From 53c5c2c1095eb21e214811fec16cd75f89d72ee2 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Mon, 28 Sep 2026 10:23:00 -0300 Subject: smb: client: require stable pages for signed connections When signing, cifs computes the SMB signature over the pagecache folios in place and then hands those same folios to the socket. If a buffered write mutates a folio while a write subrequest is still in flight, the signature no longer matches the data that follows it, the server rejects the write with STATUS_ACCESS_DENIED (-EACCES), and the error is latched in the mapping, so the next fsync()/fallocate() returns -EIO. Mark the mapping for stable writes so netfs_perform_write() waits for writeback to complete before modifying an in-flight folio. This is only needed when the connection is signed. Fixes: 3ee1a1fc3981 ("cifs: Cut over to using netfslib") 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/inode.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c index 506247499..f29555f3c 100644 --- a/fs/smb/client/inode.c +++ b/fs/smb/client/inode.c @@ -88,6 +88,8 @@ static void cifs_set_ops(struct inode *inode) else inode->i_data.a_ops = &cifs_addr_ops; mapping_set_large_folios(inode->i_mapping); + if (tcon->ses->server->sign) + mapping_set_stable_writes(inode->i_mapping); break; case S_IFDIR: if (IS_AUTOMOUNT(inode)) { -- cgit v1.3.1