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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>
72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/*
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* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#ifndef DM_BIO_RECORD_H
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#define DM_BIO_RECORD_H
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#include <linux/bio.h>
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/*
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* There are lots of mutable fields in the bio struct that get
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* changed by the lower levels of the block layer. Some targets,
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* such as multipath, may wish to resubmit a bio on error. The
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* functions in this file help the target record and restore the
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* original bio state.
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*/
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struct dm_bio_vec_details {
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#if PAGE_SIZE < 65536
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__u16 bv_len;
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__u16 bv_offset;
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#else
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unsigned bv_len;
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unsigned bv_offset;
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#endif
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};
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struct dm_bio_details {
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sector_t bi_sector;
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struct block_device *bi_bdev;
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unsigned int bi_size;
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unsigned short bi_idx;
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unsigned long bi_flags;
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struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
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};
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static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
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{
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unsigned i;
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bd->bi_sector = bio->bi_sector;
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bd->bi_bdev = bio->bi_bdev;
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bd->bi_size = bio->bi_size;
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bd->bi_idx = bio->bi_idx;
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bd->bi_flags = bio->bi_flags;
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for (i = 0; i < bio->bi_vcnt; i++) {
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bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len;
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bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset;
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}
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}
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static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
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{
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unsigned i;
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bio->bi_sector = bd->bi_sector;
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bio->bi_bdev = bd->bi_bdev;
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bio->bi_size = bd->bi_size;
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bio->bi_idx = bd->bi_idx;
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bio->bi_flags = bd->bi_flags;
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for (i = 0; i < bio->bi_vcnt; i++) {
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bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len;
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bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset;
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}
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}
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#endif
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