From 55494bf2947dccdf2d98b62374fea7365dfead84 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 13 Jan 2014 19:12:36 -0500 Subject: [PATCH] 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 Signed-off-by: Mike Snitzer --- drivers/md/Kconfig | 1 + drivers/md/dm-bufio.c | 22 +++++++++++++++++++ drivers/md/dm-bufio.h | 7 ++++++ drivers/md/dm-snap-persistent.c | 39 +++++++++++++++++++++++++++------ 4 files changed, 62 insertions(+), 7 deletions(-) diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 7441344bd214..39b540a13369 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -238,6 +238,7 @@ config DM_CRYPT 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 54bdd923316f..d86593721915 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1350,6 +1350,28 @@ void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block) } 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 b142946a9e32..3dac37627ba4 100644 --- a/drivers/md/dm-bufio.h +++ b/drivers/md/dm-bufio.h @@ -108,6 +108,13 @@ int dm_bufio_issue_flush(struct dm_bufio_client *c); */ 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 ba792ae068b7..169275050c0b 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -13,6 +13,7 @@ #include #include #include +#include "dm-bufio.h" #define DM_MSG_PREFIX "persistent snapshot" #define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */ @@ -495,27 +496,51 @@ static int read_exceptions(struct pstore *ps, 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)