release/src-rt-6.x.4708/linux/linux-2.6.36/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
  66         if (cifsi->fscache)
  67                 return;
  68
  69         cifsi->fscache = fscache_acquire_cookie(cifs_sb->tcon->fscache,
  70                                 &cifs_fscache_inode_object_def,
  71                                 cifsi);
  72         cFYI(1, "CIFS: got FH cookie (0x%p/0x%p)",
  73                         cifs_sb->tcon->fscache, 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(cifs_sb->tcon->fscache,
 121                                         &cifs_fscache_inode_object_def,
 122                                         cifsi);
 123                 cFYI(1, "CIFS: new cookie 0x%p oldcookie 0x%p",
 124                                 cifsi->fscache, old);
 125         }
 126 }
 127
 128 int cifs_fscache_release_page(struct page *page, gfp_t gfp)
 129 {
 130         if (PageFsCache(page)) {
 131                 struct inode *inode = page->mapping->host;
 132                 struct cifsInodeInfo *cifsi = CIFS_I(inode);
 133
 134                 cFYI(1, "CIFS: fscache release page (0x%p/0x%p)",
 135                                 page, cifsi->fscache);
 136                 if (!fscache_maybe_release_page(cifsi->fscache, page, gfp))
 137                         return 0;
 138         }
 139
 140         return 1;
 141 }
 142
 143 static void cifs_readpage_from_fscache_complete(struct page *page, void *ctx,
 144                                                 int error)
 145 {
 146         cFYI(1, "CFS: readpage_from_fscache_complete (0x%p/%d)",
 147                         page, error);
 148         if (!error)
 149                 SetPageUptodate(page);
 150         unlock_page(page);
 151 }
 152
 153 /*
 154  * Retrieve a page from FS-Cache
 155  */
 156 int __cifs_readpage_from_fscache(struct inode *inode, struct page *page)
 157 {
 158         int ret;
 159
 160         cFYI(1, "CIFS: readpage_from_fscache(fsc:%p, p:%p, i:0x%p",
 161                         CIFS_I(inode)->fscache, page, inode);
 162         ret = fscache_read_or_alloc_page(CIFS_I(inode)->fscache, page,
 163                                          cifs_readpage_from_fscache_complete,
 164                                          NULL,
 165                                          GFP_KERNEL);
 166         switch (ret) {
 167
 168         case 0: /* page found in fscache, read submitted */
 169                 cFYI(1, "CIFS: readpage_from_fscache: submitted");
 170                 return ret;
 171         case -ENOBUFS:  /* page won't be cached */
 172         case -ENODATA:  /* page not in cache */
 173                 cFYI(1, "CIFS: readpage_from_fscache %d", ret);
 174                 return 1;
 175
 176         default:
 177                 cERROR(1, "unknown error ret = %d", ret);
 178         }
 179         return ret;
 180 }
 181
 182 /*
 183  * Retrieve a set of pages from FS-Cache
 184  */
 185 int __cifs_readpages_from_fscache(struct inode *inode,
 186                                 struct address_space *mapping,
 187                                 struct list_head *pages,
 188                                 unsigned *nr_pages)
 189 {
 190         int ret;
 191
 192         cFYI(1, "CIFS: __cifs_readpages_from_fscache (0x%p/%u/0x%p)",
 193                         CIFS_I(inode)->fscache, *nr_pages, inode);
 194         ret = fscache_read_or_alloc_pages(CIFS_I(inode)->fscache, mapping,
 195                                           pages, nr_pages,
 196                                           cifs_readpage_from_fscache_complete,
 197                                           NULL,
 198                                           mapping_gfp_mask(mapping));
 199         switch (ret) {
 200         case 0: /* read submitted to the cache for all pages */
 201                 cFYI(1, "CIFS: readpages_from_fscache: submitted");
 202                 return ret;
 203
 204         case -ENOBUFS:  /* some pages are not cached and can't be */
 205         case -ENODATA:  /* some pages are not cached */
 206                 cFYI(1, "CIFS: readpages_from_fscache: no page");
 207                 return 1;
 208
 209         default:
 210                 cFYI(1, "unknown error ret = %d", ret);
 211         }
 212
 213         return ret;
 214 }
 215
 216 void __cifs_readpage_to_fscache(struct inode *inode, struct page *page)
 217 {
 218         int ret;
 219
 220         cFYI(1, "CIFS: readpage_to_fscache(fsc: %p, p: %p, i: %p",
 221                         CIFS_I(inode)->fscache, page, inode);
 222         ret = fscache_write_page(CIFS_I(inode)->fscache, page, GFP_KERNEL);
 223         if (ret != 0)
 224                 fscache_uncache_page(CIFS_I(inode)->fscache, page);
 225 }
 226
 227 void __cifs_fscache_invalidate_page(struct page *page, struct inode *inode)
 228 {
 229         struct cifsInodeInfo *cifsi = CIFS_I(inode);
 230         struct fscache_cookie *cookie = cifsi->fscache;
 231
 232         cFYI(1, "CIFS: fscache invalidatepage (0x%p/0x%p)", page, cookie);
 233         fscache_wait_on_page_write(cookie, page);
 234         fscache_uncache_page(cookie, page);
 235 }