Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2001-2002 Sistina Software (UK) Limited. |
| 3 | * Copyright (C) 2006-2008 Red Hat GmbH |
| 4 | * |
| 5 | * This file is released under the GPL. |
| 6 | */ |
| 7 | |
| 8 | #include "dm-exception-store.h" |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 9 | |
| 10 | #include <linux/mm.h> |
| 11 | #include <linux/pagemap.h> |
| 12 | #include <linux/vmalloc.h> |
Paul Gortmaker | daaa5f7 | 2011-05-27 15:50:58 -0400 | [diff] [blame] | 13 | #include <linux/export.h> |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 14 | #include <linux/slab.h> |
| 15 | #include <linux/dm-io.h> |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 16 | #include "dm-bufio.h" |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 17 | |
| 18 | #define DM_MSG_PREFIX "persistent snapshot" |
| 19 | #define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */ |
| 20 | |
| 21 | /*----------------------------------------------------------------- |
| 22 | * Persistent snapshots, by persistent we mean that the snapshot |
| 23 | * will survive a reboot. |
| 24 | *---------------------------------------------------------------*/ |
| 25 | |
| 26 | /* |
| 27 | * We need to store a record of which parts of the origin have |
| 28 | * been copied to the snapshot device. The snapshot code |
| 29 | * requires that we copy exception chunks to chunk aligned areas |
| 30 | * of the COW store. It makes sense therefore, to store the |
| 31 | * metadata in chunk size blocks. |
| 32 | * |
| 33 | * There is no backward or forward compatibility implemented, |
| 34 | * snapshots with different disk versions than the kernel will |
| 35 | * not be usable. It is expected that "lvcreate" will blank out |
| 36 | * the start of a fresh COW device before calling the snapshot |
| 37 | * constructor. |
| 38 | * |
| 39 | * The first chunk of the COW device just contains the header. |
| 40 | * After this there is a chunk filled with exception metadata, |
| 41 | * followed by as many exception chunks as can fit in the |
| 42 | * metadata areas. |
| 43 | * |
| 44 | * All on disk structures are in little-endian format. The end |
| 45 | * of the exceptions info is indicated by an exception with a |
| 46 | * new_chunk of 0, which is invalid since it would point to the |
| 47 | * header chunk. |
| 48 | */ |
| 49 | |
| 50 | /* |
| 51 | * Magic for persistent snapshots: "SnAp" - Feeble isn't it. |
| 52 | */ |
| 53 | #define SNAP_MAGIC 0x70416e53 |
| 54 | |
| 55 | /* |
| 56 | * The on-disk version of the metadata. |
| 57 | */ |
| 58 | #define SNAPSHOT_DISK_VERSION 1 |
| 59 | |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 60 | #define NUM_SNAPSHOT_HDR_CHUNKS 1 |
| 61 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 62 | struct disk_header { |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 63 | __le32 magic; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 64 | |
| 65 | /* |
| 66 | * Is this snapshot valid. There is no way of recovering |
| 67 | * an invalid snapshot. |
| 68 | */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 69 | __le32 valid; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 70 | |
| 71 | /* |
| 72 | * Simple, incrementing version. no backward |
| 73 | * compatibility. |
| 74 | */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 75 | __le32 version; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 76 | |
| 77 | /* In sectors */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 78 | __le32 chunk_size; |
| 79 | } __packed; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 80 | |
| 81 | struct disk_exception { |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 82 | __le64 old_chunk; |
| 83 | __le64 new_chunk; |
| 84 | } __packed; |
| 85 | |
| 86 | struct core_exception { |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 87 | uint64_t old_chunk; |
| 88 | uint64_t new_chunk; |
| 89 | }; |
| 90 | |
| 91 | struct commit_callback { |
| 92 | void (*callback)(void *, int success); |
| 93 | void *context; |
| 94 | }; |
| 95 | |
| 96 | /* |
| 97 | * The top level structure for a persistent exception store. |
| 98 | */ |
| 99 | struct pstore { |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 100 | struct dm_exception_store *store; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 101 | int version; |
| 102 | int valid; |
| 103 | uint32_t exceptions_per_area; |
| 104 | |
| 105 | /* |
| 106 | * Now that we have an asynchronous kcopyd there is no |
| 107 | * need for large chunk sizes, so it wont hurt to have a |
| 108 | * whole chunks worth of metadata in memory at once. |
| 109 | */ |
| 110 | void *area; |
| 111 | |
| 112 | /* |
| 113 | * An area of zeros used to clear the next area. |
| 114 | */ |
| 115 | void *zero_area; |
| 116 | |
| 117 | /* |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 118 | * An area used for header. The header can be written |
| 119 | * concurrently with metadata (when invalidating the snapshot), |
| 120 | * so it needs a separate buffer. |
| 121 | */ |
| 122 | void *header_area; |
| 123 | |
| 124 | /* |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 125 | * Used to keep track of which metadata area the data in |
| 126 | * 'chunk' refers to. |
| 127 | */ |
| 128 | chunk_t current_area; |
| 129 | |
| 130 | /* |
| 131 | * The next free chunk for an exception. |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 132 | * |
| 133 | * When creating exceptions, all the chunks here and above are |
| 134 | * free. It holds the next chunk to be allocated. On rare |
| 135 | * occasions (e.g. after a system crash) holes can be left in |
| 136 | * the exception store because chunks can be committed out of |
| 137 | * order. |
| 138 | * |
| 139 | * When merging exceptions, it does not necessarily mean all the |
| 140 | * chunks here and above are free. It holds the value it would |
| 141 | * have held if all chunks had been committed in order of |
| 142 | * allocation. Consequently the value may occasionally be |
| 143 | * slightly too low, but since it's only used for 'status' and |
| 144 | * it can never reach its minimum value too early this doesn't |
| 145 | * matter. |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 146 | */ |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 147 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 148 | chunk_t next_free; |
| 149 | |
| 150 | /* |
| 151 | * The index of next free exception in the current |
| 152 | * metadata area. |
| 153 | */ |
| 154 | uint32_t current_committed; |
| 155 | |
| 156 | atomic_t pending_count; |
| 157 | uint32_t callback_count; |
| 158 | struct commit_callback *callbacks; |
| 159 | struct dm_io_client *io_client; |
| 160 | |
| 161 | struct workqueue_struct *metadata_wq; |
| 162 | }; |
| 163 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 164 | static int alloc_area(struct pstore *ps) |
| 165 | { |
| 166 | int r = -ENOMEM; |
| 167 | size_t len; |
| 168 | |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 169 | len = ps->store->chunk_size << SECTOR_SHIFT; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 170 | |
| 171 | /* |
| 172 | * Allocate the chunk_size block of memory that will hold |
| 173 | * a single metadata area. |
| 174 | */ |
| 175 | ps->area = vmalloc(len); |
| 176 | if (!ps->area) |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 177 | goto err_area; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 178 | |
Joe Perches | e29e65a | 2011-08-02 12:32:02 +0100 | [diff] [blame] | 179 | ps->zero_area = vzalloc(len); |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 180 | if (!ps->zero_area) |
| 181 | goto err_zero_area; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 182 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 183 | ps->header_area = vmalloc(len); |
| 184 | if (!ps->header_area) |
| 185 | goto err_header_area; |
| 186 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 187 | return 0; |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 188 | |
| 189 | err_header_area: |
| 190 | vfree(ps->zero_area); |
| 191 | |
| 192 | err_zero_area: |
| 193 | vfree(ps->area); |
| 194 | |
| 195 | err_area: |
| 196 | return r; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 197 | } |
| 198 | |
| 199 | static void free_area(struct pstore *ps) |
| 200 | { |
Jonathan Brassow | a32079c | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 201 | if (ps->area) |
| 202 | vfree(ps->area); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 203 | ps->area = NULL; |
Jonathan Brassow | a32079c | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 204 | |
| 205 | if (ps->zero_area) |
| 206 | vfree(ps->zero_area); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 207 | ps->zero_area = NULL; |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 208 | |
| 209 | if (ps->header_area) |
| 210 | vfree(ps->header_area); |
| 211 | ps->header_area = NULL; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 212 | } |
| 213 | |
| 214 | struct mdata_req { |
| 215 | struct dm_io_region *where; |
| 216 | struct dm_io_request *io_req; |
| 217 | struct work_struct work; |
| 218 | int result; |
| 219 | }; |
| 220 | |
| 221 | static void do_metadata(struct work_struct *work) |
| 222 | { |
| 223 | struct mdata_req *req = container_of(work, struct mdata_req, work); |
| 224 | |
| 225 | req->result = dm_io(req->io_req, 1, req->where, NULL); |
| 226 | } |
| 227 | |
| 228 | /* |
| 229 | * Read or write a chunk aligned and sized block of data from a device. |
| 230 | */ |
Mikulas Patocka | 02d2fd3 | 2009-09-04 20:40:37 +0100 | [diff] [blame] | 231 | static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw, |
| 232 | int metadata) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 233 | { |
| 234 | struct dm_io_region where = { |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 235 | .bdev = dm_snap_cow(ps->store->snap)->bdev, |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 236 | .sector = ps->store->chunk_size * chunk, |
| 237 | .count = ps->store->chunk_size, |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 238 | }; |
| 239 | struct dm_io_request io_req = { |
| 240 | .bi_rw = rw, |
| 241 | .mem.type = DM_IO_VMA, |
Mikulas Patocka | 02d2fd3 | 2009-09-04 20:40:37 +0100 | [diff] [blame] | 242 | .mem.ptr.vma = area, |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 243 | .client = ps->io_client, |
| 244 | .notify.fn = NULL, |
| 245 | }; |
| 246 | struct mdata_req req; |
| 247 | |
| 248 | if (!metadata) |
| 249 | return dm_io(&io_req, 1, &where, NULL); |
| 250 | |
| 251 | req.where = &where; |
| 252 | req.io_req = &io_req; |
| 253 | |
| 254 | /* |
| 255 | * Issue the synchronous I/O from a different thread |
| 256 | * to avoid generic_make_request recursion. |
| 257 | */ |
Andrew Morton | ca1cab3 | 2010-10-26 14:22:34 -0700 | [diff] [blame] | 258 | INIT_WORK_ONSTACK(&req.work, do_metadata); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 259 | queue_work(ps->metadata_wq, &req.work); |
Mikulas Patocka | 5ea330a | 2013-09-18 19:14:22 -0400 | [diff] [blame] | 260 | flush_workqueue(ps->metadata_wq); |
Chuansheng Liu | c1a6416 | 2014-01-07 16:56:18 +0800 | [diff] [blame] | 261 | destroy_work_on_stack(&req.work); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 262 | |
| 263 | return req.result; |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * Convert a metadata area index to a chunk index. |
| 268 | */ |
| 269 | static chunk_t area_location(struct pstore *ps, chunk_t area) |
| 270 | { |
Tomohiro Kusumi | 87c961c | 2010-08-12 04:13:59 +0100 | [diff] [blame] | 271 | return NUM_SNAPSHOT_HDR_CHUNKS + ((ps->exceptions_per_area + 1) * area); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 272 | } |
| 273 | |
Mikulas Patocka | e9c6a18 | 2013-10-16 03:17:47 +0100 | [diff] [blame] | 274 | static void skip_metadata(struct pstore *ps) |
| 275 | { |
| 276 | uint32_t stride = ps->exceptions_per_area + 1; |
| 277 | chunk_t next_free = ps->next_free; |
| 278 | if (sector_div(next_free, stride) == NUM_SNAPSHOT_HDR_CHUNKS) |
| 279 | ps->next_free++; |
| 280 | } |
| 281 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 282 | /* |
| 283 | * Read or write a metadata area. Remembering to skip the first |
| 284 | * chunk which holds the header. |
| 285 | */ |
| 286 | static int area_io(struct pstore *ps, int rw) |
| 287 | { |
| 288 | int r; |
| 289 | chunk_t chunk; |
| 290 | |
| 291 | chunk = area_location(ps, ps->current_area); |
| 292 | |
Mikulas Patocka | 02d2fd3 | 2009-09-04 20:40:37 +0100 | [diff] [blame] | 293 | r = chunk_io(ps, ps->area, chunk, rw, 0); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 294 | if (r) |
| 295 | return r; |
| 296 | |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | static void zero_memory_area(struct pstore *ps) |
| 301 | { |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 302 | memset(ps->area, 0, ps->store->chunk_size << SECTOR_SHIFT); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 303 | } |
| 304 | |
| 305 | static int zero_disk_area(struct pstore *ps, chunk_t area) |
| 306 | { |
Mikulas Patocka | 02d2fd3 | 2009-09-04 20:40:37 +0100 | [diff] [blame] | 307 | return chunk_io(ps, ps->zero_area, area_location(ps, area), WRITE, 0); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 308 | } |
| 309 | |
| 310 | static int read_header(struct pstore *ps, int *new_snapshot) |
| 311 | { |
| 312 | int r; |
| 313 | struct disk_header *dh; |
Mikulas Patocka | df96eee | 2009-10-16 23:18:17 +0100 | [diff] [blame] | 314 | unsigned chunk_size; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 315 | int chunk_size_supplied = 1; |
Mikulas Patocka | ae0b744 | 2009-09-04 20:40:43 +0100 | [diff] [blame] | 316 | char *chunk_err; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 317 | |
| 318 | /* |
Mikulas Patocka | df96eee | 2009-10-16 23:18:17 +0100 | [diff] [blame] | 319 | * Use default chunk size (or logical_block_size, if larger) |
| 320 | * if none supplied |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 321 | */ |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 322 | if (!ps->store->chunk_size) { |
| 323 | ps->store->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS, |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 324 | bdev_logical_block_size(dm_snap_cow(ps->store->snap)-> |
| 325 | bdev) >> 9); |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 326 | ps->store->chunk_mask = ps->store->chunk_size - 1; |
| 327 | ps->store->chunk_shift = ffs(ps->store->chunk_size) - 1; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 328 | chunk_size_supplied = 0; |
| 329 | } |
| 330 | |
Mikulas Patocka | bda8efe | 2011-05-29 13:03:09 +0100 | [diff] [blame] | 331 | ps->io_client = dm_io_client_create(); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 332 | if (IS_ERR(ps->io_client)) |
| 333 | return PTR_ERR(ps->io_client); |
| 334 | |
| 335 | r = alloc_area(ps); |
| 336 | if (r) |
| 337 | return r; |
| 338 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 339 | r = chunk_io(ps, ps->header_area, 0, READ, 1); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 340 | if (r) |
| 341 | goto bad; |
| 342 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 343 | dh = ps->header_area; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 344 | |
| 345 | if (le32_to_cpu(dh->magic) == 0) { |
| 346 | *new_snapshot = 1; |
| 347 | return 0; |
| 348 | } |
| 349 | |
| 350 | if (le32_to_cpu(dh->magic) != SNAP_MAGIC) { |
| 351 | DMWARN("Invalid or corrupt snapshot"); |
| 352 | r = -ENXIO; |
| 353 | goto bad; |
| 354 | } |
| 355 | |
| 356 | *new_snapshot = 0; |
| 357 | ps->valid = le32_to_cpu(dh->valid); |
| 358 | ps->version = le32_to_cpu(dh->version); |
| 359 | chunk_size = le32_to_cpu(dh->chunk_size); |
| 360 | |
Mikulas Patocka | ae0b744 | 2009-09-04 20:40:43 +0100 | [diff] [blame] | 361 | if (ps->store->chunk_size == chunk_size) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 362 | return 0; |
| 363 | |
Mikulas Patocka | ae0b744 | 2009-09-04 20:40:43 +0100 | [diff] [blame] | 364 | if (chunk_size_supplied) |
Mikulas Patocka | df96eee | 2009-10-16 23:18:17 +0100 | [diff] [blame] | 365 | DMWARN("chunk size %u in device metadata overrides " |
| 366 | "table chunk size of %u.", |
| 367 | chunk_size, ps->store->chunk_size); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 368 | |
| 369 | /* We had a bogus chunk_size. Fix stuff up. */ |
| 370 | free_area(ps); |
| 371 | |
Mikulas Patocka | ae0b744 | 2009-09-04 20:40:43 +0100 | [diff] [blame] | 372 | r = dm_exception_store_set_chunk_size(ps->store, chunk_size, |
| 373 | &chunk_err); |
| 374 | if (r) { |
Mikulas Patocka | df96eee | 2009-10-16 23:18:17 +0100 | [diff] [blame] | 375 | DMERR("invalid on-disk chunk size %u: %s.", |
| 376 | chunk_size, chunk_err); |
Mikulas Patocka | ae0b744 | 2009-09-04 20:40:43 +0100 | [diff] [blame] | 377 | return r; |
| 378 | } |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 379 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 380 | r = alloc_area(ps); |
| 381 | return r; |
| 382 | |
| 383 | bad: |
| 384 | free_area(ps); |
| 385 | return r; |
| 386 | } |
| 387 | |
| 388 | static int write_header(struct pstore *ps) |
| 389 | { |
| 390 | struct disk_header *dh; |
| 391 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 392 | memset(ps->header_area, 0, ps->store->chunk_size << SECTOR_SHIFT); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 393 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 394 | dh = ps->header_area; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 395 | dh->magic = cpu_to_le32(SNAP_MAGIC); |
| 396 | dh->valid = cpu_to_le32(ps->valid); |
| 397 | dh->version = cpu_to_le32(ps->version); |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 398 | dh->chunk_size = cpu_to_le32(ps->store->chunk_size); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 399 | |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 400 | return chunk_io(ps, ps->header_area, 0, WRITE, 1); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 401 | } |
| 402 | |
| 403 | /* |
| 404 | * Access functions for the disk exceptions, these do the endian conversions. |
| 405 | */ |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 406 | static struct disk_exception *get_exception(struct pstore *ps, void *ps_area, |
| 407 | uint32_t index) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 408 | { |
| 409 | BUG_ON(index >= ps->exceptions_per_area); |
| 410 | |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 411 | return ((struct disk_exception *) ps_area) + index; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 412 | } |
| 413 | |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 414 | static void read_exception(struct pstore *ps, void *ps_area, |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 415 | uint32_t index, struct core_exception *result) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 416 | { |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 417 | struct disk_exception *de = get_exception(ps, ps_area, index); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 418 | |
| 419 | /* copy it */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 420 | result->old_chunk = le64_to_cpu(de->old_chunk); |
| 421 | result->new_chunk = le64_to_cpu(de->new_chunk); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 422 | } |
| 423 | |
| 424 | static void write_exception(struct pstore *ps, |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 425 | uint32_t index, struct core_exception *e) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 426 | { |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 427 | struct disk_exception *de = get_exception(ps, ps->area, index); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 428 | |
| 429 | /* copy it */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 430 | de->old_chunk = cpu_to_le64(e->old_chunk); |
| 431 | de->new_chunk = cpu_to_le64(e->new_chunk); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 432 | } |
| 433 | |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 434 | static void clear_exception(struct pstore *ps, uint32_t index) |
| 435 | { |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 436 | struct disk_exception *de = get_exception(ps, ps->area, index); |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 437 | |
| 438 | /* clear it */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 439 | de->old_chunk = 0; |
| 440 | de->new_chunk = 0; |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 441 | } |
| 442 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 443 | /* |
| 444 | * Registers the exceptions that are present in the current area. |
| 445 | * 'full' is filled in to indicate if the area has been |
| 446 | * filled. |
| 447 | */ |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 448 | static int insert_exceptions(struct pstore *ps, void *ps_area, |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 449 | int (*callback)(void *callback_context, |
| 450 | chunk_t old, chunk_t new), |
| 451 | void *callback_context, |
| 452 | int *full) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 453 | { |
| 454 | int r; |
| 455 | unsigned int i; |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 456 | struct core_exception e; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 457 | |
| 458 | /* presume the area is full */ |
| 459 | *full = 1; |
| 460 | |
| 461 | for (i = 0; i < ps->exceptions_per_area; i++) { |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 462 | read_exception(ps, ps_area, i, &e); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 463 | |
| 464 | /* |
| 465 | * If the new_chunk is pointing at the start of |
| 466 | * the COW device, where the first metadata area |
| 467 | * is we know that we've hit the end of the |
| 468 | * exceptions. Therefore the area is not full. |
| 469 | */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 470 | if (e.new_chunk == 0LL) { |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 471 | ps->current_committed = i; |
| 472 | *full = 0; |
| 473 | break; |
| 474 | } |
| 475 | |
| 476 | /* |
| 477 | * Keep track of the start of the free chunks. |
| 478 | */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 479 | if (ps->next_free <= e.new_chunk) |
| 480 | ps->next_free = e.new_chunk + 1; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 481 | |
| 482 | /* |
| 483 | * Otherwise we add the exception to the snapshot. |
| 484 | */ |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 485 | r = callback(callback_context, e.old_chunk, e.new_chunk); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 486 | if (r) |
| 487 | return r; |
| 488 | } |
| 489 | |
| 490 | return 0; |
| 491 | } |
| 492 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 493 | static int read_exceptions(struct pstore *ps, |
| 494 | int (*callback)(void *callback_context, chunk_t old, |
| 495 | chunk_t new), |
| 496 | void *callback_context) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 497 | { |
| 498 | int r, full = 1; |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 499 | struct dm_bufio_client *client; |
| 500 | |
| 501 | client = dm_bufio_client_create(dm_snap_cow(ps->store->snap)->bdev, |
| 502 | ps->store->chunk_size << SECTOR_SHIFT, |
| 503 | 1, 0, NULL, NULL); |
| 504 | |
| 505 | if (IS_ERR(client)) |
| 506 | return PTR_ERR(client); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 507 | |
| 508 | /* |
| 509 | * Keeping reading chunks and inserting exceptions until |
| 510 | * we find a partially full area. |
| 511 | */ |
| 512 | for (ps->current_area = 0; full; ps->current_area++) { |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 513 | struct dm_buffer *bp; |
| 514 | void *area; |
| 515 | chunk_t chunk = area_location(ps, ps->current_area); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 516 | |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 517 | area = dm_bufio_read(client, chunk, &bp); |
| 518 | if (unlikely(IS_ERR(area))) { |
| 519 | r = PTR_ERR(area); |
| 520 | goto ret_destroy_bufio; |
| 521 | } |
| 522 | |
| 523 | r = insert_exceptions(ps, area, callback, callback_context, |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 524 | &full); |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 525 | |
| 526 | dm_bufio_release(bp); |
| 527 | |
| 528 | dm_bufio_forget(client, chunk); |
| 529 | |
| 530 | if (unlikely(r)) |
| 531 | goto ret_destroy_bufio; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 532 | } |
| 533 | |
| 534 | ps->current_area--; |
| 535 | |
Mikulas Patocka | e9c6a18 | 2013-10-16 03:17:47 +0100 | [diff] [blame] | 536 | skip_metadata(ps); |
| 537 | |
Mikulas Patocka | 55494bf | 2014-01-13 19:12:36 -0500 | [diff] [blame^] | 538 | r = 0; |
| 539 | |
| 540 | ret_destroy_bufio: |
| 541 | dm_bufio_client_destroy(client); |
| 542 | |
| 543 | return r; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 544 | } |
| 545 | |
| 546 | static struct pstore *get_info(struct dm_exception_store *store) |
| 547 | { |
| 548 | return (struct pstore *) store->context; |
| 549 | } |
| 550 | |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 551 | static void persistent_usage(struct dm_exception_store *store, |
| 552 | sector_t *total_sectors, |
| 553 | sector_t *sectors_allocated, |
| 554 | sector_t *metadata_sectors) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 555 | { |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 556 | struct pstore *ps = get_info(store); |
| 557 | |
| 558 | *sectors_allocated = ps->next_free * store->chunk_size; |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 559 | *total_sectors = get_dev_size(dm_snap_cow(store->snap)->bdev); |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 560 | |
| 561 | /* |
| 562 | * First chunk is the fixed header. |
| 563 | * Then there are (ps->current_area + 1) metadata chunks, each one |
| 564 | * separated from the next by ps->exceptions_per_area data chunks. |
| 565 | */ |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 566 | *metadata_sectors = (ps->current_area + 1 + NUM_SNAPSHOT_HDR_CHUNKS) * |
| 567 | store->chunk_size; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 568 | } |
| 569 | |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 570 | static void persistent_dtr(struct dm_exception_store *store) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 571 | { |
| 572 | struct pstore *ps = get_info(store); |
| 573 | |
| 574 | destroy_workqueue(ps->metadata_wq); |
Jonathan Brassow | a32079c | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 575 | |
| 576 | /* Created in read_header */ |
| 577 | if (ps->io_client) |
| 578 | dm_io_client_destroy(ps->io_client); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 579 | free_area(ps); |
Jonathan Brassow | a32079c | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 580 | |
| 581 | /* Allocated in persistent_read_metadata */ |
| 582 | if (ps->callbacks) |
| 583 | vfree(ps->callbacks); |
| 584 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 585 | kfree(ps); |
| 586 | } |
| 587 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 588 | static int persistent_read_metadata(struct dm_exception_store *store, |
| 589 | int (*callback)(void *callback_context, |
| 590 | chunk_t old, chunk_t new), |
| 591 | void *callback_context) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 592 | { |
| 593 | int r, uninitialized_var(new_snapshot); |
| 594 | struct pstore *ps = get_info(store); |
| 595 | |
| 596 | /* |
| 597 | * Read the snapshot header. |
| 598 | */ |
| 599 | r = read_header(ps, &new_snapshot); |
| 600 | if (r) |
| 601 | return r; |
| 602 | |
| 603 | /* |
| 604 | * Now we know correct chunk_size, complete the initialisation. |
| 605 | */ |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 606 | ps->exceptions_per_area = (ps->store->chunk_size << SECTOR_SHIFT) / |
| 607 | sizeof(struct disk_exception); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 608 | ps->callbacks = dm_vcalloc(ps->exceptions_per_area, |
Jonathan Brassow | a2d2b03 | 2011-08-02 12:32:03 +0100 | [diff] [blame] | 609 | sizeof(*ps->callbacks)); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 610 | if (!ps->callbacks) |
| 611 | return -ENOMEM; |
| 612 | |
| 613 | /* |
| 614 | * Do we need to setup a new snapshot ? |
| 615 | */ |
| 616 | if (new_snapshot) { |
| 617 | r = write_header(ps); |
| 618 | if (r) { |
| 619 | DMWARN("write_header failed"); |
| 620 | return r; |
| 621 | } |
| 622 | |
| 623 | ps->current_area = 0; |
| 624 | zero_memory_area(ps); |
| 625 | r = zero_disk_area(ps, 0); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 626 | if (r) |
Jon Brassow | f5acc83 | 2009-12-10 23:52:07 +0000 | [diff] [blame] | 627 | DMWARN("zero_disk_area(0) failed"); |
| 628 | return r; |
| 629 | } |
| 630 | /* |
| 631 | * Sanity checks. |
| 632 | */ |
| 633 | if (ps->version != SNAPSHOT_DISK_VERSION) { |
| 634 | DMWARN("unable to handle snapshot disk version %d", |
| 635 | ps->version); |
| 636 | return -EINVAL; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 637 | } |
| 638 | |
Jon Brassow | f5acc83 | 2009-12-10 23:52:07 +0000 | [diff] [blame] | 639 | /* |
| 640 | * Metadata are valid, but snapshot is invalidated |
| 641 | */ |
| 642 | if (!ps->valid) |
| 643 | return 1; |
| 644 | |
| 645 | /* |
| 646 | * Read the metadata. |
| 647 | */ |
| 648 | r = read_exceptions(ps, callback, callback_context); |
| 649 | |
| 650 | return r; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 651 | } |
| 652 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 653 | static int persistent_prepare_exception(struct dm_exception_store *store, |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 654 | struct dm_exception *e) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 655 | { |
| 656 | struct pstore *ps = get_info(store); |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 657 | sector_t size = get_dev_size(dm_snap_cow(store->snap)->bdev); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 658 | |
| 659 | /* Is there enough room ? */ |
Jonathan Brassow | d021684 | 2009-04-02 19:55:32 +0100 | [diff] [blame] | 660 | if (size < ((ps->next_free + 1) * store->chunk_size)) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 661 | return -ENOSPC; |
| 662 | |
| 663 | e->new_chunk = ps->next_free; |
| 664 | |
| 665 | /* |
| 666 | * Move onto the next free pending, making sure to take |
| 667 | * into account the location of the metadata chunks. |
| 668 | */ |
Mikulas Patocka | e9c6a18 | 2013-10-16 03:17:47 +0100 | [diff] [blame] | 669 | ps->next_free++; |
| 670 | skip_metadata(ps); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 671 | |
| 672 | atomic_inc(&ps->pending_count); |
| 673 | return 0; |
| 674 | } |
| 675 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 676 | static void persistent_commit_exception(struct dm_exception_store *store, |
Jon Brassow | 1d4989c | 2009-12-10 23:52:10 +0000 | [diff] [blame] | 677 | struct dm_exception *e, |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 678 | void (*callback) (void *, int success), |
| 679 | void *callback_context) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 680 | { |
| 681 | unsigned int i; |
| 682 | struct pstore *ps = get_info(store); |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 683 | struct core_exception ce; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 684 | struct commit_callback *cb; |
| 685 | |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 686 | ce.old_chunk = e->old_chunk; |
| 687 | ce.new_chunk = e->new_chunk; |
| 688 | write_exception(ps, ps->current_committed++, &ce); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 689 | |
| 690 | /* |
| 691 | * Add the callback to the back of the array. This code |
| 692 | * is the only place where the callback array is |
| 693 | * manipulated, and we know that it will never be called |
| 694 | * multiple times concurrently. |
| 695 | */ |
| 696 | cb = ps->callbacks + ps->callback_count++; |
| 697 | cb->callback = callback; |
| 698 | cb->context = callback_context; |
| 699 | |
| 700 | /* |
| 701 | * If there are exceptions in flight and we have not yet |
| 702 | * filled this metadata area there's nothing more to do. |
| 703 | */ |
| 704 | if (!atomic_dec_and_test(&ps->pending_count) && |
| 705 | (ps->current_committed != ps->exceptions_per_area)) |
| 706 | return; |
| 707 | |
| 708 | /* |
| 709 | * If we completely filled the current area, then wipe the next one. |
| 710 | */ |
| 711 | if ((ps->current_committed == ps->exceptions_per_area) && |
Jonathan Brassow | a2d2b03 | 2011-08-02 12:32:03 +0100 | [diff] [blame] | 712 | zero_disk_area(ps, ps->current_area + 1)) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 713 | ps->valid = 0; |
| 714 | |
| 715 | /* |
| 716 | * Commit exceptions to disk. |
| 717 | */ |
Tejun Heo | d87f4c1 | 2010-09-03 11:56:19 +0200 | [diff] [blame] | 718 | if (ps->valid && area_io(ps, WRITE_FLUSH_FUA)) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 719 | ps->valid = 0; |
| 720 | |
| 721 | /* |
| 722 | * Advance to the next area if this one is full. |
| 723 | */ |
| 724 | if (ps->current_committed == ps->exceptions_per_area) { |
| 725 | ps->current_committed = 0; |
| 726 | ps->current_area++; |
| 727 | zero_memory_area(ps); |
| 728 | } |
| 729 | |
| 730 | for (i = 0; i < ps->callback_count; i++) { |
| 731 | cb = ps->callbacks + i; |
| 732 | cb->callback(cb->context, ps->valid); |
| 733 | } |
| 734 | |
| 735 | ps->callback_count = 0; |
| 736 | } |
| 737 | |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 738 | static int persistent_prepare_merge(struct dm_exception_store *store, |
| 739 | chunk_t *last_old_chunk, |
| 740 | chunk_t *last_new_chunk) |
| 741 | { |
| 742 | struct pstore *ps = get_info(store); |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 743 | struct core_exception ce; |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 744 | int nr_consecutive; |
| 745 | int r; |
| 746 | |
| 747 | /* |
| 748 | * When current area is empty, move back to preceding area. |
| 749 | */ |
| 750 | if (!ps->current_committed) { |
| 751 | /* |
| 752 | * Have we finished? |
| 753 | */ |
| 754 | if (!ps->current_area) |
| 755 | return 0; |
| 756 | |
| 757 | ps->current_area--; |
| 758 | r = area_io(ps, READ); |
| 759 | if (r < 0) |
| 760 | return r; |
| 761 | ps->current_committed = ps->exceptions_per_area; |
| 762 | } |
| 763 | |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 764 | read_exception(ps, ps->area, ps->current_committed - 1, &ce); |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 765 | *last_old_chunk = ce.old_chunk; |
| 766 | *last_new_chunk = ce.new_chunk; |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 767 | |
| 768 | /* |
| 769 | * Find number of consecutive chunks within the current area, |
| 770 | * working backwards. |
| 771 | */ |
| 772 | for (nr_consecutive = 1; nr_consecutive < ps->current_committed; |
| 773 | nr_consecutive++) { |
Mikulas Patocka | 2cadabd | 2014-01-13 19:14:04 -0500 | [diff] [blame] | 774 | read_exception(ps, ps->area, |
| 775 | ps->current_committed - 1 - nr_consecutive, &ce); |
Alasdair G Kergon | 283a832 | 2011-08-02 12:32:01 +0100 | [diff] [blame] | 776 | if (ce.old_chunk != *last_old_chunk - nr_consecutive || |
| 777 | ce.new_chunk != *last_new_chunk - nr_consecutive) |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 778 | break; |
| 779 | } |
| 780 | |
| 781 | return nr_consecutive; |
| 782 | } |
| 783 | |
| 784 | static int persistent_commit_merge(struct dm_exception_store *store, |
| 785 | int nr_merged) |
| 786 | { |
| 787 | int r, i; |
| 788 | struct pstore *ps = get_info(store); |
| 789 | |
| 790 | BUG_ON(nr_merged > ps->current_committed); |
| 791 | |
| 792 | for (i = 0; i < nr_merged; i++) |
| 793 | clear_exception(ps, ps->current_committed - 1 - i); |
| 794 | |
Mikulas Patocka | 762a80d | 2011-08-02 12:32:00 +0100 | [diff] [blame] | 795 | r = area_io(ps, WRITE_FLUSH_FUA); |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 796 | if (r < 0) |
| 797 | return r; |
| 798 | |
| 799 | ps->current_committed -= nr_merged; |
| 800 | |
| 801 | /* |
| 802 | * At this stage, only persistent_usage() uses ps->next_free, so |
| 803 | * we make no attempt to keep ps->next_free strictly accurate |
| 804 | * as exceptions may have been committed out-of-order originally. |
| 805 | * Once a snapshot has become merging, we set it to the value it |
| 806 | * would have held had all the exceptions been committed in order. |
| 807 | * |
| 808 | * ps->current_area does not get reduced by prepare_merge() until |
| 809 | * after commit_merge() has removed the nr_merged previous exceptions. |
| 810 | */ |
Tomohiro Kusumi | 87c961c | 2010-08-12 04:13:59 +0100 | [diff] [blame] | 811 | ps->next_free = area_location(ps, ps->current_area) + |
| 812 | ps->current_committed + 1; |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 813 | |
| 814 | return 0; |
| 815 | } |
| 816 | |
Jonathan Brassow | a159c1a | 2009-01-06 03:05:19 +0000 | [diff] [blame] | 817 | static void persistent_drop_snapshot(struct dm_exception_store *store) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 818 | { |
| 819 | struct pstore *ps = get_info(store); |
| 820 | |
| 821 | ps->valid = 0; |
| 822 | if (write_header(ps)) |
| 823 | DMWARN("write header failed"); |
| 824 | } |
| 825 | |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 826 | static int persistent_ctr(struct dm_exception_store *store, |
| 827 | unsigned argc, char **argv) |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 828 | { |
| 829 | struct pstore *ps; |
| 830 | |
| 831 | /* allocate the pstore */ |
Jonathan Brassow | a32079c | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 832 | ps = kzalloc(sizeof(*ps), GFP_KERNEL); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 833 | if (!ps) |
| 834 | return -ENOMEM; |
| 835 | |
Jonathan Brassow | 71fab00 | 2009-04-02 19:55:33 +0100 | [diff] [blame] | 836 | ps->store = store; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 837 | ps->valid = 1; |
| 838 | ps->version = SNAPSHOT_DISK_VERSION; |
| 839 | ps->area = NULL; |
Mikulas Patocka | 61578dc | 2009-09-04 20:40:39 +0100 | [diff] [blame] | 840 | ps->zero_area = NULL; |
| 841 | ps->header_area = NULL; |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 842 | ps->next_free = NUM_SNAPSHOT_HDR_CHUNKS + 1; /* header and 1st area */ |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 843 | ps->current_committed = 0; |
| 844 | |
| 845 | ps->callback_count = 0; |
| 846 | atomic_set(&ps->pending_count, 0); |
| 847 | ps->callbacks = NULL; |
| 848 | |
Tejun Heo | 239c8dd | 2011-01-13 19:59:59 +0000 | [diff] [blame] | 849 | ps->metadata_wq = alloc_workqueue("ksnaphd", WQ_MEM_RECLAIM, 0); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 850 | if (!ps->metadata_wq) { |
| 851 | kfree(ps); |
| 852 | DMERR("couldn't start header metadata update thread"); |
| 853 | return -ENOMEM; |
| 854 | } |
| 855 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 856 | store->context = ps; |
| 857 | |
| 858 | return 0; |
| 859 | } |
| 860 | |
Jonathan Brassow | 1e302a9 | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 861 | static unsigned persistent_status(struct dm_exception_store *store, |
| 862 | status_type_t status, char *result, |
| 863 | unsigned maxlen) |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 864 | { |
Jonathan Brassow | 1e302a9 | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 865 | unsigned sz = 0; |
| 866 | |
| 867 | switch (status) { |
| 868 | case STATUSTYPE_INFO: |
| 869 | break; |
| 870 | case STATUSTYPE_TABLE: |
Mike Snitzer | fc56f6f | 2009-12-10 23:52:12 +0000 | [diff] [blame] | 871 | DMEMIT(" P %llu", (unsigned long long)store->chunk_size); |
Jonathan Brassow | 1e302a9 | 2009-04-02 19:55:35 +0100 | [diff] [blame] | 872 | } |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 873 | |
| 874 | return sz; |
| 875 | } |
| 876 | |
| 877 | static struct dm_exception_store_type _persistent_type = { |
| 878 | .name = "persistent", |
| 879 | .module = THIS_MODULE, |
| 880 | .ctr = persistent_ctr, |
| 881 | .dtr = persistent_dtr, |
| 882 | .read_metadata = persistent_read_metadata, |
| 883 | .prepare_exception = persistent_prepare_exception, |
| 884 | .commit_exception = persistent_commit_exception, |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 885 | .prepare_merge = persistent_prepare_merge, |
| 886 | .commit_merge = persistent_commit_merge, |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 887 | .drop_snapshot = persistent_drop_snapshot, |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 888 | .usage = persistent_usage, |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 889 | .status = persistent_status, |
| 890 | }; |
| 891 | |
| 892 | static struct dm_exception_store_type _persistent_compat_type = { |
| 893 | .name = "P", |
| 894 | .module = THIS_MODULE, |
| 895 | .ctr = persistent_ctr, |
| 896 | .dtr = persistent_dtr, |
| 897 | .read_metadata = persistent_read_metadata, |
| 898 | .prepare_exception = persistent_prepare_exception, |
| 899 | .commit_exception = persistent_commit_exception, |
Mikulas Patocka | 4454a62 | 2009-12-10 23:52:29 +0000 | [diff] [blame] | 900 | .prepare_merge = persistent_prepare_merge, |
| 901 | .commit_merge = persistent_commit_merge, |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 902 | .drop_snapshot = persistent_drop_snapshot, |
Mike Snitzer | 985903b | 2009-12-10 23:52:11 +0000 | [diff] [blame] | 903 | .usage = persistent_usage, |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 904 | .status = persistent_status, |
| 905 | }; |
| 906 | |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 907 | int dm_persistent_snapshot_init(void) |
| 908 | { |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 909 | int r; |
| 910 | |
| 911 | r = dm_exception_store_type_register(&_persistent_type); |
| 912 | if (r) { |
| 913 | DMERR("Unable to register persistent exception store type"); |
| 914 | return r; |
| 915 | } |
| 916 | |
| 917 | r = dm_exception_store_type_register(&_persistent_compat_type); |
| 918 | if (r) { |
| 919 | DMERR("Unable to register old-style persistent exception " |
| 920 | "store type"); |
| 921 | dm_exception_store_type_unregister(&_persistent_type); |
| 922 | return r; |
| 923 | } |
| 924 | |
| 925 | return r; |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 926 | } |
| 927 | |
| 928 | void dm_persistent_snapshot_exit(void) |
| 929 | { |
Jonathan Brassow | 493df71 | 2009-04-02 19:55:31 +0100 | [diff] [blame] | 930 | dm_exception_store_type_unregister(&_persistent_type); |
| 931 | dm_exception_store_type_unregister(&_persistent_compat_type); |
Alasdair G Kergon | 4db6bfe | 2009-01-06 03:05:17 +0000 | [diff] [blame] | 932 | } |