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 #include <linux/namei.h>
  43
  44 #define MLOG_MASK_PREFIX ML_NAMEI
  45 #include <cluster/masklog.h>
  46
  47 #include "ocfs2.h"
  48
  49 #include "alloc.h"
  50 #include "file.h"
  51 #include "inode.h"
  52 #include "journal.h"
  53 #include "symlink.h"
  54 #include "xattr.h"
  55
  56 #include "buffer_head_io.h"
  57
  58
  59 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
  60                                         struct buffer_head **bh)
  61 {
  62         int status;
  63         char *link = NULL;
  64         struct ocfs2_dinode *fe;
  65
  66         mlog_entry_void();
  67
  68         status = ocfs2_read_inode_block(inode, bh);
  69         if (status < 0) {
  70                 mlog_errno(status);
  71                 link = ERR_PTR(status);
  72                 goto bail;
  73         }
  74
  75         fe = (struct ocfs2_dinode *) (*bh)->b_data;
  76         link = (char *) fe->id2.i_symlink;
  77 bail:
  78         mlog_exit(status);
  79
  80         return link;
  81 }
  82
  83 static int ocfs2_readlink(struct dentry *dentry,
  84                           char __user *buffer,
  85                           int buflen)
  86 {
  87         int ret;
  88         char *link;
  89         struct buffer_head *bh = NULL;
  90         struct inode *inode = dentry->d_inode;
  91
  92         mlog_entry_void();
  93
  94         link = ocfs2_fast_symlink_getlink(inode, &bh);
  95         if (IS_ERR(link)) {
  96                 ret = PTR_ERR(link);
  97                 goto out;
  98         }
  99
 100         /*
 101          * Without vfsmount we can't update atime now,
 102          * but we will update atime here ultimately.
 103          */
 104         ret = vfs_readlink(dentry, buffer, buflen, link);
 105
 106         brelse(bh);
 107 out:
 108         mlog_exit(ret);
 109         return ret;
 110 }
 111
 112 static void *ocfs2_fast_follow_link(struct dentry *dentry,
 113                                     struct nameidata *nd)
 114 {
 115         int status = 0;
 116         int len;
 117         char *target, *link = ERR_PTR(-ENOMEM);
 118         struct inode *inode = dentry->d_inode;
 119         struct buffer_head *bh = NULL;
 120
 121         mlog_entry_void();
 122
 123         BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
 124         target = ocfs2_fast_symlink_getlink(inode, &bh);
 125         if (IS_ERR(target)) {
 126                 status = PTR_ERR(target);
 127                 mlog_errno(status);
 128                 goto bail;
 129         }
 130
 131         /* Fast symlinks can't be large */
 132         len = strlen(target);
 133         link = kzalloc(len + 1, GFP_NOFS);
 134         if (!link) {
 135                 status = -ENOMEM;
 136                 mlog_errno(status);
 137                 goto bail;
 138         }
 139
 140         memcpy(link, target, len);
 141         nd_set_link(nd, link);
 142
 143 bail:
 144         brelse(bh);
 145
 146         mlog_exit(status);
 147         return status ? ERR_PTR(status) : link;
 148 }
 149
 150 static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 151 {
 152         char *link = cookie;
 153
 154         kfree(link);
 155 }
 156
 157 const struct inode_operations ocfs2_symlink_inode_operations = {
 158         .readlink       = page_readlink,
 159         .follow_link    = page_follow_link_light,
 160         .put_link       = page_put_link,
 161         .getattr        = ocfs2_getattr,
 162         .setattr        = ocfs2_setattr,
 163         .setxattr       = generic_setxattr,
 164         .getxattr       = generic_getxattr,
 165         .listxattr      = ocfs2_listxattr,
 166         .removexattr    = generic_removexattr,
 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 };