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 wait_on_page_locked(page); 71 if (!PageUptodate(page)) 72 goto async_fail; 73 *ppage = page; 74 return kmap(page); 75 76 async_fail: 77 page_cache_release(page); 78 return ERR_PTR(-EIO); 79 80 sync_fail: 81 return (char*)page; 82 } 83 84 static char *ocfs2_fast_symlink_getlink(struct inode *inode, 85 struct buffer_head **bh) 86 { 87 int status; 88 char *link = NULL; 89 struct ocfs2_dinode *fe; 90 91 mlog_entry_void(); 92 93 status = ocfs2_read_block(OCFS2_SB(inode->i_sb), 94 OCFS2_I(inode)->ip_blkno, 95 bh, 96 OCFS2_BH_CACHED, 97 inode); 98 if (status < 0) { 99 mlog_errno(status); 100 link = ERR_PTR(status); 101 goto bail; 102 } 103 104 fe = (struct ocfs2_dinode *) (*bh)->b_data; 105 link = (char *) fe->id2.i_symlink; 106 bail: 107 mlog_exit(status); 108 109 return link; 110 } 111 112 static int ocfs2_readlink(struct dentry *dentry, 113 char __user *buffer, 114 int buflen) 115 { 116 int ret; 117 char *link; 118 struct buffer_head *bh = NULL; 119 struct inode *inode = dentry->d_inode; 120 121 mlog_entry_void(); 122 123 link = ocfs2_fast_symlink_getlink(inode, &bh); 124 if (IS_ERR(link)) { 125 ret = PTR_ERR(link); 126 goto out; 127 } 128 129 ret = vfs_readlink(dentry, buffer, buflen, link); 130 131 brelse(bh); 132 out: 133 mlog_exit(ret); 134 return ret; 135 } 136 137 static void *ocfs2_follow_link(struct dentry *dentry, 138 struct nameidata *nd) 139 { 140 int status; 141 char *link; 142 struct inode *inode = dentry->d_inode; 143 struct page *page = NULL; 144 struct buffer_head *bh = NULL; 145 146 if (ocfs2_inode_is_fast_symlink(inode)) 147 link = ocfs2_fast_symlink_getlink(inode, &bh); 148 else 149 link = ocfs2_page_getlink(dentry, &page); 150 if (IS_ERR(link)) { 151 status = PTR_ERR(link); 152 mlog_errno(status); 153 goto bail; 154 } 155 156 status = vfs_follow_link(nd, link); 157 if (status && status != -ENOENT) 158 mlog_errno(status); 159 bail: 160 if (page) { 161 kunmap(page); 162 page_cache_release(page); 163 } 164 if (bh) 165 brelse(bh); 166 167 return ERR_PTR(status); 168 } 169 170 struct inode_operations ocfs2_symlink_inode_operations = { 171 .readlink = page_readlink, 172 .follow_link = ocfs2_follow_link, 173 .getattr = ocfs2_getattr, 174 }; 175 struct inode_operations ocfs2_fast_symlink_inode_operations = { 176 .readlink = ocfs2_readlink, 177 .follow_link = ocfs2_follow_link, 178 .getattr = ocfs2_getattr, 179 }; 180