dm: make flush bios explicitly 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.

Fixes: b685d3d65ac7 ("block: treat REQ_FUA and REQ_PREFLUSH as synchronous")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cd8139593ccd50655a2329460cc8de9d175eac86..840c1496b2b138ef504bde4c441b1082df183473 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1334,7 +1334,7 @@ int dm_bufio_issue_flush(struct dm_bufio_client *c)
 {
        struct dm_io_request io_req = {
                .bi_op = REQ_OP_WRITE,
-               .bi_op_flags = REQ_PREFLUSH,
+               .bi_op_flags = REQ_PREFLUSH | REQ_SYNC,
                .mem.type = DM_IO_KMEM,
                .mem.ptr.addr = NULL,
                .client = c->dm_io,

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 1feeb2ccf5a187f2ce0f43cfefc16e99db05f753..7910bfe50da4469c44b571363cc6696f74f5fa42 100644 (file)
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -783,7 +783,8 @@ static void write_journal(struct dm_integrity_c *ic, unsigned commit_start, unsi
                        for (i = 0; i < commit_sections; i++)
                                rw_section_mac(ic, commit_start + i, true);
                }
-               rw_journal(ic, REQ_OP_WRITE, REQ_FUA, commit_start, commit_sections, &io_comp);
+               rw_journal(ic, REQ_OP_WRITE, REQ_FUA | REQ_SYNC, commit_start,
+                          commit_sections, &io_comp);
        } else {
                unsigned to_end;
                io_comp.in_flight = (atomic_t)ATOMIC_INIT(2);

diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index a95cbb80fb34444144bad346b3e769c625e8c788..e61c45047c25a9ba2683c313fbc2151c9051b178 100644 (file)
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -260,7 +260,7 @@ static int mirror_flush(struct dm_target *ti)
        struct mirror *m;
        struct dm_io_request io_req = {
                .bi_op = REQ_OP_WRITE,
-               .bi_op_flags = REQ_PREFLUSH,
+               .bi_op_flags = REQ_PREFLUSH | REQ_SYNC,
                .mem.type = DM_IO_KMEM,
                .mem.ptr.addr = NULL,
                .client = ms->io_client,

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index b93476c3ba3f9767fb133fed977e7a888cc0698e..c5534d294773fc0267a1b4c7438a3316e74d417a 100644 (file)
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -741,7 +741,8 @@ static void persistent_commit_exception(struct dm_exception_store *store,
        /*
         * Commit exceptions to disk.
         */
-       if (ps->valid && area_io(ps, REQ_OP_WRITE, REQ_PREFLUSH | REQ_FUA))
+       if (ps->valid && area_io(ps, REQ_OP_WRITE,
+                                REQ_PREFLUSH | REQ_FUA | REQ_SYNC))
                ps->valid = 0;
 
        /*

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6ef9500226c0c7d789ed78e6876195f73ef9d6b7..37ccd73c79ecf2eeb4f33b5bc597f88ca5750d4b 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1657,7 +1657,7 @@ static struct mapped_device *alloc_dev(int minor)
 
        bio_init(&md->flush_bio, NULL, 0);
        md->flush_bio.bi_bdev = md->bdev;
-       md->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
+       md->flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
 
        dm_stats_init(&md->stats);