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[v2,04/42] btrfs: convert BUG_ON()'s in relocate_tree_block

Message ID f68183e94c9a9c0f9b2c0b882bbb9557be33491e.1605284383.git.josef@toxicpanda.com (mailing list archive)
State New, archived
Headers show
Series [v2,01/42] btrfs: allow error injection for btrfs_search_slot and btrfs_cow_block | expand

Commit Message

Josef Bacik Nov. 13, 2020, 4:22 p.m. UTC
We have a couple of BUG_ON()'s in relocate_tree_block() that can be
tripped if we have file system corruption.  Convert these to ASSERT()'s
so developers still get yelled at when they break the backref code, but
error out nicely for users so the whole box doesn't go down.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 fs/btrfs/relocation.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)
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Patch

diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index d4cf982c78ff..3a5e89c82fa5 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2475,8 +2475,28 @@  static int relocate_tree_block(struct btrfs_trans_handle *trans,
 
 	if (root) {
 		if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
-			BUG_ON(node->new_bytenr);
-			BUG_ON(!list_empty(&node->list));
+			/*
+			 * This block was the root block of a root, and this is
+			 * the first time we're processing the block and thus it
+			 * should not have had the ->new_bytenr modified and
+			 * should have not been included on the changed list.
+			 *
+			 * However in the case of corruption we could have
+			 * multiple refs pointing to the same block improperly,
+			 * and thus we would trip over these checks.  ASSERT()
+			 * for the developer case, because it could indicate a
+			 * bug in the backref code, however error out for a
+			 * normal user in the case of corruption.
+			 */
+			ASSERT(node->new_bytenr == 0);
+			ASSERT(list_empty(&node->list));
+			if (node->new_bytenr || !list_empty(&node->list)) {
+				btrfs_err(root->fs_info,
+				  "bytenr %llu has improper references to it",
+					  node->bytenr);
+				ret = -EUCLEAN;
+				goto out;
+			}
 			btrfs_record_root_in_trans(trans, root);
 			root = root->reloc_root;
 			node->new_bytenr = root->node->start;