* [PATCH 6.12.y 2/3] smb: client: fix race with fallocate(2) and AIO+DIO
[not found] ` <20260812000933.4158055-1-sashal@kernel.org>
@ 2026-08-12 0:09 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2026-08-12 0:09 UTC (permalink / raw)
To: stable
Cc: Paulo Alcantara, David Howells, Frank Sorenson, linux-cifs,
Steve French, Sasha Levin
From: Paulo Alcantara <pc@manguebit.org>
[ Upstream commit dba9f997c9d9a1cade05d006ed0429a63a4eed32 ]
AIO+DIO may extend the file size, hence we need to make sure ->i_size
is stable across the entire fallocate(2) operation, otherwise it would
become a truncate and then inode size reduced back down when it
finishes.
Fix this by calling netfs_wait_for_outstanding_io() right after
acquiring ->i_rwsem exclusively in cifs_fallocate() and then guarantee
a stable ->i_size across fallocate(2).
Also call netfs_wait_for_outstanding_io() after truncating pagecache
to avoid any potential races with writeback.
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Fixes: 210627b0aca9 ("smb: client: fix missing timestamp updates with O_TRUNC")
Cc: Frank Sorenson <sorenson@redhat.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Stable-dep-of: fa724e235cfd ("cifs: add fscache_resize_cookie() to cifs_setsize()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/smb/client/cifsfs.c | 22 +++++++++++++++++++---
fs/smb/client/inode.c | 1 +
fs/smb/client/smb2ops.c | 18 ++++++------------
3 files changed, 26 insertions(+), 15 deletions(-)
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 2f666c92b027b..08e7931cdda2b 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -359,11 +359,27 @@ static long cifs_fallocate(struct file *file, int mode, loff_t off, loff_t len)
struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
struct TCP_Server_Info *server = tcon->ses->server;
+ struct inode *inode = file_inode(file);
+ int rc;
+
+ if (!server->ops->fallocate)
+ return -EOPNOTSUPP;
+
+ rc = inode_lock_killable(inode);
+ if (rc)
+ return rc;
+
+ netfs_wait_for_outstanding_io(inode);
- if (server->ops->fallocate)
- return server->ops->fallocate(file, tcon, mode, off, len);
+ rc = file_modified(file);
+ if (rc)
+ goto out_unlock;
+
+ rc = server->ops->fallocate(file, tcon, mode, off, len);
- return -EOPNOTSUPP;
+out_unlock:
+ inode_unlock(inode);
+ return rc;
}
static int cifs_permission(struct mnt_idmap *idmap,
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index e7fc8d0aebee7..453a5df20f8cc 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -2965,6 +2965,7 @@ void cifs_setsize(struct inode *inode, loff_t offset)
/* Cached inode must be refreshed on truncate */
cifs_i->time = 0;
truncate_pagecache(inode, offset);
+ netfs_wait_for_outstanding_io(inode);
}
static int
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 61309fead04e5..e99b8e1f66d4f 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -3315,7 +3315,6 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
trace_smb3_zero_enter(xid, cfile->fid.persistent_fid, tcon->tid,
ses->Suid, offset, len);
- inode_lock(inode);
filemap_invalidate_lock(inode->i_mapping);
i_size = i_size_read(inode);
@@ -3333,6 +3332,7 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
* first, otherwise the data may be inconsistent with the server.
*/
truncate_pagecache_range(inode, offset, offset + len - 1);
+ netfs_wait_for_outstanding_io(inode);
/* if file not oplocked can't be sure whether asking to extend size */
rc = -EOPNOTSUPP;
@@ -3361,7 +3361,6 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
zero_range_exit:
filemap_invalidate_unlock(inode->i_mapping);
- inode_unlock(inode);
free_xid(xid);
if (rc)
trace_smb3_zero_err(xid, cfile->fid.persistent_fid, tcon->tid,
@@ -3385,7 +3384,6 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
xid = get_xid();
- inode_lock(inode);
/* Need to make file sparse, if not already, before freeing range. */
/* Consider adding equivalent for compressed since it could also work */
rc = smb2_set_sparse(xid, tcon, cfile, inode, set_sparse);
@@ -3398,6 +3396,7 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
* caches first, otherwise the data may be inconsistent with the server.
*/
truncate_pagecache_range(inode, offset, offset + len - 1);
+ netfs_wait_for_outstanding_io(inode);
cifs_dbg(FYI, "Offset %lld len %lld\n", offset, len);
@@ -3432,7 +3431,6 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
unlock:
filemap_invalidate_unlock(inode->i_mapping);
out:
- inode_unlock(inode);
free_xid(xid);
return rc;
}
@@ -3709,8 +3707,6 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
xid = get_xid();
- inode_lock(inode);
-
old_eof = i_size_read(inode);
if ((off >= old_eof) ||
off + len >= old_eof) {
@@ -3725,6 +3721,7 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
truncate_pagecache_range(inode, off, old_eof);
ictx->zero_point = old_eof;
+ netfs_wait_for_outstanding_io(inode);
rc = smb2_copychunk_range(xid, cfile, cfile, off + len,
old_eof - off - len, off);
@@ -3745,8 +3742,7 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
fscache_resize_cookie(cifs_inode_cookie(inode), new_eof);
out_2:
filemap_invalidate_unlock(inode->i_mapping);
- out:
- inode_unlock(inode);
+out:
free_xid(xid);
return rc;
}
@@ -3763,8 +3759,6 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon,
xid = get_xid();
- inode_lock(inode);
-
old_eof = i_size_read(inode);
if (off >= old_eof) {
rc = -EINVAL;
@@ -3779,6 +3773,7 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon,
if (rc < 0)
goto out_2;
truncate_pagecache_range(inode, off, old_eof);
+ netfs_wait_for_outstanding_io(inode);
rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
cfile->fid.volatile_fid, cfile->pid, new_eof);
@@ -3801,8 +3796,7 @@ static long smb3_insert_range(struct file *file, struct cifs_tcon *tcon,
rc = 0;
out_2:
filemap_invalidate_unlock(inode->i_mapping);
- out:
- inode_unlock(inode);
+out:
free_xid(xid);
return rc;
}
--
2.53.0
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