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super1: allow reshape that hasn't really started to be reverted. 

A simple revert doesn't work here because the reshape_position is
in the critical section.
The best approach is to let the reshape progress a bit and then
go backwards.
If that isn't possible, assembling with --update=revert-reshape and
--invalid-backup should work.

Reported-by-tested-by: George Rapp <george.rapp@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
NeilBrown 2016-01-28 12:57:08 +11:00
parent 9f7f28ee50
commit d5ff855d47
2 changed files with 28 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
Assemble.c
View File

@ -643,7 +643,14 @@ static int load_devices(struct devs *devices, char *devmap,
} else if (strcmp(c->update, "nodes") == 0) {
tst->nodes = c->nodes;
err = tst->ss->write_bitmap(tst, dfd, NodeNumUpdate);
} else
} else if (strcmp(c->update, "revert-reshape") == 0 &&
c->invalid_backup)
err = tst->ss->update_super(tst, content,
"revert-reshape-nobackup",
devname, c->verbose,
ident->uuid_set,
c->homehost);
else
err = tst->ss->update_super(tst, content, c->update,
devname, c->verbose,
ident->uuid_set,

21
super1.c
View File

@ -1307,7 +1307,7 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
(st->sb + MAX_SB_SIZE + BM_SUPER_SIZE);
sb->data_size = __cpu_to_le64(
misc->device_size - __le64_to_cpu(sb->data_offset));
} else if (strcmp(update, "revert-reshape") == 0) {
} else if (strncmp(update, "revert-reshape", 14) == 0) {
rv = -2;
if (!(sb->feature_map & __cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE)))
pr_err("No active reshape to revert on %s\n",
@ -1317,6 +1317,24 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
unsigned long long reshape_sectors;
long reshape_chunk;
rv = 0;
/* If the reshape hasn't started, just stop it.
* It is conceivable that a stripe was modified but
* the metadata not updated. In that case the backup
* should have been used to get passed the critical stage.
* If that couldn't happen, the "-nobackup" version
* will be used.
*/
if (strcmp(update, "revert-reshape-nobackup") == 0 &&
sb->reshape_position == 0 &&
(__le32_to_cpu(sb->delta_disks) > 0 ||
(__le32_to_cpu(sb->delta_disks) == 0 &&
!(sb->feature_map & __cpu_to_le32(MD_FEATURE_RESHAPE_BACKWARDS))))) {
sb->feature_map &= ~__cpu_to_le32(MD_FEATURE_RESHAPE_ACTIVE);
sb->raid_disks = __cpu_to_le32(__le32_to_cpu(sb->raid_disks) -
__le32_to_cpu(sb->delta_disks));
sb->delta_disks = 0;
goto done;
}
/* reshape_position is a little messy.
* Its value must be a multiple of the larger
* chunk size, and of the "after" data disks.
@ -1363,6 +1381,7 @@ static int update_super1(struct supertype *st, struct mdinfo *info,
sb->new_offset = __cpu_to_le32(-offset_delta);
sb->data_size = __cpu_to_le64(__le64_to_cpu(sb->data_size) - offset_delta);
}
done:;
}
} else if (strcmp(update, "_reshape_progress")==0)
sb->reshape_position = __cpu_to_le64(info->reshape_progress);