On Fri, 26 Nov 2010 09:06:00 +0100 Adam Kwolek <adam.kwolek@xxxxxxxxx> wrote:
> 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 <maciej.trela@xxxxxxxxx>
> Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx>
This patch makes sense, but I found the logic in choosing which devices to
remove to be vary hard to follow.
I have replaced it with the following: We select one disk to keep from each
pair, then remove the remainder.
Thanks,
NeilBrown
commit 62a48395f60965d04da1a9cbb937bda79dd071c8
Author: Adam Kwolek <adam.kwolek@xxxxxxxxx>
Date: Mon Nov 29 11:57:51 2010 +1100
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 <maciej.trela@xxxxxxxxx>
Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
diff --git a/Grow.c b/Grow.c
index ea8f493..1d92d68 100644
--- a/Grow.c
+++ b/Grow.c
@@ -771,6 +771,76 @@ static void revert_container_raid_disks(struct supertype *st, int fd, char *cont
free_mdstat(ent);
}
+int remove_disks_on_raid10_to_raid0_takeover(struct supertype *st,
+ struct mdinfo *sra,
+ int layout)
+{
+ int nr_of_copies;
+ struct mdinfo *remaining;
+ int slot;
+
+ nr_of_copies = layout & 0xff;
+
+ remaining = sra->devs;
+ sra->devs = NULL;
+ /* for each 'copy', select one device and remove from the list. */
+ for (slot = 0; slot < sra->array.raid_disks; slot += nr_of_copies) {
+ struct mdinfo **diskp;
+ int found = 0;
+
+ /* Find a working device to keep */
+ for (diskp = &remaining; *diskp ; diskp = &(*diskp)->next) {
+ struct mdinfo *disk = *diskp;
+
+ if (disk->disk.raid_disk < slot)
+ continue;
+ if (disk->disk.raid_disk >= slot + nr_of_copies)
+ continue;
+ if (disk->disk.state & (1<<MD_DISK_REMOVED))
+ continue;
+ if (disk->disk.state & (1<<MD_DISK_FAULTY))
+ continue;
+ if (!(disk->disk.state & (1<<MD_DISK_SYNC)))
+ continue;
+
+ /* We have found a good disk to use! */
+ *diskp = disk->next;
+ disk->next = sra->devs;
+ sra->devs = disk;
+ found = 1;
+ break;
+ }
+ if (!found)
+ break;
+ }
+
+ if (slot < sra->array.raid_disks) {
+ /* didn't find all slots */
+ struct mdinfo **e;
+ e = &remaining;
+ while (*e)
+ e = &(*e)->next;
+ *e = sra->devs;
+ sra->devs = remaining;
+ return 1;
+ }
+
+ /* Remove all 'remaining' devices from the array */
+ while (remaining) {
+ struct mdinfo *sd = remaining;
+ remaining = sd->next;
+
+ sysfs_set_str(sra, sd, "state", "faulty");
+ sysfs_set_str(sra, sd, "slot", "none");
+ sysfs_set_str(sra, sd, "state", "remove");
+ sd->disk.state |= (1<<MD_DISK_REMOVED);
+ sd->disk.state &= ~(1<<MD_DISK_SYNC);
+ sd->next = sra->devs;
+ sra->devs = sd;
+ }
+ return 0;
+}
+
int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
long long size,
int level, char *layout_str, int chunksize, int raid_disks)
@@ -902,7 +972,7 @@ int Grow_reshape(char *devname, int fd, int quiet, char *backup_file,
st->update_tail = &st->updates;
}
- sra = sysfs_read(fd, 0, GET_LEVEL);
+ sra = sysfs_read(fd, 0, GET_LEVEL | GET_DISKS | GET_DEVS | GET_STATE);
if (sra) {
if (st->ss->external && subarray == NULL) {
array.level = LEVEL_CONTAINER;
@@ -973,6 +1043,25 @@ 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
+ */
+ if (level == 0 && array.level == 10 &&
+ array.layout == ((1 << 8) + 2) && !(array.raid_disks & 1)) {
+ int err;
+ err = remove_disks_on_raid10_to_raid0_takeover(st, sra, array.layout);
+ if (err) {
+ dprintf(Name": Array cannot be reshaped\n");
+ if (container)
+ free(container);
+ if (cfd > -1)
+ close(cfd);
+ return 1;
+ }
+ }
+
/* ======= set level =========== */
if (level != UnSet && level != array.level) {
/* Trying to change the level.
--
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