaks into user space. The ERRORS section of "man creat(2)" says:

>	EBUSY	O_EXCL was specified in flags and pathname refers
>		to a block device that is in use by the system
>		(e.g., it is mounted).

ENOSPC is closer to what applications expect in this situation.

Note that the normal range of simple directory offset values is
2..2^63, so hitting this error is going to be rare to impossible.

Fixes: 6faddda69f62 ("libfs: Add directory operations for stable offsets")
Cc: stable@vger.kernel.org # v6.9+
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20241228175522.1854234-2-cel@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
[ cel: adjusted to apply to origin/linux-6.6.y ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/libfs.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -287,8 +287,8 @@ int simple_offset_add(struct offset_ctx
 
 	ret = xa_alloc_cyclic(&octx->xa, &offset, dentry, limit,
 			      &octx->next_offset, GFP_KERNEL);
-	if (ret < 0)
-		return ret;
+	if (unlikely(ret < 0))
+		return ret == -EBUSY ? -ENOSPC : ret;
 
 	offset_set(dentry, offset);
 	return 0;


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