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md: support 'external' metadata for md arrays 

- Add a state flag 'external' to indicate that the metadata is managed
  externally (by user-space) so important changes need to be
  left of user-space to handle.
  Alternates are non-persistant ('none') where there is no stable metadata -
  after the  array is stopped there is no record of it's status - and
  internal which can be version 0.90 or version 1.x
  These are selected by writing to the 'metadata' attribute.

- move the updating of superblocks (sync_sbs) to after we have checked if
  there are any superblocks or not.

- New array state 'write_pending'.  This means that the metadata records
  the array as 'clean', but a write has been requested, so the metadata has
  to be updated to record a 'dirty' array before the write can continue.
  This change is reported to md by writing 'active' to the array_state
  attribute.

- tidy up marking of sb_dirty:
   - don't set sb_dirty when resync finishes as md_check_recovery
     calls md_update_sb when the sync thread finishes anyway.
   - Don't set sb_dirty in multipath_run as the array might not be dirty.
   - don't mark superblock dirty when switching to 'clean' if there
     is no internal superblock (if external, userspace can choose to
     update the superblock whenever it chooses to).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
NeilBrown 2008-02-06 01:39:51 -08:00 committed by Linus Torvalds
parent b47490c9bc
commit e691063a61
2 changed files with 61 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
drivers/md/md.c
View File

@ -778,7 +778,8 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
mddev->major_version = 0;
mddev->minor_version = sb->minor_version;
mddev->patch_version = sb->patch_version;
mddev->persistent = ! sb->not_persistent;
mddev->persistent = 1;
mddev->external = 0;
mddev->chunk_size = sb->chunk_size;
mddev->ctime = sb->ctime;
mddev->utime = sb->utime;
@ -904,7 +905,7 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
sb->size = mddev->size;
sb->raid_disks = mddev->raid_disks;
sb->md_minor = mddev->md_minor;
sb->not_persistent = !mddev->persistent;
sb->not_persistent = 0;
sb->utime = mddev->utime;
sb->state = 0;
sb->events_hi = (mddev->events>>32);
@ -1158,6 +1159,7 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
mddev->major_version = 1;
mddev->patch_version = 0;
mddev->persistent = 1;
mddev->external = 0;
mddev->chunk_size = le32_to_cpu(sb->chunksize) << 9;
mddev->ctime = le64_to_cpu(sb->ctime) & ((1ULL << 32)-1);
mddev->utime = le64_to_cpu(sb->utime) & ((1ULL << 32)-1);
@ -1696,18 +1698,20 @@ repeat:
MD_BUG();
mddev->events --;
}
sync_sbs(mddev, nospares);
/*
* do not write anything to disk if using
* nonpersistent superblocks
*/
if (!mddev->persistent) {
clear_bit(MD_CHANGE_PENDING, &mddev->flags);
if (!mddev->external)
clear_bit(MD_CHANGE_PENDING, &mddev->flags);
spin_unlock_irq(&mddev->write_lock);
wake_up(&mddev->sb_wait);
return;
}
sync_sbs(mddev, nospares);
spin_unlock_irq(&mddev->write_lock);
dprintk(KERN_INFO
@ -2425,6 +2429,8 @@ array_state_show(mddev_t *mddev, char *page)
case 0:
if (mddev->in_sync)
st = clean;
else if (test_bit(MD_CHANGE_CLEAN, &mddev->flags))
st = write_pending;
else if (mddev->safemode)
st = active_idle;
else
@ -2455,11 +2461,9 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
break;
case clear:
/* stopping an active array */
if (mddev->pers) {
if (atomic_read(&mddev->active) > 1)
return -EBUSY;
err = do_md_stop(mddev, 0);
}
if (atomic_read(&mddev->active) > 1)
return -EBUSY;
err = do_md_stop(mddev, 0);
break;
case inactive:
/* stopping an active array */
@ -2467,7 +2471,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
if (atomic_read(&mddev->active) > 1)
return -EBUSY;
err = do_md_stop(mddev, 2);
}
} else
err = 0; /* already inactive */
break;
case suspended:
break; /* not supported yet */
@ -2495,9 +2500,15 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
restart_array(mddev);
spin_lock_irq(&mddev->write_lock);
if (atomic_read(&mddev->writes_pending) == 0) {
mddev->in_sync = 1;
set_bit(MD_CHANGE_CLEAN, &mddev->flags);
}
if (mddev->in_sync == 0) {
mddev->in_sync = 1;
if (mddev->persistent)
set_bit(MD_CHANGE_CLEAN,
&mddev->flags);
}
err = 0;
} else
err = -EBUSY;
spin_unlock_irq(&mddev->write_lock);
} else {
mddev->ro = 0;
@ -2508,7 +2519,8 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
case active:
if (mddev->pers) {
restart_array(mddev);
clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
if (mddev->external)
clear_bit(MD_CHANGE_CLEAN, &mddev->flags);
wake_up(&mddev->sb_wait);
err = 0;
} else {
@ -2659,7 +2671,9 @@ __ATTR(component_size, S_IRUGO|S_IWUSR, size_show, size_store);
/* Metdata version.
* This is either 'none' for arrays with externally managed metadata,
* This is one of
* 'none' for arrays with no metadata (good luck...)
* 'external' for arrays with externally managed metadata,
* or N.M for internally known formats
*/
static ssize_t
@ -2668,6 +2682,8 @@ metadata_show(mddev_t *mddev, char *page)
if (mddev->persistent)
return sprintf(page, "%d.%d\n",
mddev->major_version, mddev->minor_version);
else if (mddev->external)
return sprintf(page, "external:%s\n", mddev->metadata_type);
else
return sprintf(page, "none\n");
}
@ -2682,6 +2698,21 @@ metadata_store(mddev_t *mddev, const char *buf, size_t len)
if (cmd_match(buf, "none")) {
mddev->persistent = 0;
mddev->external = 0;
mddev->major_version = 0;
mddev->minor_version = 90;
return len;
}
if (strncmp(buf, "external:", 9) == 0) {
int namelen = len-9;
if (namelen >= sizeof(mddev->metadata_type))
namelen = sizeof(mddev->metadata_type)-1;
strncpy(mddev->metadata_type, buf+9, namelen);
mddev->metadata_type[namelen] = 0;
if (namelen && mddev->metadata_type[namelen-1] == '\n')
mddev->metadata_type[--namelen] = 0;
mddev->persistent = 0;
mddev->external = 1;
mddev->major_version = 0;
mddev->minor_version = 90;
return len;
@ -2698,6 +2729,7 @@ metadata_store(mddev_t *mddev, const char *buf, size_t len)
mddev->major_version = major;
mddev->minor_version = minor;
mddev->persistent = 1;
mddev->external = 0;
return len;
}
@ -3524,6 +3556,7 @@ static int do_md_stop(mddev_t * mddev, int mode)
mddev->raid_disks = 0;
mddev->recovery_cp = 0;
mddev->reshape_position = MaxSector;
mddev->external = 0;
} else if (mddev->pers)
printk(KERN_INFO "md: %s switched to read-only mode.\n",
@ -4165,13 +4198,15 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
else
mddev->recovery_cp = 0;
mddev->persistent = ! info->not_persistent;
mddev->external = 0;
mddev->layout = info->layout;
mddev->chunk_size = info->chunk_size;
mddev->max_disks = MD_SB_DISKS;
mddev->flags = 0;
if (mddev->persistent)
mddev->flags = 0;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
mddev->default_bitmap_offset = MD_SB_BYTES >> 9;
@ -4982,7 +5017,10 @@ static int md_seq_show(struct seq_file *seq, void *v)
mddev->major_version,
mddev->minor_version);
}
} else
} else if (mddev->external)
seq_printf(seq, " super external:%s",
mddev->metadata_type);
else
seq_printf(seq, " super non-persistent");
if (mddev->pers) {
@ -5589,7 +5627,7 @@ void md_check_recovery(mddev_t *mddev)
}
if ( ! (
mddev->flags ||
(mddev->flags && !mddev->external) ||
test_bit(MD_RECOVERY_NEEDED, &mddev->recovery) ||
test_bit(MD_RECOVERY_DONE, &mddev->recovery) ||
(mddev->safemode == 1) ||
@ -5605,7 +5643,8 @@ void md_check_recovery(mddev_t *mddev)
if (mddev->safemode && !atomic_read(&mddev->writes_pending) &&
!mddev->in_sync && mddev->recovery_cp == MaxSector) {
mddev->in_sync = 1;
set_bit(MD_CHANGE_CLEAN, &mddev->flags);
if (mddev->persistent)
set_bit(MD_CHANGE_CLEAN, &mddev->flags);
}
if (mddev->safemode == 1)
mddev->safemode = 0;

3
include/linux/raid/md_k.h
View File

@ -130,6 +130,9 @@ struct mddev_s
minor_version,
patch_version;
int persistent;
int external; /* metadata is
* managed externally */
char metadata_type[17]; /* externally set*/
int chunk_size;
time_t ctime, utime;
int level, layout;