md: Make flush bios explicitely sync

Commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as
synchronous" removed REQ_SYNC flag from WRITE_{FUA|PREFLUSH|...}
definitions.  generic_make_request_checks() however strips REQ_FUA and
REQ_PREFLUSH flags from a bio when the storage doesn't report volatile
write cache and thus write effectively becomes asynchronous which can
lead to performance regressions

Fix the problem by making sure all bios which are synchronous are
properly marked with REQ_SYNC.

CC: linux-raid@vger.kernel.org
CC: Shaohua Li <shli@kernel.org>
Fixes: b685d3d65ac791406e0dfd8779cc9b3707fea5a3
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 10367ffe92e3e37704f5e32793ea97175c8b15e6..212a6777ff3172dd9e20401dd7bf87ad5d2f7468 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -765,7 +765,7 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
            test_bit(FailFast, &rdev->flags) &&
            !test_bit(LastDev, &rdev->flags))
                ff = MD_FAILFAST;
-       bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_FUA | ff;
+       bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH | REQ_FUA | ff;
 
        atomic_inc(&mddev->pending_writes);
        submit_bio(bio);

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 4c00bc248287e4ab89b492225e0d054973725549..0a7af8b0a80a031a99a7af1742e2d64e6df0d106 100644 (file)
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1782,7 +1782,7 @@ static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
        mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
                                             mb, PAGE_SIZE));
        if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, REQ_OP_WRITE,
-                         REQ_FUA, false)) {
+                         REQ_SYNC | REQ_FUA, false)) {
                __free_page(page);
                return -EIO;
        }
@@ -2388,7 +2388,7 @@ r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
                mb->checksum = cpu_to_le32(crc32c_le(log->uuid_checksum,
                                                     mb, PAGE_SIZE));
                sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page,
-                            REQ_OP_WRITE, REQ_FUA, false);
+                            REQ_OP_WRITE, REQ_SYNC | REQ_FUA, false);
                sh->log_start = ctx->pos;
                list_add_tail(&sh->r5c, &log->stripe_in_journal_list);
                atomic_inc(&log->stripe_in_journal_count);

diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
index 5d25bebf3328e4967334465916aca3e3c750e447..ccce92e68d7fa5d8258bb7f2ca2bfa1bcd545709 100644 (file)
--- a/drivers/md/raid5-ppl.c
+++ b/drivers/md/raid5-ppl.c
@@ -907,8 +907,8 @@ static int ppl_write_empty_header(struct ppl_log *log)
        pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PAGE_SIZE));
 
        if (!sync_page_io(rdev, rdev->ppl.sector - rdev->data_offset,
-                         PPL_HEADER_SIZE, page, REQ_OP_WRITE | REQ_FUA, 0,
-                         false)) {
+                         PPL_HEADER_SIZE, page, REQ_OP_WRITE | REQ_SYNC |
+                         REQ_FUA, 0, false)) {
                md_error(rdev->mddev, rdev);
                ret = -EIO;
        }