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authorZhao Lei <zhaolei@cn.fujitsu.com>2016-01-14 18:39:00 +0800
committerDavid Sterba <dsterba@suse.com>2016-02-18 10:27:23 +0100
commit7aff8cf4a6d6190e64386f407a7f5cc5f24c60d2 (patch)
tree9175c4bc56b6af11db51e1db2e9c6582af4e05a6 /fs/btrfs/reada.c
parent4fe7a0e13864238fe5b4cc2640e963581f96429e (diff)
downloadlinux-7aff8cf4a6d6190e64386f407a7f5cc5f24c60d2.tar.gz
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 <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/reada.c')
-rw-r--r--fs/btrfs/reada.c17
1 files 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) {
 			/*