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 = inode->i_size;
 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         const struct inode* inode = &ci->vfs_inode;
 121
 122         *size = inode->i_size;
 123 }
 124
 125 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 126         void *cookie_netfs_data, const void *data, uint16_t dlen)
 127 {
 128         struct ceph_aux_inode aux;
 129         struct ceph_inode_info* ci = cookie_netfs_data;
 130         struct inode* inode = &ci->vfs_inode;
 131
 132         if (dlen != sizeof(aux))
 133                 return FSCACHE_CHECKAUX_OBSOLETE;
 134
 135         memset(&aux, 0, sizeof(aux));
 136         aux.mtime = inode->i_mtime;
 137         aux.size = inode->i_size;
 138
 139         if (memcmp(data, &aux, sizeof(aux)) != 0)
 140                 return FSCACHE_CHECKAUX_OBSOLETE;
 141
 142         dout("ceph inode 0x%p cached okay", ci);
 143         return FSCACHE_CHECKAUX_OKAY;
 144 }
 145
 146 static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
 147 {
 148         struct ceph_inode_info* ci = cookie_netfs_data;
 149         struct pagevec pvec;
 150         pgoff_t first;
 151         int loop, nr_pages;
 152
 153         pagevec_init(&pvec, 0);
 154         first = 0;
 155
 156         dout("ceph inode 0x%p now uncached", ci);
 157
 158         while (1) {
 159                 nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
 160                                           PAGEVEC_SIZE - pagevec_count(&pvec));
 161
 162                 if (!nr_pages)
 163                         break;
 164
 165                 for (loop = 0; loop < nr_pages; loop++)
 166                         ClearPageFsCache(pvec.pages[loop]);
 167
 168                 first = pvec.pages[nr_pages - 1]->index + 1;
 169
 170                 pvec.nr = nr_pages;
 171                 pagevec_release(&pvec);
 172                 cond_resched();
 173         }
 174 }
 175
 176 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 177         .name           = "CEPH.inode",
 178         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 179         .get_key        = ceph_fscache_inode_get_key,
 180         .get_attr       = ceph_fscache_inode_get_attr,
 181         .get_aux        = ceph_fscache_inode_get_aux,
 182         .check_aux      = ceph_fscache_inode_check_aux,
 183         .now_uncached   = ceph_fscache_inode_now_uncached,
 184 };
 185
 186 void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc,
 187                                         struct ceph_inode_info* ci)
 188 {
 189         struct inode* inode = &ci->vfs_inode;
 190
 191         /* No caching for filesystem */
 192         if (fsc->fscache == NULL)
 193                 return;
 194
 195         /* Only cache for regular files that are read only */
 196         if ((ci->vfs_inode.i_mode & S_IFREG) == 0)
 197                 return;
 198
 199         /* Avoid multiple racing open requests */
 200         mutex_lock(&inode->i_mutex);
 201
 202         if (ci->fscache)
 203                 goto done;
 204
 205         ci->fscache = fscache_acquire_cookie(fsc->fscache,
 206                                              &ceph_fscache_inode_object_def,
 207                                              ci, true);
 208         fscache_check_consistency(ci->fscache);
 209 done:
 210         mutex_unlock(&inode->i_mutex);
 211
 212 }
 213
 214 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 215 {
 216         struct fscache_cookie* cookie;
 217
 218         if ((cookie = ci->fscache) == NULL)
 219                 return;
 220
 221         ci->fscache = NULL;
 222
 223         fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
 224         fscache_relinquish_cookie(cookie, 0);
 225 }
 226
 227 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
 228 {
 229         if (!error)
 230                 SetPageUptodate(page);
 231
 232         unlock_page(page);
 233 }
 234
 235 static inline int cache_valid(struct ceph_inode_info *ci)
 236 {
 237         return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) &&
 238                 (ci->i_fscache_gen == ci->i_rdcache_gen));
 239 }
 240
 241
 242 /* Atempt to read from the fscache,
 243  *
 244  * This function is called from the readpage_nounlock context. DO NOT attempt to
 245  * unlock the page here (or in the callback).
 246  */
 247 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 248 {
 249         struct ceph_inode_info *ci = ceph_inode(inode);
 250         int ret;
 251
 252         if (!cache_valid(ci))
 253                 return -ENOBUFS;
 254
 255         ret = fscache_read_or_alloc_page(ci->fscache, page,
 256                                          ceph_readpage_from_fscache_complete, NULL,
 257                                          GFP_KERNEL);
 258
 259         switch (ret) {
 260                 case 0: /* Page found */
 261                         dout("page read submitted\n");
 262                         return 0;
 263                 case -ENOBUFS: /* Pages were not found, and can't be */
 264                 case -ENODATA: /* Pages were not found */
 265                         dout("page/inode not in cache\n");
 266                         return ret;
 267                 default:
 268                         dout("%s: unknown error ret = %i\n", __func__, ret);
 269                         return ret;
 270         }
 271 }
 272
 273 int ceph_readpages_from_fscache(struct inode *inode,
 274                                   struct address_space *mapping,
 275                                   struct list_head *pages,
 276                                   unsigned *nr_pages)
 277 {
 278         struct ceph_inode_info *ci = ceph_inode(inode);
 279         int ret;
 280
 281         if (!cache_valid(ci))
 282                 return -ENOBUFS;
 283
 284         ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
 285                                           ceph_readpage_from_fscache_complete,
 286                                           NULL, mapping_gfp_mask(mapping));
 287
 288         switch (ret) {
 289                 case 0: /* All pages found */
 290                         dout("all-page read submitted\n");
 291                         return 0;
 292                 case -ENOBUFS: /* Some pages were not found, and can't be */
 293                 case -ENODATA: /* some pages were not found */
 294                         dout("page/inode not in cache\n");
 295                         return ret;
 296                 default:
 297                         dout("%s: unknown error ret = %i\n", __func__, ret);
 298                         return ret;
 299         }
 300 }
 301
 302 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 303 {
 304         struct ceph_inode_info *ci = ceph_inode(inode);
 305         int ret;
 306
 307         if (!PageFsCache(page))
 308                 return;
 309
 310         if (!cache_valid(ci))
 311                 return;
 312
 313         ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
 314         if (ret)
 315                  fscache_uncache_page(ci->fscache, page);
 316 }
 317
 318 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 319 {
 320         struct ceph_inode_info *ci = ceph_inode(inode);
 321
 322         if (!PageFsCache(page))
 323                 return;
 324
 325         fscache_wait_on_page_write(ci->fscache, page);
 326         fscache_uncache_page(ci->fscache, page);
 327 }
 328
 329 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 330 {
 331         if (fsc->revalidate_wq)
 332                 destroy_workqueue(fsc->revalidate_wq);
 333
 334         fscache_relinquish_cookie(fsc->fscache, 0);
 335         fsc->fscache = NULL;
 336 }
 337
 338 static void ceph_revalidate_work(struct work_struct *work)
 339 {
 340         int issued;
 341         u32 orig_gen;
 342         struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
 343                                                   i_revalidate_work);
 344         struct inode *inode = &ci->vfs_inode;
 345
 346         spin_lock(&ci->i_ceph_lock);
 347         issued = __ceph_caps_issued(ci, NULL);
 348         orig_gen = ci->i_rdcache_gen;
 349         spin_unlock(&ci->i_ceph_lock);
 350
 351         if (!(issued & CEPH_CAP_FILE_CACHE)) {
 352                 dout("revalidate_work lost cache before validation %p\n",
 353                      inode);
 354                 goto out;
 355         }
 356
 357         if (!fscache_check_consistency(ci->fscache))
 358                 fscache_invalidate(ci->fscache);
 359
 360         spin_lock(&ci->i_ceph_lock);
 361         /* Update the new valid generation (backwards sanity check too) */
 362         if (orig_gen > ci->i_fscache_gen) {
 363                 ci->i_fscache_gen = orig_gen;
 364         }
 365         spin_unlock(&ci->i_ceph_lock);
 366
 367 out:
 368         iput(&ci->vfs_inode);
 369 }
 370
 371 void ceph_queue_revalidate(struct inode *inode)
 372 {
 373         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 374         struct ceph_inode_info *ci = ceph_inode(inode);
 375
 376         if (fsc->revalidate_wq == NULL || ci->fscache == NULL)
 377                 return;
 378
 379         ihold(inode);
 380
 381         if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq,
 382                        &ci->i_revalidate_work)) {
 383                 dout("ceph_queue_revalidate %p\n", inode);
 384         } else {
 385                 dout("ceph_queue_revalidate %p failed\n)", inode);
 386                 iput(inode);
 387         }
 388 }
 389
 390 void ceph_fscache_inode_init(struct ceph_inode_info *ci)
 391 {
 392         ci->fscache = NULL;
 393         /* The first load is verifed cookie open time */
 394         ci->i_fscache_gen = 1;
 395         INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work);
 396 }