From fee1998e9c690f9920671e1e0ef187a48cfbbde4 Mon Sep 17 00:00:00 2001 From: Jonathan Brassow Date: Thu, 2 Apr 2009 19:55:34 +0100 Subject: dm snapshot: move ctr parsing to exception store First step of having the exception stores parse their own arguments - generalizing the interface. Signed-off-by: Jonathan Brassow Signed-off-by: Alasdair G Kergon --- drivers/md/dm-exception-store.c | 109 ++++++++++++++++++++++++++++++++++------ 1 file changed, 95 insertions(+), 14 deletions(-) (limited to 'drivers/md/dm-exception-store.c') diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 2078b92470a..a2e26c24214 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -7,6 +7,7 @@ #include "dm-exception-store.h" +#include #include #include #include @@ -137,49 +138,129 @@ int dm_exception_store_type_unregister(struct dm_exception_store_type *type) } EXPORT_SYMBOL(dm_exception_store_type_unregister); -int dm_exception_store_create(const char *type_name, struct dm_target *ti, - chunk_t chunk_size, chunk_t chunk_mask, - chunk_t chunk_shift, struct dm_dev *cow, +/* + * 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) +{ + unsigned long chunk_size_ulong; + char *value; + + chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10); + if (*chunk_size_arg == '\0' || *value != '\0') { + *error = "Invalid chunk size"; + return -EINVAL; + } + + if (!chunk_size_ulong) { + store->chunk_size = store->chunk_mask = store->chunk_shift = 0; + 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); + + /* Check chunk_size is a power of 2 */ + if (!is_power_of_2(chunk_size_ulong)) { + *error = "Chunk size is not a power of 2"; + return -EINVAL; + } + + /* Validate the chunk size against the device block size */ + if (chunk_size_ulong % (bdev_hardsect_size(store->cow->bdev) >> 9)) { + *error = "Chunk size is not a multiple of device blocksize"; + return -EINVAL; + } + + store->chunk_size = chunk_size_ulong; + store->chunk_mask = chunk_size_ulong - 1; + store->chunk_shift = ffs(chunk_size_ulong) - 1; + + return 0; +} + +int dm_exception_store_create(struct dm_target *ti, int argc, char **argv, + unsigned *args_used, struct dm_exception_store **store) { int r = 0; struct dm_exception_store_type *type; struct dm_exception_store *tmp_store; + char persistent; + + if (argc < 3) { + ti->error = "Insufficient exception store arguments"; + return -EINVAL; + } tmp_store = kmalloc(sizeof(*tmp_store), GFP_KERNEL); - if (!tmp_store) + if (!tmp_store) { + ti->error = "Exception store allocation failed"; return -ENOMEM; + } - type = get_type(type_name); - if (!type) { - kfree(tmp_store); + persistent = toupper(*argv[1]); + if (persistent != 'P' && persistent != 'N') { + ti->error = "Persistent flag is not P or N"; return -EINVAL; } + type = get_type(argv[1]); + if (!type) { + ti->error = "Exception store type not recognised"; + r = -EINVAL; + goto bad_type; + } + tmp_store->type = type; tmp_store->ti = ti; - tmp_store->chunk_size = chunk_size; - tmp_store->chunk_mask = chunk_mask; - tmp_store->chunk_shift = chunk_shift; + r = dm_get_device(ti, argv[0], 0, 0, + FMODE_READ | FMODE_WRITE, &tmp_store->cow); + if (r) { + ti->error = "Cannot get COW device"; + goto bad_cow; + } - tmp_store->cow = cow; + r = set_chunk_size(tmp_store, argv[2], &ti->error); + if (r) + goto bad_cow; r = type->ctr(tmp_store, 0, NULL); if (r) { - put_type(type); - kfree(tmp_store); - return r; + ti->error = "Exception store type constructor failed"; + goto bad_ctr; } + *args_used = 3; *store = tmp_store; return 0; + +bad_ctr: + dm_put_device(ti, tmp_store->cow); +bad_cow: + put_type(type); +bad_type: + kfree(tmp_store); + return r; } EXPORT_SYMBOL(dm_exception_store_create); void dm_exception_store_destroy(struct dm_exception_store *store) { store->type->dtr(store); + dm_put_device(store->ti, store->cow); put_type(store->type); kfree(store); } -- cgit v1.2.3