dm snapshot: use dm-bufio
Use dm-bufio for initial loading of the exceptions.
Introduce a new function dm_bufio_forget that frees the given buffer.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index 7441344..39b540a 100644
--- a/drivers/md/Kconfig
+++ b/drivers/md/Kconfig
@@ -238,6 +238,7 @@
config DM_SNAPSHOT
tristate "Snapshot target"
depends on BLK_DEV_DM
+ select DM_BUFIO
---help---
Allow volume managers to take writable snapshots of a device.
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 54bdd923..d865937 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1350,6 +1350,28 @@
}
EXPORT_SYMBOL_GPL(dm_bufio_release_move);
+/*
+ * Free the given buffer.
+ *
+ * This is just a hint, if the buffer is in use or dirty, this function
+ * does nothing.
+ */
+void dm_bufio_forget(struct dm_bufio_client *c, sector_t block)
+{
+ struct dm_buffer *b;
+
+ dm_bufio_lock(c);
+
+ b = __find(c, block);
+ if (b && likely(!b->hold_count) && likely(!b->state)) {
+ __unlink_buffer(b);
+ __free_buffer_wake(b);
+ }
+
+ dm_bufio_unlock(c);
+}
+EXPORT_SYMBOL(dm_bufio_forget);
+
unsigned dm_bufio_get_block_size(struct dm_bufio_client *c)
{
return c->block_size;
diff --git a/drivers/md/dm-bufio.h b/drivers/md/dm-bufio.h
index b142946..3dac376 100644
--- a/drivers/md/dm-bufio.h
+++ b/drivers/md/dm-bufio.h
@@ -108,6 +108,13 @@
*/
void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block);
+/*
+ * Free the given buffer.
+ * This is just a hint, if the buffer is in use or dirty, this function
+ * does nothing.
+ */
+void dm_bufio_forget(struct dm_bufio_client *c, sector_t block);
+
unsigned dm_bufio_get_block_size(struct dm_bufio_client *c);
sector_t dm_bufio_get_device_size(struct dm_bufio_client *c);
sector_t dm_bufio_get_block_number(struct dm_buffer *b);
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index ba792ae..1692750 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -13,6 +13,7 @@
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/dm-io.h>
+#include "dm-bufio.h"
#define DM_MSG_PREFIX "persistent snapshot"
#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */
@@ -495,27 +496,51 @@
void *callback_context)
{
int r, full = 1;
+ struct dm_bufio_client *client;
+
+ client = dm_bufio_client_create(dm_snap_cow(ps->store->snap)->bdev,
+ ps->store->chunk_size << SECTOR_SHIFT,
+ 1, 0, NULL, NULL);
+
+ if (IS_ERR(client))
+ return PTR_ERR(client);
/*
* Keeping reading chunks and inserting exceptions until
* we find a partially full area.
*/
for (ps->current_area = 0; full; ps->current_area++) {
- r = area_io(ps, READ);
- if (r)
- return r;
+ struct dm_buffer *bp;
+ void *area;
+ chunk_t chunk = area_location(ps, ps->current_area);
- r = insert_exceptions(ps, ps->area, callback, callback_context,
+ area = dm_bufio_read(client, chunk, &bp);
+ if (unlikely(IS_ERR(area))) {
+ r = PTR_ERR(area);
+ goto ret_destroy_bufio;
+ }
+
+ r = insert_exceptions(ps, area, callback, callback_context,
&full);
- if (r)
- return r;
+
+ dm_bufio_release(bp);
+
+ dm_bufio_forget(client, chunk);
+
+ if (unlikely(r))
+ goto ret_destroy_bufio;
}
ps->current_area--;
skip_metadata(ps);
- return 0;
+ r = 0;
+
+ret_destroy_bufio:
+ dm_bufio_client_destroy(client);
+
+ return r;
}
static struct pstore *get_info(struct dm_exception_store *store)