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 #include <cluster/masklog.h>
  44
  45 #include "ocfs2.h"
  46
  47 #include "alloc.h"
  48 #include "file.h"
  49 #include "inode.h"
  50 #include "journal.h"
  51 #include "symlink.h"
  52 #include "xattr.h"
  53
  54 #include "buffer_head_io.h"
  55
  56
  57 static char *ocfs2_fast_symlink_getlink(struct inode *inode,
  58                                         struct buffer_head **bh)
  59 {
  60         int status;
  61         char *link = NULL;
  62         struct ocfs2_dinode *fe;
  63
  64         status = ocfs2_read_inode_block(inode, bh);
  65         if (status < 0) {
  66                 mlog_errno(status);
  67                 link = ERR_PTR(status);
  68                 goto bail;
  69         }
  70
  71         fe = (struct ocfs2_dinode *) (*bh)->b_data;
  72         link = (char *) fe->id2.i_symlink;
  73 bail:
  74
  75         return link;
  76 }
  77
  78 static int ocfs2_readlink(struct dentry *dentry,
  79                           char __user *buffer,
  80                           int buflen)
  81 {
  82         int ret;
  83         char *link;
  84         struct buffer_head *bh = NULL;
  85         struct inode *inode = dentry->d_inode;
  86
  87         link = ocfs2_fast_symlink_getlink(inode, &bh);
  88         if (IS_ERR(link)) {
  89                 ret = PTR_ERR(link);
  90                 goto out;
  91         }
  92
  93         /*
  94          * Without vfsmount we can't update atime now,
  95          * but we will update atime here ultimately.
  96          */
  97         ret = vfs_readlink(dentry, buffer, buflen, link);
  98
  99         brelse(bh);
 100 out:
 101         if (ret < 0)
 102                 mlog_errno(ret);
 103         return ret;
 104 }
 105
 106 static void *ocfs2_fast_follow_link(struct dentry *dentry,
 107                                     struct nameidata *nd)
 108 {
 109         int status = 0;
 110         int len;
 111         char *target, *link = ERR_PTR(-ENOMEM);
 112         struct inode *inode = dentry->d_inode;
 113         struct buffer_head *bh = NULL;
 114
 115         BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
 116         target = ocfs2_fast_symlink_getlink(inode, &bh);
 117         if (IS_ERR(target)) {
 118                 status = PTR_ERR(target);
 119                 mlog_errno(status);
 120                 goto bail;
 121         }
 122
 123         /* Fast symlinks can't be large */
 124         len = strnlen(target, ocfs2_fast_symlink_chars(inode->i_sb));
 125         link = kzalloc(len + 1, GFP_NOFS);
 126         if (!link) {
 127                 status = -ENOMEM;
 128                 mlog_errno(status);
 129                 goto bail;
 130         }
 131
 132         memcpy(link, target, len);
 133
 134 bail:
 135         nd_set_link(nd, status ? ERR_PTR(status) : link);
 136         brelse(bh);
 137
 138         if (status)
 139                 mlog_errno(status);
 140         return NULL;
 141 }
 142
 143 static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
 144 {
 145         char *link = nd_get_link(nd);
 146         if (!IS_ERR(link))
 147                 kfree(link);
 148 }
 149
 150 const struct inode_operations ocfs2_symlink_inode_operations = {
 151         .readlink       = page_readlink,
 152         .follow_link    = page_follow_link_light,
 153         .put_link       = page_put_link,
 154         .getattr        = ocfs2_getattr,
 155         .setattr        = ocfs2_setattr,
 156         .setxattr       = generic_setxattr,
 157         .getxattr       = generic_getxattr,
 158         .listxattr      = ocfs2_listxattr,
 159         .removexattr    = generic_removexattr,
 160         .fiemap         = ocfs2_fiemap,
 161 };
 162 const struct inode_operations ocfs2_fast_symlink_inode_operations = {
 163         .readlink       = ocfs2_readlink,
 164         .follow_link    = ocfs2_fast_follow_link,
 165         .put_link       = ocfs2_fast_put_link,
 166         .getattr        = ocfs2_getattr,
 167         .setattr        = ocfs2_setattr,
 168         .setxattr       = generic_setxattr,
 169         .getxattr       = generic_getxattr,
 170         .listxattr      = ocfs2_listxattr,
 171         .removexattr    = generic_removexattr,
 172         .fiemap         = ocfs2_fiemap,
 173 };