lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

md: add ->takeover method to support changing the personality managing an array

Browse Source 
Implement this for RAID6 to be able to 'takeover' a RAID5 array.  The
new RAID6 will use a layout which places Q on the last device, and
that device will be missing.
If there are any available spares, one will immediately have Q
recovered onto it.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown
2009-03-31 14:39:39 +11:00
parent 409c57f380
commit 245f46c2c2
3 changed files with 161 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

101
drivers/md/md.c
View File

@ -2649,18 +2649,101 @@ level_show(mddev_t *mddev, char *page)
static ssize_t
level_store(mddev_t *mddev, const char *buf, size_t len)
{
char level[16];
ssize_t rv = len;
if (mddev->pers)
struct mdk_personality *pers;
void *priv;
if (mddev->pers == NULL) {
if (len == 0)
return 0;
if (len >= sizeof(mddev->clevel))
return -ENOSPC;
strncpy(mddev->clevel, buf, len);
if (mddev->clevel[len-1] == '\n')
len--;
mddev->clevel[len] = 0;
mddev->level = LEVEL_NONE;
return rv;
}
/* request to change the personality. Need to ensure:
* - array is not engaged in resync/recovery/reshape
* - old personality can be suspended
* - new personality will access other array.
*/
if (mddev->sync_thread || mddev->reshape_position != MaxSector)
return -EBUSY;
if (len == 0)
return 0;
if (len >= sizeof(mddev->clevel))
return -ENOSPC;
strncpy(mddev->clevel, buf, len);
if (mddev->clevel[len-1] == '\n')
if (!mddev->pers->quiesce) {
printk(KERN_WARNING "md: %s: %s does not support online personality change\n",
mdname(mddev), mddev->pers->name);
return -EINVAL;
}
/* Now find the new personality */
if (len == 0 || len >= sizeof(level))
return -EINVAL;
strncpy(level, buf, len);
if (level[len-1] == '\n')
len--;
mddev->clevel[len] = 0;
mddev->level = LEVEL_NONE;
level[len] = 0;
request_module("md-%s", level);
spin_lock(&pers_lock);
pers = find_pers(LEVEL_NONE, level);
if (!pers || !try_module_get(pers->owner)) {
spin_unlock(&pers_lock);
printk(KERN_WARNING "md: personality %s not loaded\n", level);
return -EINVAL;
}
spin_unlock(&pers_lock);
if (pers == mddev->pers) {
/* Nothing to do! */
module_put(pers->owner);
return rv;
}
if (!pers->takeover) {
module_put(pers->owner);
printk(KERN_WARNING "md: %s: %s does not support personality takeover\n",
mdname(mddev), level);
return -EINVAL;
}
/* ->takeover must set new_* and/or delta_disks
* if it succeeds, and may set them when it fails.
*/
priv = pers->takeover(mddev);
if (IS_ERR(priv)) {
mddev->new_level = mddev->level;
mddev->new_layout = mddev->layout;
mddev->new_chunk = mddev->chunk_size;
mddev->raid_disks -= mddev->delta_disks;
mddev->delta_disks = 0;
module_put(pers->owner);
printk(KERN_WARNING "md: %s: %s would not accept array\n",
mdname(mddev), level);
return PTR_ERR(priv);
}
/* Looks like we have a winner */
mddev_suspend(mddev);
mddev->pers->stop(mddev);
module_put(mddev->pers->owner);
mddev->pers = pers;
mddev->private = priv;
strlcpy(mddev->clevel, pers->name, sizeof(mddev->clevel));
mddev->level = mddev->new_level;
mddev->layout = mddev->new_layout;
mddev->chunk_size = mddev->new_chunk;
mddev->delta_disks = 0;
pers->run(mddev);
mddev_resume(mddev);
set_bit(MD_CHANGE_DEVS, &mddev->flags);
set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
md_wakeup_thread(mddev->thread);
return rv;
}