fs/cifs: make share unaccessible at root level mountable
if, when mounting //HOST/share/sub/dir/foo we can query /sub/dir/foo but
not any of the path components above:
- store the /sub/dir/foo prefix in the cifs super_block info
- in the superblock, set root dentry to the subpath dentry (instead of
the share root)
- set a flag in the superblock to remember it
- use prefixpath when building path from a dentry
fixes bso#8950
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 5d841f3..6bbec5e 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -689,6 +689,14 @@
goto out_cifs_sb;
}
+ if (volume_info->prepath) {
+ cifs_sb->prepath = kstrdup(volume_info->prepath, GFP_KERNEL);
+ if (cifs_sb->prepath == NULL) {
+ root = ERR_PTR(-ENOMEM);
+ goto out_cifs_sb;
+ }
+ }
+
cifs_setup_cifs_sb(volume_info, cifs_sb);
rc = cifs_mount(cifs_sb, volume_info);
@@ -727,7 +735,11 @@
sb->s_flags |= MS_ACTIVE;
}
- root = cifs_get_root(volume_info, sb);
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
+ root = dget(sb->s_root);
+ else
+ root = cifs_get_root(volume_info, sb);
+
if (IS_ERR(root))
goto out_super;
