4.0-stable review patch. If anyone has any objections, please let me know.
------------------ From: Filipe Manana <[email protected]> commit 2f1f465ae6da244099af55c066e5355abd8ff620 upstream. If the clone root was not readonly or the dead flag was set on it, we were leaving without decrementing the root's send_progress counter (and before we just incremented it). If a concurrent snapshot deletion was in progress and ended up being aborted, it would be impossible to later attempt to delete again the snapshot, since the root's send_in_progress counter could never go back to 0. We were also setting clone_sources_to_rollback to i + 1 too early - if we bailed out because the clone root we got is not readonly or flagged as dead we ended up later derreferencing a null pointer because we didn't assign the clone root to sctx->clone_roots[i].root: for (i = 0; sctx && i < clone_sources_to_rollback; i++) btrfs_root_dec_send_in_progress( sctx->clone_roots[i].root); So just don't increment the send_in_progress counter if the root is readonly or flagged as dead. Signed-off-by: Filipe Manana <[email protected]> Reviewed-by: David Sterba <[email protected]> Signed-off-by: Chris Mason <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/btrfs/send.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -5852,9 +5852,7 @@ long btrfs_ioctl_send(struct file *mnt_f ret = PTR_ERR(clone_root); goto out; } - clone_sources_to_rollback = i + 1; spin_lock(&clone_root->root_item_lock); - clone_root->send_in_progress++; if (!btrfs_root_readonly(clone_root) || btrfs_root_dead(clone_root)) { spin_unlock(&clone_root->root_item_lock); @@ -5862,10 +5860,12 @@ long btrfs_ioctl_send(struct file *mnt_f ret = -EPERM; goto out; } + clone_root->send_in_progress++; spin_unlock(&clone_root->root_item_lock); srcu_read_unlock(&fs_info->subvol_srcu, index); sctx->clone_roots[i].root = clone_root; + clone_sources_to_rollback = i + 1; } vfree(clone_sources_tmp); clone_sources_tmp = NULL; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
