* [PATCH 6.11 123/695] cachefiles: Fix non-taking of sb_writers around set/removexattr
[not found] <20241002125822.467776898@linuxfoundation.org>
@ 2024-10-02 12:52 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2024-10-02 12:52 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, David Howells, Christian Brauner,
Gao Xiang, netfs, linux-erofs, linux-fsdevel, Sasha Levin
6.11-stable review patch. If anyone has any objections, please let me know.
------------------
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);
--
2.43.0
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