[PATCH] Btrfs: set scrub page's io_error if failing to submit io

[PATCH] Btrfs: set scrub page's io_error if failing to submit io

[Liu Bo]

Otherwise, we may later skip this page when repairing bad copy from
good copy.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/scrub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index b0251eb..026c2b8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1497,14 +1497,18 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 
 		bio_add_page(bio, page->page, PAGE_SIZE, 0);
 		if (!retry_failed_mirror && scrub_is_page_on_raid56(page)) {
-			if (scrub_submit_raid56_bio_wait(fs_info, bio, page))
+			if (scrub_submit_raid56_bio_wait(fs_info, bio, page)) {
+				page->io_error = 1;
 				sblock->no_io_error_seen = 0;
+			}
 		} else {
 			bio->bi_iter.bi_sector = page->physical >> 9;
 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
 
-			if (btrfsic_submit_bio_wait(bio))
+			if (btrfsic_submit_bio_wait(bio)) {
+				page->io_error = 1;
 				sblock->no_io_error_seen = 0;
+			}
 		}
 
 		bio_put(bio);
-- 
2.5.5

Re: [PATCH] Btrfs: set scrub page's io_error if failing to submit io

[David Sterba]

On Fri, Mar 24, 2017 at 04:48:00PM -0700, Liu Bo wrote:
> Otherwise, we may later skip this page when repairing bad copy from
> good copy.

Can you please enhance the changelog? At least some more pointers what
and where it could go wrong if the value is not set properly, to get the
rough idea. Thanks.

[PATCH v2] Btrfs: set scrub page's io_error if failing to submit io

[Liu Bo]

Scrub repairs data by the unit called scrub_block, which may contains
several pages.  Scrub always tries to look up a good copy of a whole
block, but if there's no such copy, it tries to do repair page by page.

If we don't set page's io_error when checking this bad copy, in the last
step, we may skip this page when repairing bad copy from good copy.

Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
v2: Put more details in changelog.

 fs/btrfs/scrub.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index b0251eb..026c2b8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -1497,14 +1497,18 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 
 		bio_add_page(bio, page->page, PAGE_SIZE, 0);
 		if (!retry_failed_mirror && scrub_is_page_on_raid56(page)) {
-			if (scrub_submit_raid56_bio_wait(fs_info, bio, page))
+			if (scrub_submit_raid56_bio_wait(fs_info, bio, page)) {
+				page->io_error = 1;
 				sblock->no_io_error_seen = 0;
+			}
 		} else {
 			bio->bi_iter.bi_sector = page->physical >> 9;
 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
 
-			if (btrfsic_submit_bio_wait(bio))
+			if (btrfsic_submit_bio_wait(bio)) {
+				page->io_error = 1;
 				sblock->no_io_error_seen = 0;
+			}
 		}
 
 		bio_put(bio);
-- 
2.5.5

Re: [PATCH v2] Btrfs: set scrub page's io_error if failing to submit io

[David Sterba]

On Wed, Mar 29, 2017 at 10:55:16AM -0700, Liu Bo wrote:
> Scrub repairs data by the unit called scrub_block, which may contains
> several pages.  Scrub always tries to look up a good copy of a whole
> block, but if there's no such copy, it tries to do repair page by page.
> 
> If we don't set page's io_error when checking this bad copy, in the last
> step, we may skip this page when repairing bad copy from good copy.

Great, thanks.

> Cc: David Sterba <dsterba@suse.cz>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>

Reviewed-by: David Sterba <dsterba@suse.com>