2 * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
4 * This file is released under the GPL.
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/blkdev.h>
12 #include <linux/bio.h>
13 #include <linux/slab.h>
17 sector_t physical_start;
23 /* The size of this target / num. stripes */
24 sector_t stripe_width;
26 /* stripe chunk size */
30 struct stripe stripe[0];
33 static inline struct stripe_c *alloc_context(unsigned int stripes)
37 if (array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
41 len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
43 return kmalloc(len, GFP_KERNEL);
47 * Parse a single <dev> <sector> pair
49 static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
50 unsigned int stripe, char **argv)
52 unsigned long long start;
54 if (sscanf(argv[1], "%llu", &start) != 1)
57 if (dm_get_device(ti, argv[0], start, sc->stripe_width,
58 dm_table_get_mode(ti->table),
59 &sc->stripe[stripe].dev))
62 sc->stripe[stripe].physical_start = start;
67 * Construct a striped mapping.
68 * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
70 static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
81 ti->error = "dm-stripe: Not enough arguments";
85 stripes = simple_strtoul(argv[0], &end, 10);
87 ti->error = "dm-stripe: Invalid stripe count";
91 chunk_size = simple_strtoul(argv[1], &end, 10);
93 ti->error = "dm-stripe: Invalid chunk_size";
98 * chunk_size is a power of two
100 if (!chunk_size || (chunk_size & (chunk_size - 1)) ||
101 (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
102 ti->error = "dm-stripe: Invalid chunk size";
106 if (ti->len & (chunk_size - 1)) {
107 ti->error = "dm-stripe: Target length not divisible by "
113 if (sector_div(width, stripes)) {
114 ti->error = "dm-stripe: Target length not divisible by "
120 * Do we have enough arguments for that many stripes ?
122 if (argc != (2 + 2 * stripes)) {
123 ti->error = "dm-stripe: Not enough destinations "
128 sc = alloc_context(stripes);
130 ti->error = "dm-stripe: Memory allocation for striped context "
135 sc->stripes = stripes;
136 sc->stripe_width = width;
137 ti->split_io = chunk_size;
139 sc->chunk_mask = ((sector_t) chunk_size) - 1;
140 for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
145 * Get the stripe destinations.
147 for (i = 0; i < stripes; i++) {
150 r = get_stripe(ti, sc, i, argv);
152 ti->error = "dm-stripe: Couldn't parse stripe "
155 dm_put_device(ti, sc->stripe[i].dev);
165 static void stripe_dtr(struct dm_target *ti)
168 struct stripe_c *sc = (struct stripe_c *) ti->private;
170 for (i = 0; i < sc->stripes; i++)
171 dm_put_device(ti, sc->stripe[i].dev);
176 static int stripe_map(struct dm_target *ti, struct bio *bio,
177 union map_info *map_context)
179 struct stripe_c *sc = (struct stripe_c *) ti->private;
181 sector_t offset = bio->bi_sector - ti->begin;
182 sector_t chunk = offset >> sc->chunk_shift;
183 uint32_t stripe = sector_div(chunk, sc->stripes);
185 bio->bi_bdev = sc->stripe[stripe].dev->bdev;
186 bio->bi_sector = sc->stripe[stripe].physical_start +
187 (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
191 static int stripe_status(struct dm_target *ti,
192 status_type_t type, char *result, unsigned int maxlen)
194 struct stripe_c *sc = (struct stripe_c *) ti->private;
199 case STATUSTYPE_INFO:
203 case STATUSTYPE_TABLE:
204 DMEMIT("%d %llu", sc->stripes,
205 (unsigned long long)sc->chunk_mask + 1);
206 for (i = 0; i < sc->stripes; i++)
207 DMEMIT(" %s %llu", sc->stripe[i].dev->name,
208 (unsigned long long)sc->stripe[i].physical_start);
214 static struct target_type stripe_target = {
217 .module = THIS_MODULE,
221 .status = stripe_status,
224 int __init dm_stripe_init(void)
228 r = dm_register_target(&stripe_target);
230 DMWARN("striped target registration failed");
235 void dm_stripe_exit(void)
237 if (dm_unregister_target(&stripe_target))
238 DMWARN("striped target unregistration failed");