From 4db6bfe02bdc7dc5048f46dd682a94801d029adc Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Tue, 6 Jan 2009 03:05:17 +0000 Subject: dm snapshot: split out exception store implementations Move the existing snapshot exception store implementations out into separate files. Later patches will place these behind a new interface in preparation for alternative implementations. Signed-off-by: Alasdair G Kergon --- drivers/md/dm-snap-transient.c | 95 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 drivers/md/dm-snap-transient.c (limited to 'drivers/md/dm-snap-transient.c') diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c new file mode 100644 index 000000000000..2a781df57fef --- /dev/null +++ b/drivers/md/dm-snap-transient.c @@ -0,0 +1,95 @@ +/* + * Copyright (C) 2001-2002 Sistina Software (UK) Limited. + * Copyright (C) 2006-2008 Red Hat GmbH + * + * This file is released under the GPL. + */ + +#include "dm-exception-store.h" +#include "dm-snap.h" + +#include +#include +#include +#include +#include + +#define DM_MSG_PREFIX "transient snapshot" + +/*----------------------------------------------------------------- + * Implementation of the store for non-persistent snapshots. + *---------------------------------------------------------------*/ +struct transient_c { + sector_t next_free; +}; + +static void transient_destroy(struct dm_exception_store *store) +{ + kfree(store->context); +} + +static int transient_read_metadata(struct dm_exception_store *store) +{ + return 0; +} + +static int transient_prepare(struct dm_exception_store *store, + struct dm_snap_exception *e) +{ + struct transient_c *tc = (struct transient_c *) store->context; + sector_t size = get_dev_size(store->snap->cow->bdev); + + if (size < (tc->next_free + store->snap->chunk_size)) + return -1; + + e->new_chunk = sector_to_chunk(store->snap, tc->next_free); + tc->next_free += store->snap->chunk_size; + + return 0; +} + +static void transient_commit(struct dm_exception_store *store, + struct dm_snap_exception *e, + void (*callback) (void *, int success), + void *callback_context) +{ + /* Just succeed */ + callback(callback_context, 1); +} + +static void transient_fraction_full(struct dm_exception_store *store, + sector_t *numerator, sector_t *denominator) +{ + *numerator = ((struct transient_c *) store->context)->next_free; + *denominator = get_dev_size(store->snap->cow->bdev); +} + +int dm_create_transient(struct dm_exception_store *store) +{ + struct transient_c *tc; + + store->destroy = transient_destroy; + store->read_metadata = transient_read_metadata; + store->prepare_exception = transient_prepare; + store->commit_exception = transient_commit; + store->drop_snapshot = NULL; + store->fraction_full = transient_fraction_full; + + tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); + if (!tc) + return -ENOMEM; + + tc->next_free = 0; + store->context = tc; + + return 0; +} + +int dm_transient_snapshot_init(void) +{ + return 0; +} + +void dm_transient_snapshot_exit(void) +{ +} -- cgit v1.2.3