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_cache_page(mapping, 0, 68 (filler_t *)mapping->a_ops->readpage, NULL); 69 if (IS_ERR(page)) 70 goto sync_fail; 71 wait_on_page_locked(page); 72 if (!PageUptodate(page)) 73 goto async_fail; 74 *ppage = page; 75 return kmap(page); 76 77 async_fail: 78 page_cache_release(page); 79 return ERR_PTR(-EIO); 80 81 sync_fail: 82 return (char*)page; 83 } 84 85 static char *ocfs2_fast_symlink_getlink(struct inode *inode, 86 struct buffer_head **bh) 87 { 88 int status; 89 char *link = NULL; 90 struct ocfs2_dinode *fe; 91 92 mlog_entry_void(); 93 94 status = ocfs2_read_block(OCFS2_SB(inode->i_sb), 95 OCFS2_I(inode)->ip_blkno, 96 bh, 97 OCFS2_BH_CACHED, 98 inode); 99 if (status < 0) { 100 mlog_errno(status); 101 link = ERR_PTR(status); 102 goto bail; 103 } 104 105 fe = (struct ocfs2_dinode *) (*bh)->b_data; 106 link = (char *) fe->id2.i_symlink; 107 bail: 108 mlog_exit(status); 109 110 return link; 111 } 112 113 static int ocfs2_readlink(struct dentry *dentry, 114 char __user *buffer, 115 int buflen) 116 { 117 int ret; 118 char *link; 119 struct buffer_head *bh = NULL; 120 struct inode *inode = dentry->d_inode; 121 122 mlog_entry_void(); 123 124 link = ocfs2_fast_symlink_getlink(inode, &bh); 125 if (IS_ERR(link)) { 126 ret = PTR_ERR(link); 127 goto out; 128 } 129 130 ret = vfs_readlink(dentry, buffer, buflen, link); 131 132 brelse(bh); 133 out: 134 mlog_exit(ret); 135 return ret; 136 } 137 138 static void *ocfs2_follow_link(struct dentry *dentry, 139 struct nameidata *nd) 140 { 141 int status; 142 char *link; 143 struct inode *inode = dentry->d_inode; 144 struct page *page = NULL; 145 struct buffer_head *bh = NULL; 146 147 if (ocfs2_inode_is_fast_symlink(inode)) 148 link = ocfs2_fast_symlink_getlink(inode, &bh); 149 else 150 link = ocfs2_page_getlink(dentry, &page); 151 if (IS_ERR(link)) { 152 status = PTR_ERR(link); 153 mlog_errno(status); 154 goto bail; 155 } 156 157 status = vfs_follow_link(nd, link); 158 if (status) 159 mlog_errno(status); 160 bail: 161 if (page) { 162 kunmap(page); 163 page_cache_release(page); 164 } 165 if (bh) 166 brelse(bh); 167 168 return ERR_PTR(status); 169 } 170 171 struct inode_operations ocfs2_symlink_inode_operations = { 172 .readlink = page_readlink, 173 .follow_link = ocfs2_follow_link, 174 .getattr = ocfs2_getattr, 175 }; 176 struct inode_operations ocfs2_fast_symlink_inode_operations = { 177 .readlink = ocfs2_readlink, 178 .follow_link = ocfs2_follow_link, 179 .getattr = ocfs2_getattr, 180 }; 181