[LU-684] replace dev_rdonly kernel patch with dm-flakey

• Type: Technical task
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.11.0
• Affects Version/s: Lustre 2.4.0, Lustre 2.8.0
• Labels: cea llnl
• Environment: RHEL6
• Story Points: 2
• Assignee: Oleg Drokin
• Reporter: Alex Zhuravlev

Description

   #define BIO_RDONLY 31 /* device is readonly */
#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)

void bio_free(struct bio *bio, struct bio_set *bs)
{
void *p;

if (bio_has_allocated_vec(bio))
bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));

...
BIO_POOL_IDX()

void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
{
BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);

with RDONLY set BIO_POOL_IDX() can get larger than BIOVEC_NR_POOLS and we hit the assertion.

Issue Links

• is blocked by: LU-8729 conf-sanity test_84: FAIL: /dev/mapper/mds1_flakey failed to initialize!
• is related to: LU-10893 all conf-sanity tests failed: format mgs: mkfs.lustre FATAL: Unable to build fs
• is related to: LU-9111 update osd-ldiskfs to not depend on dev_readonly patches
• is related to: LU-4416 support for 3.12 linux kernel