[PATCH v3 3/3] fs: btrfs: deduplicate the inode size lookup

btrfs_readdir() and btrfs_size() both open code the same search for an
inode item to read its size field. Move it into one helper.

Signed-off-by: Cole Munz <[email protected]>
---
 fs/btrfs/btrfs.c | 75 +++++++++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 33 deletions(-)

diff --git a/fs/btrfs/btrfs.c b/fs/btrfs/btrfs.c
index b2856be0662f..f5f6d638ffd3 100644
--- a/fs/btrfs/btrfs.c
+++ b/fs/btrfs/btrfs.c
@@ -88,14 +88,42 @@ static unsigned int btrfs_dirent_type_to_fs_type(u8 dirent_type)
 	}
 }
 
+/*
+ * Read the size stored in an inode item.  A missing item is -ENOENT and
+ * leaves *size untouched.
+ */
+static int btrfs_get_inode_size(struct btrfs_root *root, u64 ino, u64 *size)
+{
+	struct btrfs_inode_item *ii;
+	struct btrfs_path path;
+	struct btrfs_key key;
+	int ret;
+
+	key.objectid = ino;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+
+	btrfs_init_path(&path);
+	ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+	if (ret < 0)
+		return ret;
+	if (ret > 0)
+		ret = -ENOENT;
+	if (!ret) {
+		ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
+				    struct btrfs_inode_item);
+		*size = btrfs_inode_size(path.nodes[0], ii);
+	}
+	btrfs_release_path(&path);
+	return ret;
+}
+
 int btrfs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
 {
 	struct btrfs_dir_stream *dirs = container_of(fs_dirs, struct btrfs_dir_stream, parent);
 	struct btrfs_fs_info *fs_info = current_fs_info;
 	struct fs_dirent *dent = &dirs->dirent;
-	struct btrfs_inode_item *ii;
 	struct btrfs_root *root;
-	struct btrfs_path path;
 	struct btrfs_key location;
 	struct btrfs_key key;
 	u8 type;
@@ -127,16 +155,13 @@ int btrfs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
 	 * layer prints it, so look it up.
 	 */
 	if (location.type == BTRFS_INODE_ITEM_KEY) {
-		btrfs_init_path(&path);
-		ret = btrfs_search_slot(NULL, root, &location, &path, 0, 0);
-		if (ret == 0) {
-			ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
-					    struct btrfs_inode_item);
-			dent->size = btrfs_inode_size(path.nodes[0], ii);
-		}
-		btrfs_release_path(&path);
-		if (ret < 0)
+		u64 size;
+
+		ret = btrfs_get_inode_size(root, location.objectid, &size);
+		if (ret < 0 && ret != -ENOENT)
 			return ret;
+		if (!ret)
+			dent->size = size;
 	}
 
 	*dentp = dent;
@@ -173,10 +198,8 @@ int btrfs_exists(const char *file)
 int btrfs_size(const char *file, loff_t *size)
 {
 	struct btrfs_fs_info *fs_info = current_fs_info;
-	struct btrfs_inode_item *ii;
 	struct btrfs_root *root;
-	struct btrfs_path path;
-	struct btrfs_key key;
+	u64 isize;
 	u64 ino;
 	u8 type;
 	int ret;
@@ -191,27 +214,13 @@ int btrfs_size(const char *file, loff_t *size)
 		printf("Not a regular file: %s\n", file);
 		return -ENOENT;
 	}
-	btrfs_init_path(&path);
-	key.objectid = ino;
-	key.type = BTRFS_INODE_ITEM_KEY;
-	key.offset = 0;
-
-	ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
-	if (ret < 0) {
-		printf("Cannot lookup ino %llu\n", ino);
+	ret = btrfs_get_inode_size(root, ino, &isize);
+	if (ret) {
+		printf("Cannot read size of ino %llu\n", ino);
 		return ret;
 	}
-	if (ret > 0) {
-		printf("Ino %llu does not exist\n", ino);
-		ret = -ENOENT;
-		goto out;
-	}
-	ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
-			    struct btrfs_inode_item);
-	*size = btrfs_inode_size(path.nodes[0], ii);
-out:
-	btrfs_release_path(&path);
-	return ret;
+	*size = isize;
+	return 0;
 }
 
 int btrfs_read(const char *file, void *buf, loff_t offset, loff_t len,
-- 
2.55.0