Neil Brown wrote:
>>
>> The second 'if' is assuming that conf->last_used can't change during
>> rebuild,
>> but it can (line 1419):
>>
>>
>> disk = conf->last_used;
>> /* make sure disk is operational */
>> while (!conf->mirrors[disk].operational) {
>> if (disk <= 0) disk = conf->raid_disks;
>> disk--;
>> if (disk == conf->last_used)
>> break;
>> }
>> conf->last_used = disk;
>>
>>
>> This could only happen if a second disk failed during rebuild of a 3+
>> disk array.
>
>True, but if a disk fails during a rebuild the rebuild is aborted, so
>it doesn't really matter.
Even on a 3-disk mirror where there's a good data disk left to rebuild
from?
That sounds bad, and it looked to me like the code I quoted was looking for
another working drive if one failed during rebuild/resync.
>However there are more cosmetic changes than real content, making it
>harder for me to find the significant change. It is much easier to
>read a patch if it just does one thing.
diff -u --exclude-from=/home/me/.exclude -r linux-2.4.21-pre6-ref/drivers/md/raid1.c pre6-raid1d-a/drivers/md/raid1.c
--- linux-2.4.21-pre6-ref/drivers/md/raid1.c Thu Apr 3 13:21:37 2003
+++ pre6-raid1d-a/drivers/md/raid1.c Wed Apr 9 01:24:06 2003
@ -1188,7 +1188,7 @
for (i = 0; i < disks ; i++) {
if (!conf->mirrors[i].operational)
continue;
- if (i==conf->last_used)
+ if (conf->mirrors[i].dev == bh->b_dev)
/* we read from here, no need to write */
continue;
if (i < conf->raid_disks
I rebuilt a mirror with this patch (cut from a larger one)
applied to 2.4.20aa1 and it didn't complain:
@@ -1160,6 +1174,7 @@
raid1_conf_t *conf = data;
mddev_t *mddev = conf->mddev;
kdev_t dev;
+ static int _warned = 0; /* FIXME debug */
if (mddev->sb_dirty)
md_update_sb(mddev);
@ -1191,7 +1206,14 @
continue;
if (i==conf->last_used)
/* we read from here, no need to write */
+ { /* FIXME just checking */
+ if (_warned < 5
+ && conf->mirrors[i].dev != bh->b_dev) {
+ printk(KERN_WARNING "raid1d: dev != b_dev");
+ _warned++;
+ }
continue;
+ }
if (i < conf->raid_disks
&& !conf->resync_mirrors)
/* don't need to write this,
--
Chuck
I am not a number!
-
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