fs/ceph/cache.c

   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         struct timespec mtime;
  29         loff_t          size;
  30 };
  31
  32 struct fscache_netfs ceph_cache_netfs = {
  33         .name           = "ceph",
  34         .version        = 0,
  35 };
  36
  37 static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
  38                                              void *buffer, uint16_t maxbuf)
  39 {
  40         const struct ceph_fs_client* fsc = cookie_netfs_data;
  41         uint16_t klen;
  42
  43         klen = sizeof(fsc->client->fsid);
  44         if (klen > maxbuf)
  45                 return 0;
  46
  47         memcpy(buffer, &fsc->client->fsid, klen);
  48         return klen;
  49 }
  50
  51 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
  52         .name           = "CEPH.fsid",
  53         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  54         .get_key        = ceph_fscache_session_get_key,
  55 };
  56
  57 int ceph_fscache_register(void)
  58 {
  59         return fscache_register_netfs(&ceph_cache_netfs);
  60 }
  61
  62 void ceph_fscache_unregister(void)
  63 {
  64         fscache_unregister_netfs(&ceph_cache_netfs);
  65 }
  66
  67 int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
  68 {
  69         fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
  70                                               &ceph_fscache_fsid_object_def,
  71                                               fsc, true);
  72
  73         if (fsc->fscache == NULL) {
  74                 pr_err("Unable to resgister fsid: %p fscache cookie", fsc);
  75                 return 0;
  76         }
  77
  78         fsc->revalidate_wq = alloc_workqueue("ceph-revalidate", 0, 1);
  79         if (fsc->revalidate_wq == NULL)
  80                 return -ENOMEM;
  81
  82         return 0;
  83 }
  84
  85 static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
  86                                            void *buffer, uint16_t maxbuf)
  87 {
  88         const struct ceph_inode_info* ci = cookie_netfs_data;
  89         uint16_t klen;
  90
  91         /* use ceph virtual inode (id + snapshot) */
  92         klen = sizeof(ci->i_vino);
  93         if (klen > maxbuf)
  94                 return 0;
  95
  96         memcpy(buffer, &ci->i_vino, klen);
  97         return klen;
  98 }
  99
 100 static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
 101                                            void *buffer, uint16_t bufmax)
 102 {
 103         struct ceph_aux_inode aux;
 104         const struct ceph_inode_info* ci = cookie_netfs_data;
 105         const struct inode* inode = &ci->vfs_inode;
 106
 107         memset(&aux, 0, sizeof(aux));
 108         aux.mtime = inode->i_mtime;
 109         aux.size = i_size_read(inode);
 110
 111         memcpy(buffer, &aux, sizeof(aux));
 112
 113         return sizeof(aux);
 114 }
 115
 116 static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
 117                                         uint64_t *size)
 118 {
 119         const struct ceph_inode_info* ci = cookie_netfs_data;
 120         *size = i_size_read(&ci->vfs_inode);
 121 }
 122
 123 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 124         void *cookie_netfs_data, const void *data, uint16_t dlen)
 125 {
 126         struct ceph_aux_inode aux;
 127         struct ceph_inode_info* ci = cookie_netfs_data;
 128         struct inode* inode = &ci->vfs_inode;
 129
 130         if (dlen != sizeof(aux))
 131                 return FSCACHE_CHECKAUX_OBSOLETE;
 132
 133         memset(&aux, 0, sizeof(aux));
 134         aux.mtime = inode->i_mtime;
 135         aux.size = i_size_read(inode);
 136
 137         if (memcmp(data, &aux, sizeof(aux)) != 0)
 138                 return FSCACHE_CHECKAUX_OBSOLETE;
 139
 140         dout("ceph inode 0x%p cached okay", ci);
 141         return FSCACHE_CHECKAUX_OKAY;
 142 }
 143
 144 static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
 145 {
 146         struct ceph_inode_info* ci = cookie_netfs_data;
 147         struct pagevec pvec;
 148         pgoff_t first;
 149         int loop, nr_pages;
 150
 151         pagevec_init(&pvec, 0);
 152         first = 0;
 153
 154         dout("ceph inode 0x%p now uncached", ci);
 155
 156         while (1) {
 157                 nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
 158                                           PAGEVEC_SIZE - pagevec_count(&pvec));
 159
 160                 if (!nr_pages)
 161                         break;
 162
 163                 for (loop = 0; loop < nr_pages; loop++)
 164                         ClearPageFsCache(pvec.pages[loop]);
 165
 166                 first = pvec.pages[nr_pages - 1]->index + 1;
 167
 168                 pvec.nr = nr_pages;
 169                 pagevec_release(&pvec);
 170                 cond_resched();
 171         }
 172 }
 173
 174 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 175         .name           = "CEPH.inode",
 176         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 177         .get_key        = ceph_fscache_inode_get_key,
 178         .get_attr       = ceph_fscache_inode_get_attr,
 179         .get_aux        = ceph_fscache_inode_get_aux,
 180         .check_aux      = ceph_fscache_inode_check_aux,
 181         .now_uncached   = ceph_fscache_inode_now_uncached,
 182 };
 183
 184 void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
 185                                         struct ceph_inode_info* ci)
 186 {
 187         struct inode* inode = &ci->vfs_inode;
 188
 189         /* No caching for filesystem */
 190         if (fsc->fscache == NULL)
 191                 return;
 192
 193         /* Only cache for regular files that are read only */
 194         if ((ci->vfs_inode.i_mode & S_IFREG) == 0)
 195                 return;
 196
 197         /* Avoid multiple racing open requests */
 198         inode_lock(inode);
 199
 200         if (ci->fscache)
 201                 goto done;
 202
 203         ci->fscache = fscache_acquire_cookie(fsc->fscache,
 204                                              &ceph_fscache_inode_object_def,
 205                                              ci, true);
 206         fscache_check_consistency(ci->fscache);
 207 done:
 208         inode_unlock(inode);
 209
 210 }
 211
 212 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 213 {
 214         struct fscache_cookie* cookie;
 215
 216         if ((cookie = ci->fscache) == NULL)
 217                 return;
 218
 219         ci->fscache = NULL;
 220
 221         fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
 222         fscache_relinquish_cookie(cookie, 0);
 223 }
 224
 225 static void ceph_vfs_readpage_complete(struct page *page, void *data, int error)
 226 {
 227         if (!error)
 228                 SetPageUptodate(page);
 229 }
 230
 231 static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
 232 {
 233         if (!error)
 234                 SetPageUptodate(page);
 235
 236         unlock_page(page);
 237 }
 238
 239 static inline int cache_valid(struct ceph_inode_info *ci)
 240 {
 241         return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) &&
 242                 (ci->i_fscache_gen == ci->i_rdcache_gen));
 243 }
 244
 245
 246 /* Atempt to read from the fscache,
 247  *
 248  * This function is called from the readpage_nounlock context. DO NOT attempt to
 249  * unlock the page here (or in the callback).
 250  */
 251 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 252 {
 253         struct ceph_inode_info *ci = ceph_inode(inode);
 254         int ret;
 255
 256         if (!cache_valid(ci))
 257                 return -ENOBUFS;
 258
 259         ret = fscache_read_or_alloc_page(ci->fscache, page,
 260                                          ceph_vfs_readpage_complete, NULL,
 261                                          GFP_KERNEL);
 262
 263         switch (ret) {
 264                 case 0: /* Page found */
 265                         dout("page read submitted\n");
 266                         return 0;
 267                 case -ENOBUFS: /* Pages were not found, and can't be */
 268                 case -ENODATA: /* Pages were not found */
 269                         dout("page/inode not in cache\n");
 270                         return ret;
 271                 default:
 272                         dout("%s: unknown error ret = %i\n", __func__, ret);
 273                         return ret;
 274         }
 275 }
 276
 277 int ceph_readpages_from_fscache(struct inode *inode,
 278                                   struct address_space *mapping,
 279                                   struct list_head *pages,
 280                                   unsigned *nr_pages)
 281 {
 282         struct ceph_inode_info *ci = ceph_inode(inode);
 283         int ret;
 284
 285         if (!cache_valid(ci))
 286                 return -ENOBUFS;
 287
 288         ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
 289                                           ceph_vfs_readpage_complete_unlock,
 290                                           NULL, mapping_gfp_mask(mapping));
 291
 292         switch (ret) {
 293                 case 0: /* All pages found */
 294                         dout("all-page read submitted\n");
 295                         return 0;
 296                 case -ENOBUFS: /* Some pages were not found, and can't be */
 297                 case -ENODATA: /* some pages were not found */
 298                         dout("page/inode not in cache\n");
 299                         return ret;
 300                 default:
 301                         dout("%s: unknown error ret = %i\n", __func__, ret);
 302                         return ret;
 303         }
 304 }
 305
 306 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 307 {
 308         struct ceph_inode_info *ci = ceph_inode(inode);
 309         int ret;
 310
 311         if (!PageFsCache(page))
 312                 return;
 313
 314         if (!cache_valid(ci))
 315                 return;
 316
 317         ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
 318         if (ret)
 319                  fscache_uncache_page(ci->fscache, page);
 320 }
 321
 322 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 323 {
 324         struct ceph_inode_info *ci = ceph_inode(inode);
 325
 326         if (!PageFsCache(page))
 327                 return;
 328
 329         fscache_wait_on_page_write(ci->fscache, page);
 330         fscache_uncache_page(ci->fscache, page);
 331 }
 332
 333 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 334 {
 335         if (fsc->revalidate_wq)
 336                 destroy_workqueue(fsc->revalidate_wq);
 337
 338         fscache_relinquish_cookie(fsc->fscache, 0);
 339         fsc->fscache = NULL;
 340 }
 341
 342 static void ceph_revalidate_work(struct work_struct *work)
 343 {
 344         int issued;
 345         u32 orig_gen;
 346         struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
 347                                                   i_revalidate_work);
 348         struct inode *inode = &ci->vfs_inode;
 349
 350         spin_lock(&ci->i_ceph_lock);
 351         issued = __ceph_caps_issued(ci, NULL);
 352         orig_gen = ci->i_rdcache_gen;
 353         spin_unlock(&ci->i_ceph_lock);
 354
 355         if (!(issued & CEPH_CAP_FILE_CACHE)) {
 356                 dout("revalidate_work lost cache before validation %p\n",
 357                      inode);
 358                 goto out;
 359         }
 360
 361         if (!fscache_check_consistency(ci->fscache))
 362                 fscache_invalidate(ci->fscache);
 363
 364         spin_lock(&ci->i_ceph_lock);
 365         /* Update the new valid generation (backwards sanity check too) */
 366         if (orig_gen > ci->i_fscache_gen) {
 367                 ci->i_fscache_gen = orig_gen;
 368         }
 369         spin_unlock(&ci->i_ceph_lock);
 370
 371 out:
 372         iput(&ci->vfs_inode);
 373 }
 374
 375 void ceph_queue_revalidate(struct inode *inode)
 376 {
 377         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 378         struct ceph_inode_info *ci = ceph_inode(inode);
 379
 380         if (fsc->revalidate_wq == NULL || ci->fscache == NULL)
 381                 return;
 382
 383         ihold(inode);
 384
 385         if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq,
 386                        &ci->i_revalidate_work)) {
 387                 dout("ceph_queue_revalidate %p\n", inode);
 388         } else {
 389                 dout("ceph_queue_revalidate %p failed\n)", inode);
 390                 iput(inode);
 391         }
 392 }
 393
 394 void ceph_fscache_inode_init(struct ceph_inode_info *ci)
 395 {
 396         ci->fscache = NULL;
 397         /* The first load is verifed cookie open time */
 398         ci->i_fscache_gen = 1;
 399         INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work);
 400 }