[PATCH 02/31] Disk removal support for Raid10->Raid0 takeover

Until now Raid10->Raid0 takeover was possible only if all the mirrors where removed before md starts the takeover.
Now mdadm, when performing Raid10->raid0 takeover, will remove all unwanted mirrors from the array before actual md takeover is called.

Signed-off-by: Maciej Trela
Signed-off-by: Adam Kwolek
---

mdadm/mdadm/Grow.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 71 insertions(+), 1 deletions(-)

diff --git a/mdadm/mdadm/Grow.c b/mdadm/mdadm/Grow.c index 1054979..3721c9c 100644
--- a/mdadm/mdadm/Grow.c
+++ b/mdadm/mdadm/Grow.c
@@ -821,7 +821,7 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
st->update_tail = &st->updates;
}

- sra = sysfs_read(fd, 0, GET_VERSION | GET_LEVEL);
+ sra = sysfs_read(fd, 0, GET_VERSION | GET_LEVEL | GET_DEVS |
+GET_STATE);
if (sra) {
if (st->ss->external && st->subarray[0] == 0) {
array.level = LEVEL_CONTAINER;
@@ -892,6 +892,76 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
size = array.size;
}

+ /* ========= check for Raid10 -> Raid0 conversion ===============
+ * current implemenation assumes that following conditions must be met:
+ * - far_copies == 1
+ * - near_copies == 2
+ * - disks number must be even
+ */
+ if (level == 0 && array.level == 10 &&
+ array.layout == ((1 << 8) + 2) && !(array.raid_disks & 1)) {
+ int max_disks;
+ int nr_of_copies, in_sync, copies;
+ struct mdinfo info;
+ struct mdinfo *sd_temp;
+
+ info.array.raid_disks = MD_SB_DISKS;
+ st->ss->getinfo_super(st, &info);
+ max_disks = info.array.raid_disks;
+
+ nr_of_copies = array.layout & 0xff;
+ in_sync = nr_of_copies;
+ copies = nr_of_copies;
+
+ /* Find devices that will be removed from the array */
+ d = 0;
+ sd_temp = sra->devs;
+ for (sd = sra->devs; sd; sd = sd->next, d++) {
+ int i, remove_all = 0;
+
+ if (sd->disk.state & (1< + continue;
+ if (!(sd->disk.state & (1< + in_sync--;
+
+ copies--;
+ if (!copies) {
+ /* We reached end of "mirrored" set of devices */
+ if (!in_sync) {
+ /* The array is failed and cannot be reshaped */
+ return 1;
+ }
+
+ /* Now mark all disks to be removed as faulty
+ * (leave only one in_sync disk) */
+ for (i = (d-nr_of_copies+1); i <= d; i++, sd_temp = sd_temp->next) {
+ if (sd_temp == NULL) {
+ /* error, array is wrong built
+ */
+ return 1;
+ }
+ if ((sd_temp->disk.state & (1< + (remove_all == 0)) {
+ /* this will be the candidate for Raid 0,
+ * leave it */
+ remove_all = 1;
+ continue;
+ } else {
+ /* this one will be removed */
+ sysfs_set_str(sra, sd_temp, "state", "faulty");
+ sysfs_set_str(sra, sd_temp, "slot", "none");
+ sysfs_set_str(sra, sd_temp, "state", "remove");
+
+ }
+ }
+ /* update in_sync and copies for the next set of devices */
+ in_sync = nr_of_copies;
+ copies = nr_of_copies;
+ sd_temp = sd->next;
+ }
+ }
+ }
+
/* ======= set level =========== */
if (level != UnSet && level != array.level) {
/* Trying to change the level.

--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html