From cfad392b22163eba71d882950e17d2c4d43b2bad Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 25 Jul 2013 15:11:47 -0400 Subject: [PATCH] Btrfs: check to see if root_list is empty before adding it to dead roots A user reported a panic when running with autodefrag and deleting snapshots. This is because we could end up trying to add the root to the dead roots list twice. To fix this check to see if we are empty before adding ourselves to the dead roots list. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/transaction.c | 8 ++++---- fs/btrfs/transaction.h | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index d58cce7..af1931a 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -983,12 +983,12 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, * a dirty root struct and adds it into the list of dead roots that need to * be deleted */ -int btrfs_add_dead_root(struct btrfs_root *root) +void btrfs_add_dead_root(struct btrfs_root *root) { spin_lock(&root->fs_info->trans_lock); - list_add_tail(&root->root_list, &root->fs_info->dead_roots); + if (list_empty(&root->root_list)) + list_add_tail(&root->root_list, &root->fs_info->dead_roots); spin_unlock(&root->fs_info->trans_lock); - return 0; } /* @@ -1925,7 +1925,7 @@ int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root) } root = list_first_entry(&fs_info->dead_roots, struct btrfs_root, root_list); - list_del(&root->root_list); + list_del_init(&root->root_list); spin_unlock(&fs_info->trans_lock); pr_debug("btrfs: cleaner removing %llu\n", diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index 005b037..defbc42 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -143,7 +143,7 @@ int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid); int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, struct btrfs_root *root); -int btrfs_add_dead_root(struct btrfs_root *root); +void btrfs_add_dead_root(struct btrfs_root *root); int btrfs_defrag_root(struct btrfs_root *root); int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root); int btrfs_commit_transaction(struct btrfs_trans_handle *trans, -- 2.7.4