fs/cifs/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 -EINVAL;
  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 }
 112
 113 void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update)
 114 {
 115         if (update) {
 116                 struct cifs_fscache_inode_coherency_data cd;
 117                 loff_t i_size = i_size_read(inode);
 118
 119                 cifs_fscache_fill_coherency(inode, &cd);
 120                 fscache_unuse_cookie(cifs_inode_cookie(inode), &cd, &i_size);
 121         } else {
 122                 fscache_unuse_cookie(cifs_inode_cookie(inode), NULL, NULL);
 123         }
 124 }
 125
 126 void cifs_fscache_release_inode_cookie(struct inode *inode)
 127 {
 128         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 129         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 130
 131         if (cookie) {
 132                 cifs_dbg(FYI, "%s: (0x%p)\n", __func__, cookie);
 133                 fscache_relinquish_cookie(cookie, false);
 134                 cifsi->netfs.cache = NULL;
 135         }
 136 }
 137
 138 /*
 139  * Fallback page reading interface.
 140  */
 141 static int fscache_fallback_read_page(struct inode *inode, struct page *page)
 142 {
 143         struct netfs_cache_resources cres;
 144         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 145         struct iov_iter iter;
 146         struct bio_vec bvec;
 147         int ret;
 148
 149         memset(&cres, 0, sizeof(cres));
 150         bvec_set_page(&bvec, page, PAGE_SIZE, 0);
 151         iov_iter_bvec(&iter, ITER_DEST, &bvec, 1, PAGE_SIZE);
 152
 153         ret = fscache_begin_read_operation(&cres, cookie);
 154         if (ret < 0)
 155                 return ret;
 156
 157         ret = fscache_read(&cres, page_offset(page), &iter, NETFS_READ_HOLE_FAIL,
 158                            NULL, NULL);
 159         fscache_end_operation(&cres);
 160         return ret;
 161 }
 162
 163 /*
 164  * Fallback page writing interface.
 165  */
 166 static int fscache_fallback_write_pages(struct inode *inode, loff_t start, size_t len,
 167                                         bool no_space_allocated_yet)
 168 {
 169         struct netfs_cache_resources cres;
 170         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 171         struct iov_iter iter;
 172         int ret;
 173
 174         memset(&cres, 0, sizeof(cres));
 175         iov_iter_xarray(&iter, ITER_SOURCE, &inode->i_mapping->i_pages, start, len);
 176
 177         ret = fscache_begin_write_operation(&cres, cookie);
 178         if (ret < 0)
 179                 return ret;
 180
 181         ret = cres.ops->prepare_write(&cres, &start, &len, i_size_read(inode),
 182                                       no_space_allocated_yet);
 183         if (ret == 0)
 184                 ret = fscache_write(&cres, start, &iter, NULL, NULL);
 185         fscache_end_operation(&cres);
 186         return ret;
 187 }
 188
 189 /*
 190  * Retrieve a page from FS-Cache
 191  */
 192 int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
 193 {
 194         int ret;
 195
 196         cifs_dbg(FYI, "%s: (fsc:%p, p:%p, i:0x%p\n",
 197                  __func__, cifs_inode_cookie(inode), page, inode);
 198
 199         ret = fscache_fallback_read_page(inode, page);
 200         if (ret < 0)
 201                 return ret;
 202
 203         /* Read completed synchronously */
 204         SetPageUptodate(page);
 205         return 0;
 206 }
 207
 208 void __cifs_readahead_to_fscache(struct inode *inode, loff_t pos, size_t len)
 209 {
 210         cifs_dbg(FYI, "%s: (fsc: %p, p: %llx, l: %zx, i: %p)\n",
 211                  __func__, cifs_inode_cookie(inode), pos, len, inode);
 212
 213         fscache_fallback_write_pages(inode, pos, len, true);
 214 }
 215
 216 /*
 217  * Query the cache occupancy.
 218  */
 219 int __cifs_fscache_query_occupancy(struct inode *inode,
 220                                    pgoff_t first, unsigned int nr_pages,
 221                                    pgoff_t *_data_first,
 222                                    unsigned int *_data_nr_pages)
 223 {
 224         struct netfs_cache_resources cres;
 225         struct fscache_cookie *cookie = cifs_inode_cookie(inode);
 226         loff_t start, data_start;
 227         size_t len, data_len;
 228         int ret;
 229
 230         ret = fscache_begin_read_operation(&cres, cookie);
 231         if (ret < 0)
 232                 return ret;
 233
 234         start = first * PAGE_SIZE;
 235         len = nr_pages * PAGE_SIZE;
 236         ret = cres.ops->query_occupancy(&cres, start, len, PAGE_SIZE,
 237                                         &data_start, &data_len);
 238         if (ret == 0) {
 239                 *_data_first = data_start / PAGE_SIZE;
 240                 *_data_nr_pages = len / PAGE_SIZE;
 241         }
 242
 243         fscache_end_operation(&cres);
 244         return ret;
 245 }