[PATCH 33/43] btrfs: hold a ref on the root in create_pending_snapshot

Josef Bacik
2020-01-17T21:27:08Z

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>
---
fs/btrfs/ioctl.c | 1 +
fs/btrfs/transaction.c | 6 ++++++
2 files changed, 7 insertions(+)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 69c39b3d15a5..47953d022328 100644
--- 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 e194d3e4e3a9..7008def3391b 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1637,6 +1637,12 @@ 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) {
--
2.24.1