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path: root/drivers/md/dm-snap-persistent.c
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Diffstat (limited to 'drivers/md/dm-snap-persistent.c')
-rw-r--r--drivers/md/dm-snap-persistent.c108
1 files changed, 84 insertions, 24 deletions
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 4caa8e6d59d..d6e88178d22 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -13,10 +13,13 @@
#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 */
+#define DM_PREFETCH_CHUNKS 12
+
/*-----------------------------------------------------------------
* Persistent snapshots, by persistent we mean that the snapshot
* will survive a reboot.
@@ -257,6 +260,7 @@ static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw,
INIT_WORK_ONSTACK(&req.work, do_metadata);
queue_work(ps->metadata_wq, &req.work);
flush_workqueue(ps->metadata_wq);
+ destroy_work_on_stack(&req.work);
return req.result;
}
@@ -269,6 +273,14 @@ static chunk_t area_location(struct pstore *ps, chunk_t area)
return NUM_SNAPSHOT_HDR_CHUNKS + ((ps->exceptions_per_area + 1) * area);
}
+static void skip_metadata(struct pstore *ps)
+{
+ uint32_t stride = ps->exceptions_per_area + 1;
+ chunk_t next_free = ps->next_free;
+ if (sector_div(next_free, stride) == NUM_SNAPSHOT_HDR_CHUNKS)
+ ps->next_free++;
+}
+
/*
* Read or write a metadata area. Remembering to skip the first
* chunk which holds the header.
@@ -393,17 +405,18 @@ static int write_header(struct pstore *ps)
/*
* Access functions for the disk exceptions, these do the endian conversions.
*/
-static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
+static struct disk_exception *get_exception(struct pstore *ps, void *ps_area,
+ uint32_t index)
{
BUG_ON(index >= ps->exceptions_per_area);
- return ((struct disk_exception *) ps->area) + index;
+ return ((struct disk_exception *) ps_area) + index;
}
-static void read_exception(struct pstore *ps,
+static void read_exception(struct pstore *ps, void *ps_area,
uint32_t index, struct core_exception *result)
{
- struct disk_exception *de = get_exception(ps, index);
+ struct disk_exception *de = get_exception(ps, ps_area, index);
/* copy it */
result->old_chunk = le64_to_cpu(de->old_chunk);
@@ -413,7 +426,7 @@ static void read_exception(struct pstore *ps,
static void write_exception(struct pstore *ps,
uint32_t index, struct core_exception *e)
{
- struct disk_exception *de = get_exception(ps, index);
+ struct disk_exception *de = get_exception(ps, ps->area, index);
/* copy it */
de->old_chunk = cpu_to_le64(e->old_chunk);
@@ -422,7 +435,7 @@ static void write_exception(struct pstore *ps,
static void clear_exception(struct pstore *ps, uint32_t index)
{
- struct disk_exception *de = get_exception(ps, index);
+ struct disk_exception *de = get_exception(ps, ps->area, index);
/* clear it */
de->old_chunk = 0;
@@ -434,7 +447,7 @@ static void clear_exception(struct pstore *ps, uint32_t index)
* 'full' is filled in to indicate if the area has been
* filled.
*/
-static int insert_exceptions(struct pstore *ps,
+static int insert_exceptions(struct pstore *ps, void *ps_area,
int (*callback)(void *callback_context,
chunk_t old, chunk_t new),
void *callback_context,
@@ -448,7 +461,7 @@ static int insert_exceptions(struct pstore *ps,
*full = 1;
for (i = 0; i < ps->exceptions_per_area; i++) {
- read_exception(ps, i, &e);
+ read_exception(ps, ps_area, i, &e);
/*
* If the new_chunk is pointing at the start of
@@ -485,24 +498,75 @@ static int read_exceptions(struct pstore *ps,
void *callback_context)
{
int r, full = 1;
+ struct dm_bufio_client *client;
+ chunk_t prefetch_area = 0;
+
+ 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);
+
+ /*
+ * Setup for one current buffer + desired readahead buffers.
+ */
+ dm_bufio_set_minimum_buffers(client, 1 + DM_PREFETCH_CHUNKS);
/*
* 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;
+
+ if (unlikely(prefetch_area < ps->current_area))
+ prefetch_area = ps->current_area;
+
+ if (DM_PREFETCH_CHUNKS) do {
+ chunk_t pf_chunk = area_location(ps, prefetch_area);
+ if (unlikely(pf_chunk >= dm_bufio_get_device_size(client)))
+ break;
+ dm_bufio_prefetch(client, pf_chunk, 1);
+ prefetch_area++;
+ if (unlikely(!prefetch_area))
+ break;
+ } while (prefetch_area <= ps->current_area + DM_PREFETCH_CHUNKS);
+
+ chunk = area_location(ps, ps->current_area);
+
+ area = dm_bufio_read(client, chunk, &bp);
+ if (unlikely(IS_ERR(area))) {
+ r = PTR_ERR(area);
+ goto ret_destroy_bufio;
+ }
- r = insert_exceptions(ps, callback, callback_context, &full);
- if (r)
- return r;
+ r = insert_exceptions(ps, area, callback, callback_context,
+ &full);
+
+ if (!full)
+ memcpy(ps->area, area, ps->store->chunk_size << SECTOR_SHIFT);
+
+ dm_bufio_release(bp);
+
+ dm_bufio_forget(client, chunk);
+
+ if (unlikely(r))
+ goto ret_destroy_bufio;
}
ps->current_area--;
- return 0;
+ skip_metadata(ps);
+
+ r = 0;
+
+ret_destroy_bufio:
+ dm_bufio_client_destroy(client);
+
+ return r;
}
static struct pstore *get_info(struct dm_exception_store *store)
@@ -616,8 +680,6 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
struct dm_exception *e)
{
struct pstore *ps = get_info(store);
- uint32_t stride;
- chunk_t next_free;
sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev);
/* Is there enough room ? */
@@ -630,10 +692,8 @@ static int persistent_prepare_exception(struct dm_exception_store *store,
* Move onto the next free pending, making sure to take
* into account the location of the metadata chunks.
*/
- stride = (ps->exceptions_per_area + 1);
- next_free = ++ps->next_free;
- if (sector_div(next_free, stride) == 1)
- ps->next_free++;
+ ps->next_free++;
+ skip_metadata(ps);
atomic_inc(&ps->pending_count);
return 0;
@@ -727,7 +787,7 @@ static int persistent_prepare_merge(struct dm_exception_store *store,
ps->current_committed = ps->exceptions_per_area;
}
- read_exception(ps, ps->current_committed - 1, &ce);
+ read_exception(ps, ps->area, ps->current_committed - 1, &ce);
*last_old_chunk = ce.old_chunk;
*last_new_chunk = ce.new_chunk;
@@ -737,8 +797,8 @@ static int persistent_prepare_merge(struct dm_exception_store *store,
*/
for (nr_consecutive = 1; nr_consecutive < ps->current_committed;
nr_consecutive++) {
- read_exception(ps, ps->current_committed - 1 - nr_consecutive,
- &ce);
+ read_exception(ps, ps->area,
+ ps->current_committed - 1 - nr_consecutive, &ce);
if (ce.old_chunk != *last_old_chunk - nr_consecutive ||
ce.new_chunk != *last_new_chunk - nr_consecutive)
break;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 13:25:25 +0000