dm: add integrity support

This patch provides support for data integrity passthrough in the device
mapper.

 - If one or more component devices support integrity an integrity
   profile is preallocated for the DM device.

 - If all component devices have compatible profiles the DM device is
   flagged as capable.

 - Handle integrity metadata when splitting and cloning bios.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index e8361b191b9b..02d0b489fad6 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -879,6 +879,45 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
         return &t->targets[(KEYS_PER_NODE * n) + k];
 }
 
+/*
+ * Set the integrity profile for this device if all devices used have
+ * matching profiles.
+ */
+static void dm_table_set_integrity(struct dm_table *t)
+{
+        struct list_head *devices = dm_table_get_devices(t);
+        struct dm_dev_internal *prev = NULL, *dd = NULL;
+
+        if (!blk_get_integrity(dm_disk(t->md)))
+                return;
+
+        list_for_each_entry(dd, devices, list) {
+                if (prev &&
+                    blk_integrity_compare(prev->dm_dev.bdev->bd_disk,
+                                          dd->dm_dev.bdev->bd_disk) < 0) {
+                        DMWARN("%s: integrity not set: %s and %s mismatch",
+                               dm_device_name(t->md),
+                               prev->dm_dev.bdev->bd_disk->disk_name,
+                               dd->dm_dev.bdev->bd_disk->disk_name);
+                        goto no_integrity;
+                }
+                prev = dd;
+        }
+
+        if (!prev || !bdev_get_integrity(prev->dm_dev.bdev))
+                goto no_integrity;
+
+        blk_integrity_register(dm_disk(t->md),
+                               bdev_get_integrity(prev->dm_dev.bdev));
+
+        return;
+
+no_integrity:
+        blk_integrity_register(dm_disk(t->md), NULL);
+
+        return;
+}
+
 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
 {
         /*
@@ -899,6 +938,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
         else
                 queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
 
+        dm_table_set_integrity(t);
 }
 
 unsigned int dm_table_get_num_targets(struct dm_table *t)