Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vfs: new helper - d_make_root()
  dcache: use a dispose list in select_parent
  ceph: d_alloc_root() may fail
  ext4: fix failure exits
  isofs: inode leak on mount failure

5 files changed, 63 insertions, 53 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 11bd0fc4853..48f61a12af6 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -636,19 +636,26 @@ static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
 	req->r_num_caps = 2;
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
 	if (err == 0) {
+		struct inode *inode = req->r_target_inode;
+		req->r_target_inode = NULL;
 		dout("open_root_inode success\n");
-		if (ceph_ino(req->r_target_inode) == CEPH_INO_ROOT &&
+		if (ceph_ino(inode) == CEPH_INO_ROOT &&
 		    fsc->sb->s_root == NULL) {
-			root = d_alloc_root(req->r_target_inode);
+			root = d_alloc_root(inode);
+			if (!root) {
+				iput(inode);
+				root = ERR_PTR(-ENOMEM);
+				goto out;
+			}
 			ceph_init_dentry(root);
 		} else {
-			root = d_obtain_alias(req->r_target_inode);
+			root = d_obtain_alias(inode);
 		}
-		req->r_target_inode = NULL;
 		dout("open_root_inode success, root dentry is %p\n", root);
 	} else {
 		root = ERR_PTR(err);
 	}
+out:
 	ceph_mdsc_put_request(req);
 	return root;
 }
diff --git a/fs/dcache.c b/fs/dcache.c
index 9791b1e7eee..3c6d3113a25 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -276,15 +276,15 @@ static void dentry_lru_prune(struct dentry *dentry)
 	}
 }
 
-static void dentry_lru_move_tail(struct dentry *dentry)
+static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list)
 {
 	spin_lock(&dcache_lru_lock);
 	if (list_empty(&dentry->d_lru)) {
-		list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+		list_add_tail(&dentry->d_lru, list);
 		dentry->d_sb->s_nr_dentry_unused++;
 		dentry_stat.nr_unused++;
 	} else {
-		list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+		list_move_tail(&dentry->d_lru, list);
 	}
 	spin_unlock(&dcache_lru_lock);
 }
@@ -770,14 +770,18 @@ static void shrink_dentry_list(struct list_head *list)
 }
 
 /**
- * __shrink_dcache_sb - shrink the dentry LRU on a given superblock
- * @sb:		superblock to shrink dentry LRU.
- * @count:	number of entries to prune
- * @flags:	flags to control the dentry processing
+ * prune_dcache_sb - shrink the dcache
+ * @sb: superblock
+ * @count: number of entries to try to free
+ *
+ * Attempt to shrink the superblock dcache LRU by @count entries. This is
+ * done when we need more memory an called from the superblock shrinker
+ * function.
  *
- * If flags contains DCACHE_REFERENCED reference dentries will not be pruned.
+ * This function may fail to free any resources if all the dentries are in
+ * use.
  */
-static void __shrink_dcache_sb(struct super_block *sb, int count, int flags)
+void prune_dcache_sb(struct super_block *sb, int count)
 {
 	struct dentry *dentry;
 	LIST_HEAD(referenced);
@@ -796,13 +800,7 @@ relock:
 			goto relock;
 		}
 
-		/*
-		 * If we are honouring the DCACHE_REFERENCED flag and the
-		 * dentry has this flag set, don't free it.  Clear the flag
-		 * and put it back on the LRU.
-		 */
-		if (flags & DCACHE_REFERENCED &&
-				dentry->d_flags & DCACHE_REFERENCED) {
+		if (dentry->d_flags & DCACHE_REFERENCED) {
 			dentry->d_flags &= ~DCACHE_REFERENCED;
 			list_move(&dentry->d_lru, &referenced);
 			spin_unlock(&dentry->d_lock);
@@ -822,23 +820,6 @@ relock:
 }
 
 /**
- * prune_dcache_sb - shrink the dcache
- * @sb: superblock
- * @nr_to_scan: number of entries to try to free
- *
- * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is
- * done when we need more memory an called from the superblock shrinker
- * function.
- *
- * This function may fail to free any resources if all the dentries are in
- * use.
- */
-void prune_dcache_sb(struct super_block *sb, int nr_to_scan)
-{
-	__shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED);
-}
-
-/**
  * shrink_dcache_sb - shrink dcache for a superblock
  * @sb: superblock
  *
@@ -1092,7 +1073,7 @@ EXPORT_SYMBOL(have_submounts);
  * drop the lock and return early due to latency
  * constraints.
  */
-static int select_parent(struct dentry * parent)
+static int select_parent(struct dentry *parent, struct list_head *dispose)
 {
 	struct dentry *this_parent;
 	struct list_head *next;
@@ -1114,12 +1095,11 @@ resume:
 
 		spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
 
-		/* 
-		 * move only zero ref count dentries to the end 
-		 * of the unused list for prune_dcache
+		/*
+		 * move only zero ref count dentries to the dispose list.
 		 */
 		if (!dentry->d_count) {
-			dentry_lru_move_tail(dentry);
+			dentry_lru_move_list(dentry, dispose);
 			found++;
 		} else {
 			dentry_lru_del(dentry);
@@ -1181,14 +1161,13 @@ rename_retry:
  *
  * Prune the dcache to remove unused children of the parent dentry.
  */
- 
 void shrink_dcache_parent(struct dentry * parent)
 {
-	struct super_block *sb = parent->d_sb;
+	LIST_HEAD(dispose);
 	int found;
 
-	while ((found = select_parent(parent)) != 0)
-		__shrink_dcache_sb(sb, found, 0);
+	while ((found = select_parent(parent, &dispose)) != 0)
+		shrink_dentry_list(&dispose);
 }
 EXPORT_SYMBOL(shrink_dcache_parent);
 
@@ -1461,6 +1440,23 @@ struct dentry * d_alloc_root(struct inode * root_inode)
 }
 EXPORT_SYMBOL(d_alloc_root);
 
+struct dentry *d_make_root(struct inode *root_inode)
+{
+	struct dentry *res = NULL;
+
+	if (root_inode) {
+		static const struct qstr name = { .name = "/", .len = 1 };
+
+		res = __d_alloc(root_inode->i_sb, &name);
+		if (res)
+			d_instantiate(res, root_inode);
+		else
+			iput(root_inode);
+	}
+	return res;
+}
+EXPORT_SYMBOL(d_make_root);
+
 static struct dentry * __d_find_any_alias(struct inode *inode)
 {
 	struct dentry *alias;
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 64e2529ae9b..ed3ce82e2de 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3733,10 +3733,12 @@ no_journal:
 	}
 	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 		ext4_msg(sb, KERN_ERR, "corrupt root inode, run e2fsck");
+		iput(root);
 		goto failed_mount4;
 	}
 	sb->s_root = d_alloc_root(root);
 	if (!sb->s_root) {
+		iput(root);
 		ext4_msg(sb, KERN_ERR, "get root dentry failed");
 		ret = -ENOMEM;
 		goto failed_mount4;
@@ -3773,7 +3775,7 @@ no_journal:
 	if (err) {
 		ext4_msg(sb, KERN_ERR, "failed to initialize system "
 			 "zone (%d)", err);
-		goto failed_mount4;
+		goto failed_mount4a;
 	}
 
 	ext4_ext_init(sb);
@@ -3830,13 +3832,14 @@ cantfind_ext4:
 failed_mount7:
 	ext4_unregister_li_request(sb);
 failed_mount6:
-	ext4_ext_release(sb);
-failed_mount5:
 	ext4_mb_release(sb);
+failed_mount5:
+	ext4_ext_release(sb);
 	ext4_release_system_zone(sb);
-failed_mount4:
-	iput(root);
+failed_mount4a:
+	dput(sb->s_root);
 	sb->s_root = NULL;
+failed_mount4:
 	ext4_msg(sb, KERN_ERR, "mount failed");
 	destroy_workqueue(EXT4_SB(sb)->dio_unwritten_wq);
 failed_mount_wq:
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 7b99f5f460b..bd62c76fb5d 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -948,8 +948,11 @@ root_found:
 
 	/* get the root dentry */
 	s->s_root = d_alloc_root(inode);
-	if (!(s->s_root))
-		goto out_no_root;
+	if (!(s->s_root)) {
+		iput(inode);
+		error = -ENOMEM;
+		goto out_no_inode;
+	}
 
 	kfree(opt.iocharset);
 
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index ed9f74f6c51..a47bda5f76d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -249,6 +249,7 @@ extern int d_invalidate(struct dentry *);
 
 /* only used at mount-time */
 extern struct dentry * d_alloc_root(struct inode *);
+extern struct dentry * d_make_root(struct inode *);
 
 /* <clickety>-<click> the ramfs-type tree */
 extern void d_genocide(struct dentry *);