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 <linux/ceph/ceph_debug.h>
  10
  11 #include <linux/fs_context.h>
  12 #include "super.h"
  13 #include "cache.h"
  14
  15 struct fscache_netfs ceph_cache_netfs = {
  16         .name           = "ceph",
  17         .version        = 0,
  18 };
  19
  20 static DEFINE_MUTEX(ceph_fscache_lock);
  21 static LIST_HEAD(ceph_fscache_list);
  22
  23 struct ceph_fscache_entry {
  24         struct list_head list;
  25         struct fscache_cookie *fscache;
  26         size_t uniq_len;
  27         /* The following members must be last */
  28         struct ceph_fsid fsid;
  29         char uniquifier[];
  30 };
  31
  32 static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
  33         .name           = "CEPH.fsid",
  34         .type           = FSCACHE_COOKIE_TYPE_INDEX,
  35 };
  36
  37 int __init ceph_fscache_register(void)
  38 {
  39         return fscache_register_netfs(&ceph_cache_netfs);
  40 }
  41
  42 void ceph_fscache_unregister(void)
  43 {
  44         fscache_unregister_netfs(&ceph_cache_netfs);
  45 }
  46
  47 int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
  48 {
  49         const struct ceph_fsid *fsid = &fsc->client->fsid;
  50         const char *fscache_uniq = fsc->mount_options->fscache_uniq;
  51         size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
  52         struct ceph_fscache_entry *ent;
  53         int err = 0;
  54
  55         mutex_lock(&ceph_fscache_lock);
  56         list_for_each_entry(ent, &ceph_fscache_list, list) {
  57                 if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
  58                         continue;
  59                 if (ent->uniq_len != uniq_len)
  60                         continue;
  61                 if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
  62                         continue;
  63
  64                 errorfc(fc, "fscache cookie already registered for fsid %pU, use fsc=<uniquifier> option",
  65                        fsid);
  66                 err = -EBUSY;
  67                 goto out_unlock;
  68         }
  69
  70         ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
  71         if (!ent) {
  72                 err = -ENOMEM;
  73                 goto out_unlock;
  74         }
  75
  76         memcpy(&ent->fsid, fsid, sizeof(*fsid));
  77         if (uniq_len > 0) {
  78                 memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
  79                 ent->uniq_len = uniq_len;
  80         }
  81
  82         fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
  83                                               &ceph_fscache_fsid_object_def,
  84                                               &ent->fsid, sizeof(ent->fsid) + uniq_len,
  85                                               NULL, 0,
  86                                               fsc, 0, true);
  87
  88         if (fsc->fscache) {
  89                 ent->fscache = fsc->fscache;
  90                 list_add_tail(&ent->list, &ceph_fscache_list);
  91         } else {
  92                 kfree(ent);
  93                 errorfc(fc, "unable to register fscache cookie for fsid %pU",
  94                        fsid);
  95                 /* all other fs ignore this error */
  96         }
  97 out_unlock:
  98         mutex_unlock(&ceph_fscache_lock);
  99         return err;
 100 }
 101
 102 static enum fscache_checkaux ceph_fscache_inode_check_aux(
 103         void *cookie_netfs_data, const void *data, uint16_t dlen,
 104         loff_t object_size)
 105 {
 106         struct ceph_inode_info* ci = cookie_netfs_data;
 107         struct inode* inode = &ci->vfs_inode;
 108
 109         if (dlen != sizeof(ci->i_version) ||
 110             i_size_read(inode) != object_size)
 111                 return FSCACHE_CHECKAUX_OBSOLETE;
 112
 113         if (*(u64 *)data != ci->i_version)
 114                 return FSCACHE_CHECKAUX_OBSOLETE;
 115
 116         dout("ceph inode 0x%p cached okay\n", ci);
 117         return FSCACHE_CHECKAUX_OKAY;
 118 }
 119
 120 static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
 121         .name           = "CEPH.inode",
 122         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 123         .check_aux      = ceph_fscache_inode_check_aux,
 124 };
 125
 126 void ceph_fscache_register_inode_cookie(struct inode *inode)
 127 {
 128         struct ceph_inode_info *ci = ceph_inode(inode);
 129         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 130
 131         /* No caching for filesystem */
 132         if (!fsc->fscache)
 133                 return;
 134
 135         /* Only cache for regular files that are read only */
 136         if (!S_ISREG(inode->i_mode))
 137                 return;
 138
 139         inode_lock_nested(inode, I_MUTEX_CHILD);
 140         if (!ci->fscache) {
 141                 ci->fscache = fscache_acquire_cookie(fsc->fscache,
 142                                                      &ceph_fscache_inode_object_def,
 143                                                      &ci->i_vino, sizeof(ci->i_vino),
 144                                                      &ci->i_version, sizeof(ci->i_version),
 145                                                      ci, i_size_read(inode), false);
 146         }
 147         inode_unlock(inode);
 148 }
 149
 150 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 151 {
 152         struct fscache_cookie* cookie;
 153
 154         if ((cookie = ci->fscache) == NULL)
 155                 return;
 156
 157         ci->fscache = NULL;
 158
 159         fscache_relinquish_cookie(cookie, &ci->i_vino, false);
 160 }
 161
 162 static bool ceph_fscache_can_enable(void *data)
 163 {
 164         struct inode *inode = data;
 165         return !inode_is_open_for_write(inode);
 166 }
 167
 168 void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
 169 {
 170         struct ceph_inode_info *ci = ceph_inode(inode);
 171
 172         if (!fscache_cookie_valid(ci->fscache))
 173                 return;
 174
 175         if (inode_is_open_for_write(inode)) {
 176                 dout("fscache_file_set_cookie %p %p disabling cache\n",
 177                      inode, filp);
 178                 fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
 179         } else {
 180                 fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
 181                                       ceph_fscache_can_enable, inode);
 182                 if (fscache_cookie_enabled(ci->fscache)) {
 183                         dout("fscache_file_set_cookie %p %p enabling cache\n",
 184                              inode, filp);
 185                 }
 186         }
 187 }
 188
 189 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 190 {
 191         if (fscache_cookie_valid(fsc->fscache)) {
 192                 struct ceph_fscache_entry *ent;
 193                 bool found = false;
 194
 195                 mutex_lock(&ceph_fscache_lock);
 196                 list_for_each_entry(ent, &ceph_fscache_list, list) {
 197                         if (ent->fscache == fsc->fscache) {
 198                                 list_del(&ent->list);
 199                                 kfree(ent);
 200                                 found = true;
 201                                 break;
 202                         }
 203                 }
 204                 WARN_ON_ONCE(!found);
 205                 mutex_unlock(&ceph_fscache_lock);
 206
 207                 __fscache_relinquish_cookie(fsc->fscache, NULL, false);
 208         }
 209         fsc->fscache = NULL;
 210 }