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Fix management of backed-up region for hi-to-low reshapes. 

When reshaping from the end of the array to the start, for times
when the number of data devices is decreasing, the handling of the
backup area isn't a simple mirror of the handling on low-to-hi
reshapes as the backup areas is always low in the array.

So re-write that to make it work.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2011-01-21 07:59:53 +11:00
parent 55f1472192
commit 38dad34a35
1 changed files with 52 additions and 37 deletions
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89
Grow.c
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@ -2223,8 +2223,9 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
int advancing = (reshape->after.data_disks
>= reshape->before.data_disks);
unsigned long long need_backup; /* need to eventually backup all the way
* to here
unsigned long long need_backup; /* All data between start of array and
* here will at some point need to
* be backed up.
*/
unsigned long long read_offset, write_offset;
unsigned long long write_range;
@ -2266,37 +2267,38 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
read_offset = info->reshape_progress / reshape->before.data_disks;
write_offset = info->reshape_progress / reshape->after.data_disks;
write_range = info->new_chunk/512;
if (reshape->before.data_disks == reshape->after.data_disks)
need_backup = array_size;
else
need_backup = reshape->backup_blocks;
if (advancing) {
need_backup = 0;
if (read_offset < write_offset + write_range) {
if (read_offset < write_offset + write_range)
max_progress = backup_point;
if (reshape->before.data_disks == reshape->after.data_disks)
need_backup = array_size;
else
need_backup = reshape->backup_blocks;
} else {
else {
max_progress =
read_offset *
reshape->after.data_disks;
}
} else {
need_backup = array_size;
if (read_offset > write_offset - write_range) {
if (read_offset > write_offset - write_range)
/* Can only progress as far as has been backed up,
* which must be suspended */
max_progress = backup_point;
if (max_progress >= info->reshape_progress)
need_backup = 0;
} else {
max_progress =
read_offset *
reshape->after.data_disks;
/* If we are using internal metadata, then we can
* progress all the way to the suspend_point without
* worrying about backing-up/suspending along the
* way.
*/
if (max_progress < *suspend_point &&
info->array.major_version >= 0)
max_progress = *suspend_point;
else if (info->reshape_progress <= need_backup)
max_progress = backup_point;
else {
if (info->array.major_version >= 0)
/* Can progress until backup is needed */
max_progress = need_backup;
else {
/* Can progress until metadata update is required */
max_progress =
read_offset *
reshape->after.data_disks;
/* but data must be suspended */
if (max_progress < *suspend_point)
max_progress = *suspend_point;
}
}
}
@ -2335,16 +2337,28 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
max_progress = *suspend_point;
}
} else {
if ((need_backup < info->reshape_progress
|| info->array.major_version < 0) &&
*suspend_point > info->reshape_progress - target) {
if (need_backup > *suspend_point - 2 * target)
*suspend_point = need_backup;
else if (*suspend_point >= 2 * target)
*suspend_point -= 2 * target;
else
if (info->array.major_version >= 0) {
/* Only need to suspend when about to backup */
if (info->reshape_progress < need_backup * 2 &&
*suspend_point > 0) {
*suspend_point = 0;
sysfs_set_num(info, NULL, "suspend_lo", *suspend_point);
sysfs_set_num(info, NULL, "suspend_lo", 0);
sysfs_set_num(info, NULL, "suspend_hi", need_backup);
}
} else {
/* Need to suspend continually */
if (info->reshape_progress < *suspend_point)
*suspend_point = info->reshape_progress;
if (*suspend_point + target < info->reshape_progress)
/* No need to move suspend region yet */;
else {
if (*suspend_point >= 2 * target)
*suspend_point -= 2 * target;
else
*suspend_point = 0;
sysfs_set_num(info, NULL, "suspend_lo",
*suspend_point);
}
if (max_progress < *suspend_point)
max_progress = *suspend_point;
}
@ -2423,9 +2437,10 @@ int progress_reshape(struct mdinfo *info, struct reshape *reshape,
/* We return the need_backup flag. Caller will decide
* how much - a multiple of ->backup_blocks up to *suspend_point
*/
return advancing
? (need_backup > info->reshape_progress)
: (need_backup < info->reshape_progress);
if (advancing)
return need_backup > info->reshape_progress;
else
return need_backup >= info->reshape_progress;
check_progress:
/* if we couldn't read a number from sync_completed, then