On 05/27/2016 10:51 AM, Mikulas Patocka wrote:
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. Also, move 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 we must do atomic_inc(&lc->io_blocks) before invoking the error path to avoid underflow of lc->io_blocks. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # v4.1+
Reviewed-by: Josef Bacik <jbacik@xxxxxx> Thanks, Josef -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
