[PATCH] device-mapper: make lock_fs optional
Devices only needs syncing when creating snapshots, so make this optional when
suspending a device.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index fc335e0..0e48151 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -55,6 +55,7 @@
*/
#define DMF_BLOCK_IO 0
#define DMF_SUSPENDED 1
+#define DMF_FROZEN 2
struct mapped_device {
struct rw_semaphore io_lock;
@@ -1021,6 +1022,8 @@
return r;
}
+ set_bit(DMF_FROZEN, &md->flags);
+
/* don't bdput right now, we don't want the bdev
* to go away while it is locked.
*/
@@ -1029,8 +1032,12 @@
static void unlock_fs(struct mapped_device *md)
{
+ if (!test_bit(DMF_FROZEN, &md->flags))
+ return;
+
thaw_bdev(md->suspended_bdev, md->frozen_sb);
md->frozen_sb = NULL;
+ clear_bit(DMF_FROZEN, &md->flags);
}
/*
@@ -1040,7 +1047,7 @@
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
-int dm_suspend(struct mapped_device *md)
+int dm_suspend(struct mapped_device *md, int do_lockfs)
{
struct dm_table *map = NULL;
DECLARE_WAITQUEUE(wait, current);
@@ -1064,9 +1071,11 @@
}
/* Flush I/O to the device. */
- r = lock_fs(md);
- if (r)
- goto out;
+ if (do_lockfs) {
+ r = lock_fs(md);
+ if (r)
+ goto out;
+ }
/*
* First we set the BLOCK_IO flag so no more ios will be mapped.