[PATCH] device-mapper snapshot: metadata reading separation

From: Alasdair G Kergon
Date: Fri Nov 18 2005 - 10:01:19 EST


More snapshot metadata reading into separate function, to prepare
for changing the place it gets called from.

Signed-Off-By: Alasdair G Kergon <agk@xxxxxxxxxx>

Index: linux-2.6.14/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.14.orig/drivers/md/dm-snap.c 2005-11-17 22:17:55.000000000 +0000
+++ linux-2.6.14/drivers/md/dm-snap.c 2005-11-17 22:18:25.000000000 +0000
@@ -371,6 +371,20 @@ static inline ulong round_up(ulong n, ul
return (n + size) & ~size;
}

+static void read_snapshot_metadata(struct dm_snapshot *s)
+{
+ if (s->have_metadata)
+ return;
+
+ if (s->store.read_metadata(&s->store)) {
+ down_write(&s->lock);
+ s->valid = 0;
+ up_write(&s->lock);
+ }
+
+ s->have_metadata = 1;
+}
+
/*
* Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-size>
*/
@@ -848,16 +862,7 @@ static void snapshot_resume(struct dm_ta
{
struct dm_snapshot *s = (struct dm_snapshot *) ti->private;

- if (s->have_metadata)
- return;
-
- if (s->store.read_metadata(&s->store)) {
- down_write(&s->lock);
- s->valid = 0;
- up_write(&s->lock);
- }
-
- s->have_metadata = 1;
+ read_snapshot_metadata(s);
}

static int snapshot_status(struct dm_target *ti, status_type_t type,
-
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