Patch name: dm-raid-allow-metadata-devices.patch
Add metadata device functionality to dm-raid.c
Add the ability to parse and use metadata devices. Metadata
devices are not strictly required. If they are provided, they are used
to store a superblock and bitmap. Without the metadata area, many features of
RAID are not supported.
Signed-off-by: Jonathan Brassow <jbrassow@xxxxxxxxxx>
Index: linux-2.6/drivers/md/dm-raid.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-raid.c
+++ linux-2.6/drivers/md/dm-raid.c
@@ -148,9 +148,16 @@ static void context_free(struct raid_set
{
int i;
- for (i = 0; i < rs->md.raid_disks; i++)
+ for (i = 0; i < rs->md.raid_disks; i++) {
+ if (rs->dev[i].meta_dev)
+ dm_put_device(rs->ti, rs->dev[i].meta_dev);
+ if (rs->dev[i].rdev.sb_page)
+ put_page(rs->dev[i].rdev.sb_page);
+ rs->dev[i].rdev.sb_page = NULL;
+ rs->dev[i].rdev.sb_loaded = 0;
if (rs->dev[i].data_dev)
dm_put_device(rs->ti, rs->dev[i].data_dev);
+ }
kfree(rs);
}
@@ -160,7 +167,15 @@ static void context_free(struct raid_set
* <meta_dev>: meta device name or '-' if missing
* <data_dev>: data device name or '-' if missing
*
- * This code parses those words.
+ * The following are acceptable:
+ * - -
+ * - <data_dev>
+ * <meta_dev> <data_dev>
+ * The following is not allowed:
+ * <meta_dev> -
+ *
+ * This code parses those words. If there is a failure,
+ * context_free must be used to unwind the operations.
*/
static int dev_parms(struct raid_set *rs, char **argv)
{
@@ -183,8 +198,16 @@ static int dev_parms(struct raid_set *rs
rs->dev[i].rdev.mddev = &rs->md;
if (strcmp(argv[0], "-")) {
- rs->ti->error = "Metadata devices not supported";
- return -EINVAL;
+ ret = dm_get_device(rs->ti, argv[0],
+ dm_table_get_mode(rs->ti->table),
+ &rs->dev[i].meta_dev);
+ rs->ti->error = "RAID metadata device lookup failure";
+ if (ret)
+ return ret;
+
+ rs->dev[i].rdev.sb_page = alloc_page(GFP_KERNEL);
+ if (!rs->dev[i].rdev.sb_page)
+ return -ENOMEM;
}
if (!strcmp(argv[1], "-")) {
@@ -194,6 +217,10 @@ static int dev_parms(struct raid_set *rs
return -EINVAL;
}
+ rs->ti->error = "No data device supplied with metadata device";
+ if (rs->dev[i].meta_dev)
+ return -EINVAL;
+
continue;
}
@@ -205,6 +232,10 @@ static int dev_parms(struct raid_set *rs
return ret;
}
+ if (rs->dev[i].meta_dev) {
+ metadata_available = 1;
+ rs->dev[i].rdev.meta_bdev = rs->dev[i].meta_dev->bdev;
+ }
rs->dev[i].rdev.bdev = rs->dev[i].data_dev->bdev;
list_add(&rs->dev[i].rdev.same_set, &rs->md.disks);
if (!test_bit(In_sync, &rs->dev[i].rdev.flags))
@@ -321,12 +352,32 @@ static int parse_raid_params(struct raid
argv++;
num_raid_params--;
+ for (i = 0; i < rs->md.raid_disks; i++) {
+ /*
+ * We set each individual device as In_sync with a
+ * completed 'recovery_offset'. This is always true
+ * unless there has been a device failure/replacement.
+ * In such an event, one of the following actions
+ * will take place:
+ * 1) User specifies 'rebuild'
+ * - device is reset when param is read
+ * 2) a new device is supplied
+ * - MD doesn't find matching superblock and resets device
+ * 3) device failure was transient and returns on reload
+ * - MD notices failure and resets device for bitmap replay
+ * 4) device hadn't completed recovery after previous failure
+ * - MD reads superblock and overrides recovery_offset
+ *
+ * What is found in the superblocks of the devices is always
+ * authoritative, unless 'rebuild' or '[no]sync' was specified.
+ */
+ set_bit(In_sync, &rs->dev[i].rdev.flags);
+ rs->dev[i].rdev.recovery_offset = MaxSector;
+ }
+
/*
* Second, parse the unordered optional arguments
*/
- for (i = 0; i < rs->md.raid_disks; i++)
- set_bit(In_sync, &rs->dev[i].rdev.flags);
-
for (i = 0; i < num_raid_params; i++) {
if (!strcmp(argv[i], "nosync")) {
rs->md.recovery_cp = MaxSector;
@@ -473,8 +524,6 @@ static int raid_is_congested(struct dm_t
* <raid_type> <#raid_params> <raid_params> \
* <#raid_devs> { <meta_dev1> <dev1> .. <meta_devN> <devN> }
*
- * ** metadata devices are not supported yet, use '-' instead **
- *
* <raid_params> varies by <raid_type>. See 'parse_raid_params' for
* details on possible <raid_params>.
*/
@@ -672,7 +721,10 @@ static int raid_status(struct dm_target
DMEMIT(" %d", rs->md.raid_disks);
for (i = 0; i < rs->md.raid_disks; i++) {
- DMEMIT(" -"); /* metadata device */
+ if (rs->dev[i].meta_dev)
+ DMEMIT(" %s", rs->dev[i].meta_dev->name);
+ else
+ DMEMIT(" -");
if (rs->dev[i].data_dev)
DMEMIT(" %s", rs->dev[i].data_dev->name);
@@ -729,6 +781,7 @@ static void raid_resume(struct dm_target
{
struct raid_set *rs = ti->private;
+ bitmap_load(&rs->md);
mddev_resume(&rs->md);
}
--
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