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_block(OCFS2_SB(inode->i_sb),
  88                                   OCFS2_I(inode)->ip_blkno,
  89                                   bh,
  90                                   OCFS2_BH_CACHED,
  91                                   inode);
  92         if (status < 0) {
  93                 mlog_errno(status);
  94                 link = ERR_PTR(status);
  95                 goto bail;
  96         }
  97
  98         fe = (struct ocfs2_dinode *) (*bh)->b_data;
  99         link = (char *) fe->id2.i_symlink;
 100 bail:
 101         mlog_exit(status);
 102
 103         return link;
 104 }
 105
 106 static int ocfs2_readlink(struct dentry *dentry,
 107                           char __user *buffer,
 108                           int buflen)
 109 {
 110         int ret;
 111         char *link;
 112         struct buffer_head *bh = NULL;
 113         struct inode *inode = dentry->d_inode;
 114
 115         mlog_entry_void();
 116
 117         link = ocfs2_fast_symlink_getlink(inode, &bh);
 118         if (IS_ERR(link)) {
 119                 ret = PTR_ERR(link);
 120                 goto out;
 121         }
 122
 123         /*
 124          * Without vfsmount we can't update atime now,
 125          * but we will update atime here ultimately.
 126          */
 127         ret = vfs_readlink(dentry, buffer, buflen, link);
 128
 129         brelse(bh);
 130 out:
 131         mlog_exit(ret);
 132         return ret;
 133 }
 134
 135 static void *ocfs2_follow_link(struct dentry *dentry,
 136                                struct nameidata *nd)
 137 {
 138         int status;
 139         char *link;
 140         struct inode *inode = dentry->d_inode;
 141         struct page *page = NULL;
 142         struct buffer_head *bh = NULL;
 143
 144         if (ocfs2_inode_is_fast_symlink(inode))
 145                 link = ocfs2_fast_symlink_getlink(inode, &bh);
 146         else
 147                 link = ocfs2_page_getlink(dentry, &page);
 148         if (IS_ERR(link)) {
 149                 status = PTR_ERR(link);
 150                 mlog_errno(status);
 151                 goto bail;
 152         }
 153
 154         status = vfs_follow_link(nd, link);
 155
 156 bail:
 157         if (page) {
 158                 kunmap(page);
 159                 page_cache_release(page);
 160         }
 161         if (bh)
 162                 brelse(bh);
 163
 164         return ERR_PTR(status);
 165 }
 166
 167 const struct inode_operations ocfs2_symlink_inode_operations = {
 168         .readlink       = page_readlink,
 169         .follow_link    = ocfs2_follow_link,
 170         .getattr        = ocfs2_getattr,
 171         .setattr        = ocfs2_setattr,
 172         .setxattr       = generic_setxattr,
 173         .getxattr       = generic_getxattr,
 174         .listxattr      = ocfs2_listxattr,
 175         .removexattr    = generic_removexattr,
 176 };
 177 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
 178         .readlink       = ocfs2_readlink,
 179         .follow_link    = ocfs2_follow_link,
 180         .getattr        = ocfs2_getattr,
 181         .setattr        = ocfs2_setattr,
 182         .setxattr       = generic_setxattr,
 183         .getxattr       = generic_getxattr,
 184         .listxattr      = ocfs2_listxattr,
 185         .removexattr    = generic_removexattr,
 186 };