fs/smb/client/fscache.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *   CIFS filesystem cache interface
   4  *
   5  *   Copyright (c) 2010 Novell, Inc.
   6  *   Author(s): Suresh Jayaraman <sjayaraman@suse.de>
   7  *
   8  */
   9 #include "fscache.h"
  10 #include "cifsglob.h"
  11 #include "cifs_debug.h"
  12 #include "cifs_fs_sb.h"
  13 #include "cifsproto.h"
  14
  15 static void cifs_fscache_fill_volume_coherency(
  16         struct cifs_tcon *tcon,
  17         struct cifs_fscache_volume_coherency_data *cd)
  18 {
  19         memset(cd, 0, sizeof(*cd));
  20         cd->resource_id         = cpu_to_le64(tcon->resource_id);
  21         cd->vol_create_time     = tcon->vol_create_time;
  22         cd->vol_serial_number   = cpu_to_le32(tcon->vol_serial_number);
  23 }
  24
  25 int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
  26 {
  27         struct cifs_fscache_volume_coherency_data cd;
  28         struct TCP_Server_Info *server = tcon->ses->server;
  29         struct fscache_volume *vcookie;
  30         const struct sockaddr *sa = (struct sockaddr *)&server->dstaddr;
  31         size_t slen, i;
  32         char *sharename;
  33         char *key;
  34         int ret = -ENOMEM;
  35
  36         tcon->fscache = NULL;
  37         switch (sa->sa_family) {
  38         case AF_INET:
  39         case AF_INET6:
  40                 break;
  41         default:
  42                 cifs_dbg(VFS, "Unknown network family '%d'\n", sa->sa_family);
  43                 return -EINVAL;
  44         }
  45
  46         memset(&key, 0, sizeof(key));
  47
  48         sharename = extract_sharename(tcon->tree_name);
  49         if (IS_ERR(sharename)) {
  50                 cifs_dbg(FYI, "%s: couldn't extract sharename\n", __func__);
  51                 return PTR_ERR(sharename);
  52         }
  53
  54         slen = strlen(sharename);
  55         for (i = 0; i < slen; i++)
  56                 if (sharename[i] == '/')
  57                         sharename[i] = ';';
  58
  59         key = kasprintf(GFP_KERNEL, "cifs,%pISpc,%s", sa, sharename);
  60         if (!key)
  61                 goto out;
  62
  63         cifs_fscache_fill_volume_coherency(tcon, &cd);
  64         vcookie = fscache_acquire_volume(key,
  65                                          NULL, /* preferred_cache */
  66                                          &cd, sizeof(cd));
  67         cifs_dbg(FYI, "%s: (%s/0x%p)\n", __func__, key, vcookie);
  68         if (IS_ERR(vcookie)) {
  69                 if (vcookie != ERR_PTR(-EBUSY)) {
  70                         ret = PTR_ERR(vcookie);
  71                         goto out_2;
  72                 }
  73                 pr_err("Cache volume key already in use (%s)\n", key);
  74                 vcookie = NULL;
  75         }
  76
  77         tcon->fscache = vcookie;
  78         ret = 0;
  79 out_2:
  80         kfree(key);
  81 out:
  82         kfree(sharename);
  83         return ret;
  84 }
  85
  86 void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
  87 {
  88         struct cifs_fscache_volume_coherency_data cd;
  89
  90         cifs_dbg(FYI, "%s: (0x%p)\n", __func__, tcon->fscache);
  91
  92         cifs_fscache_fill_volume_coherency(tcon, &cd);
  93         fscache_relinquish_volume(tcon->fscache, &cd, false);
  94         tcon->fscache = NULL;
  95 }
  96
  97 void cifs_fscache_get_inode_cookie(struct inode *inode)
  98 {
  99         struct cifs_fscache_inode_coherency_data cd;
 100         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 101         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 102         struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 103
 104         cifs_fscache_fill_coherency(&cifsi->netfs.inode, &cd);
 105
 106         cifsi->netfs.cache =
 107                 fscache_acquire_cookie(tcon->fscache, 0,
 108                                        &cifsi->uniqueid, sizeof(cifsi->uniqueid),
 109                                        &cd, sizeof(cd),
 110                                        i_size_read(&cifsi->netfs.inode));
 111         if (cifsi->netfs.cache)
 112                 mapping_set_release_always(inode->i_mapping);
 113 }
 114
 115 void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
 116 {
 117         if (update) {
 118                 struct cifs_fscache_inode_coherency_data cd;
 119                 loff_t i_size = i_size_read(inode);
 120
 121                 cifs_fscache_fill_coherency(inode, &cd);
 122                 fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
 123         } else {
 124                 fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
 125         }
 126 }
 127
 128 void cifs_fscache_release_inode_cookie(struct inode *inode)
 129 {
 130         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 131         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 132
 133         if (cookie) {
 134                 cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
 135                 fscache_relinquish_cookie(cookie, false);
 136                 cifsi->netfs.cache = NULL;
 137         }
 138 }
 139
 140 /*
 141  * Fallback page reading interface.
 142  */
 143 static int fscache_fallback_read_page(struct inode *inode, struct page *page)
 144 {
 145         struct netfs_cache_resources cres;
 146         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 147         struct iov_iter iter;
 148         struct bio_vec bvec;
 149         int ret;
 150
 151         memset(&cres, 0, sizeof(cres));
 152         bvec_set_page(&bvec, page, PAGE_SIZE, 0);
 153         iov_iter_bvec(&iter, ITER_DEST, &bvec, 1, PAGE_SIZE);
 154
 155         ret = fscache_begin_read_operation(&cres, cookie);
 156         if (ret < 0)
 157                 return ret;
 158
 159         ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
 160                            NULL, NULL);
 161         fscache_end_operation(&cres);
 162         return ret;
 163 }
 164
 165 /*
 166  * Fallback page writing interface.
 167  */
 168 static int fscache_fallback_write_pages(struct inode *inode, loff_t start, size_t len,
 169                                         bool no_space_allocated_yet)
 170 {
 171         struct netfs_cache_resources cres;
 172         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 173         struct iov_iter iter;
 174         int ret;
 175
 176         memset(&cres, 0, sizeof(cres));
 177         iov_iter_xarray(&iter, ITER_SOURCE, &inode->i_mapping->i_pages, start, len);
 178
 179         ret = fscache_begin_write_operation(&cres, cookie);
 180         if (ret < 0)
 181                 return ret;
 182
 183         ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
 184                                       no_space_allocated_yet);
 185         if (ret == 0)
 186                 ret = fscache_write(&cres, start, &iter, NULL, NULL);
 187         fscache_end_operation(&cres);
 188         return ret;
 189 }
 190
 191 /*
 192  * Retrieve a page from FS-Cache
 193  */
 194 int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
 195 {
 196         int ret;
 197
 198         cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
 199                  __func__, cifs_inode_cookie(inode), page, inode);
 200
 201         ret = fscache_fallback_read_page(inode, page);
 202         if (ret < 0)
 203                 return ret;
 204
 205         /* Read completed synchronously */
 206         SetPageUptodate(page);
 207         return 0;
 208 }
 209
 210 void __cifs_readahead_to_fscache(struct inode *inode, loff_t pos, size_t len)
 211 {
 212         cifs_dbg(FYI, "%s: (fsc: %p, p: %llx, l: %zx, i: %p)\n",
 213                  __func__, cifs_inode_cookie(inode), pos, len, inode);
 214
 215         fscache_fallback_write_pages(inode, pos, len, true);
 216 }
 217
 218 /*
 219  * Query the cache occupancy.
 220  */
 221 int __cifs_fscache_query_occupancy(struct inode *inode,
 222                                    pgoff_t first, unsigned int nr_pages,
 223                                    pgoff_t *_data_first,
 224                                    unsigned int *_data_nr_pages)
 225 {
 226         struct netfs_cache_resources cres;
 227         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 228         loff_t start, data_start;
 229         size_t len, data_len;
 230         int ret;
 231
 232         ret = fscache_begin_read_operation(&cres, cookie);
 233         if (ret < 0)
 234                 return ret;
 235
 236         start = first * PAGE_SIZE;
 237         len = nr_pages * PAGE_SIZE;
 238         ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
 239                                         &data_start, &data_len);
 240         if (ret == 0) {
 241                 *_data_first = data_start / PAGE_SIZE;
 242                 *_data_nr_pages = len / PAGE_SIZE;
 243         }
 244
 245         fscache_end_operation(&cres);
 246         return ret;
 247 }