dm thin: commit before gathering status
Commit outstanding metadata before returning the status for a dm thin
pool so that the numbers reported are as up-to-date as possible.
The commit is not performed if the device is suspended or if
the DM_NOFLUSH_FLAG is supplied by userspace and passed to the target
through a new 'status_flags' parameter in the target's dm_status_fn.
The userspace dmsetup tool will support the --noflush flag with the
'dmsetup status' and 'dmsetup wait' commands from version 1.02.76
onwards.
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 087e9b3..af1fc3b 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -5,6 +5,7 @@
*/
#include "dm-thin-metadata.h"
+#include "dm.h"
#include <linux/device-mapper.h>
#include <linux/dm-io.h>
@@ -2619,7 +2620,7 @@
* <used data sectors>/<total data sectors> <held metadata root>
*/
static int pool_status(struct dm_target *ti, status_type_t type,
- char *result, unsigned maxlen)
+ unsigned status_flags, char *result, unsigned maxlen)
{
int r;
unsigned sz = 0;
@@ -2641,6 +2642,10 @@
break;
}
+ /* Commit to ensure statistics aren't out-of-date */
+ if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
+ (void) commit_or_fallback(pool);
+
r = dm_pool_get_metadata_transaction_id(pool->pmd,
&transaction_id);
if (r)
@@ -2968,7 +2973,7 @@
* <nr mapped sectors> <highest mapped sector>
*/
static int thin_status(struct dm_target *ti, status_type_t type,
- char *result, unsigned maxlen)
+ unsigned status_flags, char *result, unsigned maxlen)
{
int r;
ssize_t sz = 0;