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authorJosef Bacik <jbacik@fb.com>2014-03-27 14:56:51 -0400
committerChris Mason <clm@fb.com>2014-04-06 20:34:35 -0400
commitba8b0289333a70f0d69923fd63350d0b0201b904 (patch)
treee3e7b84c5a61b7156577c72ca3ea386738bad9c0 /fs/btrfs
parent00fdf13a2e9f313a044288aa59d3b8ec29ff904a (diff)
Btrfs: do not reset last_snapshot after relocation
This was done to allow NO_COW to continue to be NO_COW after relocation but it is not right. When relocating we will convert blocks to FULL_BACKREF that we relocate. We can leave some of these full backref blocks behind if they are not cow'ed out during the relocation, like if we fail the relocation with ENOSPC and then just drop the reloc tree. Then when we go to cow the block again we won't lookup the extent flags because we won't think there has been a snapshot recently which means we will do our normal ref drop thing instead of adding back a tree ref and dropping the shared ref. This will cause btrfs_free_extent to blow up because it can't find the ref we are trying to free. This was found with my ref verifying tool. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs')
-rw-r--r--fs/btrfs/relocation.c21
1 files changed, 0 insertions, 21 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index def428a25b2a..7f92ab1daa87 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2317,7 +2317,6 @@ void free_reloc_roots(struct list_head *list)
2317static noinline_for_stack 2317static noinline_for_stack
2318int merge_reloc_roots(struct reloc_control *rc) 2318int merge_reloc_roots(struct reloc_control *rc)
2319{ 2319{
2320 struct btrfs_trans_handle *trans;
2321 struct btrfs_root *root; 2320 struct btrfs_root *root;
2322 struct btrfs_root *reloc_root; 2321 struct btrfs_root *reloc_root;
2323 u64 last_snap; 2322 u64 last_snap;
@@ -2375,26 +2374,6 @@ again:
2375 list_add_tail(&reloc_root->root_list, 2374 list_add_tail(&reloc_root->root_list,
2376 &reloc_roots); 2375 &reloc_roots);
2377 goto out; 2376 goto out;
2378 } else if (!ret) {
2379 /*
2380 * recover the last snapshot tranid to avoid
2381 * the space balance break NOCOW.
2382 */
2383 root = read_fs_root(rc->extent_root->fs_info,
2384 objectid);
2385 if (IS_ERR(root))
2386 continue;
2387
2388 trans = btrfs_join_transaction(root);
2389 BUG_ON(IS_ERR(trans));
2390
2391 /* Check if the fs/file tree was snapshoted or not. */
2392 if (btrfs_root_last_snapshot(&root->root_item) ==
2393 otransid - 1)
2394 btrfs_set_root_last_snapshot(&root->root_item,
2395 last_snap);
2396
2397 btrfs_end_transaction(trans, root);
2398 } 2377 }
2399 } 2378 }
2400 2379