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authorMike Snitzer <snitzer@redhat.com>2014-10-28 18:34:52 -0400
committerMike Snitzer <snitzer@redhat.com>2014-11-19 12:31:17 -0500
commitffcc39364160663cda1a3c358f4537302a92459b (patch)
treebc7defa66e5c79b036ed21092a8005b72879559b /drivers/md/dm.h
parent80e96c5484be788f277eead9cabf88cf8e430419 (diff)
dm: enhance internal suspend and resume interface
Rename dm_internal_{suspend,resume} to dm_internal_{suspend,resume}_fast -- dm-stats will continue using these methods to avoid all the extra suspend/resume logic that is not needed in order to quickly flush IO. Introduce dm_internal_suspend_noflush() variant that actually calls the mapped_device's target callbacks -- otherwise target-specific hooks are avoided (e.g. dm-thin's thin_presuspend and thin_postsuspend). Common code between dm_internal_{suspend_noflush,resume} and dm_{suspend,resume} was factored out as __dm_{suspend,resume}. Update dm_internal_{suspend_noflush,resume} to always take and release the mapped_device's suspend_lock. Also update dm_{suspend,resume} to be aware of potential for DM_INTERNAL_SUSPEND_FLAG to be set and respond accordingly by interruptibly waiting for the DM_INTERNAL_SUSPEND_FLAG to be cleared. Add lockdep annotation to dm_suspend() and dm_resume(). The existing DM_SUSPEND_FLAG remains unchanged. DM_INTERNAL_SUSPEND_FLAG is set by dm_internal_suspend_noflush() and cleared by dm_internal_resume(). Both DM_SUSPEND_FLAG and DM_INTERNAL_SUSPEND_FLAG may be set if a device was already suspended when dm_internal_suspend_noflush() was called -- this can be thought of as a "nested suspend". A "nested suspend" can occur with legacy userspace dm-thin code that might suspend all active thin volumes before suspending the pool for resize. But otherwise, in the normal dm-thin-pool suspend case moving forward: the thin-pool will have DM_SUSPEND_FLAG set and all active thins from that thin-pool will have DM_INTERNAL_SUSPEND_FLAG set. Also add DM_INTERNAL_SUSPEND_FLAG to status report. This new DM_INTERNAL_SUSPEND_FLAG state is being reported to assist with debugging (e.g. 'dmsetup info' will report an internally suspended device accordingly). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
Diffstat (limited to 'drivers/md/dm.h')
-rw-r--r--drivers/md/dm.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 781994093bf5..84b0f9e4ba6c 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -130,6 +130,15 @@ int dm_deleting_md(struct mapped_device *md);
int dm_suspended_md(struct mapped_device *md);
/*
+ * Internal suspend and resume methods.
+ */
+int dm_suspended_internally_md(struct mapped_device *md);
+void dm_internal_suspend_fast(struct mapped_device *md);
+void dm_internal_resume_fast(struct mapped_device *md);
+void dm_internal_suspend_noflush(struct mapped_device *md);
+void dm_internal_resume(struct mapped_device *md);
+
+/*
* Test if the device is scheduled for deferred remove.
*/
int dm_test_deferred_remove_flag(struct mapped_device *md);