[PATCH] dm snapshot: tidy pending_complete
This patch rearranges the pending_complete() code so that the functional
changes in subsequent patches are clearer.
By consolidating the error and the non-error paths, we can move
error_snapshot_bios() and __flush_bios() in line.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index c5449f2..d929801 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -609,26 +609,6 @@
}
}
-static inline void error_snapshot_bios(struct pending_exception *pe)
-{
- error_bios(bio_list_get(&pe->snapshot_bios));
-}
-
-static struct bio *__flush_bios(struct pending_exception *pe)
-{
- /*
- * If this pe is involved in a write to the origin and
- * it is the last sibling to complete then release
- * the bios for the original write to the origin.
- */
-
- if (pe->primary_pe &&
- atomic_dec_and_test(&pe->primary_pe->sibling_count))
- return bio_list_get(&pe->primary_pe->origin_bios);
-
- return NULL;
-}
-
static void __invalidate_snapshot(struct dm_snapshot *s,
struct pending_exception *pe, int err)
{
@@ -656,16 +636,15 @@
struct exception *e;
struct pending_exception *primary_pe;
struct dm_snapshot *s = pe->snap;
- struct bio *flush = NULL;
+ struct bio *origin_bios = NULL;
+ struct bio *snapshot_bios = NULL;
+ int error = 0;
if (!success) {
/* Read/write error - snapshot is unusable */
down_write(&s->lock);
__invalidate_snapshot(s, pe, -EIO);
- flush = __flush_bios(pe);
- up_write(&s->lock);
-
- error_snapshot_bios(pe);
+ error = 1;
goto out;
}
@@ -673,42 +652,40 @@
if (!e) {
down_write(&s->lock);
__invalidate_snapshot(s, pe, -ENOMEM);
- flush = __flush_bios(pe);
- up_write(&s->lock);
-
- error_snapshot_bios(pe);
+ error = 1;
goto out;
}
*e = pe->e;
+ down_write(&s->lock);
+ if (!s->valid) {
+ free_exception(e);
+ error = 1;
+ goto out;
+ }
+
/*
* Add a proper exception, and remove the
* in-flight exception from the list.
*/
- down_write(&s->lock);
- if (!s->valid) {
- flush = __flush_bios(pe);
- up_write(&s->lock);
-
- free_exception(e);
-
- error_snapshot_bios(pe);
- goto out;
- }
-
insert_exception(&s->complete, e);
remove_exception(&pe->e);
- flush = __flush_bios(pe);
-
- up_write(&s->lock);
-
- /* Submit any pending write bios */
- flush_bios(bio_list_get(&pe->snapshot_bios));
out:
+ snapshot_bios = bio_list_get(&pe->snapshot_bios);
+
primary_pe = pe->primary_pe;
/*
+ * If this pe is involved in a write to the origin and
+ * it is the last sibling to complete then release
+ * the bios for the original write to the origin.
+ */
+ if (primary_pe &&
+ atomic_dec_and_test(&primary_pe->sibling_count))
+ origin_bios = bio_list_get(&primary_pe->origin_bios);
+
+ /*
* Free the pe if it's not linked to an origin write or if
* it's not itself a primary pe.
*/
@@ -721,8 +698,15 @@
if (primary_pe && !atomic_read(&primary_pe->sibling_count))
free_pending_exception(primary_pe);
- if (flush)
- flush_bios(flush);
+ up_write(&s->lock);
+
+ /* Submit any pending write bios */
+ if (error)
+ error_bios(snapshot_bios);
+ else
+ flush_bios(snapshot_bios);
+
+ flush_bios(origin_bios);
}
static void commit_callback(void *context, int success)