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 54 #include "buffer_head_io.h" 55 56 static char *ocfs2_page_getlink(struct dentry * dentry, 57 struct page **ppage); 58 static char *ocfs2_fast_symlink_getlink(struct inode *inode, 59 struct buffer_head **bh); 60 61 /* get the link contents into pagecache */ 62 static char *ocfs2_page_getlink(struct dentry * dentry, 63 struct page **ppage) 64 { 65 struct page * page; 66 struct address_space *mapping = dentry->d_inode->i_mapping; 67 page = read_mapping_page(mapping, 0, NULL); 68 if (IS_ERR(page)) 69 goto sync_fail; 70 *ppage = page; 71 return kmap(page); 72 73 sync_fail: 74 return (char*)page; 75 } 76 77 static char *ocfs2_fast_symlink_getlink(struct inode *inode, 78 struct buffer_head **bh) 79 { 80 int status; 81 char *link = NULL; 82 struct ocfs2_dinode *fe; 83 84 mlog_entry_void(); 85 86 status = ocfs2_read_block(OCFS2_SB(inode->i_sb), 87 OCFS2_I(inode)->ip_blkno, 88 bh, 89 OCFS2_BH_CACHED, 90 inode); 91 if (status < 0) { 92 mlog_errno(status); 93 link = ERR_PTR(status); 94 goto bail; 95 } 96 97 fe = (struct ocfs2_dinode *) (*bh)->b_data; 98 link = (char *) fe->id2.i_symlink; 99 bail: 100 mlog_exit(status); 101 102 return link; 103 } 104 105 static int ocfs2_readlink(struct dentry *dentry, 106 char __user *buffer, 107 int buflen) 108 { 109 int ret; 110 char *link; 111 struct buffer_head *bh = NULL; 112 struct inode *inode = dentry->d_inode; 113 114 mlog_entry_void(); 115 116 link = ocfs2_fast_symlink_getlink(inode, &bh); 117 if (IS_ERR(link)) { 118 ret = PTR_ERR(link); 119 goto out; 120 } 121 122 /* 123 * Without vfsmount we can't update atime now, 124 * but we will update atime here ultimately. 125 */ 126 ret = vfs_readlink(dentry, buffer, buflen, link); 127 128 brelse(bh); 129 out: 130 mlog_exit(ret); 131 return ret; 132 } 133 134 static void *ocfs2_follow_link(struct dentry *dentry, 135 struct nameidata *nd) 136 { 137 int status; 138 char *link; 139 struct inode *inode = dentry->d_inode; 140 struct page *page = NULL; 141 struct buffer_head *bh = NULL; 142 143 if (ocfs2_inode_is_fast_symlink(inode)) 144 link = ocfs2_fast_symlink_getlink(inode, &bh); 145 else 146 link = ocfs2_page_getlink(dentry, &page); 147 if (IS_ERR(link)) { 148 status = PTR_ERR(link); 149 mlog_errno(status); 150 goto bail; 151 } 152 153 status = vfs_follow_link(nd, link); 154 155 bail: 156 if (page) { 157 kunmap(page); 158 page_cache_release(page); 159 } 160 if (bh) 161 brelse(bh); 162 163 return ERR_PTR(status); 164 } 165 166 const struct inode_operations ocfs2_symlink_inode_operations = { 167 .readlink = page_readlink, 168 .follow_link = ocfs2_follow_link, 169 .getattr = ocfs2_getattr, 170 .setattr = ocfs2_setattr, 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 }; 178