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authorRoman Peniaev <r.peniaev@gmail.com>2014-03-08 21:59:14 +0900
committerBrian Norris <computersforpeace@gmail.com>2014-04-15 23:25:37 -0700
commit566c0d6a74169dc5cc9f353ff4a8d579d96a85ff (patch)
tree11e9a6727d03c958f40843454be9c810e5f70f7b
parent47570bb1f533b2a48e5222db8545b7842c229331 (diff)
mtd: mtd_blkdevs: handle REQ_FLUSH request and do explicit flush of writeback buffer
mtd_blkdevs is device with volatile cache (writeback buffer), so it should support REQ_FLUSH to do explicit flush. Without this patch 'sync' does not guarantee that writeback buffer will be flushed on disk in case of power off, e.g.: $ cp some_file /mnt $ sync ### POWER OFF In case of this sequence writeback buffer will not be flushed on disk. This patch fixes this behaviour and explicitly reports to block layer that flush requests are being supported. Signed-off-by: Roman Peniaev <r.peniaev@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: linux-mtd@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Brian Norris <computersforpeace@gmail.com>
-rw-r--r--drivers/mtd/mtd_blkdevs.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 0b2ccb68c0d0..d2f0da91a5bd 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -88,6 +88,9 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
if (req->cmd_type != REQ_TYPE_FS)
return -EIO;
+ if (req->cmd_flags & REQ_FLUSH)
+ return tr->flush(dev);
+
if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
get_capacity(req->rq_disk))
return -EIO;
@@ -408,6 +411,9 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
if (!new->rq)
goto error3;
+ if (tr->flush)
+ blk_queue_flush(new->rq, REQ_FLUSH);
+
new->rq->queuedata = new;
blk_queue_logical_block_size(new->rq, tr->blksize);