Since the zoned filesystem requires sequential write out of metadata, we
cannot proceed with a hole in tree-log pages. When such a hole exists,
btree_write_cache_pages() will return -EAGAIN. We cannot wait for the range
to be written, because it will cause a deadlock. So, let's bail out to a
full commit in this case.
Cc: Filipe Manana <fdmanana@xxxxxxxxx>
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/tree-log.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
This patch solves a regression introduced by fixing patch 40. I'm
sorry for the confusing patch numbering.
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 4e72794342c0..629e605cd62d 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3120,6 +3120,14 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
*/
blk_start_plug(&plug);
ret = btrfs_write_marked_extents(fs_info, &log->dirty_log_pages, mark);
+ /*
+ * There is a hole writing out the extents and cannot proceed it on
+ * zoned filesystem, which require sequential writing. We can
+ * ignore the error for now, since we don't wait for completion for
+ * now.
+ */
+ if (ret == -EAGAIN)
+ ret = 0;
if (ret) {
blk_finish_plug(&plug);
btrfs_abort_transaction(trans, ret);
@@ -3229,7 +3237,16 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans,
&log_root_tree->dirty_log_pages,
EXTENT_DIRTY | EXTENT_NEW);
blk_finish_plug(&plug);
- if (ret) {
+ /*
+ * There is a hole in the extents, and failed to sequential write
+ * on zoned filesystem. We cannot wait for this write outs, sinc it
+ * cause a deadlock. Bail out to the full commit, instead.
+ */
+ if (ret == -EAGAIN) {
+ btrfs_wait_tree_log_extents(log, mark);
+ mutex_unlock(&log_root_tree->log_mutex);
+ goto out_wake_log_root;
+ } else if (ret) {
btrfs_set_log_full_commit(trans);
btrfs_abort_transaction(trans, ret);
mutex_unlock(&log_root_tree->log_mutex);
--
2.30.0
