btrfs: hold a ref on the root in create_pending_snapshot

We create the snapshot and then use it for a bunch of things, we need to
hold a ref on it while we're messing with it.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5fde22d..f36aa06 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -875,6 +875,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
        d_instantiate(dentry, inode);
        ret = 0;
 fail:
+       btrfs_put_fs_root(pending_snapshot->snap);
        btrfs_subvolume_release_metadata(fs_info, &pending_snapshot->block_rsv);
 dec_and_free:
        if (snapshot_force_cow)

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index bcf23b0..3fa2e7d 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1639,6 +1639,12 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
                btrfs_abort_transaction(trans, ret);
                goto fail;
        }
+       if (!btrfs_grab_fs_root(pending->snap)) {
+               ret = -ENOENT;
+               pending->snap = NULL;
+               btrfs_abort_transaction(trans, ret);
+               goto fail;
+       }
 
        ret = btrfs_reloc_post_snapshot(trans, pending);
        if (ret) {