dm thin metadata: introduce dm_pool_metadata_set_read_only
Introduce dm_pool_metadata_set_read_only to put the underlying block
manager into read-only mode.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 4f5b11c..d30bc09 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -184,6 +184,7 @@
uint64_t trans_id;
unsigned long flags;
sector_t data_block_size;
+ bool read_only:1;
};
struct dm_thin_device {
@@ -807,6 +808,7 @@
init_rwsem(&pmd->root_lock);
pmd->time = 0;
INIT_LIST_HEAD(&pmd->thin_devices);
+ pmd->read_only = false;
pmd->bdev = bdev;
pmd->data_block_size = data_block_size;
@@ -849,10 +851,12 @@
return -EBUSY;
}
- r = __commit_transaction(pmd);
- if (r < 0)
- DMWARN("%s: __commit_transaction() failed, error = %d",
- __func__, r);
+ if (!pmd->read_only) {
+ r = __commit_transaction(pmd);
+ if (r < 0)
+ DMWARN("%s: __commit_transaction() failed, error = %d",
+ __func__, r);
+ }
__destroy_persistent_data_objects(pmd);
kfree(pmd);
@@ -1587,3 +1591,11 @@
return r;
}
+
+void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
+{
+ down_write(&pmd->root_lock);
+ pmd->read_only = true;
+ dm_bm_set_read_only(pmd->bm);
+ up_write(&pmd->root_lock);
+}
diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
index 1632fec..2bbe622 100644
--- a/drivers/md/dm-thin-metadata.h
+++ b/drivers/md/dm-thin-metadata.h
@@ -174,6 +174,12 @@
*/
int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
+/*
+ * Flicks the underlying block manager into read only mode, so you know
+ * that nothing is changing.
+ */
+void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd);
+
/*----------------------------------------------------------------*/
#endif