release/src-rt-6.x.4708/linux/linux-2.6.36/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/namei.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
  58 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
  59                                         struct buffer_head **bh)
  60 {
  61         int status;
  62         char *link = NULL;
  63         struct ocfs2_dinode *fe;
  64
  65         mlog_entry_void();
  66
  67         status = ocfs2_read_inode_block(inode, bh);
  68         if (status < 0) {
  69                 mlog_errno(status);
  70                 link = ERR_PTR(status);
  71                 goto bail;
  72         }
  73
  74         fe = (struct ocfs2_dinode *) (*bh)->b_data;
  75         link = (char *) fe->id2.i_symlink;
  76 bail:
  77         mlog_exit(status);
  78
  79         return link;
  80 }
  81
  82 static int ocfs2_readlink(struct dentry *dentry,
  83                           char __user *buffer,
  84                           int buflen)
  85 {
  86         int ret;
  87         char *link;
  88         struct buffer_head *bh = NULL;
  89         struct inode *inode = dentry->d_inode;
  90
  91         mlog_entry_void();
  92
  93         link = ocfs2_fast_symlink_getlink(inode, &bh);
  94         if (IS_ERR(link)) {
  95                 ret = PTR_ERR(link);
  96                 goto out;
  97         }
  98
  99         /*
 100          * Without vfsmount we can't update atime now,
 101          * but we will update atime here ultimately.
 102          */
 103         ret = vfs_readlink(dentry, buffer, buflen, link);
 104
 105         brelse(bh);
 106 out:
 107         mlog_exit(ret);
 108         return ret;
 109 }
 110
 111 static void *ocfs2_fast_follow_link(struct dentry *dentry,
 112                                     struct nameidata *nd)
 113 {
 114         int status = 0;
 115         int len;
 116         char *target, *link = ERR_PTR(-ENOMEM);
 117         struct inode *inode = dentry->d_inode;
 118         struct buffer_head *bh = NULL;
 119
 120         mlog_entry_void();
 121
 122         BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
 123         target = ocfs2_fast_symlink_getlink(inode, &bh);
 124         if (IS_ERR(target)) {
 125                 status = PTR_ERR(target);
 126                 mlog_errno(status);
 127                 goto bail;
 128         }
 129
 130         /* Fast symlinks can't be large */
 131         len = strnlen(target, ocfs2_fast_symlink_chars(inode->i_sb));
 132         link = kzalloc(len + 1, GFP_NOFS);
 133         if (!link) {
 134                 status = -ENOMEM;
 135                 mlog_errno(status);
 136                 goto bail;
 137         }
 138
 139         memcpy(link, target, len);
 140
 141 bail:
 142         nd_set_link(nd, status ? ERR_PTR(status) : link);
 143         brelse(bh);
 144
 145         mlog_exit(status);
 146         return NULL;
 147 }
 148
 149 static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 150 {
 151         char *link = nd_get_link(nd);
 152         if (!IS_ERR(link))
 153                 kfree(link);
 154 }
 155
 156 const struct inode_operations ocfs2_symlink_inode_operations = {
 157         .readlink       = page_readlink,
 158         .follow_link    = page_follow_link_light,
 159         .put_link       = page_put_link,
 160         .getattr        = ocfs2_getattr,
 161         .setattr        = ocfs2_setattr,
 162         .setxattr       = generic_setxattr,
 163         .getxattr       = generic_getxattr,
 164         .listxattr      = ocfs2_listxattr,
 165         .removexattr    = generic_removexattr,
 166         .fiemap         = ocfs2_fiemap,
 167 };
 168 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
 169         .readlink       = ocfs2_readlink,
 170         .follow_link    = ocfs2_fast_follow_link,
 171         .put_link       = ocfs2_fast_put_link,
 172         .getattr        = ocfs2_getattr,
 173         .setattr        = ocfs2_setattr,
 174         .setxattr       = generic_setxattr,
 175         .getxattr       = generic_getxattr,
 176         .listxattr      = ocfs2_listxattr,
 177         .removexattr    = generic_removexattr,
 178         .fiemap         = ocfs2_fiemap,
 179 };