diff options
| -rw-r--r-- | drivers/md/dm-flakey.c | 104 |
1 files changed, 95 insertions, 9 deletions
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c index bd80bcafbe50..079d48b29628 100644 --- a/drivers/md/dm-flakey.c +++ b/drivers/md/dm-flakey.c @@ -322,11 +322,7 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) */ bio_for_each_segment(bvec, bio, iter) { if (bio_iter_len(bio, iter) > corrupt_bio_byte) { - char *segment; - struct page *page = bio_iter_page(bio, iter); - if (unlikely(page == ZERO_PAGE(0))) - break; - segment = bvec_kmap_local(&bvec); + char *segment = bvec_kmap_local(&bvec); segment[corrupt_bio_byte] = fc->corrupt_bio_value; kunmap_local(segment); DMDEBUG("Corrupting data bio=%p by writing %u to byte %u " @@ -340,6 +336,92 @@ static void corrupt_bio_data(struct bio *bio, struct flakey_c *fc) } } +static void clone_free(struct bio *clone) +{ + struct folio_iter fi; + + if (clone->bi_vcnt > 0) { /* bio_for_each_folio_all crashes with an empty bio */ + bio_for_each_folio_all(fi, clone) + folio_put(fi.folio); + } + + bio_uninit(clone); + kfree(clone); +} + +static void clone_endio(struct bio *clone) +{ + struct bio *bio = clone->bi_private; + bio->bi_status = clone->bi_status; + clone_free(clone); + bio_endio(bio); +} + +static struct bio *clone_bio(struct dm_target *ti, struct flakey_c *fc, struct bio *bio) +{ + struct bio *clone; + unsigned size, remaining_size, nr_iovecs, order; + struct bvec_iter iter = bio->bi_iter; + + if (unlikely(bio->bi_iter.bi_size > UIO_MAXIOV << PAGE_SHIFT)) + dm_accept_partial_bio(bio, UIO_MAXIOV << PAGE_SHIFT >> SECTOR_SHIFT); + + size = bio->bi_iter.bi_size; + nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + + clone = bio_kmalloc(nr_iovecs, GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN); + if (!clone) + return NULL; + + bio_init(clone, fc->dev->bdev, bio->bi_inline_vecs, nr_iovecs, bio->bi_opf); + + clone->bi_iter.bi_sector = flakey_map_sector(ti, bio->bi_iter.bi_sector); + clone->bi_private = bio; + clone->bi_end_io = clone_endio; + + remaining_size = size; + + order = MAX_ORDER - 1; + while (remaining_size) { + struct page *pages; + unsigned size_to_add, to_copy; + unsigned char *virt; + unsigned remaining_order = __fls((remaining_size + PAGE_SIZE - 1) >> PAGE_SHIFT); + order = min(order, remaining_order); + +retry_alloc_pages: + pages = alloc_pages(GFP_NOIO | __GFP_NORETRY | __GFP_NOWARN | __GFP_COMP, order); + if (unlikely(!pages)) { + if (order) { + order--; + goto retry_alloc_pages; + } + clone_free(clone); + return NULL; + } + size_to_add = min((unsigned)PAGE_SIZE << order, remaining_size); + + virt = page_to_virt(pages); + to_copy = size_to_add; + do { + struct bio_vec bvec = bvec_iter_bvec(bio->bi_io_vec, iter); + unsigned this_step = min(bvec.bv_len, to_copy); + void *map = bvec_kmap_local(&bvec); + memcpy(virt, map, this_step); + kunmap_local(map); + + bvec_iter_advance(bio->bi_io_vec, &iter, this_step); + to_copy -= this_step; + virt += this_step; + } while (to_copy); + + __bio_add_page(clone, pages, size_to_add, 0); + remaining_size -= size_to_add; + } + + return clone; +} + static int flakey_map(struct dm_target *ti, struct bio *bio) { struct flakey_c *fc = ti->private; @@ -383,10 +465,14 @@ static int flakey_map(struct dm_target *ti, struct bio *bio) /* * Corrupt matching writes. */ - if (fc->corrupt_bio_byte) { - if (fc->corrupt_bio_rw == WRITE) { - if (all_corrupt_bio_flags_match(bio, fc)) - corrupt_bio_data(bio, fc); + if (fc->corrupt_bio_byte && fc->corrupt_bio_rw == WRITE) { + if (all_corrupt_bio_flags_match(bio, fc)) { + struct bio *clone = clone_bio(ti, fc, bio); + if (clone) { + corrupt_bio_data(clone, fc); + submit_bio(clone); + return DM_MAPIO_SUBMITTED; + } } goto map_bio; } |