Abhishek Kulkarni | 60e78d2 | 2009-09-23 13:00:27 -0500 | [diff] [blame] | 1 | /* |
| 2 | * V9FS cache definitions. |
| 3 | * |
| 4 | * Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 |
| 8 | * as published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to: |
| 17 | * Free Software Foundation |
| 18 | * 51 Franklin Street, Fifth Floor |
| 19 | * Boston, MA 02111-1301 USA |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <linux/jiffies.h> |
| 24 | #include <linux/file.h> |
| 25 | #include <linux/stat.h> |
| 26 | #include <linux/sched.h> |
| 27 | #include <linux/fs.h> |
| 28 | #include <net/9p/9p.h> |
| 29 | |
| 30 | #include "v9fs.h" |
| 31 | #include "cache.h" |
| 32 | |
| 33 | #define CACHETAG_LEN 11 |
| 34 | |
| 35 | struct kmem_cache *vcookie_cache; |
| 36 | |
| 37 | struct fscache_netfs v9fs_cache_netfs = { |
| 38 | .name = "9p", |
| 39 | .version = 0, |
| 40 | }; |
| 41 | |
| 42 | static void init_once(void *foo) |
| 43 | { |
| 44 | struct v9fs_cookie *vcookie = (struct v9fs_cookie *) foo; |
| 45 | vcookie->fscache = NULL; |
| 46 | vcookie->qid = NULL; |
| 47 | inode_init_once(&vcookie->inode); |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * v9fs_init_vcookiecache - initialize a cache for vcookies to maintain |
| 52 | * vcookie to inode mapping |
| 53 | * |
| 54 | * Returns 0 on success. |
| 55 | */ |
| 56 | |
| 57 | static int v9fs_init_vcookiecache(void) |
| 58 | { |
| 59 | vcookie_cache = kmem_cache_create("vcookie_cache", |
| 60 | sizeof(struct v9fs_cookie), |
| 61 | 0, (SLAB_RECLAIM_ACCOUNT| |
| 62 | SLAB_MEM_SPREAD), |
| 63 | init_once); |
| 64 | if (!vcookie_cache) |
| 65 | return -ENOMEM; |
| 66 | |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * v9fs_destroy_vcookiecache - destroy the cache of vcookies |
| 72 | * |
| 73 | */ |
| 74 | |
| 75 | static void v9fs_destroy_vcookiecache(void) |
| 76 | { |
| 77 | kmem_cache_destroy(vcookie_cache); |
| 78 | } |
| 79 | |
| 80 | int __v9fs_cache_register(void) |
| 81 | { |
| 82 | int ret; |
| 83 | ret = v9fs_init_vcookiecache(); |
| 84 | if (ret < 0) |
| 85 | return ret; |
| 86 | |
| 87 | return fscache_register_netfs(&v9fs_cache_netfs); |
| 88 | } |
| 89 | |
| 90 | void __v9fs_cache_unregister(void) |
| 91 | { |
| 92 | v9fs_destroy_vcookiecache(); |
| 93 | fscache_unregister_netfs(&v9fs_cache_netfs); |
| 94 | } |
| 95 | |
| 96 | /** |
| 97 | * v9fs_random_cachetag - Generate a random tag to be associated |
| 98 | * with a new cache session. |
| 99 | * |
| 100 | * The value of jiffies is used for a fairly randomly cache tag. |
| 101 | */ |
| 102 | |
| 103 | static |
| 104 | int v9fs_random_cachetag(struct v9fs_session_info *v9ses) |
| 105 | { |
| 106 | v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL); |
| 107 | if (!v9ses->cachetag) |
| 108 | return -ENOMEM; |
| 109 | |
| 110 | return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies); |
| 111 | } |
| 112 | |
| 113 | static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data, |
| 114 | void *buffer, uint16_t bufmax) |
| 115 | { |
| 116 | struct v9fs_session_info *v9ses; |
| 117 | uint16_t klen = 0; |
| 118 | |
| 119 | v9ses = (struct v9fs_session_info *)cookie_netfs_data; |
| 120 | P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses, |
| 121 | buffer, bufmax); |
| 122 | |
| 123 | if (v9ses->cachetag) |
| 124 | klen = strlen(v9ses->cachetag); |
| 125 | |
| 126 | if (klen > bufmax) |
| 127 | return 0; |
| 128 | |
| 129 | memcpy(buffer, v9ses->cachetag, klen); |
| 130 | P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag); |
| 131 | return klen; |
| 132 | } |
| 133 | |
| 134 | const struct fscache_cookie_def v9fs_cache_session_index_def = { |
| 135 | .name = "9P.session", |
| 136 | .type = FSCACHE_COOKIE_TYPE_INDEX, |
| 137 | .get_key = v9fs_cache_session_get_key, |
| 138 | }; |
| 139 | |
| 140 | void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses) |
| 141 | { |
| 142 | /* If no cache session tag was specified, we generate a random one. */ |
| 143 | if (!v9ses->cachetag) |
| 144 | v9fs_random_cachetag(v9ses); |
| 145 | |
| 146 | v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index, |
| 147 | &v9fs_cache_session_index_def, |
| 148 | v9ses); |
| 149 | P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses, |
| 150 | v9ses->fscache); |
| 151 | } |
| 152 | |
| 153 | void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses) |
| 154 | { |
| 155 | P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses, |
| 156 | v9ses->fscache); |
| 157 | fscache_relinquish_cookie(v9ses->fscache, 0); |
| 158 | v9ses->fscache = NULL; |
| 159 | } |
| 160 | |
| 161 | |
| 162 | static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data, |
| 163 | void *buffer, uint16_t bufmax) |
| 164 | { |
| 165 | const struct v9fs_cookie *vcookie = cookie_netfs_data; |
| 166 | memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path)); |
| 167 | |
| 168 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode, |
| 169 | vcookie->qid->path); |
| 170 | return sizeof(vcookie->qid->path); |
| 171 | } |
| 172 | |
| 173 | static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data, |
| 174 | uint64_t *size) |
| 175 | { |
| 176 | const struct v9fs_cookie *vcookie = cookie_netfs_data; |
| 177 | *size = i_size_read(&vcookie->inode); |
| 178 | |
| 179 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode, |
| 180 | *size); |
| 181 | } |
| 182 | |
| 183 | static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data, |
| 184 | void *buffer, uint16_t buflen) |
| 185 | { |
| 186 | const struct v9fs_cookie *vcookie = cookie_netfs_data; |
| 187 | memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version)); |
| 188 | |
| 189 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode, |
| 190 | vcookie->qid->version); |
| 191 | return sizeof(vcookie->qid->version); |
| 192 | } |
| 193 | |
| 194 | static enum |
| 195 | fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data, |
| 196 | const void *buffer, |
| 197 | uint16_t buflen) |
| 198 | { |
| 199 | const struct v9fs_cookie *vcookie = cookie_netfs_data; |
| 200 | |
| 201 | if (buflen != sizeof(vcookie->qid->version)) |
| 202 | return FSCACHE_CHECKAUX_OBSOLETE; |
| 203 | |
| 204 | if (memcmp(buffer, &vcookie->qid->version, |
| 205 | sizeof(vcookie->qid->version))) |
| 206 | return FSCACHE_CHECKAUX_OBSOLETE; |
| 207 | |
| 208 | return FSCACHE_CHECKAUX_OKAY; |
| 209 | } |
| 210 | |
| 211 | static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data) |
| 212 | { |
| 213 | struct v9fs_cookie *vcookie = cookie_netfs_data; |
| 214 | struct pagevec pvec; |
| 215 | pgoff_t first; |
| 216 | int loop, nr_pages; |
| 217 | |
| 218 | pagevec_init(&pvec, 0); |
| 219 | first = 0; |
| 220 | |
| 221 | for (;;) { |
| 222 | nr_pages = pagevec_lookup(&pvec, vcookie->inode.i_mapping, |
| 223 | first, |
| 224 | PAGEVEC_SIZE - pagevec_count(&pvec)); |
| 225 | if (!nr_pages) |
| 226 | break; |
| 227 | |
| 228 | for (loop = 0; loop < nr_pages; loop++) |
| 229 | ClearPageFsCache(pvec.pages[loop]); |
| 230 | |
| 231 | first = pvec.pages[nr_pages - 1]->index + 1; |
| 232 | |
| 233 | pvec.nr = nr_pages; |
| 234 | pagevec_release(&pvec); |
| 235 | cond_resched(); |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | const struct fscache_cookie_def v9fs_cache_inode_index_def = { |
| 240 | .name = "9p.inode", |
| 241 | .type = FSCACHE_COOKIE_TYPE_DATAFILE, |
| 242 | .get_key = v9fs_cache_inode_get_key, |
| 243 | .get_attr = v9fs_cache_inode_get_attr, |
| 244 | .get_aux = v9fs_cache_inode_get_aux, |
| 245 | .check_aux = v9fs_cache_inode_check_aux, |
| 246 | .now_uncached = v9fs_cache_inode_now_uncached, |
| 247 | }; |
| 248 | |
| 249 | void v9fs_cache_inode_get_cookie(struct inode *inode) |
| 250 | { |
| 251 | struct v9fs_cookie *vcookie; |
| 252 | struct v9fs_session_info *v9ses; |
| 253 | |
| 254 | if (!S_ISREG(inode->i_mode)) |
| 255 | return; |
| 256 | |
| 257 | vcookie = v9fs_inode2cookie(inode); |
| 258 | if (vcookie->fscache) |
| 259 | return; |
| 260 | |
| 261 | v9ses = v9fs_inode2v9ses(inode); |
| 262 | vcookie->fscache = fscache_acquire_cookie(v9ses->fscache, |
| 263 | &v9fs_cache_inode_index_def, |
| 264 | vcookie); |
| 265 | |
| 266 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode, |
| 267 | vcookie->fscache); |
| 268 | } |
| 269 | |
| 270 | void v9fs_cache_inode_put_cookie(struct inode *inode) |
| 271 | { |
| 272 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 273 | |
| 274 | if (!vcookie->fscache) |
| 275 | return; |
| 276 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode, |
| 277 | vcookie->fscache); |
| 278 | |
| 279 | fscache_relinquish_cookie(vcookie->fscache, 0); |
| 280 | vcookie->fscache = NULL; |
| 281 | } |
| 282 | |
| 283 | void v9fs_cache_inode_flush_cookie(struct inode *inode) |
| 284 | { |
| 285 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 286 | |
| 287 | if (!vcookie->fscache) |
| 288 | return; |
| 289 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode, |
| 290 | vcookie->fscache); |
| 291 | |
| 292 | fscache_relinquish_cookie(vcookie->fscache, 1); |
| 293 | vcookie->fscache = NULL; |
| 294 | } |
| 295 | |
| 296 | void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp) |
| 297 | { |
| 298 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 299 | struct p9_fid *fid; |
| 300 | |
| 301 | if (!vcookie->fscache) |
| 302 | return; |
| 303 | |
| 304 | spin_lock(&vcookie->lock); |
| 305 | fid = filp->private_data; |
| 306 | if ((filp->f_flags & O_ACCMODE) != O_RDONLY) |
| 307 | v9fs_cache_inode_flush_cookie(inode); |
| 308 | else |
| 309 | v9fs_cache_inode_get_cookie(inode); |
| 310 | |
| 311 | spin_unlock(&vcookie->lock); |
| 312 | } |
| 313 | |
| 314 | void v9fs_cache_inode_reset_cookie(struct inode *inode) |
| 315 | { |
| 316 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 317 | struct v9fs_session_info *v9ses; |
| 318 | struct fscache_cookie *old; |
| 319 | |
| 320 | if (!vcookie->fscache) |
| 321 | return; |
| 322 | |
| 323 | old = vcookie->fscache; |
| 324 | |
| 325 | spin_lock(&vcookie->lock); |
| 326 | fscache_relinquish_cookie(vcookie->fscache, 1); |
| 327 | |
| 328 | v9ses = v9fs_inode2v9ses(inode); |
| 329 | vcookie->fscache = fscache_acquire_cookie(v9ses->fscache, |
| 330 | &v9fs_cache_inode_index_def, |
| 331 | vcookie); |
| 332 | |
| 333 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p", |
| 334 | inode, old, vcookie->fscache); |
| 335 | |
| 336 | spin_unlock(&vcookie->lock); |
| 337 | } |
| 338 | |
| 339 | int __v9fs_fscache_release_page(struct page *page, gfp_t gfp) |
| 340 | { |
| 341 | struct inode *inode = page->mapping->host; |
| 342 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 343 | |
| 344 | BUG_ON(!vcookie->fscache); |
| 345 | |
| 346 | if (PageFsCache(page)) { |
| 347 | if (fscache_check_page_write(vcookie->fscache, page)) { |
| 348 | if (!(gfp & __GFP_WAIT)) |
| 349 | return 0; |
| 350 | fscache_wait_on_page_write(vcookie->fscache, page); |
| 351 | } |
| 352 | |
| 353 | fscache_uncache_page(vcookie->fscache, page); |
| 354 | ClearPageFsCache(page); |
| 355 | } |
| 356 | |
| 357 | return 1; |
| 358 | } |
| 359 | |
| 360 | void __v9fs_fscache_invalidate_page(struct page *page) |
| 361 | { |
| 362 | struct inode *inode = page->mapping->host; |
| 363 | struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 364 | |
| 365 | BUG_ON(!vcookie->fscache); |
| 366 | |
| 367 | if (PageFsCache(page)) { |
| 368 | fscache_wait_on_page_write(vcookie->fscache, page); |
| 369 | BUG_ON(!PageLocked(page)); |
| 370 | fscache_uncache_page(vcookie->fscache, page); |
| 371 | ClearPageFsCache(page); |
| 372 | } |
| 373 | } |
| 374 | |
| 375 | static void v9fs_vfs_readpage_complete(struct page *page, void *data, |
| 376 | int error) |
| 377 | { |
| 378 | if (!error) |
| 379 | SetPageUptodate(page); |
| 380 | |
| 381 | unlock_page(page); |
| 382 | } |
| 383 | |
| 384 | /** |
| 385 | * __v9fs_readpage_from_fscache - read a page from cache |
| 386 | * |
| 387 | * Returns 0 if the pages are in cache and a BIO is submitted, |
| 388 | * 1 if the pages are not in cache and -error otherwise. |
| 389 | */ |
| 390 | |
| 391 | int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page) |
| 392 | { |
| 393 | int ret; |
| 394 | const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 395 | |
| 396 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page); |
| 397 | if (!vcookie->fscache) |
| 398 | return -ENOBUFS; |
| 399 | |
| 400 | ret = fscache_read_or_alloc_page(vcookie->fscache, |
| 401 | page, |
| 402 | v9fs_vfs_readpage_complete, |
| 403 | NULL, |
| 404 | GFP_KERNEL); |
| 405 | switch (ret) { |
| 406 | case -ENOBUFS: |
| 407 | case -ENODATA: |
| 408 | P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret); |
| 409 | return 1; |
| 410 | case 0: |
| 411 | P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted"); |
| 412 | return ret; |
| 413 | default: |
| 414 | P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret); |
| 415 | return ret; |
| 416 | } |
| 417 | } |
| 418 | |
| 419 | /** |
| 420 | * __v9fs_readpages_from_fscache - read multiple pages from cache |
| 421 | * |
| 422 | * Returns 0 if the pages are in cache and a BIO is submitted, |
| 423 | * 1 if the pages are not in cache and -error otherwise. |
| 424 | */ |
| 425 | |
| 426 | int __v9fs_readpages_from_fscache(struct inode *inode, |
| 427 | struct address_space *mapping, |
| 428 | struct list_head *pages, |
| 429 | unsigned *nr_pages) |
| 430 | { |
| 431 | int ret; |
| 432 | const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 433 | |
| 434 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages); |
| 435 | if (!vcookie->fscache) |
| 436 | return -ENOBUFS; |
| 437 | |
| 438 | ret = fscache_read_or_alloc_pages(vcookie->fscache, |
| 439 | mapping, pages, nr_pages, |
| 440 | v9fs_vfs_readpage_complete, |
| 441 | NULL, |
| 442 | mapping_gfp_mask(mapping)); |
| 443 | switch (ret) { |
| 444 | case -ENOBUFS: |
| 445 | case -ENODATA: |
| 446 | P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret); |
| 447 | return 1; |
| 448 | case 0: |
| 449 | BUG_ON(!list_empty(pages)); |
| 450 | BUG_ON(*nr_pages != 0); |
| 451 | P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted"); |
| 452 | return ret; |
| 453 | default: |
| 454 | P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret); |
| 455 | return ret; |
| 456 | } |
| 457 | } |
| 458 | |
| 459 | /** |
| 460 | * __v9fs_readpage_to_fscache - write a page to the cache |
| 461 | * |
| 462 | */ |
| 463 | |
| 464 | void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page) |
| 465 | { |
| 466 | int ret; |
| 467 | const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode); |
| 468 | |
| 469 | P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page); |
| 470 | ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL); |
| 471 | P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret); |
| 472 | if (ret != 0) |
| 473 | v9fs_uncache_page(inode, page); |
| 474 | } |