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, 21 insertions, 0 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index f01096549a93..823ceba6efa8 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1047,6 +1047,19 @@ static int populate_table(struct dm_table *table,
         return dm_table_complete(table);
 }
 
+static int table_prealloc_integrity(struct dm_table *t,
+                                    struct mapped_device *md)
+{
+        struct list_head *devices = dm_table_get_devices(t);
+        struct dm_dev_internal *dd;
+
+        list_for_each_entry(dd, devices, list)
+                if (bdev_get_integrity(dd->dm_dev.bdev))
+                        return blk_integrity_register(dm_disk(md), NULL);
+
+        return 0;
+}
+
 static int table_load(struct dm_ioctl *param, size_t param_size)
 {
         int r;
@@ -1068,6 +1081,14 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
                 goto out;
         }
 
+        r = table_prealloc_integrity(t, md);
+        if (r) {
+                DMERR("%s: could not register integrity profile.",
+                      dm_device_name(md));
+                dm_table_destroy(t);
+                goto out;
+        }
+
         down_write(&_hash_lock);
         hc = dm_get_mdptr(md);
         if (!hc || hc->md != md) {