diff mbox

[linux-cifs-client] cifs: guard against hardlinking directories

Message ID 1273241032-6404-1-git-send-email-jlayton@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jeff Layton May 7, 2010, 2:03 p.m. UTC
None
diff mbox

Patch

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index ecf0ffb..0c2fd17 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -502,6 +502,7 @@  struct dfs_info3_param {
 #define CIFS_FATTR_DFS_REFERRAL		0x1
 #define CIFS_FATTR_DELETE_PENDING	0x2
 #define CIFS_FATTR_NEED_REVAL		0x4
+#define CIFS_FATTR_INO_COLLISION	0x8
 
 struct cifs_fattr {
 	u32		cf_flags;
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ee35c97..fb20f11 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -714,6 +714,16 @@  cifs_find_inode(struct inode *inode, void *opaque)
 	if (CIFS_I(inode)->uniqueid != fattr->cf_uniqueid)
 		return 0;
 
+	/*
+	 * uh oh -- it's a directory. We can't use it since hardlinked dirs are
+	 * verboten. Disable serverino and return it as if it were found, the
+	 * caller can discard it, generate a uniqueid and retry the find
+	 */
+	if (S_ISDIR(inode->i_mode)) {
+		fattr->cf_flags |= CIFS_FATTR_INO_COLLISION;
+		cifs_autodisable_serverino(CIFS_SB(inode->i_sb));
+	}
+
 	return 1;
 }
 
@@ -733,15 +743,22 @@  cifs_iget(struct super_block *sb, struct cifs_fattr *fattr)
 	unsigned long hash;
 	struct inode *inode;
 
+retry_iget5_locked:
 	cFYI(1, ("looking for uniqueid=%llu", fattr->cf_uniqueid));
 
 	/* hash down to 32-bits on 32-bit arch */
 	hash = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
 
 	inode = iget5_locked(sb, hash, cifs_find_inode, cifs_init_inode, fattr);
-
-	/* we have fattrs in hand, update the inode */
 	if (inode) {
+		/* was there a problematic inode number collision? */
+		if (fattr->cf_flags & CIFS_FATTR_INO_COLLISION) {
+			iput(inode);
+			fattr->cf_uniqueid = iunique(sb, ROOT_I);
+			fattr->cf_flags &= ~CIFS_FATTR_INO_COLLISION;
+			goto retry_iget5_locked;
+		}
+
 		cifs_fattr_to_inode(inode, fattr);
 		if (sb->s_flags & MS_NOATIME)
 			inode->i_flags |= S_NOATIME | S_NOCMTIME;