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Diffstat (limited to 'fs/bio-integrity.c')
| -rw-r--r-- | fs/bio-integrity.c | 708 |
1 files changed, 708 insertions, 0 deletions
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c new file mode 100644 index 000000000000..31b08878913d --- /dev/null +++ b/fs/bio-integrity.c @@ -0,0 +1,708 @@ +/* + * bio-integrity.c - bio data integrity extensions + * + * Copyright (C) 2007, 2008 Oracle Corporation + * Written by: Martin K. Petersen <martin.petersen@oracle.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, + * USA. + * + */ + +#include <linux/blkdev.h> +#include <linux/mempool.h> +#include <linux/bio.h> +#include <linux/workqueue.h> + +static struct kmem_cache *bio_integrity_slab __read_mostly; +static struct workqueue_struct *kintegrityd_wq; + +/** + * bio_integrity_alloc_bioset - Allocate integrity payload and attach it to bio + * @bio: bio to attach integrity metadata to + * @gfp_mask: Memory allocation mask + * @nr_vecs: Number of integrity metadata scatter-gather elements + * @bs: bio_set to allocate from + * + * Description: This function prepares a bio for attaching integrity + * metadata. nr_vecs specifies the maximum number of pages containing + * integrity metadata that can be attached. + */ +struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs, struct bio_set *bs) +{ + struct bio_integrity_payload *bip; + struct bio_vec *iv; + unsigned long idx; + + BUG_ON(bio == NULL); + + bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask); + if (unlikely(bip == NULL)) { + printk(KERN_ERR "%s: could not alloc bip\n", __func__); + return NULL; + } + + memset(bip, 0, sizeof(*bip)); + + iv = bvec_alloc_bs(gfp_mask, nr_vecs, &idx, bs); + if (unlikely(iv == NULL)) { + printk(KERN_ERR "%s: could not alloc bip_vec\n", __func__); + mempool_free(bip, bs->bio_integrity_pool); + return NULL; + } + + bip->bip_pool = idx; + bip->bip_vec = iv; + bip->bip_bio = bio; + bio->bi_integrity = bip; + + return bip; +} +EXPORT_SYMBOL(bio_integrity_alloc_bioset); + +/** + * bio_integrity_alloc - Allocate integrity payload and attach it to bio + * @bio: bio to attach integrity metadata to + * @gfp_mask: Memory allocation mask + * @nr_vecs: Number of integrity metadata scatter-gather elements + * + * Description: This function prepares a bio for attaching integrity + * metadata. nr_vecs specifies the maximum number of pages containing + * integrity metadata that can be attached. + */ +struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs) +{ + return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set); +} +EXPORT_SYMBOL(bio_integrity_alloc); + +/** + * bio_integrity_free - Free bio integrity payload + * @bio: bio containing bip to be freed + * @bs: bio_set this bio was allocated from + * + * Description: Used to free the integrity portion of a bio. Usually + * called from bio_free(). + */ +void bio_integrity_free(struct bio *bio, struct bio_set *bs) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + + BUG_ON(bip == NULL); + + /* A cloned bio doesn't own the integrity metadata */ + if (!bio_flagged(bio, BIO_CLONED) && bip->bip_buf != NULL) + kfree(bip->bip_buf); + + mempool_free(bip->bip_vec, bs->bvec_pools[bip->bip_pool]); + mempool_free(bip, bs->bio_integrity_pool); + + bio->bi_integrity = NULL; +} +EXPORT_SYMBOL(bio_integrity_free); + +/** + * bio_integrity_add_page - Attach integrity metadata + * @bio: bio to update + * @page: page containing integrity metadata + * @len: number of bytes of integrity metadata in page + * @offset: start offset within page + * + * Description: Attach a page containing integrity metadata to bio. + */ +int bio_integrity_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + struct bio_vec *iv; + + if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_pool)) { + printk(KERN_ERR "%s: bip_vec full\n", __func__); + return 0; + } + + iv = bip_vec_idx(bip, bip->bip_vcnt); + BUG_ON(iv == NULL); + BUG_ON(iv->bv_page != NULL); + + iv->bv_page = page; + iv->bv_len = len; + iv->bv_offset = offset; + bip->bip_vcnt++; + + return len; +} +EXPORT_SYMBOL(bio_integrity_add_page); + +/** + * bio_integrity_enabled - Check whether integrity can be passed + * @bio: bio to check + * + * Description: Determines whether bio_integrity_prep() can be called + * on this bio or not. bio data direction and target device must be + * set prior to calling. The functions honors the write_generate and + * read_verify flags in sysfs. + */ +int bio_integrity_enabled(struct bio *bio) +{ + /* Already protected? */ + if (bio_integrity(bio)) + return 0; + + return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio)); +} +EXPORT_SYMBOL(bio_integrity_enabled); + +/** + * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto + * @bi: blk_integrity profile for device + * @sectors: Number of 512 sectors to convert + * + * Description: The block layer calculates everything in 512 byte + * sectors but integrity metadata is done in terms of the hardware + * sector size of the storage device. Convert the block layer sectors + * to physical sectors. + */ +static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi, unsigned int sectors) +{ + /* At this point there are only 512b or 4096b DIF/EPP devices */ + if (bi->sector_size == 4096) + return sectors >>= 3; + + return sectors; +} + +/** + * bio_integrity_tag_size - Retrieve integrity tag space + * @bio: bio to inspect + * + * Description: Returns the maximum number of tag bytes that can be + * attached to this bio. Filesystems can use this to determine how + * much metadata to attach to an I/O. + */ +unsigned int bio_integrity_tag_size(struct bio *bio) +{ + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + + BUG_ON(bio->bi_size == 0); + + return bi->tag_size * (bio->bi_size / bi->sector_size); +} +EXPORT_SYMBOL(bio_integrity_tag_size); + +int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + unsigned int nr_sectors; + + BUG_ON(bip->bip_buf == NULL); + + if (bi->tag_size == 0) + return -1; + + nr_sectors = bio_integrity_hw_sectors(bi, DIV_ROUND_UP(len, bi->tag_size)); + + if (nr_sectors * bi->tuple_size > bip->bip_size) { + printk(KERN_ERR "%s: tag too big for bio: %u > %u\n", + __func__, nr_sectors * bi->tuple_size, bip->bip_size); + return -1; + } + + if (set) + bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors); + else + bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors); + + return 0; +} + +/** + * bio_integrity_set_tag - Attach a tag buffer to a bio + * @bio: bio to attach buffer to + * @tag_buf: Pointer to a buffer containing tag data + * @len: Length of the included buffer + * + * Description: Use this function to tag a bio by leveraging the extra + * space provided by devices formatted with integrity protection. The + * size of the integrity buffer must be <= to the size reported by + * bio_integrity_tag_size(). + */ +int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len) +{ + BUG_ON(bio_data_dir(bio) != WRITE); + + return bio_integrity_tag(bio, tag_buf, len, 1); +} +EXPORT_SYMBOL(bio_integrity_set_tag); + +/** + * bio_integrity_get_tag - Retrieve a tag buffer from a bio + * @bio: bio to retrieve buffer from + * @tag_buf: Pointer to a buffer for the tag data + * @len: Length of the target buffer + * + * Description: Use this function to retrieve the tag buffer from a + * completed I/O. The size of the integrity buffer must be <= to the + * size reported by bio_integrity_tag_size(). + */ +int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len) +{ + BUG_ON(bio_data_dir(bio) != READ); + + return bio_integrity_tag(bio, tag_buf, len, 0); +} +EXPORT_SYMBOL(bio_integrity_get_tag); + +/** + * bio_integrity_generate - Generate integrity metadata for a bio + * @bio: bio to generate integrity metadata for + * + * Description: Generates integrity metadata for a bio by calling the + * block device's generation callback function. The bio must have a + * bip attached with enough room to accommodate the generated + * integrity metadata. + */ +static void bio_integrity_generate(struct bio *bio) +{ + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + struct blk_integrity_exchg bix; + struct bio_vec *bv; + sector_t sector = bio->bi_sector; + unsigned int i, sectors, total; + void *prot_buf = bio->bi_integrity->bip_buf; + + total = 0; + bix.disk_name = bio->bi_bdev->bd_disk->disk_name; + bix.sector_size = bi->sector_size; + + bio_for_each_segment(bv, bio, i) { + void *kaddr = kmap_atomic(bv->bv_page, KM_USER0); + bix.data_buf = kaddr + bv->bv_offset; + bix.data_size = bv->bv_len; + bix.prot_buf = prot_buf; + bix.sector = sector; + + bi->generate_fn(&bix); + + sectors = bv->bv_len / bi->sector_size; + sector += sectors; + prot_buf += sectors * bi->tuple_size; + total += sectors * bi->tuple_size; + BUG_ON(total > bio->bi_integrity->bip_size); + + kunmap_atomic(kaddr, KM_USER0); + } +} + +/** + * bio_integrity_prep - Prepare bio for integrity I/O + * @bio: bio to prepare + * + * Description: Allocates a buffer for integrity metadata, maps the + * pages and attaches them to a bio. The bio must have data + * direction, target device and start sector set priot to calling. In + * the WRITE case, integrity metadata will be generated using the + * block device's integrity function. In the READ case, the buffer + * will be prepared for DMA and a suitable end_io handler set up. + */ +int bio_integrity_prep(struct bio *bio) +{ + struct bio_integrity_payload *bip; + struct blk_integrity *bi; + struct request_queue *q; + void *buf; + unsigned long start, end; + unsigned int len, nr_pages; + unsigned int bytes, offset, i; + unsigned int sectors; + + bi = bdev_get_integrity(bio->bi_bdev); + q = bdev_get_queue(bio->bi_bdev); + BUG_ON(bi == NULL); + BUG_ON(bio_integrity(bio)); + + sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio)); + + /* Allocate kernel buffer for protection data */ + len = sectors * blk_integrity_tuple_size(bi); + buf = kmalloc(len, GFP_NOIO | __GFP_NOFAIL | q->bounce_gfp); + if (unlikely(buf == NULL)) { + printk(KERN_ERR "could not allocate integrity buffer\n"); + return -EIO; + } + + end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT; + start = ((unsigned long) buf) >> PAGE_SHIFT; + nr_pages = end - start; + + /* Allocate bio integrity payload and integrity vectors */ + bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages); + if (unlikely(bip == NULL)) { + printk(KERN_ERR "could not allocate data integrity bioset\n"); + kfree(buf); + return -EIO; + } + + bip->bip_buf = buf; + bip->bip_size = len; + bip->bip_sector = bio->bi_sector; + + /* Map it */ + offset = offset_in_page(buf); + for (i = 0 ; i < nr_pages ; i++) { + int ret; + bytes = PAGE_SIZE - offset; + + if (len <= 0) + break; + + if (bytes > len) + bytes = len; + + ret = bio_integrity_add_page(bio, virt_to_page(buf), + bytes, offset); + + if (ret == 0) + return 0; + + if (ret < bytes) + break; + + buf += bytes; + len -= bytes; + offset = 0; + } + + /* Install custom I/O completion handler if read verify is enabled */ + if (bio_data_dir(bio) == READ) { + bip->bip_end_io = bio->bi_end_io; + bio->bi_end_io = bio_integrity_endio; + } + + /* Auto-generate integrity metadata if this is a write */ + if (bio_data_dir(bio) == WRITE) + bio_integrity_generate(bio); + + return 0; +} +EXPORT_SYMBOL(bio_integrity_prep); + +/** + * bio_integrity_verify - Verify integrity metadata for a bio + * @bio: bio to verify + * + * Description: This function is called to verify the integrity of a + * bio. The data in the bio io_vec is compared to the integrity + * metadata returned by the HBA. + */ +static int bio_integrity_verify(struct bio *bio) +{ + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + struct blk_integrity_exchg bix; + struct bio_vec *bv; + sector_t sector = bio->bi_integrity->bip_sector; + unsigned int i, sectors, total, ret; + void *prot_buf = bio->bi_integrity->bip_buf; + + ret = total = 0; + bix.disk_name = bio->bi_bdev->bd_disk->disk_name; + bix.sector_size = bi->sector_size; + + bio_for_each_segment(bv, bio, i) { + void *kaddr = kmap_atomic(bv->bv_page, KM_USER0); + bix.data_buf = kaddr + bv->bv_offset; + bix.data_size = bv->bv_len; + bix.prot_buf = prot_buf; + bix.sector = sector; + + ret = bi->verify_fn(&bix); + + if (ret) { + kunmap_atomic(kaddr, KM_USER0); + break; + } + + sectors = bv->bv_len / bi->sector_size; + sector += sectors; + prot_buf += sectors * bi->tuple_size; + total += sectors * bi->tuple_size; + BUG_ON(total > bio->bi_integrity->bip_size); + + kunmap_atomic(kaddr, KM_USER0); + } + + return ret; +} + +/** + * bio_integrity_verify_fn - Integrity I/O completion worker + * @work: Work struct stored in bio to be verified + * + * Description: This workqueue function is called to complete a READ + * request. The function verifies the transferred integrity metadata + * and then calls the original bio end_io function. + */ +static void bio_integrity_verify_fn(struct work_struct *work) +{ + struct bio_integrity_payload *bip = + container_of(work, struct bio_integrity_payload, bip_work); + struct bio *bio = bip->bip_bio; + int error = bip->bip_error; + + if (bio_integrity_verify(bio)) { + clear_bit(BIO_UPTODATE, &bio->bi_flags); + error = -EIO; + } + + /* Restore original bio completion handler */ + bio->bi_end_io = bip->bip_end_io; + + if (bio->bi_end_io) + bio->bi_end_io(bio, error); +} + +/** + * bio_integrity_endio - Integrity I/O completion function + * @bio: Protected bio + * @error: Pointer to errno + * + * Description: Completion for integrity I/O + * + * Normally I/O completion is done in interrupt context. However, + * verifying I/O integrity is a time-consuming task which must be run + * in process context. This function postpones completion + * accordingly. + */ +void bio_integrity_endio(struct bio *bio, int error) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + + BUG_ON(bip->bip_bio != bio); + + bip->bip_error = error; + INIT_WORK(&bip->bip_work, bio_integrity_verify_fn); + queue_work(kintegrityd_wq, &bip->bip_work); +} +EXPORT_SYMBOL(bio_integrity_endio); + +/** + * bio_integrity_mark_head - Advance bip_vec skip bytes + * @bip: Integrity vector to advance + * @skip: Number of bytes to advance it + */ +void bio_integrity_mark_head(struct bio_integrity_payload *bip, unsigned int skip) +{ + struct bio_vec *iv; + unsigned int i; + + bip_for_each_vec(iv, bip, i) { + if (skip == 0) { + bip->bip_idx = i; + return; + } else if (skip >= iv->bv_len) { + skip -= iv->bv_len; + } else { /* skip < iv->bv_len) */ + iv->bv_offset += skip; + iv->bv_len -= skip; + bip->bip_idx = i; + return; + } + } +} + +/** + * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long + * @bip: Integrity vector to truncate + * @len: New length of integrity vector + */ +void bio_integrity_mark_tail(struct bio_integrity_payload *bip, unsigned int len) +{ + struct bio_vec *iv; + unsigned int i; + + bip_for_each_vec(iv, bip, i) { + if (len == 0) { + bip->bip_vcnt = i; + return; + } else if (len >= iv->bv_len) { + len -= iv->bv_len; + } else { /* len < iv->bv_len) */ + iv->bv_len = len; + len = 0; + } + } +} + +/** + * bio_integrity_advance - Advance integrity vector + * @bio: bio whose integrity vector to update + * @bytes_done: number of data bytes that have been completed + * + * Description: This function calculates how many integrity bytes the + * number of completed data bytes correspond to and advances the + * integrity vector accordingly. + */ +void bio_integrity_advance(struct bio *bio, unsigned int bytes_done) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + unsigned int nr_sectors; + + BUG_ON(bip == NULL); + BUG_ON(bi == NULL); + + nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9); + bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size); +} +EXPORT_SYMBOL(bio_integrity_advance); + +/** + * bio_integrity_trim - Trim integrity vector + * @bio: bio whose integrity vector to update + * @offset: offset to first data sector + * @sectors: number of data sectors + * + * Description: Used to trim the integrity vector in a cloned bio. + * The ivec will be advanced corresponding to 'offset' data sectors + * and the length will be truncated corresponding to 'len' data + * sectors. + */ +void bio_integrity_trim(struct bio *bio, unsigned int offset, unsigned int sectors) +{ + struct bio_integrity_payload *bip = bio->bi_integrity; + struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); + unsigned int nr_sectors; + + BUG_ON(bip == NULL); + BUG_ON(bi == NULL); + BUG_ON(!bio_flagged(bio, BIO_CLONED)); + + nr_sectors = bio_integrity_hw_sectors(bi, sectors); + bip->bip_sector = bip->bip_sector + offset; + bio_integrity_mark_head(bip, offset * bi->tuple_size); + bio_integrity_mark_tail(bip, sectors * bi->tuple_size); +} +EXPORT_SYMBOL(bio_integrity_trim); + +/** + * bio_integrity_split - Split integrity metadata + * @bio: Protected bio + * @bp: Resulting bio_pair + * @sectors: Offset + * + * Description: Splits an integrity page into a bio_pair. + */ +void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors) +{ + struct blk_integrity *bi; + struct bio_integrity_payload *bip = bio->bi_integrity; + unsigned int nr_sectors; + + if (bio_integrity(bio) == 0) + return; + + bi = bdev_get_integrity(bio->bi_bdev); + BUG_ON(bi == NULL); + BUG_ON(bip->bip_vcnt != 1); + + nr_sectors = bio_integrity_hw_sectors(bi, sectors); + + bp->bio1.bi_integrity = &bp->bip1; + bp->bio2.bi_integrity = &bp->bip2; + + bp->iv1 = bip->bip_vec[0]; + bp->iv2 = bip->bip_vec[0]; + + bp->bip1.bip_vec = &bp->iv1; + bp->bip2.bip_vec = &bp->iv2; + + bp->iv1.bv_len = sectors * bi->tuple_size; + bp->iv2.bv_offset += sectors * bi->tuple_size; + bp->iv2.bv_len -= sectors * bi->tuple_size; + + bp->bip1.bip_sector = bio->bi_integrity->bip_sector; + bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors; + + bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1; + bp->bip1.bip_idx = bp->bip2.bip_idx = 0; +} +EXPORT_SYMBOL(bio_integrity_split); + +/** + * bio_integrity_clone - Callback for cloning bios with integrity metadata + * @bio: New bio + * @bio_src: Original bio + * @bs: bio_set to allocate bip from + * + * Description: Called to allocate a bip when cloning a bio + */ +int bio_integrity_clone(struct bio *bio, struct bio *bio_src, struct bio_set *bs) +{ + struct bio_integrity_payload *bip_src = bio_src->bi_integrity; + struct bio_integrity_payload *bip; + + BUG_ON(bip_src == NULL); + + bip = bio_integrity_alloc_bioset(bio, GFP_NOIO, bip_src->bip_vcnt, bs); + + if (bip == NULL) + return -EIO; + + memcpy(bip->bip_vec, bip_src->bip_vec, + bip_src->bip_vcnt * sizeof(struct bio_vec)); + + bip->bip_sector = bip_src->bip_sector; + bip->bip_vcnt = bip_src->bip_vcnt; + bip->bip_idx = bip_src->bip_idx; + + return 0; +} +EXPORT_SYMBOL(bio_integrity_clone); + +int bioset_integrity_create(struct bio_set *bs, int pool_size) +{ + bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, + bio_integrity_slab); + if (!bs->bio_integrity_pool) + return -1; + + return 0; +} +EXPORT_SYMBOL(bioset_integrity_create); + +void bioset_integrity_free(struct bio_set *bs) +{ + if (bs->bio_integrity_pool) + mempool_destroy(bs->bio_integrity_pool); +} +EXPORT_SYMBOL(bioset_integrity_free); + +void __init bio_integrity_init_slab(void) +{ + bio_integrity_slab = KMEM_CACHE(bio_integrity_payload, + SLAB_HWCACHE_ALIGN|SLAB_PANIC); +} +EXPORT_SYMBOL(bio_integrity_init_slab); + +static int __init integrity_init(void) +{ + kintegrityd_wq = create_workqueue("kintegrityd"); + + if (!kintegrityd_wq) + panic("Failed to create kintegrityd\n"); + + return 0; +} +subsys_initcall(integrity_init); |