While testing my backport I noticed there was a panic if I ran generic/416 generic/417 generic/418 all in a row. This just happened to uncover a race where we had outstanding IO after we destroy all of our workqueues, and then we'd go to queue the endio work on those free'd workqueues. This is because we aren't waiting for the caching threads to be done before freeing everything up, so to fix this make sure we wait on any outstanding caching that's being done before we free up the block group, so we're sure to be done with all IO by the time we get to btrfs_stop_all_workers(). This fixes the panic I was seeing consistently in testing.
Signed-off-by: Josef Bacik <jo...@toxicpanda.com> Reviewed-by: Omar Sandoval <osan...@fb.com> --- fs/btrfs/extent-tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 922dd509591a..262e0f7f2ea1 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9890,6 +9890,7 @@ void btrfs_put_block_group_cache(struct btrfs_fs_info *info) block_group = btrfs_lookup_first_block_group(info, last); while (block_group) { + wait_block_group_cache_done(block_group); spin_lock(&block_group->lock); if (block_group->iref) break; -- 2.14.3