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 (milosz@adfin.com)
   7  */
   8
   9 #include <linux/ceph/ceph_debug.h>
  10
  11 #include <linux/fs_context.h>
  12 #include "super.h"
  13 #include "cache.h"
  14
  15 struct ceph_aux_inode {
  16         u64     version;
  17         u64     mtime_sec;
  18         u64     mtime_nsec;
  19 };
  20
  21 struct fscache_netfs ceph_cache_netfs = {
  22         .name           = "ceph",
  23         .version        = 0,
  24 };
  25
  26 static DEFINE_MUTEX(ceph_fscache_lock);
  27 static LIST_HEAD(ceph_fscache_list);
  28
  29 struct ceph_fscache_entry {
  30         struct list_head list;
  31         struct fscache_cookie *fscache;
  32         size_t uniq_len;
  33         /* The following members must be last */
  34         struct ceph_fsid fsid;
  35         char uniquifier[];
  36 };
  37
  38 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
  39         .name           = "CEPH.fsid",
  40         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  41 };
  42
  43 int __init ceph_fscache_register(void)
  44 {
  45         return fscache_register_netfs(&ceph_cache_netfs);
  46 }
  47
  48 void ceph_fscache_unregister(void)
  49 {
  50         fscache_unregister_netfs(&ceph_cache_netfs);
  51 }
  52
  53 int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
  54 {
  55         const struct ceph_fsid *fsid = &fsc->client->fsid;
  56         const char *fscache_uniq = fsc->mount_options->fscache_uniq;
  57         size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
  58         struct ceph_fscache_entry *ent;
  59         int err = 0;
  60
  61         mutex_lock(&ceph_fscache_lock);
  62         list_for_each_entry(ent, &ceph_fscache_list, list) {
  63                 if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
  64                         continue;
  65                 if (ent->uniq_len != uniq_len)
  66                         continue;
  67                 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
  68                         continue;
  69
  70                 errorfc(fc, "fscache cookie already registered for fsid %pU, use fsc=<uniquifier> option",
  71                        fsid);
  72                 err = -EBUSY;
  73                 goto out_unlock;
  74         }
  75
  76         ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
  77         if (!ent) {
  78                 err = -ENOMEM;
  79                 goto out_unlock;
  80         }
  81
  82         memcpy(&ent->fsid, fsid, sizeof(*fsid));
  83         if (uniq_len > 0) {
  84                 memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
  85                 ent->uniq_len = uniq_len;
  86         }
  87
  88         fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
  89                                               &ceph_fscache_fsid_object_def,
  90                                               &ent->fsid, sizeof(ent->fsid) + uniq_len,
  91                                               NULL, 0,
  92                                               fsc, 0, true);
  93
  94         if (fsc->fscache) {
  95                 ent->fscache = fsc->fscache;
  96                 list_add_tail(&ent->list, &ceph_fscache_list);
  97         } else {
  98                 kfree(ent);
  99                 errorfc(fc, "unable to register fscache cookie for fsid %pU",
 100                        fsid);
 101                 /* all other fs ignore this error */
 102         }
 103 out_unlock:
 104         mutex_unlock(&ceph_fscache_lock);
 105         return err;
 106 }
 107
 108 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 109         void *cookie_netfs_data, const void *data, uint16_t dlen,
 110         loff_t object_size)
 111 {
 112         struct ceph_aux_inode aux;
 113         struct ceph_inode_info* ci = cookie_netfs_data;
 114         struct inode* inode = &ci->vfs_inode;
 115
 116         if (dlen != sizeof(aux) ||
 117             i_size_read(inode) != object_size)
 118                 return FSCACHE_CHECKAUX_OBSOLETE;
 119
 120         memset(&aux, 0, sizeof(aux));
 121         aux.version = ci->i_version;
 122         aux.mtime_sec = inode->i_mtime.tv_sec;
 123         aux.mtime_nsec = inode->i_mtime.tv_nsec;
 124
 125         if (memcmp(data, &aux, sizeof(aux)) != 0)
 126                 return FSCACHE_CHECKAUX_OBSOLETE;
 127
 128         dout("ceph inode 0x%p cached okay\n", ci);
 129         return FSCACHE_CHECKAUX_OKAY;
 130 }
 131
 132 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 133         .name           = "CEPH.inode",
 134         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 135         .check_aux      = ceph_fscache_inode_check_aux,
 136 };
 137
 138 void ceph_fscache_register_inode_cookie(struct inode *inode)
 139 {
 140         struct ceph_inode_info *ci = ceph_inode(inode);
 141         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 142         struct ceph_aux_inode aux;
 143
 144         /* No caching for filesystem */
 145         if (!fsc->fscache)
 146                 return;
 147
 148         /* Only cache for regular files that are read only */
 149         if (!S_ISREG(inode->i_mode))
 150                 return;
 151
 152         inode_lock_nested(inode, I_MUTEX_CHILD);
 153         if (!ci->fscache) {
 154                 memset(&aux, 0, sizeof(aux));
 155                 aux.version = ci->i_version;
 156                 aux.mtime_sec = inode->i_mtime.tv_sec;
 157                 aux.mtime_nsec = inode->i_mtime.tv_nsec;
 158                 ci->fscache = fscache_acquire_cookie(fsc->fscache,
 159                                                      &ceph_fscache_inode_object_def,
 160                                                      &ci->i_vino, sizeof(ci->i_vino),
 161                                                      &aux, sizeof(aux),
 162                                                      ci, i_size_read(inode), false);
 163         }
 164         inode_unlock(inode);
 165 }
 166
 167 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 168 {
 169         struct fscache_cookie* cookie;
 170
 171         if ((cookie = ci->fscache) == NULL)
 172                 return;
 173
 174         ci->fscache = NULL;
 175
 176         fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
 177         fscache_relinquish_cookie(cookie, &ci->i_vino, false);
 178 }
 179
 180 static bool ceph_fscache_can_enable(void *data)
 181 {
 182         struct inode *inode = data;
 183         return !inode_is_open_for_write(inode);
 184 }
 185
 186 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
 187 {
 188         struct ceph_inode_info *ci = ceph_inode(inode);
 189
 190         if (!fscache_cookie_valid(ci->fscache))
 191                 return;
 192
 193         if (inode_is_open_for_write(inode)) {
 194                 dout("fscache_file_set_cookie %p %p disabling cache\n",
 195                      inode, filp);
 196                 fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
 197                 fscache_uncache_all_inode_pages(ci->fscache, inode);
 198         } else {
 199                 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
 200                                       ceph_fscache_can_enable, inode);
 201                 if (fscache_cookie_enabled(ci->fscache)) {
 202                         dout("fscache_file_set_cookie %p %p enabling cache\n",
 203                              inode, filp);
 204                 }
 205         }
 206 }
 207
 208 static void ceph_readpage_from_fscache_complete(struct page *page, void *data, int error)
 209 {
 210         if (!error)
 211                 SetPageUptodate(page);
 212
 213         unlock_page(page);
 214 }
 215
 216 static inline bool cache_valid(struct ceph_inode_info *ci)
 217 {
 218         return ci->i_fscache_gen == ci->i_rdcache_gen;
 219 }
 220
 221
 222 /* Atempt to read from the fscache,
 223  *
 224  * This function is called from the readpage_nounlock context. DO NOT attempt to
 225  * unlock the page here (or in the callback).
 226  */
 227 int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
 228 {
 229         struct ceph_inode_info *ci = ceph_inode(inode);
 230         int ret;
 231
 232         if (!cache_valid(ci))
 233                 return -ENOBUFS;
 234
 235         ret = fscache_read_or_alloc_page(ci->fscache, page,
 236                                          ceph_readpage_from_fscache_complete, NULL,
 237                                          GFP_KERNEL);
 238
 239         switch (ret) {
 240                 case 0: /* Page found */
 241                         dout("page read submitted\n");
 242                         return 0;
 243                 case -ENOBUFS: /* Pages were not found, and can't be */
 244                 case -ENODATA: /* Pages were not found */
 245                         dout("page/inode not in cache\n");
 246                         return ret;
 247                 default:
 248                         dout("%s: unknown error ret = %i\n", __func__, ret);
 249                         return ret;
 250         }
 251 }
 252
 253 int ceph_readpages_from_fscache(struct inode *inode,
 254                                   struct address_space *mapping,
 255                                   struct list_head *pages,
 256                                   unsigned *nr_pages)
 257 {
 258         struct ceph_inode_info *ci = ceph_inode(inode);
 259         int ret;
 260
 261         if (!cache_valid(ci))
 262                 return -ENOBUFS;
 263
 264         ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
 265                                           ceph_readpage_from_fscache_complete,
 266                                           NULL, mapping_gfp_mask(mapping));
 267
 268         switch (ret) {
 269                 case 0: /* All pages found */
 270                         dout("all-page read submitted\n");
 271                         return 0;
 272                 case -ENOBUFS: /* Some pages were not found, and can't be */
 273                 case -ENODATA: /* some pages were not found */
 274                         dout("page/inode not in cache\n");
 275                         return ret;
 276                 default:
 277                         dout("%s: unknown error ret = %i\n", __func__, ret);
 278                         return ret;
 279         }
 280 }
 281
 282 void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
 283 {
 284         struct ceph_inode_info *ci = ceph_inode(inode);
 285         int ret;
 286
 287         if (!PageFsCache(page))
 288                 return;
 289
 290         if (!cache_valid(ci))
 291                 return;
 292
 293         ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
 294                                  GFP_KERNEL);
 295         if (ret)
 296                  fscache_uncache_page(ci->fscache, page);
 297 }
 298
 299 void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
 300 {
 301         struct ceph_inode_info *ci = ceph_inode(inode);
 302
 303         if (!PageFsCache(page))
 304                 return;
 305
 306         fscache_wait_on_page_write(ci->fscache, page);
 307         fscache_uncache_page(ci->fscache, page);
 308 }
 309
 310 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 311 {
 312         if (fscache_cookie_valid(fsc->fscache)) {
 313                 struct ceph_fscache_entry *ent;
 314                 bool found = false;
 315
 316                 mutex_lock(&ceph_fscache_lock);
 317                 list_for_each_entry(ent, &ceph_fscache_list, list) {
 318                         if (ent->fscache == fsc->fscache) {
 319                                 list_del(&ent->list);
 320                                 kfree(ent);
 321                                 found = true;
 322                                 break;
 323                         }
 324                 }
 325                 WARN_ON_ONCE(!found);
 326                 mutex_unlock(&ceph_fscache_lock);
 327
 328                 __fscache_relinquish_cookie(fsc->fscache, NULL, false);
 329         }
 330         fsc->fscache = NULL;
 331 }
 332
 333 /*
 334  * caller should hold CEPH_CAP_FILE_{RD,CACHE}
 335  */
 336 void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
 337 {
 338         if (cache_valid(ci))
 339                 return;
 340
 341         /* resue i_truncate_mutex. There should be no pending
 342          * truncate while the caller holds CEPH_CAP_FILE_RD */
 343         mutex_lock(&ci->i_truncate_mutex);
 344         if (!cache_valid(ci)) {
 345                 if (fscache_check_consistency(ci->fscache, &ci->i_vino))
 346                         fscache_invalidate(ci->fscache);
 347                 spin_lock(&ci->i_ceph_lock);
 348                 ci->i_fscache_gen = ci->i_rdcache_gen;
 349                 spin_unlock(&ci->i_ceph_lock);
 350         }
 351         mutex_unlock(&ci->i_truncate_mutex);
 352 }