[PATCH] md: allow raid1 to check consistency
Where performing a user-requested 'check' or 'repair', we read all readable
devices, and compare the contents. We only write to blocks which had read
errors, or blocks with content that differs from the first good device found.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a8bc93d..7fbb608 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -106,15 +106,30 @@
}
/*
* Allocate RESYNC_PAGES data pages and attach them to
- * the first bio;
+ * the first bio.
+ * If this is a user-requested check/repair, allocate
+ * RESYNC_PAGES for each bio.
*/
- bio = r1_bio->bios[0];
- for (i = 0; i < RESYNC_PAGES; i++) {
- page = alloc_page(gfp_flags);
- if (unlikely(!page))
- goto out_free_pages;
+ if (test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery))
+ j = pi->raid_disks;
+ else
+ j = 1;
+ while(j--) {
+ bio = r1_bio->bios[j];
+ for (i = 0; i < RESYNC_PAGES; i++) {
+ page = alloc_page(gfp_flags);
+ if (unlikely(!page))
+ goto out_free_pages;
- bio->bi_io_vec[i].bv_page = page;
+ bio->bi_io_vec[i].bv_page = page;
+ }
+ }
+ /* If not user-requests, copy the page pointers to all bios */
+ if (!test_bit(MD_RECOVERY_REQUESTED, &pi->mddev->recovery)) {
+ for (i=0; i<RESYNC_PAGES ; i++)
+ for (j=1; j<pi->raid_disks; j++)
+ r1_bio->bios[j]->bi_io_vec[i].bv_page =
+ r1_bio->bios[0]->bi_io_vec[i].bv_page;
}
r1_bio->master_bio = NULL;
@@ -122,8 +137,10 @@
return r1_bio;
out_free_pages:
- for ( ; i > 0 ; i--)
- __free_page(bio->bi_io_vec[i-1].bv_page);
+ for (i=0; i < RESYNC_PAGES ; i++)
+ for (j=0 ; j < pi->raid_disks; j++)
+ __free_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
+ j = -1;
out_free_bio:
while ( ++j < pi->raid_disks )
bio_put(r1_bio->bios[j]);
@@ -134,14 +151,16 @@
static void r1buf_pool_free(void *__r1_bio, void *data)
{
struct pool_info *pi = data;
- int i;
+ int i,j;
r1bio_t *r1bio = __r1_bio;
- struct bio *bio = r1bio->bios[0];
- for (i = 0; i < RESYNC_PAGES; i++) {
- __free_page(bio->bi_io_vec[i].bv_page);
- bio->bi_io_vec[i].bv_page = NULL;
- }
+ for (i = 0; i < RESYNC_PAGES; i++)
+ for (j = pi->raid_disks; j-- ;) {
+ if (j == 0 ||
+ r1bio->bios[j]->bi_io_vec[i].bv_page !=
+ r1bio->bios[0]->bi_io_vec[i].bv_page)
+ __free_page(r1bio->bios[j]->bi_io_vec[i].bv_page);
+ }
for (i=0 ; i < pi->raid_disks; i++)
bio_put(r1bio->bios[i]);
@@ -1077,13 +1096,16 @@
static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
{
r1bio_t * r1_bio = (r1bio_t *)(bio->bi_private);
+ int i;
if (bio->bi_size)
return 1;
- if (r1_bio->bios[r1_bio->read_disk] != bio)
- BUG();
- update_head_pos(r1_bio->read_disk, r1_bio);
+ for (i=r1_bio->mddev->raid_disks; i--; )
+ if (r1_bio->bios[i] == bio)
+ break;
+ BUG_ON(i < 0);
+ update_head_pos(i, r1_bio);
/*
* we have read a block, now it needs to be re-written,
* or re-read if the read failed.
@@ -1091,7 +1113,9 @@
*/
if (test_bit(BIO_UPTODATE, &bio->bi_flags))
set_bit(R1BIO_Uptodate, &r1_bio->state);
- reschedule_retry(r1_bio);
+
+ if (atomic_dec_and_test(&r1_bio->remaining))
+ reschedule_retry(r1_bio);
return 0;
}
@@ -1134,9 +1158,65 @@
bio = r1_bio->bios[r1_bio->read_disk];
- /*
- * schedule writes
- */
+ if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+ /* We have read all readable devices. If we haven't
+ * got the block, then there is no hope left.
+ * If we have, then we want to do a comparison
+ * and skip the write if everything is the same.
+ * If any blocks failed to read, then we need to
+ * attempt an over-write
+ */
+ int primary;
+ if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
+ for (i=0; i<mddev->raid_disks; i++)
+ if (r1_bio->bios[i]->bi_end_io == end_sync_read)
+ md_error(mddev, conf->mirrors[i].rdev);
+
+ md_done_sync(mddev, r1_bio->sectors, 1);
+ put_buf(r1_bio);
+ return;
+ }
+ for (primary=0; primary<mddev->raid_disks; primary++)
+ if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
+ test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) {
+ r1_bio->bios[primary]->bi_end_io = NULL;
+ break;
+ }
+ r1_bio->read_disk = primary;
+ for (i=0; i<mddev->raid_disks; i++)
+ if (r1_bio->bios[i]->bi_end_io == end_sync_read &&
+ test_bit(BIO_UPTODATE, &r1_bio->bios[i]->bi_flags)) {
+ int j;
+ int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
+ struct bio *pbio = r1_bio->bios[primary];
+ struct bio *sbio = r1_bio->bios[i];
+ for (j = vcnt; j-- ; )
+ if (memcmp(page_address(pbio->bi_io_vec[j].bv_page),
+ page_address(sbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE))
+ break;
+ if (j >= 0)
+ mddev->resync_mismatches += r1_bio->sectors;
+ if (j < 0 || test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
+ sbio->bi_end_io = NULL;
+ else {
+ /* fixup the bio for reuse */
+ sbio->bi_vcnt = vcnt;
+ sbio->bi_size = r1_bio->sectors << 9;
+ sbio->bi_idx = 0;
+ sbio->bi_phys_segments = 0;
+ sbio->bi_hw_segments = 0;
+ sbio->bi_hw_front_size = 0;
+ sbio->bi_hw_back_size = 0;
+ sbio->bi_flags &= ~(BIO_POOL_MASK - 1);
+ sbio->bi_flags |= 1 << BIO_UPTODATE;
+ sbio->bi_next = NULL;
+ sbio->bi_sector = r1_bio->sector +
+ conf->mirrors[i].rdev->data_offset;
+ sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
+ }
+ }
+ }
if (!test_bit(R1BIO_Uptodate, &r1_bio->state)) {
/* ouch - failed to read all of that.
* Try some synchronous reads of other devices to get
@@ -1216,6 +1296,10 @@
idx ++;
}
}
+
+ /*
+ * schedule writes
+ */
atomic_set(&r1_bio->remaining, 1);
for (i = 0; i < disks ; i++) {
wbio = r1_bio->bios[i];
@@ -1618,10 +1702,10 @@
for (i=0 ; i < conf->raid_disks; i++) {
bio = r1_bio->bios[i];
if (bio->bi_end_io) {
- page = r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page;
+ page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
if (bio_add_page(bio, page, len, 0) == 0) {
/* stop here */
- r1_bio->bios[0]->bi_io_vec[bio->bi_vcnt].bv_page = page;
+ bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
while (i > 0) {
i--;
bio = r1_bio->bios[i];
@@ -1641,12 +1725,28 @@
sync_blocks -= (len>>9);
} while (r1_bio->bios[disk]->bi_vcnt < RESYNC_PAGES);
bio_full:
- bio = r1_bio->bios[r1_bio->read_disk];
r1_bio->sectors = nr_sectors;
- md_sync_acct(conf->mirrors[r1_bio->read_disk].rdev->bdev, nr_sectors);
+ /* For a user-requested sync, we read all readable devices and do a
+ * compare
+ */
+ if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
+ atomic_set(&r1_bio->remaining, read_targets);
+ for (i=0; i<conf->raid_disks; i++) {
+ bio = r1_bio->bios[i];
+ if (bio->bi_end_io == end_sync_read) {
+ md_sync_acct(conf->mirrors[i].rdev->bdev, nr_sectors);
+ generic_make_request(bio);
+ }
+ }
+ } else {
+ atomic_set(&r1_bio->remaining, 1);
+ bio = r1_bio->bios[r1_bio->read_disk];
+ md_sync_acct(conf->mirrors[r1_bio->read_disk].rdev->bdev,
+ nr_sectors);
+ generic_make_request(bio);
- generic_make_request(bio);
+ }
return nr_sectors;
}