fs: btrfs: Use btrfs_lookup_path() to implement btrfs_exists() and btrfs_size()

After this the only remaining function that still utilizes
__btrfs_lookup_path() is btrfs_read().

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Marek Behún <marek.behun@nic.cz>

diff --git a/fs/btrfs/btrfs.c b/fs/btrfs/btrfs.c
index 2278b52e4d0e84c4f7decc9eb8fc72d54ae052ea..aec91a57eceb131d4efdcb7355904e54ff9c729f 100644 (file)
--- a/fs/btrfs/btrfs.c
+++ b/fs/btrfs/btrfs.c
@@ -188,37 +188,66 @@ int btrfs_ls(const char *path)
 
 int btrfs_exists(const char *file)
 {
-       struct __btrfs_root root = btrfs_info.fs_root;
-       u64 inr;
+       struct btrfs_fs_info *fs_info = current_fs_info;
+       struct btrfs_root *root;
+       u64 ino;
        u8 type;
+       int ret;
+
+       ASSERT(fs_info);
 
-       inr = __btrfs_lookup_path(&root, root.root_dirid, file, &type, NULL, 40);
+       ret = btrfs_lookup_path(fs_info->fs_root, BTRFS_FIRST_FREE_OBJECTID,
+                               file, &root, &ino, &type, 40);
+       if (ret < 0)
+               return 0;
 
-       return (inr != -1ULL && type == BTRFS_FT_REG_FILE);
+       if (type == BTRFS_FT_REG_FILE)
+               return 1;
+       return 0;
 }
 
 int btrfs_size(const char *file, loff_t *size)
 {
-       struct __btrfs_root root = btrfs_info.fs_root;
-       struct btrfs_inode_item inode;
-       u64 inr;
+       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 ino;
        u8 type;
+       int ret;
 
-       inr = __btrfs_lookup_path(&root, root.root_dirid, file, &type, &inode,
-                               40);
-
-       if (inr == -1ULL) {
+       ret = btrfs_lookup_path(fs_info->fs_root, BTRFS_FIRST_FREE_OBJECTID,
+                               file, &root, &ino, &type, 40);
+       if (ret < 0) {
                printf("Cannot lookup file %s\n", file);
-               return -1;
+               return ret;
        }
-
        if (type != BTRFS_FT_REG_FILE) {
                printf("Not a regular file: %s\n", file);
-               return -1;
+               return -ENOENT;
        }
+       btrfs_init_path(&path);
+       key.objectid = ino;
+       key.type = BTRFS_INODE_ITEM_KEY;
+       key.offset = 0;
 
-       *size = inode.size;
-       return 0;
+       ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+       if (ret < 0) {
+               printf("Cannot lookup 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;
 }
 
 int btrfs_read(const char *file, void *buf, loff_t offset, loff_t len,
@@ -270,7 +299,9 @@ void btrfs_close(void)
 int btrfs_uuid(char *uuid_str)
 {
 #ifdef CONFIG_LIB_UUID
-       uuid_bin_to_str(btrfs_info.sb.fsid, uuid_str, UUID_STR_FORMAT_STD);
+       if (current_fs_info)
+               uuid_bin_to_str(current_fs_info->super_copy->fsid, uuid_str,
+                               UUID_STR_FORMAT_STD);
        return 0;
 #endif
        return -ENOSYS;