fs/ocfs2/symlink.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  *  linux/cluster/ssi/cfs/symlink.c
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License as
   8  *      published by the Free Software Foundation; either version 2 of
   9  *      the License, or (at your option) any later version.
  10  *
  11  *      This program is distributed in the hope that it will be useful,
  12  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *      MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE
  14  *      or NON INFRINGEMENT.  See the GNU General Public License for more
  15  *      details.
  16  *
  17  *      You should have received a copy of the GNU General Public License
  18  *      along with this program; if not, write to the Free Software
  19  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  *      Questions/Comments/Bugfixes to ssic-linux-devel@lists.sourceforge.net
  22  *
  23  *  Copyright (C) 1992  Rick Sladkey
  24  *
  25  *  Optimization changes Copyright (C) 1994 Florian La Roche
  26  *
  27  *  Jun 7 1999, cache symlink lookups in the page cache.  -DaveM
  28  *
  29  *  Portions Copyright (C) 2001 Compaq Computer Corporation
  30  *
  31  *  ocfs2 symlink handling code.
  32  *
  33  *  Copyright (C) 2004, 2005 Oracle.
  34  *
  35  */
  36
  37 #include <linux/fs.h>
  38 #include <linux/types.h>
  39 #include <linux/slab.h>
  40 #include <linux/pagemap.h>
  41 #include <linux/utsname.h>
  42
  43 #define MLOG_MASK_PREFIX ML_NAMEI
  44 #include <cluster/masklog.h>
  45
  46 #include "ocfs2.h"
  47
  48 #include "alloc.h"
  49 #include "file.h"
  50 #include "inode.h"
  51 #include "journal.h"
  52 #include "symlink.h"
  53 #include "xattr.h"
  54
  55 #include "buffer_head_io.h"
  56
  57 static char *ocfs2_page_getlink(struct dentry * dentry,
  58                                 struct page **ppage);
  59 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
  60                                         struct buffer_head **bh);
  61
  62 /* get the link contents into pagecache */
  63 static char *ocfs2_page_getlink(struct dentry * dentry,
  64                                 struct page **ppage)
  65 {
  66         struct page * page;
  67         struct address_space *mapping = dentry->d_inode->i_mapping;
  68         page = read_mapping_page(mapping, 0, NULL);
  69         if (IS_ERR(page))
  70                 goto sync_fail;
  71         *ppage = page;
  72         return kmap(page);
  73
  74 sync_fail:
  75         return (char*)page;
  76 }
  77
  78 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
  79                                         struct buffer_head **bh)
  80 {
  81         int status;
  82         char *link = NULL;
  83         struct ocfs2_dinode *fe;
  84
  85         mlog_entry_void();
  86
  87         status = ocfs2_read_inode_block(inode, bh);
  88         if (status < 0) {
  89                 mlog_errno(status);
  90                 link = ERR_PTR(status);
  91                 goto bail;
  92         }
  93
  94         fe = (struct ocfs2_dinode *) (*bh)->b_data;
  95         link = (char *) fe->id2.i_symlink;
  96 bail:
  97         mlog_exit(status);
  98
  99         return link;
 100 }
 101
 102 static int ocfs2_readlink(struct dentry *dentry,
 103                           char __user *buffer,
 104                           int buflen)
 105 {
 106         int ret;
 107         char *link;
 108         struct buffer_head *bh = NULL;
 109         struct inode *inode = dentry->d_inode;
 110
 111         mlog_entry_void();
 112
 113         link = ocfs2_fast_symlink_getlink(inode, &bh);
 114         if (IS_ERR(link)) {
 115                 ret = PTR_ERR(link);
 116                 goto out;
 117         }
 118
 119         /*
 120          * Without vfsmount we can't update atime now,
 121          * but we will update atime here ultimately.
 122          */
 123         ret = vfs_readlink(dentry, buffer, buflen, link);
 124
 125         brelse(bh);
 126 out:
 127         mlog_exit(ret);
 128         return ret;
 129 }
 130
 131 static void *ocfs2_follow_link(struct dentry *dentry,
 132                                struct nameidata *nd)
 133 {
 134         int status;
 135         char *link;
 136         struct inode *inode = dentry->d_inode;
 137         struct page *page = NULL;
 138         struct buffer_head *bh = NULL;
 139
 140         if (ocfs2_inode_is_fast_symlink(inode))
 141                 link = ocfs2_fast_symlink_getlink(inode, &bh);
 142         else
 143                 link = ocfs2_page_getlink(dentry, &page);
 144         if (IS_ERR(link)) {
 145                 status = PTR_ERR(link);
 146                 mlog_errno(status);
 147                 goto bail;
 148         }
 149
 150         status = vfs_follow_link(nd, link);
 151
 152 bail:
 153         if (page) {
 154                 kunmap(page);
 155                 page_cache_release(page);
 156         }
 157         brelse(bh);
 158
 159         return ERR_PTR(status);
 160 }
 161
 162 const struct inode_operations ocfs2_symlink_inode_operations = {
 163         .readlink       = page_readlink,
 164         .follow_link    = ocfs2_follow_link,
 165         .getattr        = ocfs2_getattr,
 166         .setattr        = ocfs2_setattr,
 167         .setxattr       = generic_setxattr,
 168         .getxattr       = generic_getxattr,
 169         .listxattr      = ocfs2_listxattr,
 170         .removexattr    = generic_removexattr,
 171 };
 172 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
 173         .readlink       = ocfs2_readlink,
 174         .follow_link    = ocfs2_follow_link,
 175         .getattr        = ocfs2_getattr,
 176         .setattr        = ocfs2_setattr,
 177         .setxattr       = generic_setxattr,
 178         .getxattr       = generic_getxattr,
 179         .listxattr      = ocfs2_listxattr,
 180         .removexattr    = generic_removexattr,
 181 };