From 7aff8cf4a6d6190e64386f407a7f5cc5f24c60d2 Mon Sep 17 00:00:00 2001 From: Zhao Lei Date: Thu, 14 Jan 2016 18:39:00 +0800 Subject: [PATCH] btrfs: reada: ignore creating reada_extent for a non-existent device For a non-existent device, old code bypasses 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 an exception for the first stripe, in short, the first stripe will always be processed whether the device exists or not. Actually we have a better way for the above request: just bypass creation of the reada_extent for non-existent device, it will make code simple and effective. Signed-off-by: Zhao Lei Signed-off-by: David Sterba --- fs/btrfs/reada.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c index 5bcd567f4827..dd5f361f1a8e 100644 --- a/fs/btrfs/reada.c +++ b/fs/btrfs/reada.c @@ -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) { /* -- 2.20.1