From: Qu Wenruo wqu@suse.com
[ Upstream commit df94a342efb451deb0e32b495d1d6cd4bb3a1648 ]
[BUG] Even after all the error fixes related the "ASSERT(list_empty(&fs_info->delayed_iputs));" in close_ctree(), I can still hit it reliably with my experimental 2K block size.
[CAUSE] In my case, all the error is triggered after the fs is already in error status.
I find the following call trace to be the cause of race:
Main thread | endio_write_workers ---------------------------------------------+--------------------------- close_ctree() | |- btrfs_error_commit_super() | | |- btrfs_cleanup_transaction() | | | |- btrfs_destroy_all_ordered_extents() | | | |- btrfs_wait_ordered_roots() | | |- btrfs_run_delayed_iputs() | | | btrfs_finish_ordered_io() | | |- btrfs_put_ordered_extent() | | |- btrfs_add_delayed_iput() |- ASSERT(list_empty(delayed_iputs)) | !!! Triggered !!!
The root cause is that, btrfs_wait_ordered_roots() only wait for ordered extents to finish their IOs, not to wait for them to finish and removed.
[FIX] Since btrfs_error_commit_super() will flush and wait for all ordered extents, it should be executed early, before we start flushing the workqueues.
And since btrfs_error_commit_super() now runs early, there is no need to run btrfs_run_delayed_iputs() inside it, so just remove the btrfs_run_delayed_iputs() call from btrfs_error_commit_super().
Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Qu Wenruo wqu@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/disk-io.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index de4f590fe30f2..6670188b9eb6b 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4641,6 +4641,14 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) /* clear out the rbtree of defraggable inodes */ btrfs_cleanup_defrag_inodes(fs_info);
+ /* + * Handle the error fs first, as it will flush and wait for all ordered + * extents. This will generate delayed iputs, thus we want to handle + * it first. + */ + if (unlikely(BTRFS_FS_ERROR(fs_info))) + btrfs_error_commit_super(fs_info); + /* * Wait for any fixup workers to complete. * If we don't wait for them here and they are still running by the time @@ -4730,9 +4738,6 @@ void __cold close_ctree(struct btrfs_fs_info *fs_info) btrfs_err(fs_info, "commit super ret %d", ret); }
- if (BTRFS_FS_ERROR(fs_info)) - btrfs_error_commit_super(fs_info); - kthread_stop(fs_info->transaction_kthread); kthread_stop(fs_info->cleaner_kthread);
@@ -4888,10 +4893,6 @@ static void btrfs_error_commit_super(struct btrfs_fs_info *fs_info) /* cleanup FS via transaction */ btrfs_cleanup_transaction(fs_info);
- mutex_lock(&fs_info->cleaner_mutex); - btrfs_run_delayed_iputs(fs_info); - mutex_unlock(&fs_info->cleaner_mutex); - down_write(&fs_info->cleanup_work_sem); up_write(&fs_info->cleanup_work_sem); }