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 + snaphot) */
  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_vfs_readpage_complete(struct page *page, void *data, int error)
 228 {
 229         if (!error)
 230                 SetPageUptodate(page);
 231 }
 232
 233 static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
 234 {
 235         if (!error)
 236                 SetPageUptodate(page);
 237
 238         unlock_page(page);
 239 }
 240
 241 static inline int cache_valid(struct ceph_inode_info *ci)
 242 {
 243         return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) &&
 244                 (ci->i_fscache_gen == ci->i_rdcache_gen));
 245 }
 246
 247
 248 /* Atempt to read from the fscache,
 249  *
 250  * This function is called from the readpage_nounlock context. DO NOT attempt to
 251  * unlock the page here (or in the callback).
 252  */
 253 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 254 {
 255         struct ceph_inode_info *ci = ceph_inode(inode);
 256         int ret;
 257
 258         if (!cache_valid(ci))
 259                 return -ENOBUFS;
 260
 261         ret = fscache_read_or_alloc_page(ci->fscache, page,
 262                                          ceph_vfs_readpage_complete, NULL,
 263                                          GFP_KERNEL);
 264
 265         switch (ret) {
 266                 case 0: /* Page found */
 267                         dout("page read submitted\n");
 268                         return 0;
 269                 case -ENOBUFS: /* Pages were not found, and can't be */
 270                 case -ENODATA: /* Pages were not found */
 271                         dout("page/inode not in cache\n");
 272                         return ret;
 273                 default:
 274                         dout("%s: unknown error ret = %i\n", __func__, ret);
 275                         return ret;
 276         }
 277 }
 278
 279 int ceph_readpages_from_fscache(struct inode *inode,
 280                                   struct address_space *mapping,
 281                                   struct list_head *pages,
 282                                   unsigned *nr_pages)
 283 {
 284         struct ceph_inode_info *ci = ceph_inode(inode);
 285         int ret;
 286
 287         if (!cache_valid(ci))
 288                 return -ENOBUFS;
 289
 290         ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
 291                                           ceph_vfs_readpage_complete_unlock,
 292                                           NULL, mapping_gfp_mask(mapping));
 293
 294         switch (ret) {
 295                 case 0: /* All pages found */
 296                         dout("all-page read submitted\n");
 297                         return 0;
 298                 case -ENOBUFS: /* Some pages were not found, and can't be */
 299                 case -ENODATA: /* some pages were not found */
 300                         dout("page/inode not in cache\n");
 301                         return ret;
 302                 default:
 303                         dout("%s: unknown error ret = %i\n", __func__, ret);
 304                         return ret;
 305         }
 306 }
 307
 308 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 309 {
 310         struct ceph_inode_info *ci = ceph_inode(inode);
 311         int ret;
 312
 313         if (!PageFsCache(page))
 314                 return;
 315
 316         if (!cache_valid(ci))
 317                 return;
 318
 319         ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
 320         if (ret)
 321                  fscache_uncache_page(ci->fscache, page);
 322 }
 323
 324 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 325 {
 326         struct ceph_inode_info *ci = ceph_inode(inode);
 327
 328         if (!PageFsCache(page))
 329                 return;
 330
 331         fscache_wait_on_page_write(ci->fscache, page);
 332         fscache_uncache_page(ci->fscache, page);
 333 }
 334
 335 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 336 {
 337         if (fsc->revalidate_wq)
 338                 destroy_workqueue(fsc->revalidate_wq);
 339
 340         fscache_relinquish_cookie(fsc->fscache, 0);
 341         fsc->fscache = NULL;
 342 }
 343
 344 static void ceph_revalidate_work(struct work_struct *work)
 345 {
 346         int issued;
 347         u32 orig_gen;
 348         struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info,
 349                                                   i_revalidate_work);
 350         struct inode *inode = &ci->vfs_inode;
 351
 352         spin_lock(&ci->i_ceph_lock);
 353         issued = __ceph_caps_issued(ci, NULL);
 354         orig_gen = ci->i_rdcache_gen;
 355         spin_unlock(&ci->i_ceph_lock);
 356
 357         if (!(issued & CEPH_CAP_FILE_CACHE)) {
 358                 dout("revalidate_work lost cache before validation %p\n",
 359                      inode);
 360                 goto out;
 361         }
 362
 363         if (!fscache_check_consistency(ci->fscache))
 364                 fscache_invalidate(ci->fscache);
 365
 366         spin_lock(&ci->i_ceph_lock);
 367         /* Update the new valid generation (backwards sanity check too) */
 368         if (orig_gen > ci->i_fscache_gen) {
 369                 ci->i_fscache_gen = orig_gen;
 370         }
 371         spin_unlock(&ci->i_ceph_lock);
 372
 373 out:
 374         iput(&ci->vfs_inode);
 375 }
 376
 377 void ceph_queue_revalidate(struct inode *inode)
 378 {
 379         struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
 380         struct ceph_inode_info *ci = ceph_inode(inode);
 381
 382         if (fsc->revalidate_wq == NULL || ci->fscache == NULL)
 383                 return;
 384
 385         ihold(inode);
 386
 387         if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq,
 388                        &ci->i_revalidate_work)) {
 389                 dout("ceph_queue_revalidate %p\n", inode);
 390         } else {
 391                 dout("ceph_queue_revalidate %p failed\n)", inode);
 392                 iput(inode);
 393         }
 394 }
 395
 396 void ceph_fscache_inode_init(struct ceph_inode_info *ci)
 397 {
 398         ci->fscache = NULL;
 399         /* The first load is verifed cookie open time */
 400         ci->i_fscache_gen = 1;
 401         INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work);
 402 }