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