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, "%s: (0x%p/0x%p)", __func__, server,
  32                         server->fscache);
  33 }
  34
  35 void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
  36 {
  37         cFYI(1, "%s: (0x%p/0x%p)", __func__, 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 cifs_tcon *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, "%s: (0x%p/0x%p)", __func__, server->fscache,
  51                         tcon->fscache);
  52 }
  53
  54 void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon)
  55 {
  56         cFYI(1, "%s: (0x%p)", __func__, 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 cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
  66
  67         if (cifsi->fscache)
  68                 return;
  69
  70         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_FSCACHE) {
  71                 cifsi->fscache = fscache_acquire_cookie(tcon->fscache,
  72                                 &cifs_fscache_inode_object_def, cifsi);
  73                 cFYI(1, "%s: got FH cookie (0x%p/0x%p)", __func__,
  74                                 tcon->fscache, cifsi->fscache);
  75         }
  76 }
  77
  78 void cifs_fscache_release_inode_cookie(struct inode *inode)
  79 {
  80         struct cifsInodeInfo *cifsi = CIFS_I(inode);
  81
  82         if (cifsi->fscache) {
  83                 cFYI(1, "%s: (0x%p)", __func__, cifsi->fscache);
  84                 fscache_relinquish_cookie(cifsi->fscache, 0);
  85                 cifsi->fscache = NULL;
  86         }
  87 }
  88
  89 static void cifs_fscache_disable_inode_cookie(struct inode *inode)
  90 {
  91         struct cifsInodeInfo *cifsi = CIFS_I(inode);
  92
  93         if (cifsi->fscache) {
  94                 cFYI(1, "%s: (0x%p)", __func__, 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 }
 107
 108 void cifs_fscache_reset_inode_cookie(struct inode *inode)
 109 {
 110         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 111         struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 112         struct fscache_cookie *old = cifsi->fscache;
 113
 114         if (cifsi->fscache) {
 115                 /* retire the current fscache cache and get a new one */
 116                 fscache_relinquish_cookie(cifsi->fscache, 1);
 117
 118                 cifsi->fscache = fscache_acquire_cookie(
 119                                         cifs_sb_master_tcon(cifs_sb)->fscache,
 120                                         &cifs_fscache_inode_object_def,
 121                                         cifsi);
 122                 cFYI(1, "%s: new cookie 0x%p oldcookie 0x%p",
 123                                 __func__, cifsi->fscache, old);
 124         }
 125 }
 126
 127 int cifs_fscache_release_page(struct page *page, gfp_t gfp)
 128 {
 129         if (PageFsCache(page)) {
 130                 struct inode *inode = page->mapping->host;
 131                 struct cifsInodeInfo *cifsi = CIFS_I(inode);
 132
 133                 cFYI(1, "%s: (0x%p/0x%p)", __func__, page,
 134                                 cifsi->fscache);
 135                 if (!fscache_maybe_release_page(cifsi->fscache, page, gfp))
 136                         return 0;
 137         }
 138
 139         return 1;
 140 }
 141
 142 static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
 143                                                 int error)
 144 {
 145         cFYI(1, "%s: (0x%p/%d)", __func__, page, error);
 146         if (!error)
 147                 SetPageUptodate(page);
 148         unlock_page(page);
 149 }
 150
 151 /*
 152  * Retrieve a page from FS-Cache
 153  */
 154 int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
 155 {
 156         int ret;
 157
 158         cFYI(1, "%s: (fsc:%p, p:%p, i:0x%p", __func__,
 159                         CIFS_I(inode)->fscache, page, inode);
 160         ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
 161                                          cifs_readpage_from_fscache_complete,
 162                                          NULL,
 163                                          GFP_KERNEL);
 164         switch (ret) {
 165
 166         case 0: /* page found in fscache, read submitted */
 167                 cFYI(1, "%s: submitted", __func__);
 168                 return ret;
 169         case -ENOBUFS:  /* page won't be cached */
 170         case -ENODATA:  /* page not in cache */
 171                 cFYI(1, "%s: %d", __func__, ret);
 172                 return 1;
 173
 174         default:
 175                 cERROR(1, "unknown error ret = %d", ret);
 176         }
 177         return ret;
 178 }
 179
 180 /*
 181  * Retrieve a set of pages from FS-Cache
 182  */
 183 int __cifs_readpages_from_fscache(struct inode *inode,
 184                                 struct address_space *mapping,
 185                                 struct list_head *pages,
 186                                 unsigned *nr_pages)
 187 {
 188         int ret;
 189
 190         cFYI(1, "%s: (0x%p/%u/0x%p)", __func__,
 191                         CIFS_I(inode)->fscache, *nr_pages, inode);
 192         ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
 193                                           pages, nr_pages,
 194                                           cifs_readpage_from_fscache_complete,
 195                                           NULL,
 196                                           mapping_gfp_mask(mapping));
 197         switch (ret) {
 198         case 0: /* read submitted to the cache for all pages */
 199                 cFYI(1, "%s: submitted", __func__);
 200                 return ret;
 201
 202         case -ENOBUFS:  /* some pages are not cached and can't be */
 203         case -ENODATA:  /* some pages are not cached */
 204                 cFYI(1, "%s: no page", __func__);
 205                 return 1;
 206
 207         default:
 208                 cFYI(1, "unknown error ret = %d", ret);
 209         }
 210
 211         return ret;
 212 }
 213
 214 void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
 215 {
 216         int ret;
 217
 218         cFYI(1, "%s: (fsc: %p, p: %p, i: %p)", __func__,
 219                         CIFS_I(inode)->fscache, page, inode);
 220         ret = fscache_write_page(CIFS_I(inode)->fscache, page, GFP_KERNEL);
 221         if (ret != 0)
 222                 fscache_uncache_page(CIFS_I(inode)->fscache, page);
 223 }
 224
 225 void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
 226 {
 227         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 228         struct fscache_cookie *cookie = cifsi->fscache;
 229
 230         cFYI(1, "%s: (0x%p/0x%p)", __func__, page, cookie);
 231         fscache_wait_on_page_write(cookie, page);
 232         fscache_uncache_page(cookie, page);
 233 }
 234