fs/ceph/cache.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Ceph cache definitions.
   4  *
   5  *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
   6  *  Written by Milosz Tanski ([email protected])
   7  */
   8
   9 #include "super.h"
  10 #include "cache.h"
  11
  12 struct ceph_aux_inode {
  13         u64     version;
  14         u64     mtime_sec;
  15         u64     mtime_nsec;
  16 };
  17
  18 struct fscache_netfs ceph_cache_netfs = {
  19         .name           = "ceph",
  20         .version        = 0,
  21 };
  22
  23 static DEFINE_MUTEX(ceph_fscache_lock);
  24 static LIST_HEAD(ceph_fscache_list);
  25
  26 struct ceph_fscache_entry {
  27         struct list_head list;
  28         struct fscache_cookie *fscache;
  29         size_t uniq_len;
  30         /* The following members must be last */
  31         struct ceph_fsid fsid;
  32         char uniquifier[0];
  33 };
  34
  35 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
  36         .name           = "CEPH.fsid",
  37         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  38 };
  39
  40 int __init ceph_fscache_register(void)
  41 {
  42         return fscache_register_netfs(&ceph_cache_netfs);
  43 }
  44
  45 void ceph_fscache_unregister(void)
  46 {
  47         fscache_unregister_netfs(&ceph_cache_netfs);
  48 }
  49
  50 int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
  51 {
  52         const struct ceph_fsid *fsid = &fsc->client->fsid;
  53         const char *fscache_uniq = fsc->mount_options->fscache_uniq;
  54         size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
  55         struct ceph_fscache_entry *ent;
  56         int err = 0;
  57
  58         mutex_lock(&ceph_fscache_lock);
  59         list_for_each_entry(ent, &ceph_fscache_list, list) {
  60                 if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
  61                         continue;
  62                 if (ent->uniq_len != uniq_len)
  63                         continue;
  64                 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
  65                         continue;
  66
  67                 pr_err("fscache cookie already registered for fsid %pU\n", fsid);
  68                 pr_err("  use fsc=%%s mount option to specify a uniquifier\n");
  69                 err = -EBUSY;
  70                 goto out_unlock;
  71         }
  72
  73         ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
  74         if (!ent) {
  75                 err = -ENOMEM;
  76                 goto out_unlock;
  77         }
  78
  79         memcpy(&ent->fsid, fsid, sizeof(*fsid));
  80         if (uniq_len > 0) {
  81                 memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
  82                 ent->uniq_len = uniq_len;
  83         }
  84
  85         fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
  86                                               &ceph_fscache_fsid_object_def,
  87                                               &ent->fsid, sizeof(ent->fsid) + uniq_len,
  88                                               NULL, 0,
  89                                               fsc, 0, true);
  90
  91         if (fsc->fscache) {
  92                 ent->fscache = fsc->fscache;
  93                 list_add_tail(&ent->list, &ceph_fscache_list);
  94         } else {
  95                 kfree(ent);
  96                 pr_err("unable to register fscache cookie for fsid %pU\n",
  97                        fsid);
  98                 /* all other fs ignore this error */
  99         }
 100 out_unlock:
 101         mutex_unlock(&ceph_fscache_lock);
 102         return err;
 103 }
 104
 105 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 106         void *cookie_netfs_data, const void *data, uint16_t dlen,
 107         loff_t object_size)
 108 {
 109         struct ceph_aux_inode aux;
 110         struct ceph_inode_info* ci = cookie_netfs_data;
 111         struct inode* inode = &ci->vfs_inode;
 112
 113         if (dlen != sizeof(aux) ||
 114             i_size_read(inode) != object_size)
 115                 return FSCACHE_CHECKAUX_OBSOLETE;
 116
 117         memset(&aux, 0, sizeof(aux));
 118         aux.version = ci->i_version;
 119         aux.mtime_sec = inode->i_mtime.tv_sec;
 120         aux.mtime_nsec = inode->i_mtime.tv_nsec;
 121
 122         if (memcmp(data, &aux, sizeof(aux)) != 0)
 123                 return FSCACHE_CHECKAUX_OBSOLETE;
 124
 125         dout("ceph inode 0x%p cached okay\n", ci);
 126         return FSCACHE_CHECKAUX_OKAY;
 127 }
 128
 129 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 130         .name           = "CEPH.inode",
 131         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 132         .check_aux      = ceph_fscache_inode_check_aux,
 133 };
 134
 135 void ceph_fscache_register_inode_cookie(struct inode *inode)
 136 {
 137         struct ceph_inode_info *ci = ceph_inode(inode);
 138         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 139         struct ceph_aux_inode aux;
 140
 141         /* No caching for filesystem */
 142         if (!fsc->fscache)
 143                 return;
 144
 145         /* Only cache for regular files that are read only */
 146         if (!S_ISREG(inode->i_mode))
 147                 return;
 148
 149         inode_lock_nested(inode, I_MUTEX_CHILD);
 150         if (!ci->fscache) {
 151                 memset(&aux, 0, sizeof(aux));
 152                 aux.version = ci->i_version;
 153                 aux.mtime_sec = inode->i_mtime.tv_sec;
 154                 aux.mtime_nsec = inode->i_mtime.tv_nsec;
 155                 ci->fscache = fscache_acquire_cookie(fsc->fscache,
 156                                                      &ceph_fscache_inode_object_def,
 157                                                      &ci->i_vino, sizeof(ci->i_vino),
 158                                                      &aux, sizeof(aux),
 159                                                      ci, i_size_read(inode), false);
 160         }
 161         inode_unlock(inode);
 162 }
 163
 164 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 165 {
 166         struct fscache_cookie* cookie;
 167
 168         if ((cookie = ci->fscache) == NULL)
 169                 return;
 170
 171         ci->fscache = NULL;
 172
 173         fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
 174         fscache_relinquish_cookie(cookie, &ci->i_vino, false);
 175 }
 176
 177 static bool ceph_fscache_can_enable(void *data)
 178 {
 179         struct inode *inode = data;
 180         return !inode_is_open_for_write(inode);
 181 }
 182
 183 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
 184 {
 185         struct ceph_inode_info *ci = ceph_inode(inode);
 186
 187         if (!fscache_cookie_valid(ci->fscache))
 188                 return;
 189
 190         if (inode_is_open_for_write(inode)) {
 191                 dout("fscache_file_set_cookie %p %p disabling cache\n",
 192                      inode, filp);
 193                 fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
 194                 fscache_uncache_all_inode_pages(ci->fscache, inode);
 195         } else {
 196                 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
 197                                       ceph_fscache_can_enable, inode);
 198                 if (fscache_cookie_enabled(ci->fscache)) {
 199                         dout("fscache_file_set_cookie %p %p enabling cache\n",
 200                              inode, filp);
 201                 }
 202         }
 203 }
 204
 205 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
 206 {
 207         if (!error)
 208                 SetPageUptodate(page);
 209
 210         unlock_page(page);
 211 }
 212
 213 static inline bool cache_valid(struct ceph_inode_info *ci)
 214 {
 215         return ci->i_fscache_gen == ci->i_rdcache_gen;
 216 }
 217
 218
 219 /* Atempt to read from the fscache,
 220  *
 221  * This function is called from the readpage_nounlock context. DO NOT attempt to
 222  * unlock the page here (or in the callback).
 223  */
 224 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 225 {
 226         struct ceph_inode_info *ci = ceph_inode(inode);
 227         int ret;
 228
 229         if (!cache_valid(ci))
 230                 return -ENOBUFS;
 231
 232         ret = fscache_read_or_alloc_page(ci->fscache, page,
 233                                          ceph_readpage_from_fscache_complete, NULL,
 234                                          GFP_KERNEL);
 235
 236         switch (ret) {
 237                 case 0: /* Page found */
 238                         dout("page read submitted\n");
 239                         return 0;
 240                 case -ENOBUFS: /* Pages were not found, and can't be */
 241                 case -ENODATA: /* Pages were not found */
 242                         dout("page/inode not in cache\n");
 243                         return ret;
 244                 default:
 245                         dout("%s: unknown error ret = %i\n", __func__, ret);
 246                         return ret;
 247         }
 248 }
 249
 250 int ceph_readpages_from_fscache(struct inode *inode,
 251                                   struct address_space *mapping,
 252                                   struct list_head *pages,
 253                                   unsigned *nr_pages)
 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_pages(ci->fscache, mapping, pages, nr_pages,
 262                                           ceph_readpage_from_fscache_complete,
 263                                           NULL, mapping_gfp_mask(mapping));
 264
 265         switch (ret) {
 266                 case 0: /* All pages found */
 267                         dout("all-page read submitted\n");
 268                         return 0;
 269                 case -ENOBUFS: /* Some pages were not found, and can't be */
 270                 case -ENODATA: /* some 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 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 280 {
 281         struct ceph_inode_info *ci = ceph_inode(inode);
 282         int ret;
 283
 284         if (!PageFsCache(page))
 285                 return;
 286
 287         if (!cache_valid(ci))
 288                 return;
 289
 290         ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
 291                                  GFP_KERNEL);
 292         if (ret)
 293                  fscache_uncache_page(ci->fscache, page);
 294 }
 295
 296 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 297 {
 298         struct ceph_inode_info *ci = ceph_inode(inode);
 299
 300         if (!PageFsCache(page))
 301                 return;
 302
 303         fscache_wait_on_page_write(ci->fscache, page);
 304         fscache_uncache_page(ci->fscache, page);
 305 }
 306
 307 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 308 {
 309         if (fscache_cookie_valid(fsc->fscache)) {
 310                 struct ceph_fscache_entry *ent;
 311                 bool found = false;
 312
 313                 mutex_lock(&ceph_fscache_lock);
 314                 list_for_each_entry(ent, &ceph_fscache_list, list) {
 315                         if (ent->fscache == fsc->fscache) {
 316                                 list_del(&ent->list);
 317                                 kfree(ent);
 318                                 found = true;
 319                                 break;
 320                         }
 321                 }
 322                 WARN_ON_ONCE(!found);
 323                 mutex_unlock(&ceph_fscache_lock);
 324
 325                 __fscache_relinquish_cookie(fsc->fscache, NULL, false);
 326         }
 327         fsc->fscache = NULL;
 328 }
 329
 330 /*
 331  * caller should hold CEPH_CAP_FILE_{RD,CACHE}
 332  */
 333 void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
 334 {
 335         if (cache_valid(ci))
 336                 return;
 337
 338         /* resue i_truncate_mutex. There should be no pending
 339          * truncate while the caller holds CEPH_CAP_FILE_RD */
 340         mutex_lock(&ci->i_truncate_mutex);
 341         if (!cache_valid(ci)) {
 342                 if (fscache_check_consistency(ci->fscache, &ci->i_vino))
 343                         fscache_invalidate(ci->fscache);
 344                 spin_lock(&ci->i_ceph_lock);
 345                 ci->i_fscache_gen = ci->i_rdcache_gen;
 346                 spin_unlock(&ci->i_ceph_lock);
 347         }
 348         mutex_unlock(&ci->i_truncate_mutex);
 349 }