Merge tag 'v6.11-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client fixes from Steve French:

 - fix for clang warning - additional null check

 - fix for cached write with posix locks

 - flexible structure fix

* tag 'v6.11-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  smb: smb2pdu.h: Use static_assert() to check struct sizes
  smb3: fix lock breakage for cached writes
  smb/client: avoid possible NULL dereference in cifs_free_subrequest()

fs/smb/client/file.c

@@ -316,7 +316,7 @@ static void cifs_free_subrequest(struct netfs_io_subrequest *subreq)
 #endif
 	}
 
-	if (rdata->credits.value != 0)
+	if (rdata->credits.value != 0) {
 		trace_smb3_rw_credits(rdata->rreq->debug_id,
 				      rdata->subreq.debug_index,
 				      rdata->credits.value,
@@ -324,8 +324,12 @@ static void cifs_free_subrequest(struct netfs_io_subrequest *subreq)
 				      rdata->server ? rdata->server->in_flight : 0,
 				      -rdata->credits.value,
 				      cifs_trace_rw_credits_free_subreq);
+		if (rdata->server)
+			add_credits_and_wake_if(rdata->server, &rdata->credits, 0);
+		else
+			rdata->credits.value = 0;
+	}
 
-	add_credits_and_wake_if(rdata->server, &rdata->credits, 0);
 	if (rdata->have_xid)
 		free_xid(rdata->xid);
 }
@@ -2750,6 +2754,7 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	struct inode *inode = file->f_mapping->host;
 	struct cifsInodeInfo *cinode = CIFS_I(inode);
 	struct TCP_Server_Info *server = tlink_tcon(cfile->tlink)->ses->server;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 	ssize_t rc;
 
 	rc = netfs_start_io_write(inode);
@@ -2766,12 +2771,16 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 	if (rc <= 0)
 		goto out;
 
-	if (!cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) &&
+	    (cifs_find_lock_conflict(cfile, iocb->ki_pos, iov_iter_count(from),
 				     server->vals->exclusive_lock_type, 0,
-				     NULL, CIFS_WRITE_OP))
-		rc = netfs_buffered_write_iter_locked(iocb, from, NULL);
-	else
+				     NULL, CIFS_WRITE_OP))) {
 		rc = -EACCES;
+		goto out;
+	}
+
+	rc = netfs_buffered_write_iter_locked(iocb, from, NULL);
+
 out:
 	up_read(&cinode->lock_sem);
 	netfs_end_io_write(inode);

fs/smb/common/smb2pdu.h

@@ -1216,6 +1216,8 @@ struct create_context {
 	);
 	__u8 Buffer[];
 } __packed;
+static_assert(offsetof(struct create_context, Buffer) == sizeof(struct create_context_hdr),
+	      "struct member likely outside of __struct_group()");
 
 struct smb2_create_req {
 	struct smb2_hdr hdr;