Introduce btrfs_iget helper

Date: Mon, 21 Jul 2008 02:01:04 +0530
This patch introduces a btrfs_iget helper to be used in NFS support.
Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

fs/btrfs/ctree.h

@@ -1700,6 +1700,8 @@ struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
 				struct btrfs_root *root);
 struct inode *btrfs_ilookup(struct super_block *s, u64 objectid,
 			    u64 root_objectid);
+struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
+			 struct btrfs_root *root, int *is_new);
 int btrfs_commit_write(struct file *file, struct page *page,
 		       unsigned from, unsigned to);
 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,

fs/btrfs/inode.c

@@ -1840,6 +1840,33 @@ struct inode *btrfs_iget_locked(struct super_block *s, u64 objectid,
 	return inode;
 }
 
+/* Get an inode object given its location and corresponding root.
+ * Returns in *is_new if the inode was read from disk
+ */
+struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
+			 struct btrfs_root *root, int *is_new)
+{
+	struct inode *inode;
+
+	inode = btrfs_iget_locked(s, location->objectid, root);
+	if (!inode)
+		return ERR_PTR(-EACCES);
+
+	if (inode->i_state & I_NEW) {
+		BTRFS_I(inode)->root = root;
+		memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
+		btrfs_read_locked_inode(inode);
+		unlock_new_inode(inode);
+		if (is_new)
+			*is_new = 1;
+	} else {
+		if (is_new)
+			*is_new = 0;
+	}
+
+	return inode;
+}
+
 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 				   struct nameidata *nd)
 {
@@ -1848,7 +1875,7 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 	struct btrfs_root *root = bi->root;
 	struct btrfs_root *sub_root = root;
 	struct btrfs_key location;
-	int ret, do_orphan = 0;
+	int ret, new, do_orphan = 0;
 
 	if (dentry->d_name.len > BTRFS_NAME_LEN)
 		return ERR_PTR(-ENAMETOOLONG);
@@ -1866,24 +1893,16 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
 			return ERR_PTR(ret);
 		if (ret > 0)
 			return ERR_PTR(-ENOENT);
+		inode = btrfs_iget(dir->i_sb, &location, sub_root, &new);
+		if (IS_ERR(inode))
+			return ERR_CAST(inode);
 
-		inode = btrfs_iget_locked(dir->i_sb, location.objectid,
-					  sub_root);
-		if (!inode)
-			return ERR_PTR(-EACCES);
-		if (inode->i_state & I_NEW) {
 		/* the inode and parent dir are two different roots */
-			if (sub_root != root) {
+		if (new && root != sub_root) {
 			igrab(inode);
 			sub_root->inode = inode;
 			do_orphan = 1;
 		}
-			BTRFS_I(inode)->root = sub_root;
-			memcpy(&BTRFS_I(inode)->location, &location,
-			       sizeof(location));
-			btrfs_read_locked_inode(inode);
-			unlock_new_inode(inode);
-		}
 	}
 
 	if (unlikely(do_orphan))