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cachevol: allow forced detaching of damaged or invalid cachevol

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A cachevol can be forcibly detached when it's missing devices.
Also allow this if it's damaged/invalid and unrepairable.
This would be needed to recover data from the origin LV after
a cachevol is lost or damaged beyond repair.
This commit is contained in:
David Teigland 2021-01-12 11:53:02 -06:00
parent ae2af1d5ed
commit cb54d0801d
2 changed files with 54 additions and 7 deletions
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34
test/shell/writecache-split.sh
View File

@ -153,6 +153,40 @@ vgextend --restoremissing $vg "$dev3"
vgremove -ff $vg
#
# split while cachevol is damaged
#
vgcreate $SHARED $vg "$dev1" "$dev2" "$dev3" "$dev4"
lvcreate -n $lv1 -l 16 -an $vg "$dev1" "$dev4"
lvcreate -n $lv2 -l 4 -an $vg "$dev2"
lvchange -ay $vg/$lv1
mkfs_mount_umount $lv1
lvconvert -y --type writecache --cachevol $lv2 $vg/$lv1
mount "$DM_DEV_DIR/$vg/$lv1" "$mount_dir"
diff pattern1 "$mount_dir/pattern1"
cp pattern1 "$mount_dir/pattern2"
umount "$mount_dir"
lvchange -an $vg/$lv1
dd if=/dev/zero of="$dev2" seek=1 bs=1M count=16
lvconvert --splitcache --force --yes $vg/$lv1
lvchange -ay $vg/$lv1
mount "$DM_DEV_DIR/$vg/$lv1" "$mount_dir"
diff pattern1 "$mount_dir/pattern1"
umount "$mount_dir"
lvchange -an $vg/$lv1
vgremove -ff $vg
#
# splitcache when origin is raid
#

27
tools/lvconvert.c
View File

@ -1882,12 +1882,22 @@ static int _lvconvert_split_and_keep_cachevol(struct cmd_context *cmd,
char cvol_name[NAME_LEN];
struct lv_segment *cache_seg = first_seg(lv);
int cache_mode = cache_seg->cache_mode;
int direct_detach = 0;
if (!archive(lv->vg))
return_0;
log_debug("Detaching cachevol %s from LV %s.", display_lvname(lv_fast), display_lvname(lv));
/*
* Allow forcible detach without activating or flushing
* in case the cache is corrupt/damaged/invalid.
* This would generally be done to rescue data from
* the origin if the cache could not be repaired.
*/
if (!lv_is_active(lv) && arg_count(cmd, force_ARG))
direct_detach = 1;
/*
* Detaching a writeback cache generally requires flushing;
* doing otherwise can mean data loss/corruption.
@ -1902,7 +1912,10 @@ static int _lvconvert_split_and_keep_cachevol(struct cmd_context *cmd,
log_error("Conversion aborted.");
return 0;
}
direct_detach = 1;
}
if (direct_detach) {
log_warn("WARNING: Data may be lost by detaching writeback cache without flushing.");
if (!arg_count(cmd, yes_ARG) &&
@ -5554,7 +5567,13 @@ static int _lvconvert_detach_writecache(struct cmd_context *cmd,
if (!archive(lv->vg))
return_0;
if (lv_is_partial(lv_fast)) {
/*
* If the LV is inactive when we begin, then we want to
* deactivate the LV at the end.
*/
active_begin = lv_is_active(lv);
if (lv_is_partial(lv_fast) || (!active_begin && arg_count(cmd, force_ARG))) {
if (!arg_count(cmd, force_ARG)) {
log_warn("WARNING: writecache on %s is not complete and cannot be flushed.", display_lvname(lv_fast));
log_warn("WARNING: cannot detach writecache from %s without --force.", display_lvname(lv));
@ -5574,12 +5593,6 @@ static int _lvconvert_detach_writecache(struct cmd_context *cmd,
noflush = 1;
}
/*
* If the LV is inactive when we begin, then we want to
* deactivate the LV at the end.
*/
active_begin = lv_is_active(lv);
if (!noflush) {
/*
* --cachesettings cleaner=0 means to skip the use of the cleaner