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Subject[PATCH 4.7 112/184] dm log writes: move IO accounting earlier to fix error path
Date
4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mikulas Patocka <mpatocka@redhat.com>

commit a5d60783df61fbb67b7596b8a0f6b4b2e05251d5 upstream.

Move log_one_block()'s atomic_inc(&lc->io_blocks) before bio_alloc() to
fix a bug that the target hangs if bio_alloc() fails. The error path
does put_io_block(lc), so atomic_inc(&lc->io_blocks) must occur before
invoking the error path to avoid underflow of lc->io_blocks.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-log-writes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -258,12 +258,12 @@ static int log_one_block(struct log_writ
goto out;
sector++;

+ atomic_inc(&lc->io_blocks);
bio = bio_alloc(GFP_KERNEL, block->vec_cnt);
if (!bio) {
DMERR("Couldn't alloc log bio");
goto error;
}
- atomic_inc(&lc->io_blocks);
bio->bi_iter.bi_size = 0;
bio->bi_iter.bi_sector = sector;
bio->bi_bdev = lc->logdev->bdev;

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