From 3581f843defa0bb30fd7da1e7dba170465e13a95 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Fri, 25 Sep 2026 20:16:09 -0300 Subject: [PATCH] smb: client: drain outstanding I/O before truncating on O_TRUNC open cifs_do_truncate() flushes the pagecache with filemap_write_and_wait() before resetting the file size to zero, but that does not wait for direct/async I/O that was already in flight, which can complete after the truncate and reinstate stale data past the new EOF. Drain outstanding netfs I/O with netfs_wait_for_outstanding_io() before resizing the file. Reported-by: Frank Sorenson Fixes: a8603b52b39f ("smb: client: fix data corruption with concurrent writes and O_TRUNC") Reviewed-by: David Howells Reviewed-by: Namjae Jeon Signed-off-by: Paulo Alcantara Cc: Christian Brauner Cc: Matthew Wilcox Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org --- fs/smb/client/file.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 4bcb87610897..11355d6bf89d 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -1012,6 +1012,8 @@ static int cifs_do_truncate(const unsigned int xid, struct dentry *dentry) } mapping_set_error(inode->i_mapping, rc); + netfs_wait_for_outstanding_io(inode); + cfile = find_writable_file(cinode, FIND_FSUID_ONLY); rc = cifs_file_flush(xid, inode, cfile); if (!rc) {