1 /* 2 * Ceph cache definitions. 3 * 4 * Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved. 5 * Written by Milosz Tanski (milosz@adfin.com) 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 9 * as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to: 18 * Free Software Foundation 19 * 51 Franklin Street, Fifth Floor 20 * Boston, MA 02111-1301 USA 21 * 22 */ 23 24 #include "super.h" 25 #include "cache.h" 26 27 struct ceph_aux_inode { 28 u64 version; 29 struct timespec mtime; 30 loff_t size; 31 }; 32 33 struct fscache_netfs ceph_cache_netfs = { 34 .name = "ceph", 35 .version = 0, 36 }; 37 38 static DEFINE_MUTEX(ceph_fscache_lock); 39 static LIST_HEAD(ceph_fscache_list); 40 41 struct ceph_fscache_entry { 42 struct list_head list; 43 struct fscache_cookie *fscache; 44 struct ceph_fsid fsid; 45 size_t uniq_len; 46 char uniquifier[0]; 47 }; 48 49 static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data, 50 void *buffer, uint16_t maxbuf) 51 { 52 const struct ceph_fs_client* fsc = cookie_netfs_data; 53 const char *fscache_uniq = fsc->mount_options->fscache_uniq; 54 uint16_t fsid_len, uniq_len; 55 56 fsid_len = sizeof(fsc->client->fsid); 57 uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0; 58 if (fsid_len + uniq_len > maxbuf) 59 return 0; 60 61 memcpy(buffer, &fsc->client->fsid, fsid_len); 62 if (uniq_len) 63 memcpy(buffer + fsid_len, fscache_uniq, uniq_len); 64 65 return fsid_len + uniq_len; 66 } 67 68 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = { 69 .name = "CEPH.fsid", 70 .type = FSCACHE_COOKIE_TYPE_INDEX, 71 .get_key = ceph_fscache_session_get_key, 72 }; 73 74 int ceph_fscache_register(void) 75 { 76 return fscache_register_netfs(&ceph_cache_netfs); 77 } 78 79 void ceph_fscache_unregister(void) 80 { 81 fscache_unregister_netfs(&ceph_cache_netfs); 82 } 83 84 int ceph_fscache_register_fs(struct ceph_fs_client* fsc) 85 { 86 const struct ceph_fsid *fsid = &fsc->client->fsid; 87 const char *fscache_uniq = fsc->mount_options->fscache_uniq; 88 size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0; 89 struct ceph_fscache_entry *ent; 90 int err = 0; 91 92 mutex_lock(&ceph_fscache_lock); 93 list_for_each_entry(ent, &ceph_fscache_list, list) { 94 if (memcmp(&ent->fsid, fsid, sizeof(*fsid))) 95 continue; 96 if (ent->uniq_len != uniq_len) 97 continue; 98 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len)) 99 continue; 100 101 pr_err("fscache cookie already registered for fsid %pU\n", fsid); 102 pr_err(" use fsc=%%s mount option to specify a uniquifier\n"); 103 err = -EBUSY; 104 goto out_unlock; 105 } 106 107 ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL); 108 if (!ent) { 109 err = -ENOMEM; 110 goto out_unlock; 111 } 112 113 fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index, 114 &ceph_fscache_fsid_object_def, 115 fsc, true); 116 117 if (fsc->fscache) { 118 memcpy(&ent->fsid, fsid, sizeof(*fsid)); 119 if (uniq_len > 0) { 120 memcpy(&ent->uniquifier, fscache_uniq, uniq_len); 121 ent->uniq_len = uniq_len; 122 } 123 ent->fscache = fsc->fscache; 124 list_add_tail(&ent->list, &ceph_fscache_list); 125 } else { 126 kfree(ent); 127 pr_err("unable to register fscache cookie for fsid %pU\n", 128 fsid); 129 /* all other fs ignore this error */ 130 } 131 out_unlock: 132 mutex_unlock(&ceph_fscache_lock); 133 return err; 134 } 135 136 static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data, 137 void *buffer, uint16_t maxbuf) 138 { 139 const struct ceph_inode_info* ci = cookie_netfs_data; 140 uint16_t klen; 141 142 /* use ceph virtual inode (id + snapshot) */ 143 klen = sizeof(ci->i_vino); 144 if (klen > maxbuf) 145 return 0; 146 147 memcpy(buffer, &ci->i_vino, klen); 148 return klen; 149 } 150 151 static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data, 152 void *buffer, uint16_t bufmax) 153 { 154 struct ceph_aux_inode aux; 155 const struct ceph_inode_info* ci = cookie_netfs_data; 156 const struct inode* inode = &ci->vfs_inode; 157 158 memset(&aux, 0, sizeof(aux)); 159 aux.version = ci->i_version; 160 aux.mtime = inode->i_mtime; 161 aux.size = i_size_read(inode); 162 163 memcpy(buffer, &aux, sizeof(aux)); 164 165 return sizeof(aux); 166 } 167 168 static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data, 169 uint64_t *size) 170 { 171 const struct ceph_inode_info* ci = cookie_netfs_data; 172 *size = i_size_read(&ci->vfs_inode); 173 } 174 175 static enum fscache_checkaux ceph_fscache_inode_check_aux( 176 void *cookie_netfs_data, const void *data, uint16_t dlen) 177 { 178 struct ceph_aux_inode aux; 179 struct ceph_inode_info* ci = cookie_netfs_data; 180 struct inode* inode = &ci->vfs_inode; 181 182 if (dlen != sizeof(aux)) 183 return FSCACHE_CHECKAUX_OBSOLETE; 184 185 memset(&aux, 0, sizeof(aux)); 186 aux.version = ci->i_version; 187 aux.mtime = inode->i_mtime; 188 aux.size = i_size_read(inode); 189 190 if (memcmp(data, &aux, sizeof(aux)) != 0) 191 return FSCACHE_CHECKAUX_OBSOLETE; 192 193 dout("ceph inode 0x%p cached okay", ci); 194 return FSCACHE_CHECKAUX_OKAY; 195 } 196 197 static const struct fscache_cookie_def ceph_fscache_inode_object_def = { 198 .name = "CEPH.inode", 199 .type = FSCACHE_COOKIE_TYPE_DATAFILE, 200 .get_key = ceph_fscache_inode_get_key, 201 .get_attr = ceph_fscache_inode_get_attr, 202 .get_aux = ceph_fscache_inode_get_aux, 203 .check_aux = ceph_fscache_inode_check_aux, 204 }; 205 206 void ceph_fscache_register_inode_cookie(struct inode *inode) 207 { 208 struct ceph_inode_info *ci = ceph_inode(inode); 209 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 210 211 /* No caching for filesystem */ 212 if (!fsc->fscache) 213 return; 214 215 /* Only cache for regular files that are read only */ 216 if (!S_ISREG(inode->i_mode)) 217 return; 218 219 inode_lock_nested(inode, I_MUTEX_CHILD); 220 if (!ci->fscache) { 221 ci->fscache = fscache_acquire_cookie(fsc->fscache, 222 &ceph_fscache_inode_object_def, 223 ci, false); 224 } 225 inode_unlock(inode); 226 } 227 228 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci) 229 { 230 struct fscache_cookie* cookie; 231 232 if ((cookie = ci->fscache) == NULL) 233 return; 234 235 ci->fscache = NULL; 236 237 fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode); 238 fscache_relinquish_cookie(cookie, 0); 239 } 240 241 static bool ceph_fscache_can_enable(void *data) 242 { 243 struct inode *inode = data; 244 return !inode_is_open_for_write(inode); 245 } 246 247 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp) 248 { 249 struct ceph_inode_info *ci = ceph_inode(inode); 250 251 if (!fscache_cookie_valid(ci->fscache)) 252 return; 253 254 if (inode_is_open_for_write(inode)) { 255 dout("fscache_file_set_cookie %p %p disabling cache\n", 256 inode, filp); 257 fscache_disable_cookie(ci->fscache, false); 258 fscache_uncache_all_inode_pages(ci->fscache, inode); 259 } else { 260 fscache_enable_cookie(ci->fscache, ceph_fscache_can_enable, 261 inode); 262 if (fscache_cookie_enabled(ci->fscache)) { 263 dout("fscache_file_set_cookie %p %p enabling cache\n", 264 inode, filp); 265 } 266 } 267 } 268 269 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error) 270 { 271 if (!error) 272 SetPageUptodate(page); 273 274 unlock_page(page); 275 } 276 277 static inline bool cache_valid(struct ceph_inode_info *ci) 278 { 279 return ci->i_fscache_gen == ci->i_rdcache_gen; 280 } 281 282 283 /* Atempt to read from the fscache, 284 * 285 * This function is called from the readpage_nounlock context. DO NOT attempt to 286 * unlock the page here (or in the callback). 287 */ 288 int ceph_readpage_from_fscache(struct inode *inode, struct page *page) 289 { 290 struct ceph_inode_info *ci = ceph_inode(inode); 291 int ret; 292 293 if (!cache_valid(ci)) 294 return -ENOBUFS; 295 296 ret = fscache_read_or_alloc_page(ci->fscache, page, 297 ceph_readpage_from_fscache_complete, NULL, 298 GFP_KERNEL); 299 300 switch (ret) { 301 case 0: /* Page found */ 302 dout("page read submitted\n"); 303 return 0; 304 case -ENOBUFS: /* Pages were not found, and can't be */ 305 case -ENODATA: /* Pages were not found */ 306 dout("page/inode not in cache\n"); 307 return ret; 308 default: 309 dout("%s: unknown error ret = %i\n", __func__, ret); 310 return ret; 311 } 312 } 313 314 int ceph_readpages_from_fscache(struct inode *inode, 315 struct address_space *mapping, 316 struct list_head *pages, 317 unsigned *nr_pages) 318 { 319 struct ceph_inode_info *ci = ceph_inode(inode); 320 int ret; 321 322 if (!cache_valid(ci)) 323 return -ENOBUFS; 324 325 ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages, 326 ceph_readpage_from_fscache_complete, 327 NULL, mapping_gfp_mask(mapping)); 328 329 switch (ret) { 330 case 0: /* All pages found */ 331 dout("all-page read submitted\n"); 332 return 0; 333 case -ENOBUFS: /* Some pages were not found, and can't be */ 334 case -ENODATA: /* some pages were not found */ 335 dout("page/inode not in cache\n"); 336 return ret; 337 default: 338 dout("%s: unknown error ret = %i\n", __func__, ret); 339 return ret; 340 } 341 } 342 343 void ceph_readpage_to_fscache(struct inode *inode, struct page *page) 344 { 345 struct ceph_inode_info *ci = ceph_inode(inode); 346 int ret; 347 348 if (!PageFsCache(page)) 349 return; 350 351 if (!cache_valid(ci)) 352 return; 353 354 ret = fscache_write_page(ci->fscache, page, GFP_KERNEL); 355 if (ret) 356 fscache_uncache_page(ci->fscache, page); 357 } 358 359 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page) 360 { 361 struct ceph_inode_info *ci = ceph_inode(inode); 362 363 if (!PageFsCache(page)) 364 return; 365 366 fscache_wait_on_page_write(ci->fscache, page); 367 fscache_uncache_page(ci->fscache, page); 368 } 369 370 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc) 371 { 372 if (fscache_cookie_valid(fsc->fscache)) { 373 struct ceph_fscache_entry *ent; 374 bool found = false; 375 376 mutex_lock(&ceph_fscache_lock); 377 list_for_each_entry(ent, &ceph_fscache_list, list) { 378 if (ent->fscache == fsc->fscache) { 379 list_del(&ent->list); 380 kfree(ent); 381 found = true; 382 break; 383 } 384 } 385 WARN_ON_ONCE(!found); 386 mutex_unlock(&ceph_fscache_lock); 387 388 __fscache_relinquish_cookie(fsc->fscache, 0); 389 } 390 fsc->fscache = NULL; 391 } 392 393 /* 394 * caller should hold CEPH_CAP_FILE_{RD,CACHE} 395 */ 396 void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci) 397 { 398 if (cache_valid(ci)) 399 return; 400 401 /* resue i_truncate_mutex. There should be no pending 402 * truncate while the caller holds CEPH_CAP_FILE_RD */ 403 mutex_lock(&ci->i_truncate_mutex); 404 if (!cache_valid(ci)) { 405 if (fscache_check_consistency(ci->fscache)) 406 fscache_invalidate(ci->fscache); 407 spin_lock(&ci->i_ceph_lock); 408 ci->i_fscache_gen = ci->i_rdcache_gen; 409 spin_unlock(&ci->i_ceph_lock); 410 } 411 mutex_unlock(&ci->i_truncate_mutex); 412 } 413