diff mbox

[3/3] cifs: reduce false positives with inode aliasing serverino autodisable

Message ID 1277723413-23769-4-git-send-email-jlayton@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jeff Layton June 28, 2010, 11:10 a.m. UTC
None
diff mbox

Patch

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 35e2466..1bfb8ec 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -736,15 +736,9 @@  cifs_find_inode(struct inode *inode, void *opaque)
 	if ((inode->i_mode & S_IFMT) != (fattr->cf_mode & S_IFMT))
 		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) && !list_empty(&inode->i_dentry)) {
+	/* if it's not a directory or has no dentries, then flag it */
+	if (S_ISDIR(inode->i_mode) && !list_empty(&inode->i_dentry))
 		fattr->cf_flags |= CIFS_FATTR_INO_COLLISION;
-		cifs_autodisable_serverino(CIFS_SB(inode->i_sb));
-	}
 
 	return 1;
 }
@@ -759,6 +753,27 @@  cifs_init_inode(struct inode *inode, void *opaque)
 	return 0;
 }
 
+/*
+ * walk dentry list for an inode and report whether it has aliases that
+ * are hashed. We use this to determine if a directory inode can actually
+ * be used.
+ */
+static bool
+inode_has_hashed_dentries(struct inode *inode)
+{
+	struct dentry *dentry;
+
+	spin_lock(&dcache_lock);
+	list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+		if (!d_unhashed(dentry) || IS_ROOT(dentry)) {
+			spin_unlock(&dcache_lock);
+			return true;
+		}
+	}
+	spin_unlock(&dcache_lock);
+	return false;
+}
+
 /* Given fattrs, get a corresponding inode */
 struct inode *
 cifs_iget(struct super_block *sb, struct cifs_fattr *fattr)
@@ -774,12 +789,16 @@  retry_iget5_locked:
 
 	inode = iget5_locked(sb, hash, cifs_find_inode, cifs_init_inode, fattr);
 	if (inode) {
-		/* was there a problematic inode number collision? */
+		/* was there a potentially problematic inode 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;
+
+			if (inode_has_hashed_dentries(inode)) {
+				cifs_autodisable_serverino(CIFS_SB(sb));
+				iput(inode);
+				fattr->cf_uniqueid = iunique(sb, ROOT_I);
+				goto retry_iget5_locked;
+			}
 		}
 
 		cifs_fattr_to_inode(inode, fattr);