fs/cifs/fscache.c

   1 /*
   2  *   fs/cifs/fscache.c - CIFS filesystem cache interface
   3  *
   4  *   Copyright (c) 2010 Novell, Inc.
   5  *   Author(s): Suresh Jayaraman (sjayaraman@suse.de>
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21 #include "fscache.h"
  22 #include "cifsglob.h"
  23 #include "cifs_debug.h"
  24 #include "cifs_fs_sb.h"
  25
  26 void cifs_fscache_get_client_cookie(struct TCP_Server_Info *server)
  27 {
  28         server->fscache =
  29                 fscache_acquire_cookie(cifs_fscache_netfs.primary_index,
  30                                 &cifs_fscache_server_index_def, server);
  31         cFYI(1, "CIFS: get client cookie (0x%p/0x%p)", server,
  32                                 server->fscache);
  33 }
  34
  35 void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
  36 {
  37         cFYI(1, "CIFS: release client cookie (0x%p/0x%p)", server,
  38                                 server->fscache);
  39         fscache_relinquish_cookie(server->fscache, 0);
  40         server->fscache = NULL;
  41 }
  42
  43 void cifs_fscache_get_super_cookie(struct cifsTconInfo *tcon)
  44 {
  45         struct TCP_Server_Info *server = tcon->ses->server;
  46
  47         tcon->fscache =
  48                 fscache_acquire_cookie(server->fscache,
  49                                 &cifs_fscache_super_index_def, tcon);
  50         cFYI(1, "CIFS: get superblock cookie (0x%p/0x%p)",
  51                                 server->fscache, tcon->fscache);
  52 }
  53
  54 void cifs_fscache_release_super_cookie(struct cifsTconInfo *tcon)
  55 {
  56         cFYI(1, "CIFS: releasing superblock cookie (0x%p)", tcon->fscache);
  57         fscache_relinquish_cookie(tcon->fscache, 0);
  58         tcon->fscache = NULL;
  59 }
  60
  61 static void cifs_fscache_enable_inode_cookie(struct inode *inode)
  62 {
  63         struct cifsInodeInfo *cifsi = CIFS_I(inode);
  64         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
  65         struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
  66
  67         if (cifsi->fscache)
  68                 return;
  69
  70         cifsi->fscache = fscache_acquire_cookie(tcon->fscache,
  71                                 &cifs_fscache_inode_object_def, cifsi);
  72         cFYI(1, "CIFS: got FH cookie (0x%p/0x%p)", tcon->fscache,
  73                                 cifsi->fscache);
  74 }
  75
  76 void cifs_fscache_release_inode_cookie(struct inode *inode)
  77 {
  78         struct cifsInodeInfo *cifsi = CIFS_I(inode);
  79
  80         if (cifsi->fscache) {
  81                 cFYI(1, "CIFS releasing inode cookie (0x%p)",
  82                                 cifsi->fscache);
  83                 fscache_relinquish_cookie(cifsi->fscache, 0);
  84                 cifsi->fscache = NULL;
  85         }
  86 }
  87
  88 static void cifs_fscache_disable_inode_cookie(struct inode *inode)
  89 {
  90         struct cifsInodeInfo *cifsi = CIFS_I(inode);
  91
  92         if (cifsi->fscache) {
  93                 cFYI(1, "CIFS disabling inode cookie (0x%p)",
  94                                 cifsi->fscache);
  95                 fscache_relinquish_cookie(cifsi->fscache, 1);
  96                 cifsi->fscache = NULL;
  97         }
  98 }
  99
 100 void cifs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
 101 {
 102         if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
 103                 cifs_fscache_disable_inode_cookie(inode);
 104         else {
 105                 cifs_fscache_enable_inode_cookie(inode);
 106                 cFYI(1, "CIFS: fscache inode cookie set");
 107         }
 108 }
 109
 110 void cifs_fscache_reset_inode_cookie(struct inode *inode)
 111 {
 112         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 113         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 114         struct fscache_cookie *old = cifsi->fscache;
 115
 116         if (cifsi->fscache) {
 117                 /* retire the current fscache cache and get a new one */
 118                 fscache_relinquish_cookie(cifsi->fscache, 1);
 119
 120                 cifsi->fscache = fscache_acquire_cookie(
 121                                         cifs_sb_master_tcon(cifs_sb)->fscache,
 122                                         &cifs_fscache_inode_object_def,
 123                                         cifsi);
 124                 cFYI(1, "CIFS: new cookie 0x%p oldcookie 0x%p",
 125                                 cifsi->fscache, old);
 126         }
 127 }
 128
 129 int cifs_fscache_release_page(struct page *page, gfp_t gfp)
 130 {
 131         if (PageFsCache(page)) {
 132                 struct inode *inode = page->mapping->host;
 133                 struct cifsInodeInfo *cifsi = CIFS_I(inode);
 134
 135                 cFYI(1, "CIFS: fscache release page (0x%p/0x%p)",
 136                                 page, cifsi->fscache);
 137                 if (!fscache_maybe_release_page(cifsi->fscache, page, gfp))
 138                         return 0;
 139         }
 140
 141         return 1;
 142 }
 143
 144 static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
 145                                                 int error)
 146 {
 147         cFYI(1, "CFS: readpage_from_fscache_complete (0x%p/%d)",
 148                         page, error);
 149         if (!error)
 150                 SetPageUptodate(page);
 151         unlock_page(page);
 152 }
 153
 154 /*
 155  * Retrieve a page from FS-Cache
 156  */
 157 int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
 158 {
 159         int ret;
 160
 161         cFYI(1, "CIFS: readpage_from_fscache(fsc:%p, p:%p, i:0x%p",
 162                         CIFS_I(inode)->fscache, page, inode);
 163         ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
 164                                          cifs_readpage_from_fscache_complete,
 165                                          NULL,
 166                                          GFP_KERNEL);
 167         switch (ret) {
 168
 169         case 0: /* page found in fscache, read submitted */
 170                 cFYI(1, "CIFS: readpage_from_fscache: submitted");
 171                 return ret;
 172         case -ENOBUFS:  /* page won't be cached */
 173         case -ENODATA:  /* page not in cache */
 174                 cFYI(1, "CIFS: readpage_from_fscache %d", ret);
 175                 return 1;
 176
 177         default:
 178                 cERROR(1, "unknown error ret = %d", ret);
 179         }
 180         return ret;
 181 }
 182
 183 /*
 184  * Retrieve a set of pages from FS-Cache
 185  */
 186 int __cifs_readpages_from_fscache(struct inode *inode,
 187                                 struct address_space *mapping,
 188                                 struct list_head *pages,
 189                                 unsigned *nr_pages)
 190 {
 191         int ret;
 192
 193         cFYI(1, "CIFS: __cifs_readpages_from_fscache (0x%p/%u/0x%p)",
 194                         CIFS_I(inode)->fscache, *nr_pages, inode);
 195         ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
 196                                           pages, nr_pages,
 197                                           cifs_readpage_from_fscache_complete,
 198                                           NULL,
 199                                           mapping_gfp_mask(mapping));
 200         switch (ret) {
 201         case 0: /* read submitted to the cache for all pages */
 202                 cFYI(1, "CIFS: readpages_from_fscache: submitted");
 203                 return ret;
 204
 205         case -ENOBUFS:  /* some pages are not cached and can't be */
 206         case -ENODATA:  /* some pages are not cached */
 207                 cFYI(1, "CIFS: readpages_from_fscache: no page");
 208                 return 1;
 209
 210         default:
 211                 cFYI(1, "unknown error ret = %d", ret);
 212         }
 213
 214         return ret;
 215 }
 216
 217 void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
 218 {
 219         int ret;
 220
 221         cFYI(1, "CIFS: readpage_to_fscache(fsc: %p, p: %p, i: %p",
 222                         CIFS_I(inode)->fscache, page, inode);
 223         ret = fscache_write_page(CIFS_I(inode)->fscache, page, GFP_KERNEL);
 224         if (ret != 0)
 225                 fscache_uncache_page(CIFS_I(inode)->fscache, page);
 226 }
 227
 228 void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
 229 {
 230         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 231         struct fscache_cookie *cookie = cifsi->fscache;
 232
 233         cFYI(1, "CIFS: fscache invalidatepage (0x%p/0x%p)", page, cookie);
 234         fscache_wait_on_page_write(cookie, page);
 235         fscache_uncache_page(cookie, page);
 236 }
 237