[PATCH] md: Core of raid5 resize process

This patch provides the core of the resize/expand process.

sync_request notices if a 'reshape' is happening and acts accordingly.

It allocated new stripe_heads for the next chunk-wide-stripe in the target
geometry, marking them STRIPE_EXPANDING.

Then it finds which stripe heads in the old geometry can provide data needed
by these and marks them STRIPE_EXPAND_SOURCE.  This causes stripe_handle to
read all blocks on those stripes.

Once all blocks on a STRIPE_EXPAND_SOURCE stripe_head are read, any that are
needed are copied into the corresponding STRIPE_EXPANDING stripe_head.  Once a
STRIPE_EXPANDING stripe_head is full, it is marks STRIPE_EXPAND_READY and then
is written out and released.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index c7b7656f9aa5..8e65986bc63f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2165,7 +2165,9 @@ action_show(mddev_t *mddev, char *page)
         char *type = "idle";
         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
             test_bit(MD_RECOVERY_NEEDED, &mddev->recovery)) {
-                if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
+                if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+                        type = "reshape";
+                else if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
                         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery))
                                 type = "resync";
                         else if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
@@ -4088,8 +4090,10 @@ static void status_resync(struct seq_file *seq, mddev_t * mddev)
                 seq_printf(seq, "] ");
         }
         seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
+                   (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
+                    "reshape" :
                       (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
-                       "resync" : "recovery"),
+                       "resync" : "recovery")),
                       per_milli/10, per_milli % 10,
                    (unsigned long long) resync,
                    (unsigned long long) max_blocks);
@@ -4543,7 +4547,9 @@ static void md_do_sync(mddev_t *mddev)
                  */
                 max_sectors = mddev->resync_max_sectors;
                 mddev->resync_mismatches = 0;
-        } else
+        } else if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+                max_sectors = mddev->size << 1;
+        else
                 /* recovery follows the physical size of devices */
                 max_sectors = mddev->size << 1;
 
@@ -4679,6 +4685,8 @@ static void md_do_sync(mddev_t *mddev)
         mddev->pers->sync_request(mddev, max_sectors, &skipped, 1);
 
         if (!test_bit(MD_RECOVERY_ERR, &mddev->recovery) &&
+            test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
+            !test_bit(MD_RECOVERY_CHECK, &mddev->recovery) &&
             mddev->curr_resync > 2 &&
             mddev->curr_resync >= mddev->recovery_cp) {
                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {