6.6-stable review patch. If anyone has any objections, please let me know.
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From: David Howells dhowells@redhat.com
[ Upstream commit 80887f31672970abae3aaa9cf62ac72a124e7c89 ]
Unlike other vfs_xxxx() calls, vfs_setxattr() and vfs_removexattr() don't take the sb_writers lock, so the caller should do it for them.
Fix cachefiles to do this.
Fixes: 9ae326a69004 ("CacheFiles: A cache that backs onto a mounted filesystem") Signed-off-by: David Howells dhowells@redhat.com cc: Christian Brauner brauner@kernel.org cc: Gao Xiang xiang@kernel.org cc: netfs@lists.linux.dev cc: linux-erofs@lists.ozlabs.org cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20240814203850.2240469-3-dhowells@redhat.com/ # v2 Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/cachefiles/xattr.c | 34 ++++++++++++++++++++++++++-------- 1 file changed, 26 insertions(+), 8 deletions(-)
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c index 4dd8a993c60a8..7c6f260a3be56 100644 --- a/fs/cachefiles/xattr.c +++ b/fs/cachefiles/xattr.c @@ -64,9 +64,15 @@ int cachefiles_set_object_xattr(struct cachefiles_object *object) memcpy(buf->data, fscache_get_aux(object->cookie), len);
ret = cachefiles_inject_write_error(); - if (ret == 0) - ret = vfs_setxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, - buf, sizeof(struct cachefiles_xattr) + len, 0); + if (ret == 0) { + ret = mnt_want_write_file(file); + if (ret == 0) { + ret = vfs_setxattr(&nop_mnt_idmap, dentry, + cachefiles_xattr_cache, buf, + sizeof(struct cachefiles_xattr) + len, 0); + mnt_drop_write_file(file); + } + } if (ret < 0) { trace_cachefiles_vfs_error(object, file_inode(file), ret, cachefiles_trace_setxattr_error); @@ -151,8 +157,14 @@ int cachefiles_remove_object_xattr(struct cachefiles_cache *cache, int ret;
ret = cachefiles_inject_remove_error(); - if (ret == 0) - ret = vfs_removexattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache); + if (ret == 0) { + ret = mnt_want_write(cache->mnt); + if (ret == 0) { + ret = vfs_removexattr(&nop_mnt_idmap, dentry, + cachefiles_xattr_cache); + mnt_drop_write(cache->mnt); + } + } if (ret < 0) { trace_cachefiles_vfs_error(object, d_inode(dentry), ret, cachefiles_trace_remxattr_error); @@ -208,9 +220,15 @@ bool cachefiles_set_volume_xattr(struct cachefiles_volume *volume) memcpy(buf->data, p, volume->vcookie->coherency_len);
ret = cachefiles_inject_write_error(); - if (ret == 0) - ret = vfs_setxattr(&nop_mnt_idmap, dentry, cachefiles_xattr_cache, - buf, len, 0); + if (ret == 0) { + ret = mnt_want_write(volume->cache->mnt); + if (ret == 0) { + ret = vfs_setxattr(&nop_mnt_idmap, dentry, + cachefiles_xattr_cache, + buf, len, 0); + mnt_drop_write(volume->cache->mnt); + } + } if (ret < 0) { trace_cachefiles_vfs_error(NULL, d_inode(dentry), ret, cachefiles_trace_setxattr_error);