[CIFS] fix oops in cifs_lookup during net boot
Steve French [Tue, 24 Nov 2009 22:17:59 +0000 (22:17 +0000)]
Fixes bugzilla.kernel.org bug number 14641

Lookup called during network boot (network root filesystem
for diskless workstation) has case where nd is null in
lookup.  This patch fixes that in cifs_lookup.

(Shirish noted that 2.6.30 and 2.6.31 stable need the same check)

Signed-off-by: Shirish Pargaonkar <shirishp@us.ibm.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Tested-by:  Vladimir Stavrinov <vs@inist.ru>
CC: Stable <stable@kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/dir.c

index 627a60a..32771f5 100644 (file)
@@ -643,7 +643,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         * O_EXCL: optimize away the lookup, but don't hash the dentry. Let
         * the VFS handle the create.
         */
-       if (nd->flags & LOOKUP_EXCL) {
+       if (nd && (nd->flags & LOOKUP_EXCL)) {
                d_instantiate(direntry, NULL);
                return 0;
        }
@@ -675,7 +675,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
         * reduction in network traffic in the other paths.
         */
        if (pTcon->unix_ext) {
-               if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY)) &&
+               if (nd && !(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY)) &&
                     (nd->flags & LOOKUP_OPEN) && !pTcon->broken_posix_open &&
                     (nd->intent.open.flags & O_CREAT)) {
                        rc = cifs_posix_open(full_path, &newInode, nd->path.mnt,