1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Ceph cache definitions. 4 * 5 * Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved. 6 * Written by Milosz Tanski (milosz@adfin.com) 7 */ 8 9 #include <linux/ceph/ceph_debug.h> 10 11 #include "super.h" 12 #include "cache.h" 13 14 struct ceph_aux_inode { 15 u64 version; 16 u64 mtime_sec; 17 u64 mtime_nsec; 18 }; 19 20 struct fscache_netfs ceph_cache_netfs = { 21 .name = "ceph", 22 .version = 0, 23 }; 24 25 static DEFINE_MUTEX(ceph_fscache_lock); 26 static LIST_HEAD(ceph_fscache_list); 27 28 struct ceph_fscache_entry { 29 struct list_head list; 30 struct fscache_cookie *fscache; 31 size_t uniq_len; 32 /* The following members must be last */ 33 struct ceph_fsid fsid; 34 char uniquifier[0]; 35 }; 36 37 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = { 38 .name = "CEPH.fsid", 39 .type = FSCACHE_COOKIE_TYPE_INDEX, 40 }; 41 42 int __init ceph_fscache_register(void) 43 { 44 return fscache_register_netfs(&ceph_cache_netfs); 45 } 46 47 void ceph_fscache_unregister(void) 48 { 49 fscache_unregister_netfs(&ceph_cache_netfs); 50 } 51 52 int ceph_fscache_register_fs(struct ceph_fs_client* fsc) 53 { 54 const struct ceph_fsid *fsid = &fsc->client->fsid; 55 const char *fscache_uniq = fsc->mount_options->fscache_uniq; 56 size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0; 57 struct ceph_fscache_entry *ent; 58 int err = 0; 59 60 mutex_lock(&ceph_fscache_lock); 61 list_for_each_entry(ent, &ceph_fscache_list, list) { 62 if (memcmp(&ent->fsid, fsid, sizeof(*fsid))) 63 continue; 64 if (ent->uniq_len != uniq_len) 65 continue; 66 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len)) 67 continue; 68 69 pr_err("fscache cookie already registered for fsid %pU\n", fsid); 70 pr_err(" use fsc=%%s mount option to specify a uniquifier\n"); 71 err = -EBUSY; 72 goto out_unlock; 73 } 74 75 ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL); 76 if (!ent) { 77 err = -ENOMEM; 78 goto out_unlock; 79 } 80 81 memcpy(&ent->fsid, fsid, sizeof(*fsid)); 82 if (uniq_len > 0) { 83 memcpy(&ent->uniquifier, fscache_uniq, uniq_len); 84 ent->uniq_len = uniq_len; 85 } 86 87 fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index, 88 &ceph_fscache_fsid_object_def, 89 &ent->fsid, sizeof(ent->fsid) + uniq_len, 90 NULL, 0, 91 fsc, 0, true); 92 93 if (fsc->fscache) { 94 ent->fscache = fsc->fscache; 95 list_add_tail(&ent->list, &ceph_fscache_list); 96 } else { 97 kfree(ent); 98 pr_err("unable to register fscache cookie for fsid %pU\n", 99 fsid); 100 /* all other fs ignore this error */ 101 } 102 out_unlock: 103 mutex_unlock(&ceph_fscache_lock); 104 return err; 105 } 106 107 static enum fscache_checkaux ceph_fscache_inode_check_aux( 108 void *cookie_netfs_data, const void *data, uint16_t dlen, 109 loff_t object_size) 110 { 111 struct ceph_aux_inode aux; 112 struct ceph_inode_info* ci = cookie_netfs_data; 113 struct inode* inode = &ci->vfs_inode; 114 115 if (dlen != sizeof(aux) || 116 i_size_read(inode) != object_size) 117 return FSCACHE_CHECKAUX_OBSOLETE; 118 119 memset(&aux, 0, sizeof(aux)); 120 aux.version = ci->i_version; 121 aux.mtime_sec = inode->i_mtime.tv_sec; 122 aux.mtime_nsec = inode->i_mtime.tv_nsec; 123 124 if (memcmp(data, &aux, sizeof(aux)) != 0) 125 return FSCACHE_CHECKAUX_OBSOLETE; 126 127 dout("ceph inode 0x%p cached okay\n", ci); 128 return FSCACHE_CHECKAUX_OKAY; 129 } 130 131 static const struct fscache_cookie_def ceph_fscache_inode_object_def = { 132 .name = "CEPH.inode", 133 .type = FSCACHE_COOKIE_TYPE_DATAFILE, 134 .check_aux = ceph_fscache_inode_check_aux, 135 }; 136 137 void ceph_fscache_register_inode_cookie(struct inode *inode) 138 { 139 struct ceph_inode_info *ci = ceph_inode(inode); 140 struct ceph_fs_client *fsc = ceph_inode_to_client(inode); 141 struct ceph_aux_inode aux; 142 143 /* No caching for filesystem */ 144 if (!fsc->fscache) 145 return; 146 147 /* Only cache for regular files that are read only */ 148 if (!S_ISREG(inode->i_mode)) 149 return; 150 151 inode_lock_nested(inode, I_MUTEX_CHILD); 152 if (!ci->fscache) { 153 memset(&aux, 0, sizeof(aux)); 154 aux.version = ci->i_version; 155 aux.mtime_sec = inode->i_mtime.tv_sec; 156 aux.mtime_nsec = inode->i_mtime.tv_nsec; 157 ci->fscache = fscache_acquire_cookie(fsc->fscache, 158 &ceph_fscache_inode_object_def, 159 &ci->i_vino, sizeof(ci->i_vino), 160 &aux, sizeof(aux), 161 ci, i_size_read(inode), false); 162 } 163 inode_unlock(inode); 164 } 165 166 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci) 167 { 168 struct fscache_cookie* cookie; 169 170 if ((cookie = ci->fscache) == NULL) 171 return; 172 173 ci->fscache = NULL; 174 175 fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode); 176 fscache_relinquish_cookie(cookie, &ci->i_vino, false); 177 } 178 179 static bool ceph_fscache_can_enable(void *data) 180 { 181 struct inode *inode = data; 182 return !inode_is_open_for_write(inode); 183 } 184 185 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp) 186 { 187 struct ceph_inode_info *ci = ceph_inode(inode); 188 189 if (!fscache_cookie_valid(ci->fscache)) 190 return; 191 192 if (inode_is_open_for_write(inode)) { 193 dout("fscache_file_set_cookie %p %p disabling cache\n", 194 inode, filp); 195 fscache_disable_cookie(ci->fscache, &ci->i_vino, false); 196 fscache_uncache_all_inode_pages(ci->fscache, inode); 197 } else { 198 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode), 199 ceph_fscache_can_enable, inode); 200 if (fscache_cookie_enabled(ci->fscache)) { 201 dout("fscache_file_set_cookie %p %p enabling cache\n", 202 inode, filp); 203 } 204 } 205 } 206 207 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error) 208 { 209 if (!error) 210 SetPageUptodate(page); 211 212 unlock_page(page); 213 } 214 215 static inline bool cache_valid(struct ceph_inode_info *ci) 216 { 217 return ci->i_fscache_gen == ci->i_rdcache_gen; 218 } 219 220 221 /* Atempt to read from the fscache, 222 * 223 * This function is called from the readpage_nounlock context. DO NOT attempt to 224 * unlock the page here (or in the callback). 225 */ 226 int ceph_readpage_from_fscache(struct inode *inode, struct page *page) 227 { 228 struct ceph_inode_info *ci = ceph_inode(inode); 229 int ret; 230 231 if (!cache_valid(ci)) 232 return -ENOBUFS; 233 234 ret = fscache_read_or_alloc_page(ci->fscache, page, 235 ceph_readpage_from_fscache_complete, NULL, 236 GFP_KERNEL); 237 238 switch (ret) { 239 case 0: /* Page found */ 240 dout("page read submitted\n"); 241 return 0; 242 case -ENOBUFS: /* Pages were not found, and can't be */ 243 case -ENODATA: /* Pages were not found */ 244 dout("page/inode not in cache\n"); 245 return ret; 246 default: 247 dout("%s: unknown error ret = %i\n", __func__, ret); 248 return ret; 249 } 250 } 251 252 int ceph_readpages_from_fscache(struct inode *inode, 253 struct address_space *mapping, 254 struct list_head *pages, 255 unsigned *nr_pages) 256 { 257 struct ceph_inode_info *ci = ceph_inode(inode); 258 int ret; 259 260 if (!cache_valid(ci)) 261 return -ENOBUFS; 262 263 ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages, 264 ceph_readpage_from_fscache_complete, 265 NULL, mapping_gfp_mask(mapping)); 266 267 switch (ret) { 268 case 0: /* All pages found */ 269 dout("all-page read submitted\n"); 270 return 0; 271 case -ENOBUFS: /* Some pages were not found, and can't be */ 272 case -ENODATA: /* some pages were not found */ 273 dout("page/inode not in cache\n"); 274 return ret; 275 default: 276 dout("%s: unknown error ret = %i\n", __func__, ret); 277 return ret; 278 } 279 } 280 281 void ceph_readpage_to_fscache(struct inode *inode, struct page *page) 282 { 283 struct ceph_inode_info *ci = ceph_inode(inode); 284 int ret; 285 286 if (!PageFsCache(page)) 287 return; 288 289 if (!cache_valid(ci)) 290 return; 291 292 ret = fscache_write_page(ci->fscache, page, i_size_read(inode), 293 GFP_KERNEL); 294 if (ret) 295 fscache_uncache_page(ci->fscache, page); 296 } 297 298 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page) 299 { 300 struct ceph_inode_info *ci = ceph_inode(inode); 301 302 if (!PageFsCache(page)) 303 return; 304 305 fscache_wait_on_page_write(ci->fscache, page); 306 fscache_uncache_page(ci->fscache, page); 307 } 308 309 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc) 310 { 311 if (fscache_cookie_valid(fsc->fscache)) { 312 struct ceph_fscache_entry *ent; 313 bool found = false; 314 315 mutex_lock(&ceph_fscache_lock); 316 list_for_each_entry(ent, &ceph_fscache_list, list) { 317 if (ent->fscache == fsc->fscache) { 318 list_del(&ent->list); 319 kfree(ent); 320 found = true; 321 break; 322 } 323 } 324 WARN_ON_ONCE(!found); 325 mutex_unlock(&ceph_fscache_lock); 326 327 __fscache_relinquish_cookie(fsc->fscache, NULL, false); 328 } 329 fsc->fscache = NULL; 330 } 331 332 /* 333 * caller should hold CEPH_CAP_FILE_{RD,CACHE} 334 */ 335 void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci) 336 { 337 if (cache_valid(ci)) 338 return; 339 340 /* resue i_truncate_mutex. There should be no pending 341 * truncate while the caller holds CEPH_CAP_FILE_RD */ 342 mutex_lock(&ci->i_truncate_mutex); 343 if (!cache_valid(ci)) { 344 if (fscache_check_consistency(ci->fscache, &ci->i_vino)) 345 fscache_invalidate(ci->fscache); 346 spin_lock(&ci->i_ceph_lock); 347 ci->i_fscache_gen = ci->i_rdcache_gen; 348 spin_unlock(&ci->i_ceph_lock); 349 } 350 mutex_unlock(&ci->i_truncate_mutex); 351 } 352