Commit 70bcecdb authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues

md-cluster: Improve md_reload_sb to be less error prone

md_reload_sb is too simplistic and it explicitly needs to determine
the changes made by the writing node. However, there are multiple areas
where a simple reload could fail.

Instead, read the superblock of one of the "good" rdevs and update
the necessary information:

- read the superblock into a newly allocated page, by temporarily
  swapping out rdev->sb_page and calling ->load_super.
- if that fails return
- if it succeeds, call check_sb_changes
  1. iterates over list of active devices and checks the matching
   dev_roles[] value.
   	If that is 'faulty', the device must be  marked as faulty
	 - call md_error to mark the device as faulty. Make sure
	   not to set CHANGE_DEVS and wakeup mddev->thread or else
	   it would initiate a resync process, which is the responsibility
	   of the "primary" node.
	 - clear the Blocked bit
	 - Call remove_and_add_spares() to hot remove the device.
	If the device is 'spare':
	 - call remove_and_add_spares() to get the number of spares
	   added in this operation.
	 - Reduce mddev->degraded to mark the array as not degraded.
  2. reset recovery_cp
- read the rest of the rdevs to update recovery_offset. If recovery_offset
  is equal to MaxSector, call spare_active() to set it In_sync

This required that recovery_offset be initialized to MaxSector, as
opposed to zero so as to communicate the end of sync for a rdev.
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
parent 2910ff17
......@@ -427,8 +427,7 @@ static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
{
struct md_cluster_info *cinfo = mddev->cluster_info;
md_reload_sb(mddev);
md_reload_sb(mddev, le32_to_cpu(msg->raid_slot));
dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
}
......@@ -834,11 +833,23 @@ static int metadata_update_finish(struct mddev *mddev)
{
struct md_cluster_info *cinfo = mddev->cluster_info;
struct cluster_msg cmsg;
int ret;
struct md_rdev *rdev;
int ret = 0;
memset(&cmsg, 0, sizeof(cmsg));
cmsg.type = cpu_to_le32(METADATA_UPDATED);
ret = __sendmsg(cinfo, &cmsg);
cmsg.raid_slot = -1;
/* Pick up a good active device number to send.
*/
rdev_for_each(rdev, mddev)
if (rdev->raid_disk > -1 && !test_bit(Faulty, &rdev->flags)) {
cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
break;
}
if (cmsg.raid_slot >= 0)
ret = __sendmsg(cinfo, &cmsg);
else
pr_warn("md-cluster: No good device id found to send\n");
unlock_comm(cinfo);
return ret;
}
......@@ -922,15 +933,9 @@ static int add_new_disk_start(struct mddev *mddev, struct md_rdev *rdev)
static int add_new_disk_finish(struct mddev *mddev)
{
struct cluster_msg cmsg;
struct md_cluster_info *cinfo = mddev->cluster_info;
int ret;
/* Write sb and inform others */
md_update_sb(mddev, 1);
cmsg.type = METADATA_UPDATED;
ret = __sendmsg(cinfo, &cmsg);
unlock_comm(cinfo);
return ret;
return metadata_update_finish(mddev);
}
static int new_disk_ack(struct mddev *mddev, bool ack)
......
......@@ -8924,25 +8924,118 @@ static int __init md_init(void)
return ret;
}
void md_reload_sb(struct mddev *mddev)
static void check_sb_changes(struct mddev *mddev, struct md_rdev *rdev)
{
struct md_rdev *rdev, *tmp;
struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
struct md_rdev *rdev2;
int role, ret;
char b[BDEVNAME_SIZE];
rdev_for_each_safe(rdev, tmp, mddev) {
rdev->sb_loaded = 0;
ClearPageUptodate(rdev->sb_page);
/* Check for change of roles in the active devices */
rdev_for_each(rdev2, mddev) {
if (test_bit(Faulty, &rdev2->flags))
continue;
/* Check if the roles changed */
role = le16_to_cpu(sb->dev_roles[rdev2->desc_nr]);
if (role != rdev2->raid_disk) {
/* got activated */
if (rdev2->raid_disk == -1 && role != 0xffff) {
rdev2->saved_raid_disk = role;
ret = remove_and_add_spares(mddev, rdev2);
pr_info("Activated spare: %s\n",
bdevname(rdev2->bdev,b));
continue;
}
/* device faulty
* We just want to do the minimum to mark the disk
* as faulty. The recovery is performed by the
* one who initiated the error.
*/
if ((role == 0xfffe) || (role == 0xfffd)) {
md_error(mddev, rdev2);
clear_bit(Blocked, &rdev2->flags);
}
}
}
mddev->raid_disks = 0;
analyze_sbs(mddev);
rdev_for_each_safe(rdev, tmp, mddev) {
struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
/* since we don't write to faulty devices, we figure out if the
* disk is faulty by comparing events
*/
if (mddev->events > sb->events)
set_bit(Faulty, &rdev->flags);
/* recovery_cp changed */
if (le64_to_cpu(sb->resync_offset) != mddev->recovery_cp)
mddev->recovery_cp = le64_to_cpu(sb->resync_offset);
/* Finally set the event to be up to date */
mddev->events = le64_to_cpu(sb->events);
}
static int read_rdev(struct mddev *mddev, struct md_rdev *rdev)
{
int err;
struct page *swapout = rdev->sb_page;
struct mdp_superblock_1 *sb;
/* Store the sb page of the rdev in the swapout temporary
* variable in case we err in the future
*/
rdev->sb_page = NULL;
alloc_disk_sb(rdev);
ClearPageUptodate(rdev->sb_page);
rdev->sb_loaded = 0;
err = super_types[mddev->major_version].load_super(rdev, NULL, mddev->minor_version);
if (err < 0) {
pr_warn("%s: %d Could not reload rdev(%d) err: %d. Restoring old values\n",
__func__, __LINE__, rdev->desc_nr, err);
put_page(rdev->sb_page);
rdev->sb_page = swapout;
rdev->sb_loaded = 1;
return err;
}
sb = page_address(rdev->sb_page);
/* Read the offset unconditionally, even if MD_FEATURE_RECOVERY_OFFSET
* is not set
*/
if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RECOVERY_OFFSET))
rdev->recovery_offset = le64_to_cpu(sb->recovery_offset);
/* The other node finished recovery, call spare_active to set
* device In_sync and mddev->degraded
*/
if (rdev->recovery_offset == MaxSector &&
!test_bit(In_sync, &rdev->flags) &&
mddev->pers->spare_active(mddev))
sysfs_notify(&mddev->kobj, NULL, "degraded");
put_page(swapout);
return 0;
}
void md_reload_sb(struct mddev *mddev, int nr)
{
struct md_rdev *rdev;
int err;
/* Find the rdev */
rdev_for_each_rcu(rdev, mddev) {
if (rdev->desc_nr == nr)
break;
}
if (!rdev || rdev->desc_nr != nr) {
pr_warn("%s: %d Could not find rdev with nr %d\n", __func__, __LINE__, nr);
return;
}
err = read_rdev(mddev, rdev);
if (err < 0)
return;
check_sb_changes(mddev, rdev);
/* Read all rdev's to update recovery_offset */
rdev_for_each_rcu(rdev, mddev)
read_rdev(mddev, rdev);
}
EXPORT_SYMBOL(md_reload_sb);
......
......@@ -658,7 +658,7 @@ extern struct bio *bio_alloc_mddev(gfp_t gfp_mask, int nr_iovecs,
struct mddev *mddev);
extern void md_unplug(struct blk_plug_cb *cb, bool from_schedule);
extern void md_reload_sb(struct mddev *mddev);
extern void md_reload_sb(struct mddev *mddev, int raid_disk);
extern void md_update_sb(struct mddev *mddev, int force);
extern void md_kick_rdev_from_array(struct md_rdev * rdev);
struct md_rdev *md_find_rdev_nr_rcu(struct mddev *mddev, int nr);
......
......@@ -1592,6 +1592,15 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;
/*
* find the disk ... but prefer rdev->saved_raid_disk
* if possible.
*/
if (rdev->saved_raid_disk >= 0 &&
rdev->saved_raid_disk >= first &&
conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
first = last = rdev->saved_raid_disk;
for (mirror = first; mirror <= last; mirror++) {
p = conf->mirrors+mirror;
if (!p->rdev) {
......
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