md/raid1: don't clear bitmap bits on interrupted recovery.

sync_request_write no longer submits writes to a Faulty device. This has
the unfortunate side effect that bitmap bits can be incorrectly cleared
if a recovery is interrupted (previously, end_sync_write would have
prevented this). This means the next recovery may not copy everything
it should, potentially corrupting data.

Add a function for doing the proper md_bitmap_end_sync, called from
end_sync_write and the Faulty case in sync_request_write.

backport note to 4.14: s/md_bitmap_end_sync/bitmap_end_sync
Cc: stable@vger.kernel.org 4.14+
Fixes: 0c9d5b127f69 ("md/raid1: avoid reusing a resync bio after error handling.")
Reviewed-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Tested-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Nate Dailey <nate.dailey@stratus.com>
Signed-off-by: Song Liu <songliubraving@fb.com>

1 files changed, 18 insertions, 10 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 1d54109071cc..fa47249fa3e4 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1863,6 +1863,20 @@ static void end_sync_read(struct bio *bio)
                 reschedule_retry(r1_bio);
 }
 
+static void abort_sync_write(struct mddev *mddev, struct r1bio *r1_bio)
+{
+        sector_t sync_blocks = 0;
+        sector_t s = r1_bio->sector;
+        long sectors_to_go = r1_bio->sectors;
+
+        /* make sure these bits don't get cleared. */
+        do {
+                md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
+                s += sync_blocks;
+                sectors_to_go -= sync_blocks;
+        } while (sectors_to_go > 0);
+}
+
 static void end_sync_write(struct bio *bio)
 {
         int uptodate = !bio->bi_status;
@@ -1874,15 +1888,7 @@ static void end_sync_write(struct bio *bio)
         struct md_rdev *rdev = conf->mirrors[find_bio_disk(r1_bio, bio)].rdev;
 
         if (!uptodate) {
-                sector_t sync_blocks = 0;
-                sector_t s = r1_bio->sector;
-                long sectors_to_go = r1_bio->sectors;
-                /* make sure these bits doesn't get cleared. */
-                do {
-                        md_bitmap_end_sync(mddev->bitmap, s, &sync_blocks, 1);
-                        s += sync_blocks;
-                        sectors_to_go -= sync_blocks;
-                } while (sectors_to_go > 0);
+                abort_sync_write(mddev, r1_bio);
                 set_bit(WriteErrorSeen, &rdev->flags);
                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
                         set_bit(MD_RECOVERY_NEEDED, &
@@ -2172,8 +2178,10 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
                      (i == r1_bio->read_disk ||
                       !test_bit(MD_RECOVERY_SYNC, &mddev->recovery))))
                         continue;
-                if (test_bit(Faulty, &conf->mirrors[i].rdev->flags))
+                if (test_bit(Faulty, &conf->mirrors[i].rdev->flags)) {
+                        abort_sync_write(mddev, r1_bio);
                         continue;
+                }
 
                 bio_set_op_attrs(wbio, REQ_OP_WRITE, 0);
                 if (test_bit(FailFast, &conf->mirrors[i].rdev->flags))