Commit 6f3e5e4d authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Sasha Levin

dm log writes: fix bug with too large bios

[ Upstream commit 7efb3673 ]

bio_alloc() can allocate a bio with at most BIO_MAX_PAGES (256) vector
entries.  However, the incoming bio may have more vector entries if it
was allocated by other means.  For example, bcache submits bios with
more than BIO_MAX_PAGES entries.  This results in bio_alloc() failure.

To avoid the failure, change the code so that it allocates bio with at
most BIO_MAX_PAGES entries.  If the incoming bio has more entries,
bio_add_page() will fail and a new bio will be allocated - the code that
handles bio_add_page() failure already exists in the dm-log-writes
target.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: default avatarJosef Bacik <jbacik@fb,com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v4.1+
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 0fe71822
......@@ -260,7 +260,7 @@ static int log_one_block(struct log_writes_c *lc,
sector++;
atomic_inc(&lc->io_blocks);
bio = bio_alloc(GFP_KERNEL, block->vec_cnt);
bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt, BIO_MAX_PAGES));
if (!bio) {
DMERR("Couldn't alloc log bio");
goto error;
......@@ -282,7 +282,7 @@ static int log_one_block(struct log_writes_c *lc,
if (ret != block->vecs[i].bv_len) {
atomic_inc(&lc->io_blocks);
submit_bio(WRITE, bio);
bio = bio_alloc(GFP_KERNEL, block->vec_cnt - i);
bio = bio_alloc(GFP_KERNEL, min(block->vec_cnt - i, BIO_MAX_PAGES));
if (!bio) {
DMERR("Couldn't alloc log bio");
goto error;
......
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