Revert "dm mirror: use all available legs on multiple failures"
This reverts commit 12a7cf5ba6c776a2621d8972c7d42e8d3d959d20.
This commit apparently attempted to fix an issue that didn't really
exist, furthermore: this commit is the source of deadlocks and crashes
seen in multiple cases related to failing the primary mirror dev while
syncing.
Reported-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index e61c450..4da8858 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -145,6 +145,7 @@ static void dispatch_bios(void *context, struct bio_list *bio_list)
struct dm_raid1_bio_record {
struct mirror *m;
+ /* if details->bi_bdev == NULL, details were not saved */
struct dm_bio_details details;
region_t write_region;
};
@@ -1198,6 +1199,8 @@ static int mirror_map(struct dm_target *ti, struct bio *bio)
struct dm_raid1_bio_record *bio_record =
dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
+ bio_record->details.bi_bdev = NULL;
+
if (rw == WRITE) {
/* Save region for mirror_end_io() handler */
bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
@@ -1256,12 +1259,22 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
}
if (error == -EOPNOTSUPP)
- return error;
+ goto out;
if ((error == -EWOULDBLOCK) && (bio->bi_opf & REQ_RAHEAD))
- return error;
+ goto out;
if (unlikely(error)) {
+ if (!bio_record->details.bi_bdev) {
+ /*
+ * There wasn't enough memory to record necessary
+ * information for a retry or there was no other
+ * mirror in-sync.
+ */
+ DMERR_LIMIT("Mirror read failed.");
+ return -EIO;
+ }
+
m = bio_record->m;
DMERR("Mirror read failed from %s. Trying alternative device.",
@@ -1277,6 +1290,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
bd = &bio_record->details;
dm_bio_restore(bd, bio);
+ bio_record->details.bi_bdev = NULL;
bio->bi_error = 0;
queue_bio(ms, bio, rw);
@@ -1285,6 +1299,9 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
DMERR("All replicated volumes dead, failing I/O");
}
+out:
+ bio_record->details.bi_bdev = NULL;
+
return error;
}