dm raid: add prerequisite functions and definitions for reshaping
Add rs_is_reshapable(), rs_data_stripes(), rs_reshape_requested(),
rs_set_dev_and_array_sectors() and rs_adjust_data_offsets()
Remove superfluous check for reshape message
Correct runtime bit definitions to be incremental
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index a32cddb..14835ae 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -19,6 +19,11 @@
#define DM_MSG_PREFIX "raid"
#define MAX_RAID_DEVICES 253 /* md-raid kernel limit */
+/*
+ * Minimum sectors of free reshape space per raid device
+ */
+#define MIN_FREE_RESHAPE_SPACE to_sector(4*4096)
+
static bool devices_handle_discard_safely = false;
/*
@@ -180,10 +185,10 @@
* e.g. to prevent another resume from preresume processing
* the raid set all over again.
*/
-#define RT_FLAG_RS_PRERESUMED 0x1
-#define RT_FLAG_RS_RESUMED 0x2
-#define RT_FLAG_RS_BITMAP_LOADED 0x4
-#define RT_FLAG_UPDATE_SBS 0x8
+#define RT_FLAG_RS_PRERESUMED 0
+#define RT_FLAG_RS_RESUMED 1
+#define RT_FLAG_RS_BITMAP_LOADED 2
+#define RT_FLAG_UPDATE_SBS 3
/* Array elements of 64 bit needed for rebuild/write_mostly bits */
#define DISKS_ARRAY_ELEMS ((MAX_RAID_DEVICES + (sizeof(uint64_t) * 8 - 1)) / sizeof(uint64_t) / 8)
@@ -337,6 +342,20 @@
return rs->md.level == 10;
}
+/* Return true, if raid set in @rs is level 4, 5 or 6 */
+static bool rs_is_raid456(struct raid_set *rs)
+{
+ return __within_range(rs->md.level, 4, 6);
+}
+
+/* Return true, if raid set in @rs is reshapable */
+static unsigned int __is_raid10_far(int layout);
+static bool rs_is_reshapable(struct raid_set *rs)
+{
+ return rs_is_raid456(rs) ||
+ (rs_is_raid10(rs) && !__is_raid10_far(rs->md.new_layout));
+}
+
/*
* bool helpers to test for various raid levels of a raid type
*/
@@ -899,7 +918,7 @@
rebuilds_per_group = 0;
d = i % rs->md.raid_disks;
if ((!rs->dev[d].rdev.sb_page ||
- !test_bit(In_sync, &rs->dev[d].rdev.flags)) &&
+ !test_bit(In_sync, &rs->dev[i].rdev.flags)) &&
(++rebuilds_per_group >= copies))
goto too_many;
}
@@ -971,7 +990,6 @@
unsigned raid10_copies = 2;
unsigned i;
unsigned value, region_size = 0;
- sector_t sectors_per_dev = rs->ti->len;
sector_t max_io_len;
const char *arg, *key;
struct raid_dev *rd;
@@ -1286,20 +1304,10 @@
return -EINVAL;
}
- /* (Len * #mirrors) / #devices */
- sectors_per_dev = rs->ti->len * raid10_copies;
- sector_div(sectors_per_dev, rs->md.raid_disks);
-
- rs->md.layout = raid10_format_to_md_layout(rs, raid10_format, raid10_copies);
- rs->md.new_layout = rs->md.layout;
- } else if (!rt_is_raid1(rt) &&
- sector_div(sectors_per_dev, (rs->md.raid_disks - rt->parity_devs))) {
- rs->ti->error = "Target length not divisible by number of data devices";
- return -EINVAL;
+ rs->md.layout = rs->md.new_layout;
}
rs->raid10_copies = raid10_copies;
- rs->md.dev_sectors = sectors_per_dev;
/* Assume there are no metadata devices until the drives are parsed */
rs->md.persistent = 0;
@@ -1315,6 +1323,66 @@
return rs->md.raid_disks - rs->raid_type->parity_devs;
}
+/* Return # of data stripes of @rs (i.e. as of ctr) */
+static unsigned int rs_data_stripes(struct raid_set *rs)
+{
+ return rs->raid_disks - rs->raid_type->parity_devs;
+}
+
+/* Calculate the sectors per device and per array used for @rs */
+static int rs_set_dev_and_array_sectors(struct raid_set *rs, bool use_mddev)
+{
+ int delta_disks;
+ unsigned int data_stripes;
+ struct mddev *mddev = &rs->md;
+ struct md_rdev *rdev;
+ sector_t array_sectors = rs->ti->len, dev_sectors = rs->ti->len;
+
+ if (use_mddev) {
+ delta_disks = mddev->delta_disks;
+ data_stripes = mddev_data_stripes(rs);
+ } else {
+ delta_disks = rs->delta_disks;
+ data_stripes = rs_data_stripes(rs);
+ }
+
+ /* Special raid1 case w/o delta_disks support (yet) */
+ if (rt_is_raid1(rs->raid_type))
+ ;
+ else if (rt_is_raid10(rs->raid_type)) {
+ if (rs->raid10_copies < 2 ||
+ delta_disks < 0) {
+ rs->ti->error = "Bogus raid10 data copies or delta disks";
+ return EINVAL;
+ }
+
+ dev_sectors *= rs->raid10_copies;
+ if (sector_div(dev_sectors, data_stripes))
+ goto bad;
+
+ array_sectors = (data_stripes + delta_disks) * dev_sectors;
+ if (sector_div(array_sectors, rs->raid10_copies))
+ goto bad;
+
+ } else if (sector_div(dev_sectors, data_stripes))
+ goto bad;
+
+ else
+ /* Striped layouts */
+ array_sectors = (data_stripes + delta_disks) * dev_sectors;
+
+ rdev_for_each(rdev, mddev)
+ rdev->sectors = dev_sectors;
+
+ mddev->array_sectors = array_sectors;
+ mddev->dev_sectors = dev_sectors;
+
+ return 0;
+bad:
+ rs->ti->error = "Target length not divisible by number of data devices";
+ return EINVAL;
+}
+
static void do_table_event(struct work_struct *ws)
{
struct raid_set *rs = container_of(ws, struct raid_set, md.event_work);
@@ -1487,6 +1555,21 @@
return rs->md.new_level != rs->md.level;
}
+/* True if @rs is requested to reshape by ctr */
+static bool rs_reshape_requested(struct raid_set *rs)
+{
+ struct mddev *mddev = &rs->md;
+
+ if (!mddev->level)
+ return false;
+
+ return !__is_raid10_far(mddev->new_layout) &&
+ mddev->new_level == mddev->level &&
+ (mddev->new_layout != mddev->layout ||
+ mddev->new_chunk_sectors != mddev->chunk_sectors ||
+ rs->raid_disks + rs->delta_disks != mddev->raid_disks);
+}
+
/* Features */
#define FEATURE_FLAG_SUPPORTS_V190 0x1 /* Supports extended superblock */
@@ -2110,6 +2193,97 @@
return 0;
}
+/*
+ * Adjust data_offset and new_data_offset on all disk members of @rs
+ * for out of place reshaping if requested by contructor
+ *
+ * We need free space at the beginning of each raid disk for forward
+ * and at the end for backward reshapes which userspace has to provide
+ * via remapping/reordering of space.
+ */
+static int rs_adjust_data_offsets(struct raid_set *rs)
+{
+ sector_t data_offset = 0, new_data_offset = 0;
+ struct md_rdev *rdev;
+
+ /* Constructor did not request data offset change */
+ if (!test_bit(__CTR_FLAG_DATA_OFFSET, &rs->ctr_flags)) {
+ if (!rs_is_reshapable(rs))
+ goto out;
+
+ return 0;
+ }
+
+ /* HM FIXME: get InSync raid_dev? */
+ rdev = &rs->dev[0].rdev;
+
+ if (rs->delta_disks < 0) {
+ /*
+ * Removing disks (reshaping backwards):
+ *
+ * - before reshape: data is at offset 0 and free space
+ * is at end of each component LV
+ *
+ * - after reshape: data is at offset rs->data_offset != 0 on each component LV
+ */
+ data_offset = 0;
+ new_data_offset = rs->data_offset;
+
+ } else if (rs->delta_disks > 0) {
+ /*
+ * Adding disks (reshaping forwards):
+ *
+ * - before reshape: data is at offset rs->data_offset != 0 and
+ * free space is at begin of each component LV
+ *
+ * - after reshape: data is at offset 0 on each component LV
+ */
+ data_offset = rs->data_offset;
+ new_data_offset = 0;
+
+ } else {
+ /*
+ * User space passes in 0 for data offset after having removed reshape space
+ *
+ * - or - (data offset != 0)
+ *
+ * Changing RAID layout or chunk size -> toggle offsets
+ *
+ * - before reshape: data is at offset rs->data_offset 0 and
+ * free space is at end of each component LV
+ * -or-
+ * data is at offset rs->data_offset != 0 and
+ * free space is at begin of each component LV
+ *
+ * - after reshape: data is at offset 0 if i was at offset != 0
+ * of at offset != 0 if it was at offset 0
+ * on each component LV
+ *
+ */
+ data_offset = rs->data_offset ? rdev->data_offset : 0;
+ new_data_offset = data_offset ? 0 : rs->data_offset;
+ set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
+ }
+
+ /*
+ * Make sure we got a minimum amount of free sectors per device
+ */
+ if (rs->data_offset &&
+ to_sector(i_size_read(rdev->bdev->bd_inode)) - rdev->sectors < MIN_FREE_RESHAPE_SPACE) {
+ rs->ti->error = data_offset ? "No space for forward reshape" :
+ "No space for backward reshape";
+ return -ENOSPC;
+ }
+out:
+ /* Adjust data offsets on all rdevs */
+ rdev_for_each(rdev, &rs->md) {
+ rdev->data_offset = data_offset;
+ rdev->new_data_offset = new_data_offset;
+ }
+
+ return 0;
+}
+
/* Userpace reordered disks -> adjust raid_disk indexes in @rs */
static void __reorder_raid_disk_indexes(struct raid_set *rs)
{
@@ -2286,6 +2460,10 @@
rs->md.sync_super = super_sync;
+ r = rs_set_dev_and_array_sectors(rs, false);
+ if (r)
+ return r;
+
/*
* Backup any new raid set level, layout, ...
* requested to be able to compare to superblock
@@ -2320,9 +2498,16 @@
/* Tell preresume to update superblocks with new layout */
set_bit(RT_FLAG_UPDATE_SBS, &rs->runtime_flags);
rs_set_new(rs);
+ } else if (rs_reshape_requested(rs)) {
+ rs_set_cur(rs); /* Dummy to reject, fill in */
} else
rs_set_cur(rs);
+ /* If constructor requested it, change data and new_data offsets */
+ r = rs_adjust_data_offsets(rs);
+ if (r)
+ return r;
+
/* Start raid set read-only and assumed clean to change in raid_resume() */
rs->md.ro = 1;
rs->md.in_sync = 1;
@@ -2657,11 +2842,6 @@
struct raid_set *rs = ti->private;
struct mddev *mddev = &rs->md;
- if (!strcasecmp(argv[0], "reshape")) {
- DMERR("Reshape not supported.");
- return -EINVAL;
- }
-
if (!mddev->pers || !mddev->pers->sync_request)
return -EINVAL;