1 files changed, 121 insertions, 43 deletions

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index cacd008d6864..197f62681db5 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -46,6 +46,20 @@
  */
 #define NR_RAID1_BIOS 256
 
+/* when we get a read error on a read-only array, we redirect to another
+ * device without failing the first device, or trying to over-write to
+ * correct the read error.  To keep track of bad blocks on a per-bio
+ * level, we store IO_BLOCKED in the appropriate 'bios' pointer
+ */
+#define IO_BLOCKED ((struct bio *)1)
+/* When we successfully write to a known bad-block, we need to remove the
+ * bad-block marking which must be done from process context.  So we record
+ * the success by setting devs[n].bio to IO_MADE_GOOD
+ */
+#define IO_MADE_GOOD ((struct bio *)2)
+
+#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
+
 /* When there are this many requests queue to be written by
  * the raid1 thread, we become 'congested' to provide back-pressure
  * for writeback.
@@ -483,12 +497,14 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
         const sector_t this_sector = r1_bio->sector;
         int sectors;
         int best_good_sectors;
-        int start_disk;
-        int best_disk;
-        int i;
+        int best_disk, best_dist_disk, best_pending_disk;
+        int has_nonrot_disk;
+        int disk;
         sector_t best_dist;
+        unsigned int min_pending;
         struct md_rdev *rdev;
         int choose_first;
+        int choose_next_idle;
 
         rcu_read_lock();
         /*
@@ -499,26 +515,26 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
  retry:
         sectors = r1_bio->sectors;
         best_disk = -1;
+        best_dist_disk = -1;
         best_dist = MaxSector;
+        best_pending_disk = -1;
+        min_pending = UINT_MAX;
         best_good_sectors = 0;
+        has_nonrot_disk = 0;
+        choose_next_idle = 0;
 
         if (conf->mddev->recovery_cp < MaxSector &&
-            (this_sector + sectors >= conf->next_resync)) {
+            (this_sector + sectors >= conf->next_resync))
                 choose_first = 1;
-                start_disk = 0;
-        } else {
+        else
                 choose_first = 0;
-                start_disk = conf->last_used;
-        }
 
-        for (i = 0 ; i < conf->raid_disks * 2 ; i++) {
+        for (disk = 0 ; disk < conf->raid_disks * 2 ; disk++) {
                 sector_t dist;
                 sector_t first_bad;
                 int bad_sectors;
-
-                int disk = start_disk + i;
-                if (disk >= conf->raid_disks * 2)
-                        disk -= conf->raid_disks * 2;
+                unsigned int pending;
+                bool nonrot;
 
                 rdev = rcu_dereference(conf->mirrors[disk].rdev);
                 if (r1_bio->bios[disk] == IO_BLOCKED
@@ -577,22 +593,77 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
                 } else
                         best_good_sectors = sectors;
 
+                nonrot = blk_queue_nonrot(bdev_get_queue(rdev->bdev));
+                has_nonrot_disk |= nonrot;
+                pending = atomic_read(&rdev->nr_pending);
                 dist = abs(this_sector - conf->mirrors[disk].head_position);
-                if (choose_first
-                    /* Don't change to another disk for sequential reads */
-                    || conf->next_seq_sect == this_sector
-                    || dist == 0
-                    /* If device is idle, use it */
-                    || atomic_read(&rdev->nr_pending) == 0) {
+                if (choose_first) {
+                        best_disk = disk;
+                        break;
+                }
+                /* Don't change to another disk for sequential reads */
+                if (conf->mirrors[disk].next_seq_sect == this_sector
+                    || dist == 0) {
+                        int opt_iosize = bdev_io_opt(rdev->bdev) >> 9;
+                        struct raid1_info *mirror = &conf->mirrors[disk];
+
+                        best_disk = disk;
+                        /*
+                         * If buffered sequential IO size exceeds optimal
+                         * iosize, check if there is idle disk. If yes, choose
+                         * the idle disk. read_balance could already choose an
+                         * idle disk before noticing it's a sequential IO in
+                         * this disk. This doesn't matter because this disk
+                         * will idle, next time it will be utilized after the
+                         * first disk has IO size exceeds optimal iosize. In
+                         * this way, iosize of the first disk will be optimal
+                         * iosize at least. iosize of the second disk might be
+                         * small, but not a big deal since when the second disk
+                         * starts IO, the first disk is likely still busy.
+                         */
+                        if (nonrot && opt_iosize > 0 &&
+                            mirror->seq_start != MaxSector &&
+                            mirror->next_seq_sect > opt_iosize &&
+                            mirror->next_seq_sect - opt_iosize >=
+                            mirror->seq_start) {
+                                choose_next_idle = 1;
+                                continue;
+                        }
+                        break;
+                }
+                /* If device is idle, use it */
+                if (pending == 0) {
                         best_disk = disk;
                         break;
                 }
+
+                if (choose_next_idle)
+                        continue;
+
+                if (min_pending > pending) {
+                        min_pending = pending;
+                        best_pending_disk = disk;
+                }
+
                 if (dist < best_dist) {
                         best_dist = dist;
-                        best_disk = disk;
+                        best_dist_disk = disk;
                 }
         }
 
+        /*
+         * If all disks are rotational, choose the closest disk. If any disk is
+         * non-rotational, choose the disk with less pending request even the
+         * disk is rotational, which might/might not be optimal for raids with
+         * mixed ratation/non-rotational disks depending on workload.
+         */
+        if (best_disk == -1) {
+                if (has_nonrot_disk)
+                        best_disk = best_pending_disk;
+                else
+                        best_disk = best_dist_disk;
+        }
+
         if (best_disk >= 0) {
                 rdev = rcu_dereference(conf->mirrors[best_disk].rdev);
                 if (!rdev)
@@ -606,8 +677,11 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
                         goto retry;
                 }
                 sectors = best_good_sectors;
-                conf->next_seq_sect = this_sector + sectors;
-                conf->last_used = best_disk;
+
+                if (conf->mirrors[best_disk].next_seq_sect != this_sector)
+                        conf->mirrors[best_disk].seq_start = this_sector;
+
+                conf->mirrors[best_disk].next_seq_sect = this_sector + sectors;
         }
         rcu_read_unlock();
         *max_sectors = sectors;
@@ -873,7 +947,7 @@ do_sync_io:
 static void make_request(struct mddev *mddev, struct bio * bio)
 {
         struct r1conf *conf = mddev->private;
-        struct mirror_info *mirror;
+        struct raid1_info *mirror;
         struct r1bio *r1_bio;
         struct bio *read_bio;
         int i, disks;
@@ -1364,7 +1438,7 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
         struct r1conf *conf = mddev->private;
         int err = -EEXIST;
         int mirror = 0;
-        struct mirror_info *p;
+        struct raid1_info *p;
         int first = 0;
         int last = conf->raid_disks - 1;
         struct request_queue *q = bdev_get_queue(rdev->bdev);
@@ -1433,7 +1507,7 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
         struct r1conf *conf = mddev->private;
         int err = 0;
         int number = rdev->raid_disk;
-        struct mirror_info *p = conf->mirrors+ number;
+        struct raid1_info *p = conf->mirrors + number;
 
         if (rdev != p->rdev)
                 p = conf->mirrors + conf->raid_disks + number;
@@ -2371,6 +2445,18 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
                                 bio->bi_rw = READ;
                                 bio->bi_end_io = end_sync_read;
                                 read_targets++;
+                        } else if (!test_bit(WriteErrorSeen, &rdev->flags) &&
+                                test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
+                                !test_bit(MD_RECOVERY_CHECK, &mddev->recovery)) {
+                                /*
+                                 * The device is suitable for reading (InSync),
+                                 * but has bad block(s) here. Let's try to correct them,
+                                 * if we are doing resync or repair. Otherwise, leave
+                                 * this device alone for this sync request.
+                                 */
+                                bio->bi_rw = WRITE;
+                                bio->bi_end_io = end_sync_write;
+                                write_targets++;
                         }
                 }
                 if (bio->bi_end_io) {
@@ -2428,7 +2514,10 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr, int *skipp
                 /* There is nowhere to write, so all non-sync
                  * drives must be failed - so we are finished
                  */
-                sector_t rv = max_sector - sector_nr;
+                sector_t rv;
+                if (min_bad > 0)
+                        max_sector = sector_nr + min_bad;
+                rv = max_sector - sector_nr;
                 *skipped = 1;
                 put_buf(r1_bio);
                 return rv;
@@ -2521,7 +2610,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
 {
         struct r1conf *conf;
         int i;
-        struct mirror_info *disk;
+        struct raid1_info *disk;
         struct md_rdev *rdev;
         int err = -ENOMEM;
 
@@ -2529,7 +2618,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
         if (!conf)
                 goto abort;
 
-        conf->mirrors = kzalloc(sizeof(struct mirror_info)
+        conf->mirrors = kzalloc(sizeof(struct raid1_info)
                                 * mddev->raid_disks * 2,
                                  GFP_KERNEL);
         if (!conf->mirrors)
@@ -2572,6 +2661,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
                         mddev->merge_check_needed = 1;
 
                 disk->head_position = 0;
+                disk->seq_start = MaxSector;
         }
         conf->raid_disks = mddev->raid_disks;
         conf->mddev = mddev;
@@ -2585,7 +2675,6 @@ static struct r1conf *setup_conf(struct mddev *mddev)
         conf->recovery_disabled = mddev->recovery_disabled - 1;
 
         err = -EIO;
-        conf->last_used = -1;
         for (i = 0; i < conf->raid_disks * 2; i++) {
 
                 disk = conf->mirrors + i;
@@ -2611,19 +2700,9 @@ static struct r1conf *setup_conf(struct mddev *mddev)
                         if (disk->rdev &&
                             (disk->rdev->saved_raid_disk < 0))
                                 conf->fullsync = 1;
-                } else if (conf->last_used < 0)
-                        /*
-                         * The first working device is used as a
-                         * starting point to read balancing.
-                         */
-                        conf->last_used = i;
+                }
         }
 
-        if (conf->last_used < 0) {
-                printk(KERN_ERR "md/raid1:%s: no operational mirrors\n",
-                       mdname(mddev));
-                goto abort;
-        }
         err = -ENOMEM;
         conf->thread = md_register_thread(raid1d, mddev, "raid1");
         if (!conf->thread) {
@@ -2798,7 +2877,7 @@ static int raid1_reshape(struct mddev *mddev)
          */
         mempool_t *newpool, *oldpool;
         struct pool_info *newpoolinfo;
-        struct mirror_info *newmirrors;
+        struct raid1_info *newmirrors;
         struct r1conf *conf = mddev->private;
         int cnt, raid_disks;
         unsigned long flags;
@@ -2841,7 +2920,7 @@ static int raid1_reshape(struct mddev *mddev)
                 kfree(newpoolinfo);
                 return -ENOMEM;
         }
-        newmirrors = kzalloc(sizeof(struct mirror_info) * raid_disks * 2,
+        newmirrors = kzalloc(sizeof(struct raid1_info) * raid_disks * 2,
                              GFP_KERNEL);
         if (!newmirrors) {
                 kfree(newpoolinfo);
@@ -2880,7 +2959,6 @@ static int raid1_reshape(struct mddev *mddev)
         conf->raid_disks = mddev->raid_disks = raid_disks;
         mddev->delta_disks = 0;
 
-        conf->last_used = 0; /* just make sure it is in-range */
         lower_barrier(conf);
 
         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);