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| author | Mikulas Patocka <mpatocka@redhat.com> | 2016-08-30 16:20:55 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-07 15:23:47 +0200 |
| commit | 7eb0153fc42d98d301a5ca946ed31366cd33526f (patch) | |
| tree | 063b62a21747ce447b286d54ee6dcd8ad8805f6f | |
| parent | bceea9fee1c606f567a156b7dee9c9564a2f5c19 (diff) | |
| download | lwn-7eb0153fc42d98d301a5ca946ed31366cd33526f.tar.gz lwn-7eb0153fc42d98d301a5ca946ed31366cd33526f.zip | |
dm log writes: fix bug with too large bios
commit 7efb367320f56fc4d549875b6f3a6940018ef2e5 upstream.
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: 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>
| -rw-r--r-- | drivers/md/dm-log-writes.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c index d8956b4a7b09..c8b513ee117c 100644 --- a/drivers/md/dm-log-writes.c +++ b/drivers/md/dm-log-writes.c @@ -259,7 +259,7 @@ 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; @@ -280,7 +280,7 @@ 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; |