btrfs: allow cross-subvolume file clone

Lift the EXDEV condition and allow different root trees for files being
cloned, then pass source inode's root when searching for extents.
Cloning is not allowed to cross vfsmounts, ie. when two subvolumes from
one filesystem are mounted separately.

Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0e92e5763005214b5d55d091d6fcfb94d73f4875..7011871c45b829b71da376e76c5672dbcc42fa0b 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2340,6 +2340,10 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                goto out_drop_write;
        }
 
+       ret = -EXDEV;
+       if (src_file->f_path.mnt != file->f_path.mnt)
+               goto out_fput;
+
        src = src_file->f_dentry->d_inode;
 
        ret = -EINVAL;
@@ -2360,7 +2364,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                goto out_fput;
 
        ret = -EXDEV;
-       if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root)
+       if (src->i_sb != inode->i_sb)
                goto out_fput;
 
        ret = -ENOMEM;
@@ -2434,13 +2438,14 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                 * note the key will change type as we walk through the
                 * tree.
                 */
-               ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+               ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
+                               0, 0);
                if (ret < 0)
                        goto out;
 
                nritems = btrfs_header_nritems(path->nodes[0]);
                if (path->slots[0] >= nritems) {
-                       ret = btrfs_next_leaf(root, path);
+                       ret = btrfs_next_leaf(BTRFS_I(src)->root, path);
                        if (ret < 0)
                                goto out;
                        if (ret > 0)