The following commit has been merged in the linux branch: commit c1cc65caa19bb8a1b2e371000ef2719581db1691 Author: Mikulas Patocka mpatocka@redhat.com Date: Fri Oct 16 23:18:22 2009 +0100
dm snapshot: allow chunk size to be less than page size
Allow the snapshot chunk size to be smaller than the page size The code is now capable of handling this due to some previous fixes and enhancements.
As the page size varies between computers, prior to this patch, the chunk size of a snapshot dictated which machines could read it: Snapshots created on one machine might not be readable on another.
Signed-off-by: Mikulas Patocka mpatocka@redhat.com Reviewed-by: Mike Snitzer snitzer@redhat.com Reviewed-by: Jonathan Brassow jbrassow@redhat.com Signed-off-by: Alasdair G Kergon agk@redhat.com
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 932d1b1..7dbe652 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -138,16 +138,6 @@ int dm_exception_store_type_unregister(struct dm_exception_store_type *type) } EXPORT_SYMBOL(dm_exception_store_type_unregister);
-/* - * Round a number up to the nearest 'size' boundary. size must - * be a power of 2. - */ -static ulong round_up(ulong n, ulong size) -{ - size--; - return (n + size) & ~size; -} - static int set_chunk_size(struct dm_exception_store *store, const char *chunk_size_arg, char **error) { @@ -166,12 +156,6 @@ static int set_chunk_size(struct dm_exception_store *store, return 0; }
- /* - * Chunk size must be multiple of page size. Silently - * round up if it's not. - */ - chunk_size_ulong = round_up(chunk_size_ulong, PAGE_SIZE >> 9); - return dm_exception_store_set_chunk_size(store, (unsigned) chunk_size_ulong, error);