a920f6b3ac
Device mapper saves and restores various fields in the bio, but it doesn't save bi_io_vec. If the device driver modifies this after a partially successful request, dm-raid1 and dm-multipath may attempt to resubmit a bio that has bi_size inconsistent with the size of vector. To make requests resubmittable in dm-raid1 and dm-multipath, we must save and restore the bio vector as well. To reduce the memory overhead involved in this, we do not save the pages in a vector and use a 16-bit field size if the page size is less than 65536. Cc: stable@kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
/*
|
|
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#ifndef DM_BIO_RECORD_H
|
|
#define DM_BIO_RECORD_H
|
|
|
|
#include <linux/bio.h>
|
|
|
|
/*
|
|
* There are lots of mutable fields in the bio struct that get
|
|
* changed by the lower levels of the block layer. Some targets,
|
|
* such as multipath, may wish to resubmit a bio on error. The
|
|
* functions in this file help the target record and restore the
|
|
* original bio state.
|
|
*/
|
|
|
|
struct dm_bio_vec_details {
|
|
#if PAGE_SIZE < 65536
|
|
__u16 bv_len;
|
|
__u16 bv_offset;
|
|
#else
|
|
unsigned bv_len;
|
|
unsigned bv_offset;
|
|
#endif
|
|
};
|
|
|
|
struct dm_bio_details {
|
|
sector_t bi_sector;
|
|
struct block_device *bi_bdev;
|
|
unsigned int bi_size;
|
|
unsigned short bi_idx;
|
|
unsigned long bi_flags;
|
|
struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
|
|
};
|
|
|
|
static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
|
|
{
|
|
unsigned i;
|
|
|
|
bd->bi_sector = bio->bi_sector;
|
|
bd->bi_bdev = bio->bi_bdev;
|
|
bd->bi_size = bio->bi_size;
|
|
bd->bi_idx = bio->bi_idx;
|
|
bd->bi_flags = bio->bi_flags;
|
|
|
|
for (i = 0; i < bio->bi_vcnt; i++) {
|
|
bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len;
|
|
bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset;
|
|
}
|
|
}
|
|
|
|
static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
|
|
{
|
|
unsigned i;
|
|
|
|
bio->bi_sector = bd->bi_sector;
|
|
bio->bi_bdev = bd->bi_bdev;
|
|
bio->bi_size = bd->bi_size;
|
|
bio->bi_idx = bd->bi_idx;
|
|
bio->bi_flags = bd->bi_flags;
|
|
|
|
for (i = 0; i < bio->bi_vcnt; i++) {
|
|
bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len;
|
|
bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset;
|
|
}
|
|
}
|
|
|
|
#endif
|