md/raid10: Introduce 'prev' geometry to support reshape.

When RAID10 supports reshape it will need a 'previous' and a 'current'
geometry, so introduce that here.
Use the 'prev' geometry when before the reshape_position, and the
current 'geo' when beyond it.  At other times, use both as
appropriate.

For now, both are identical (And reshape_position is never set).

When we use the 'prev' geometry, we must use the old data_offset.
When we use the current (And a reshape is happening) we must use
the new_data_offset.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 36f445f..1c90005 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -504,15 +504,13 @@ static void raid10_end_write_request(struct bio *bio, int error)
  * sector offset to a virtual address
  */
 
-static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
+static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
 {
        int n,f;
        sector_t sector;
        sector_t chunk;
        sector_t stripe;
        int dev;
-       struct geom *geo = &conf->geo;
-
        int slot = 0;
 
        /* now calculate first sector/dev */
@@ -550,12 +548,29 @@ static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
                        sector += (geo->chunk_mask + 1);
                }
        }
-       BUG_ON(slot != conf->copies);
+}
+
+static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
+{
+       struct geom *geo = &conf->geo;
+
+       if (conf->reshape_progress != MaxSector &&
+           ((r10bio->sector >= conf->reshape_progress) !=
+            conf->mddev->reshape_backwards)) {
+               set_bit(R10BIO_Previous, &r10bio->state);
+               geo = &conf->prev;
+       } else
+               clear_bit(R10BIO_Previous, &r10bio->state);
+
+       __raid10_find_phys(geo, r10bio);
 }
 
 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 {
        sector_t offset, chunk, vchunk;
+       /* Never use conf->prev as this is only called during resync
+        * or recovery, so reshape isn't happening
+        */
        struct geom *geo = &conf->geo;
 
        offset = sector & geo->chunk_mask;
@@ -603,6 +618,11 @@ static int raid10_mergeable_bvec(struct request_queue *q,
        unsigned int bio_sectors = bvm->bi_size >> 9;
        struct geom *geo = &conf->geo;
 
+       if (conf->reshape_progress != MaxSector &&
+           ((sector >= conf->reshape_progress) !=
+            conf->mddev->reshape_backwards))
+               geo = &conf->prev;
+
        if (geo->near_copies < geo->raid_disks) {
                max = (chunk_sectors - ((sector & (chunk_sectors - 1))
                                        + bio_sectors)) << 9;
@@ -617,6 +637,12 @@ static int raid10_mergeable_bvec(struct request_queue *q,
        if (mddev->merge_check_needed) {
                struct r10bio r10_bio;
                int s;
+               if (conf->reshape_progress != MaxSector) {
+                       /* Cannot give any guidance during reshape */
+                       if (max <= biovec->bv_len && bio_sectors == 0)
+                               return biovec->bv_len;
+                       return 0;
+               }
                r10_bio.sector = sector;
                raid10_find_phys(conf, &r10_bio);
                rcu_read_lock();
@@ -816,7 +842,10 @@ static int raid10_congested(void *data, int bits)
        if (mddev_congested(mddev, bits))
                return 1;
        rcu_read_lock();
-       for (i = 0; i < conf->geo.raid_disks && ret == 0; i++) {
+       for (i = 0;
+            (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
+                    && ret == 0;
+            i++) {
                struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
                if (rdev && !test_bit(Faulty, &rdev->flags)) {
                        struct request_queue *q = bdev_get_queue(rdev->bdev);
@@ -977,13 +1006,23 @@ static void unfreeze_array(struct r10conf *conf)
        spin_unlock_irq(&conf->resync_lock);
 }
 
+static sector_t choose_data_offset(struct r10bio *r10_bio,
+                                  struct md_rdev *rdev)
+{
+       if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
+           test_bit(R10BIO_Previous, &r10_bio->state))
+               return rdev->data_offset;
+       else
+               return rdev->new_data_offset;
+}
+
 static void make_request(struct mddev *mddev, struct bio * bio)
 {
        struct r10conf *conf = mddev->private;
        struct r10bio *r10_bio;
        struct bio *read_bio;
        int i;
-       sector_t chunk_mask = conf->geo.chunk_mask;
+       sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
        int chunk_sects = chunk_mask + 1;
        const int rw = bio_data_dir(bio);
        const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
@@ -1004,7 +1043,8 @@ static void make_request(struct mddev *mddev, struct bio * bio)
         */
        if (unlikely((bio->bi_sector & chunk_mask) + (bio->bi_size >> 9)
                     > chunk_sects
-                    && conf->geo.near_copies < conf->geo.raid_disks)) {
+                    && (conf->geo.near_copies < conf->geo.raid_disks
+                        || conf->prev.near_copies < conf->prev.raid_disks))) {
                struct bio_pair *bp;
                /* Sanity check -- queue functions should prevent this happening */
                if (bio->bi_vcnt != 1 ||
@@ -1098,7 +1138,7 @@ read_again:
                r10_bio->devs[slot].rdev = rdev;
 
                read_bio->bi_sector = r10_bio->devs[slot].addr +
-                       rdev->data_offset;
+                       choose_data_offset(r10_bio, rdev);
                read_bio->bi_bdev = rdev->bdev;
                read_bio->bi_end_io = raid10_end_read_request;
                read_bio->bi_rw = READ | do_sync;
@@ -1302,7 +1342,8 @@ retry_write:
                r10_bio->devs[i].bio = mbio;
 
                mbio->bi_sector = (r10_bio->devs[i].addr+
-                                  conf->mirrors[d].rdev->data_offset);
+                                  choose_data_offset(r10_bio,
+                                                     conf->mirrors[d].rdev));
                mbio->bi_bdev = conf->mirrors[d].rdev->bdev;
                mbio->bi_end_io = raid10_end_write_request;
                mbio->bi_rw = WRITE | do_sync | do_fua;
@@ -1326,8 +1367,10 @@ retry_write:
                 * so it cannot disappear, so the replacement cannot
                 * become NULL here
                 */
-               mbio->bi_sector = (r10_bio->devs[i].addr+
-                                  conf->mirrors[d].replacement->data_offset);
+               mbio->bi_sector = (r10_bio->devs[i].addr +
+                                  choose_data_offset(
+                                          r10_bio,
+                                          conf->mirrors[d].replacement));
                mbio->bi_bdev = conf->mirrors[d].replacement->bdev;
                mbio->bi_end_io = raid10_end_write_request;
                mbio->bi_rw = WRITE | do_sync | do_fua;
@@ -1397,7 +1440,7 @@ static void status(struct seq_file *seq, struct mddev *mddev)
  * Don't consider the device numbered 'ignore'
  * as we might be about to remove it.
  */
-static int enough(struct r10conf *conf, int ignore)
+static int _enough(struct r10conf *conf, struct geom *geo, int ignore)
 {
        int first = 0;
 
@@ -1408,7 +1451,7 @@ static int enough(struct r10conf *conf, int ignore)
                        if (conf->mirrors[first].rdev &&
                            first != ignore)
                                cnt++;
-                       first = (first+1) % conf->geo.raid_disks;
+                       first = (first+1) % geo->raid_disks;
                }
                if (cnt == 0)
                        return 0;
@@ -1416,6 +1459,12 @@ static int enough(struct r10conf *conf, int ignore)
        return 1;
 }
 
+static int enough(struct r10conf *conf, int ignore)
+{
+       return _enough(conf, &conf->geo, ignore) &&
+               _enough(conf, &conf->prev, ignore);
+}
+
 static void error(struct mddev *mddev, struct md_rdev *rdev)
 {
        char b[BDEVNAME_SIZE];
@@ -1548,7 +1597,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                 * very different from resync
                 */
                return -EBUSY;
-       if (rdev->saved_raid_disk < 0 && !enough(conf, -1))
+       if (rdev->saved_raid_disk < 0 && !_enough(conf, &conf->prev, -1))
                return -EINVAL;
 
        if (rdev->raid_disk >= 0)
@@ -2223,7 +2272,9 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
                                       " (%d sectors at %llu on %s)\n",
                                       mdname(mddev), s,
                                       (unsigned long long)(
-                                              sect + rdev->data_offset),
+                                              sect +
+                                              choose_data_offset(r10_bio,
+                                                                 rdev)),
                                       bdevname(rdev->bdev, b));
                                printk(KERN_NOTICE "md/raid10:%s: %s: failing "
                                       "drive\n",
@@ -2261,7 +2312,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
                                       " (%d sectors at %llu on %s)\n",
                                       mdname(mddev), s,
                                       (unsigned long long)(
-                                              sect + rdev->data_offset),
+                                              sect +
+                                              choose_data_offset(r10_bio, rdev)),
                                       bdevname(rdev->bdev, b));
                                printk(KERN_NOTICE "md/raid10:%s: %s: failing "
                                       "drive\n",
@@ -2274,7 +2326,8 @@ static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10
                                       " (%d sectors at %llu on %s)\n",
                                       mdname(mddev), s,
                                       (unsigned long long)(
-                                              sect + rdev->data_offset),
+                                              sect +
+                                              choose_data_offset(r10_bio, rdev)),
                                       bdevname(rdev->bdev, b));
                                atomic_add(s, &rdev->corrected_errors);
                        }
@@ -2348,7 +2401,7 @@ static int narrow_write_error(struct r10bio *r10_bio, int i)
                wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
                md_trim_bio(wbio, sector - bio->bi_sector, sectors);
                wbio->bi_sector = (r10_bio->devs[i].addr+
-                                  rdev->data_offset+
+                                  choose_data_offset(r10_bio, rdev) +
                                   (sector - r10_bio->sector));
                wbio->bi_bdev = rdev->bdev;
                if (submit_bio_wait(WRITE, wbio) == 0)
@@ -2425,7 +2478,7 @@ read_more:
        r10_bio->devs[slot].bio = bio;
        r10_bio->devs[slot].rdev = rdev;
        bio->bi_sector = r10_bio->devs[slot].addr
-               + rdev->data_offset;
+               + choose_data_offset(r10_bio, rdev);
        bio->bi_bdev = rdev->bdev;
        bio->bi_rw = READ | do_sync;
        bio->bi_private = r10_bio;
@@ -3254,6 +3307,8 @@ static struct r10conf *setup_conf(struct mddev *mddev)
                goto out;
 
        calc_sectors(conf, mddev->dev_sectors);
+       conf->prev = conf->geo;
+       conf->reshape_progress = MaxSector;
 
        spin_lock_init(&conf->device_lock);
        INIT_LIST_HEAD(&conf->retry_list);
@@ -3319,8 +3374,10 @@ static int run(struct mddev *mddev)
        rdev_for_each(rdev, mddev) {
 
                disk_idx = rdev->raid_disk;
-               if (disk_idx >= conf->geo.raid_disks
-                   || disk_idx < 0)
+               if (disk_idx < 0)
+                       continue;
+               if (disk_idx >= conf->geo.raid_disks &&
+                   disk_idx >= conf->prev.raid_disks)
                        continue;
                disk = conf->mirrors + disk_idx;
 
@@ -3347,7 +3404,10 @@ static int run(struct mddev *mddev)
        }
 
        mddev->degraded = 0;
-       for (i = 0; i < conf->geo.raid_disks; i++) {
+       for (i = 0;
+            i < conf->geo.raid_disks
+                    || i < conf->prev.raid_disks;
+            i++) {
 
                disk = conf->mirrors + i;
 
@@ -3466,6 +3526,9 @@ static int raid10_resize(struct mddev *mddev, sector_t sectors)
        struct r10conf *conf = mddev->private;
        sector_t oldsize, size;
 
+       if (mddev->reshape_position != MaxSector)
+               return -EBUSY;
+
        if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
                return -EINVAL;
 

diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 4c4942a..37509d7 100644 (file)
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -34,13 +34,14 @@ struct r10conf {
                                               */
                int             chunk_shift; /* shift from chunks to sectors */
                sector_t        chunk_mask;
-       } geo;
+       } prev, geo;
        int                     copies;       /* near_copies * far_copies.
                                               * must be <= raid_disks
                                               */
 
        sector_t                dev_sectors;  /* temp copy of
                                               * mddev->dev_sectors */
+       sector_t                reshape_progress;
 
        struct list_head        retry_list;
        /* queue pending writes and submit them on unplug */
@@ -147,5 +148,10 @@ enum r10bio_state {
  */
        R10BIO_MadeGood,
        R10BIO_WriteError,
+/* During a reshape we might be performing IO on the
+ * 'previous' part of the array, in which case this
+ * flag is set
+ */
+       R10BIO_Previous,
 };
 #endif