@@ -371,6 +371,11 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
struct reada_zone *zone;
dev = bbio->stripes[nzones].dev;
+
+ /* cannot read ahead on missing device. */
+ if (!dev->bdev)
+ continue;
+
zone = reada_find_zone(fs_info, dev, logical, bbio);
if (!zone)
continue;
@@ -423,15 +428,9 @@ static struct reada_extent *reada_find_extent(struct btrfs_root *root,
*/
continue;
}
- if (!dev->bdev) {
- /*
- * cannot read ahead on missing device, but for RAID5/6,
- * REQ_GET_READ_MIRRORS return 1. So don't skip missing
- * device for such case.
- */
- if (nzones > 1)
- continue;
- }
+ if (!dev->bdev)
+ continue;
+
if (dev_replace_is_ongoing &&
dev == fs_info->dev_replace.tgtdev) {
/*
For a non-exist device, old code bypass adding it in dev's reada queue. And to solve problem of unfinished waitting in raid5/6, commit 5fbc7c59fd22 ("Btrfs: fix unfinished readahead thread for raid5/6 degraded mounting") adding a exception for the first strip, in short, the first strip will always be processed whether the device exist or not. Actually we have a better way for above request: just bypass creation of the reada_extent for non-exist device, it will make code simple and effective. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/reada.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-)