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authorMikulas Patocka <mpatocka@redhat.com>2009-04-02 19:55:23 +0100
committerAlasdair G Kergon <agk@redhat.com>2009-04-02 19:55:23 +0100
commita920f6b3accc77d9dddbc98a7426be23ee479625 (patch)
treebff633328b5f1362d99a04f7e513a6a4b2084ad8 /drivers/md
parent833bb3046b6cb320e775ea2160ddca87d53260d5 (diff)
dm: preserve bi_io_vec when resubmitting bios
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>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-bio-record.h26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/md/dm-bio-record.h b/drivers/md/dm-bio-record.h
index d3ec217847d..3a8cfa2645c 100644
--- a/drivers/md/dm-bio-record.h
+++ b/drivers/md/dm-bio-record.h
@@ -16,30 +16,56 @@
* 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