2 files changed, 40 insertions, 31 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index ab8113cff7c..e7768e37f36 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -135,7 +135,7 @@ out_free_pages:
                         put_page(r1_bio->bios[j]->bi_io_vec[i].bv_page);
         j = -1;
 out_free_bio:
-        while ( ++j < pi->raid_disks )
+        while (++j < pi->raid_disks)
                 bio_put(r1_bio->bios[j]);
         r1bio_pool_free(r1_bio, data);
         return NULL;
@@ -164,7 +164,7 @@ static void put_all_bios(struct r1conf *conf, struct r1bio *r1_bio)
 {
         int i;
 
-        for (i = 0; i < conf->raid_disks; i++) {
+        for (i = 0; i < conf->raid_disks * 2; i++) {
                 struct bio **bio = r1_bio->bios + i;
                 if (!BIO_SPECIAL(*bio))
                         bio_put(*bio);
@@ -185,7 +185,7 @@ static void put_buf(struct r1bio *r1_bio)
         struct r1conf *conf = r1_bio->mddev->private;
         int i;
 
-        for (i=0; i<conf->raid_disks; i++) {
+        for (i = 0; i < conf->raid_disks * 2; i++) {
                 struct bio *bio = r1_bio->bios[i];
                 if (bio->bi_end_io)
                         rdev_dec_pending(conf->mirrors[i].rdev, r1_bio->mddev);
@@ -280,11 +280,11 @@ static int find_bio_disk(struct r1bio *r1_bio, struct bio *bio)
         struct r1conf *conf = r1_bio->mddev->private;
         int raid_disks = conf->raid_disks;
 
-        for (mirror = 0; mirror < raid_disks; mirror++)
+        for (mirror = 0; mirror < raid_disks * 2; mirror++)
                 if (r1_bio->bios[mirror] == bio)
                         break;
 
-        BUG_ON(mirror == raid_disks);
+        BUG_ON(mirror == raid_disks * 2);
         update_head_pos(mirror, r1_bio);
 
         return mirror;
@@ -506,7 +506,7 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
                 start_disk = conf->last_used;
         }
 
-        for (i = 0 ; i < conf->raid_disks ; i++) {
+        for (i = 0 ; i < conf->raid_disks * 2 ; i++) {
                 sector_t dist;
                 sector_t first_bad;
                 int bad_sectors;
@@ -975,7 +975,7 @@ read_again:
          */
         plugged = mddev_check_plugged(mddev);
 
-        disks = conf->raid_disks;
+        disks = conf->raid_disks * 2;
  retry_write:
         blocked_rdev = NULL;
         rcu_read_lock();
@@ -989,7 +989,8 @@ read_again:
                 }
                 r1_bio->bios[i] = NULL;
                 if (!rdev || test_bit(Faulty, &rdev->flags)) {
-                        set_bit(R1BIO_Degraded, &r1_bio->state);
+                        if (i < conf->raid_disks)
+                                set_bit(R1BIO_Degraded, &r1_bio->state);
                         continue;
                 }
 
@@ -1493,7 +1494,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
                                 }
                         }
                         d++;
-                        if (d == conf->raid_disks)
+                        if (d == conf->raid_disks * 2)
                                 d = 0;
                 } while (!success && d != r1_bio->read_disk);
 
@@ -1510,7 +1511,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
                                mdname(mddev),
                                bdevname(bio->bi_bdev, b),
                                (unsigned long long)r1_bio->sector);
-                        for (d = 0; d < conf->raid_disks; d++) {
+                        for (d = 0; d < conf->raid_disks * 2; d++) {
                                 rdev = conf->mirrors[d].rdev;
                                 if (!rdev || test_bit(Faulty, &rdev->flags))
                                         continue;
@@ -1536,7 +1537,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
                 /* write it back and re-read */
                 while (d != r1_bio->read_disk) {
                         if (d == 0)
-                                d = conf->raid_disks;
+                                d = conf->raid_disks * 2;
                         d--;
                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
                                 continue;
@@ -1551,7 +1552,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
                 d = start;
                 while (d != r1_bio->read_disk) {
                         if (d == 0)
-                                d = conf->raid_disks;
+                                d = conf->raid_disks * 2;
                         d--;
                         if (r1_bio->bios[d]->bi_end_io != end_sync_read)
                                 continue;
@@ -1584,7 +1585,7 @@ static int process_checks(struct r1bio *r1_bio)
         int primary;
         int i;
 
-        for (primary = 0; primary < conf->raid_disks; primary++)
+        for (primary = 0; primary < conf->raid_disks * 2; 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;
@@ -1592,7 +1593,7 @@ static int process_checks(struct r1bio *r1_bio)
                         break;
                 }
         r1_bio->read_disk = primary;
-        for (i = 0; i < conf->raid_disks; i++) {
+        for (i = 0; i < conf->raid_disks * 2; i++) {
                 int j;
                 int vcnt = r1_bio->sectors >> (PAGE_SHIFT- 9);
                 struct bio *pbio = r1_bio->bios[primary];
@@ -1656,7 +1657,7 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
 {
         struct r1conf *conf = mddev->private;
         int i;
-        int disks = conf->raid_disks;
+        int disks = conf->raid_disks * 2;
         struct bio *bio, *wbio;
 
         bio = r1_bio->bios[r1_bio->read_disk];
@@ -1737,7 +1738,7 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
                                 success = 1;
                         else {
                                 d++;
-                                if (d == conf->raid_disks)
+                                if (d == conf->raid_disks * 2)
                                         d = 0;
                         }
                 } while (!success && d != read_disk);
@@ -1753,7 +1754,7 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
                 start = d;
                 while (d != read_disk) {
                         if (d==0)
-                                d = conf->raid_disks;
+                                d = conf->raid_disks * 2;
                         d--;
                         rdev = conf->mirrors[d].rdev;
                         if (rdev &&
@@ -1765,7 +1766,7 @@ static void fix_read_error(struct r1conf *conf, int read_disk,
                 while (d != read_disk) {
                         char b[BDEVNAME_SIZE];
                         if (d==0)
-                                d = conf->raid_disks;
+                                d = conf->raid_disks * 2;
                         d--;
                         rdev = conf->mirrors[d].rdev;
                         if (rdev &&
@@ -1887,7 +1888,7 @@ static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio
 {
         int m;
         int s = r1_bio->sectors;
-        for (m = 0; m < conf->raid_disks ; m++) {
+        for (m = 0; m < conf->raid_disks * 2 ; m++) {
                 struct md_rdev *rdev = conf->mirrors[m].rdev;
                 struct bio *bio = r1_bio->bios[m];
                 if (bio->bi_end_io == NULL)
@@ -1909,7 +1910,7 @@ static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio
 static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio)
 {
         int m;
-        for (m = 0; m < conf->raid_disks ; m++)
+        for (m = 0; m < conf->raid_disks * 2 ; m++)
                 if (r1_bio->bios[m] == IO_MADE_GOOD) {
                         struct md_rdev *rdev = conf->mirrors[m].rdev;
                         rdev_clear_badblocks(rdev,
@@ -2184,7 +2185,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
         r1_bio->state = 0;
         set_bit(R1BIO_IsSync, &r1_bio->state);
 
-        for (i=0; i < conf->raid_disks; i++) {
+        for (i = 0; i < conf->raid_disks * 2; i++) {
                 struct md_rdev *rdev;
                 bio = r1_bio->bios[i];
 
@@ -2203,7 +2204,8 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
                 rdev = rcu_dereference(conf->mirrors[i].rdev);
                 if (rdev == NULL ||
                     test_bit(Faulty, &rdev->flags)) {
-                        still_degraded = 1;
+                        if (i < conf->raid_disks)
+                                still_degraded = 1;
                 } else if (!test_bit(In_sync, &rdev->flags)) {
                         bio->bi_rw = WRITE;
                         bio->bi_end_io = end_sync_write;
@@ -2254,7 +2256,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
                  * need to mark them bad on all write targets
                  */
                 int ok = 1;
-                for (i = 0 ; i < conf->raid_disks ; i++)
+                for (i = 0 ; i < conf->raid_disks * 2 ; i++)
                         if (r1_bio->bios[i]->bi_end_io == end_sync_write) {
                                 struct md_rdev *rdev =
                                         rcu_dereference(conf->mirrors[i].rdev);
@@ -2323,7 +2325,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
                                 len = sync_blocks<<9;
                 }
 
-                for (i=0 ; i < conf->raid_disks; i++) {
+                for (i = 0 ; i < conf->raid_disks * 2; i++) {
                         bio = r1_bio->bios[i];
                         if (bio->bi_end_io) {
                                 page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
@@ -2356,7 +2358,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
          */
         if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) {
                 atomic_set(&r1_bio->remaining, read_targets);
-                for (i=0; i<conf->raid_disks; i++) {
+                for (i = 0; i < conf->raid_disks * 2; i++) {
                         bio = r1_bio->bios[i];
                         if (bio->bi_end_io == end_sync_read) {
                                 md_sync_acct(bio->bi_bdev, nr_sectors);
@@ -2393,7 +2395,8 @@ static struct r1conf *setup_conf(struct mddev *mddev)
         if (!conf)
                 goto abort;
 
-        conf->mirrors = kzalloc(sizeof(struct mirror_info)*mddev->raid_disks,
+        conf->mirrors = kzalloc(sizeof(struct mirror_info)
+                                * mddev->raid_disks * 2,
                                  GFP_KERNEL);
         if (!conf->mirrors)
                 goto abort;
@@ -2405,7 +2408,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
         conf->poolinfo = kzalloc(sizeof(*conf->poolinfo), GFP_KERNEL);
         if (!conf->poolinfo)
                 goto abort;
-        conf->poolinfo->raid_disks = mddev->raid_disks;
+        conf->poolinfo->raid_disks = mddev->raid_disks * 2;
         conf->r1bio_pool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
                                           r1bio_pool_free,
                                           conf->poolinfo);
@@ -2438,7 +2441,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
         conf->recovery_disabled = mddev->recovery_disabled - 1;
 
         conf->last_used = -1;
-        for (i = 0; i < conf->raid_disks; i++) {
+        for (i = 0; i < conf->raid_disks * 2; i++) {
 
                 disk = conf->mirrors + i;
 
@@ -2665,7 +2668,7 @@ static int raid1_reshape(struct mddev *mddev)
         if (!newpoolinfo)
                 return -ENOMEM;
         newpoolinfo->mddev = mddev;
-        newpoolinfo->raid_disks = raid_disks;
+        newpoolinfo->raid_disks = raid_disks * 2;
 
         newpool = mempool_create(NR_RAID1_BIOS, r1bio_pool_alloc,
                                  r1bio_pool_free, newpoolinfo);
@@ -2673,7 +2676,8 @@ static int raid1_reshape(struct mddev *mddev)
                 kfree(newpoolinfo);
                 return -ENOMEM;
         }
-        newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks, GFP_KERNEL);
+        newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks * 2,
+                             GFP_KERNEL);
         if (!newmirrors) {
                 kfree(newpoolinfo);
                 mempool_destroy(newpool);
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index c732b6cce93..80ded139314 100644
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -12,6 +12,9 @@ struct mirror_info {
  * pool was allocated for, so they know how much to allocate and free.
  * mddev->raid_disks cannot be used, as it can change while a pool is active
  * These two datums are stored in a kmalloced struct.
+ * The 'raid_disks' here is twice the raid_disks in r1conf.
+ * This allows space for each 'real' device can have a replacement in the
+ * second half of the array.
  */
 
 struct pool_info {
@@ -21,7 +24,9 @@ struct pool_info {
 
 struct r1conf {
         struct mddev            *mddev;
-        struct mirror_info              *mirrors;
+        struct mirror_info      *mirrors;       /* twice 'raid_disks' to
+                                                 * allow for replacements.
+                                                 */
         int                     raid_disks;
 
         /* When choose the best device for a read (read_balance())