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_relinquish_cookie(cookie, &ci->i_vino, false);
 177 }
 178
 179 static bool ceph_fscache_can_enable(void *data)
 180 {
 181         struct inode *inode = data;
 182         return !inode_is_open_for_write(inode);
 183 }
 184
 185 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
 186 {
 187         struct ceph_inode_info *ci = ceph_inode(inode);
 188
 189         if (!fscache_cookie_valid(ci->fscache))
 190                 return;
 191
 192         if (inode_is_open_for_write(inode)) {
 193                 dout("fscache_file_set_cookie %p %p disabling cache\n",
 194                      inode, filp);
 195                 fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
 196         } else {
 197                 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
 198                                       ceph_fscache_can_enable, inode);
 199                 if (fscache_cookie_enabled(ci->fscache)) {
 200                         dout("fscache_file_set_cookie %p %p enabling cache\n",
 201                              inode, filp);
 202                 }
 203         }
 204 }
 205
 206 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 207 {
 208         if (fscache_cookie_valid(fsc->fscache)) {
 209                 struct ceph_fscache_entry *ent;
 210                 bool found = false;
 211
 212                 mutex_lock(&ceph_fscache_lock);
 213                 list_for_each_entry(ent, &ceph_fscache_list, list) {
 214                         if (ent->fscache == fsc->fscache) {
 215                                 list_del(&ent->list);
 216                                 kfree(ent);
 217                                 found = true;
 218                                 break;
 219                         }
 220                 }
 221                 WARN_ON_ONCE(!found);
 222                 mutex_unlock(&ceph_fscache_lock);
 223
 224                 __fscache_relinquish_cookie(fsc->fscache, NULL, false);
 225         }
 226         fsc->fscache = NULL;
 227 }