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         u64     mtime_sec;
  30         u64     mtime_nsec;
  31 };
  32
  33 struct fscache_netfs ceph_cache_netfs = {
  34         .name           = "ceph",
  35         .version        = 0,
  36 };
  37
  38 static DEFINE_MUTEX(ceph_fscache_lock);
  39 static LIST_HEAD(ceph_fscache_list);
  40
  41 struct ceph_fscache_entry {
  42         struct list_head list;
  43         struct fscache_cookie *fscache;
  44         size_t uniq_len;
  45         /* The following members must be last */
  46         struct ceph_fsid fsid;
  47         char uniquifier[0];
  48 };
  49
  50 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
  51         .name           = "CEPH.fsid",
  52         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  53 };
  54
  55 int __init ceph_fscache_register(void)
  56 {
  57         return fscache_register_netfs(&ceph_cache_netfs);
  58 }
  59
  60 void ceph_fscache_unregister(void)
  61 {
  62         fscache_unregister_netfs(&ceph_cache_netfs);
  63 }
  64
  65 int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
  66 {
  67         const struct ceph_fsid *fsid = &fsc->client->fsid;
  68         const char *fscache_uniq = fsc->mount_options->fscache_uniq;
  69         size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
  70         struct ceph_fscache_entry *ent;
  71         int err = 0;
  72
  73         mutex_lock(&ceph_fscache_lock);
  74         list_for_each_entry(ent, &ceph_fscache_list, list) {
  75                 if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
  76                         continue;
  77                 if (ent->uniq_len != uniq_len)
  78                         continue;
  79                 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
  80                         continue;
  81
  82                 pr_err("fscache cookie already registered for fsid %pU\n", fsid);
  83                 pr_err("  use fsc=%%s mount option to specify a uniquifier\n");
  84                 err = -EBUSY;
  85                 goto out_unlock;
  86         }
  87
  88         ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
  89         if (!ent) {
  90                 err = -ENOMEM;
  91                 goto out_unlock;
  92         }
  93
  94         memcpy(&ent->fsid, fsid, sizeof(*fsid));
  95         if (uniq_len > 0) {
  96                 memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
  97                 ent->uniq_len = uniq_len;
  98         }
  99
 100         fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
 101                                               &ceph_fscache_fsid_object_def,
 102                                               &ent->fsid, sizeof(ent->fsid) + uniq_len,
 103                                               NULL, 0,
 104                                               fsc, 0, true);
 105
 106         if (fsc->fscache) {
 107                 ent->fscache = fsc->fscache;
 108                 list_add_tail(&ent->list, &ceph_fscache_list);
 109         } else {
 110                 kfree(ent);
 111                 pr_err("unable to register fscache cookie for fsid %pU\n",
 112                        fsid);
 113                 /* all other fs ignore this error */
 114         }
 115 out_unlock:
 116         mutex_unlock(&ceph_fscache_lock);
 117         return err;
 118 }
 119
 120 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 121         void *cookie_netfs_data, const void *data, uint16_t dlen,
 122         loff_t object_size)
 123 {
 124         struct ceph_aux_inode aux;
 125         struct ceph_inode_info* ci = cookie_netfs_data;
 126         struct inode* inode = &ci->vfs_inode;
 127
 128         if (dlen != sizeof(aux) ||
 129             i_size_read(inode) != object_size)
 130                 return FSCACHE_CHECKAUX_OBSOLETE;
 131
 132         memset(&aux, 0, sizeof(aux));
 133         aux.version = ci->i_version;
 134         aux.mtime_sec = inode->i_mtime.tv_sec;
 135         aux.mtime_nsec = inode->i_mtime.tv_nsec;
 136
 137         if (memcmp(data, &aux, sizeof(aux)) != 0)
 138                 return FSCACHE_CHECKAUX_OBSOLETE;
 139
 140         dout("ceph inode 0x%p cached okay\n", ci);
 141         return FSCACHE_CHECKAUX_OKAY;
 142 }
 143
 144 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 145         .name           = "CEPH.inode",
 146         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 147         .check_aux      = ceph_fscache_inode_check_aux,
 148 };
 149
 150 void ceph_fscache_register_inode_cookie(struct inode *inode)
 151 {
 152         struct ceph_inode_info *ci = ceph_inode(inode);
 153         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 154         struct ceph_aux_inode aux;
 155
 156         /* No caching for filesystem */
 157         if (!fsc->fscache)
 158                 return;
 159
 160         /* Only cache for regular files that are read only */
 161         if (!S_ISREG(inode->i_mode))
 162                 return;
 163
 164         inode_lock_nested(inode, I_MUTEX_CHILD);
 165         if (!ci->fscache) {
 166                 memset(&aux, 0, sizeof(aux));
 167                 aux.version = ci->i_version;
 168                 aux.mtime_sec = inode->i_mtime.tv_sec;
 169                 aux.mtime_nsec = inode->i_mtime.tv_nsec;
 170                 ci->fscache = fscache_acquire_cookie(fsc->fscache,
 171                                                      &ceph_fscache_inode_object_def,
 172                                                      &ci->i_vino, sizeof(ci->i_vino),
 173                                                      &aux, sizeof(aux),
 174                                                      ci, i_size_read(inode), false);
 175         }
 176         inode_unlock(inode);
 177 }
 178
 179 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 180 {
 181         struct fscache_cookie* cookie;
 182
 183         if ((cookie = ci->fscache) == NULL)
 184                 return;
 185
 186         ci->fscache = NULL;
 187
 188         fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
 189         fscache_relinquish_cookie(cookie, &ci->i_vino, false);
 190 }
 191
 192 static bool ceph_fscache_can_enable(void *data)
 193 {
 194         struct inode *inode = data;
 195         return !inode_is_open_for_write(inode);
 196 }
 197
 198 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
 199 {
 200         struct ceph_inode_info *ci = ceph_inode(inode);
 201
 202         if (!fscache_cookie_valid(ci->fscache))
 203                 return;
 204
 205         if (inode_is_open_for_write(inode)) {
 206                 dout("fscache_file_set_cookie %p %p disabling cache\n",
 207                      inode, filp);
 208                 fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
 209                 fscache_uncache_all_inode_pages(ci->fscache, inode);
 210         } else {
 211                 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
 212                                       ceph_fscache_can_enable, inode);
 213                 if (fscache_cookie_enabled(ci->fscache)) {
 214                         dout("fscache_file_set_cookie %p %p enabling cache\n",
 215                              inode, filp);
 216                 }
 217         }
 218 }
 219
 220 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
 221 {
 222         if (!error)
 223                 SetPageUptodate(page);
 224
 225         unlock_page(page);
 226 }
 227
 228 static inline bool cache_valid(struct ceph_inode_info *ci)
 229 {
 230         return ci->i_fscache_gen == ci->i_rdcache_gen;
 231 }
 232
 233
 234 /* Atempt to read from the fscache,
 235  *
 236  * This function is called from the readpage_nounlock context. DO NOT attempt to
 237  * unlock the page here (or in the callback).
 238  */
 239 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 240 {
 241         struct ceph_inode_info *ci = ceph_inode(inode);
 242         int ret;
 243
 244         if (!cache_valid(ci))
 245                 return -ENOBUFS;
 246
 247         ret = fscache_read_or_alloc_page(ci->fscache, page,
 248                                          ceph_readpage_from_fscache_complete, NULL,
 249                                          GFP_KERNEL);
 250
 251         switch (ret) {
 252                 case 0: /* Page found */
 253                         dout("page read submitted\n");
 254                         return 0;
 255                 case -ENOBUFS: /* Pages were not found, and can't be */
 256                 case -ENODATA: /* Pages were not found */
 257                         dout("page/inode not in cache\n");
 258                         return ret;
 259                 default:
 260                         dout("%s: unknown error ret = %i\n", __func__, ret);
 261                         return ret;
 262         }
 263 }
 264
 265 int ceph_readpages_from_fscache(struct inode *inode,
 266                                   struct address_space *mapping,
 267                                   struct list_head *pages,
 268                                   unsigned *nr_pages)
 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_pages(ci->fscache, mapping, pages, nr_pages,
 277                                           ceph_readpage_from_fscache_complete,
 278                                           NULL, mapping_gfp_mask(mapping));
 279
 280         switch (ret) {
 281                 case 0: /* All pages found */
 282                         dout("all-page read submitted\n");
 283                         return 0;
 284                 case -ENOBUFS: /* Some pages were not found, and can't be */
 285                 case -ENODATA: /* some 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 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 295 {
 296         struct ceph_inode_info *ci = ceph_inode(inode);
 297         int ret;
 298
 299         if (!PageFsCache(page))
 300                 return;
 301
 302         if (!cache_valid(ci))
 303                 return;
 304
 305         ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
 306                                  GFP_KERNEL);
 307         if (ret)
 308                  fscache_uncache_page(ci->fscache, page);
 309 }
 310
 311 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 312 {
 313         struct ceph_inode_info *ci = ceph_inode(inode);
 314
 315         if (!PageFsCache(page))
 316                 return;
 317
 318         fscache_wait_on_page_write(ci->fscache, page);
 319         fscache_uncache_page(ci->fscache, page);
 320 }
 321
 322 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 323 {
 324         if (fscache_cookie_valid(fsc->fscache)) {
 325                 struct ceph_fscache_entry *ent;
 326                 bool found = false;
 327
 328                 mutex_lock(&ceph_fscache_lock);
 329                 list_for_each_entry(ent, &ceph_fscache_list, list) {
 330                         if (ent->fscache == fsc->fscache) {
 331                                 list_del(&ent->list);
 332                                 kfree(ent);
 333                                 found = true;
 334                                 break;
 335                         }
 336                 }
 337                 WARN_ON_ONCE(!found);
 338                 mutex_unlock(&ceph_fscache_lock);
 339
 340                 __fscache_relinquish_cookie(fsc->fscache, NULL, false);
 341         }
 342         fsc->fscache = NULL;
 343 }
 344
 345 /*
 346  * caller should hold CEPH_CAP_FILE_{RD,CACHE}
 347  */
 348 void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
 349 {
 350         if (cache_valid(ci))
 351                 return;
 352
 353         /* resue i_truncate_mutex. There should be no pending
 354          * truncate while the caller holds CEPH_CAP_FILE_RD */
 355         mutex_lock(&ci->i_truncate_mutex);
 356         if (!cache_valid(ci)) {
 357                 if (fscache_check_consistency(ci->fscache, &ci->i_vino))
 358                         fscache_invalidate(ci->fscache);
 359                 spin_lock(&ci->i_ceph_lock);
 360                 ci->i_fscache_gen = ci->i_rdcache_gen;
 361                 spin_unlock(&ci->i_ceph_lock);
 362         }
 363         mutex_unlock(&ci->i_truncate_mutex);
 364 }