[PATCH 4.19 03/22] dm integrity: fix flush with external metadata device

Greg Kroah-Hartman
2021-01-22T18:56:22Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit 9b5948267adc9e689da609eb61cf7ed49cae5fa8 upstream.

With external metadata device, flush requests are not passed down to the
data device.

Fix this by submitting the flush request in dm_integrity_flush_buffers. In
order to not degrade performance, we overlap the data device flush with
the metadata device flush.

Reported-by: Lukas Straub <lukasstraub2@web.de>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-bufio.c | 6 +++++
drivers/md/dm-integrity.c | 50 +++++++++++++++++++++++++++++++++++++++++-----
include/linux/dm-bufio.h | 1
3 files changed, 52 insertions(+), 5 deletions(-)

--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1471,6 +1471,12 @@ sector_t dm_bufio_get_device_size(struct
}
EXPORT_SYMBOL_GPL(dm_bufio_get_device_size);

+struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c)
+{
+ return c->dm_io;
+}
+EXPORT_SYMBOL_GPL(dm_bufio_get_dm_io_client);
+
sector_t dm_bufio_get_block_number(struct dm_buffer *b)
{
return b->block;
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -1153,12 +1153,52 @@ static int dm_integrity_rw_tag(struct dm
return 0;
}

-static void dm_integrity_flush_buffers(struct dm_integrity_c *ic)
+struct flush_request {
+ struct dm_io_request io_req;
+ struct dm_io_region io_reg;
+ struct dm_integrity_c *ic;
+ struct completion comp;
+};
+
+static void flush_notify(unsigned long error, void *fr_)
+{
+ struct flush_request *fr = fr_;
+ if (unlikely(error != 0))
+ dm_integrity_io_error(fr->ic, "flusing disk cache", -EIO);
+ complete(&fr->comp);
+}
+
+static void dm_integrity_flush_buffers(struct dm_integrity_c *ic, bool flush_data)
{
int r;
+
+ struct flush_request fr;
+
+ if (!ic->meta_dev)
+ flush_data = false;
+ if (flush_data) {
+ fr.io_req.bi_op = REQ_OP_WRITE,
+ fr.io_req.bi_op_flags = REQ_PREFLUSH | REQ_SYNC,
+ fr.io_req.mem.type = DM_IO_KMEM,
+ fr.io_req.mem.ptr.addr = NULL,
+ fr.io_req.notify.fn = flush_notify,
+ fr.io_req.notify.context = &fr;
+ fr.io_req.client = dm_bufio_get_dm_io_client(ic->bufio),
+ fr.io_reg.bdev = ic->dev->bdev,
+ fr.io_reg.sector = 0,
+ fr.io_reg.count = 0,
+ fr.ic = ic;
+ init_completion(&fr.comp);
+ r = dm_io(&fr.io_req, 1, &fr.io_reg, NULL);
+ BUG_ON(r);
+ }
+
r = dm_bufio_write_dirty_buffers(ic->bufio);
if (unlikely(r))
dm_integrity_io_error(ic, "writing tags", r);
+
+ if (flush_data)
+ wait_for_completion(&fr.comp);
}

static void sleep_on_endio_wait(struct dm_integrity_c *ic)
@@ -1846,7 +1886,7 @@ static void integrity_commit(struct work
flushes = bio_list_get(&ic->flush_bio_list);
if (unlikely(ic->mode != 'J')) {
spin_unlock_irq(&ic->endio_wait.lock);
- dm_integrity_flush_buffers(ic);
+ dm_integrity_flush_buffers(ic, true);
goto release_flush_bios;
}

@@ -2057,7 +2097,7 @@ skip_io:
complete_journal_op(&comp);
wait_for_completion_io(&comp.comp);

- dm_integrity_flush_buffers(ic);
+ dm_integrity_flush_buffers(ic, true);
}

static void integrity_writer(struct work_struct *w)
@@ -2099,7 +2139,7 @@ static void recalc_write_super(struct dm
{
int r;

- dm_integrity_flush_buffers(ic);
+ dm_integrity_flush_buffers(ic, false);
if (dm_integrity_failed(ic))
return;

@@ -2409,7 +2449,7 @@ static void dm_integrity_postsuspend(str
if (ic->meta_dev)
queue_work(ic->writer_wq, &ic->writer_work);
drain_workqueue(ic->writer_wq);
- dm_integrity_flush_buffers(ic);
+ dm_integrity_flush_buffers(ic, true);
}

BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress));
--- a/include/linux/dm-bufio.h
+++ b/include/linux/dm-bufio.h
@@ -138,6 +138,7 @@ void dm_bufio_set_minimum_buffers(struct

unsigned dm_bufio_get_block_size(struct dm_bufio_client *c);
sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
+struct dm_io_client *dm_bufio_get_dm_io_client(struct dm_bufio_client *c);
sector_t dm_bufio_get_block_number(struct dm_buffer *b);
void *dm_bufio_get_block_data(struct dm_buffer *b);
void *dm_bufio_get_aux_data(struct dm_buffer *b);