1 /*
2 * Copyright (c) 2000-2001 Christoph Hellwig.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions, and the following disclaimer,
10 * without modification.
11 * 2. The name of the author may not be used to endorse or promote products
12 * derived from this software without specific prior written permission.
13 *
14 * Alternatively, this software may be distributed under the terms of the
15 * GNU General Public License ("GPL").
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
21 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #ident "$Id: vxfs_immed.c,v 1.10 2001/04/25 18:11:23 hch Exp hch $"
31
32 /*
33 * Veritas filesystem driver - support for 'immed' inodes.
34 */
35 #include <linux/fs.h>
36 #include <linux/pagemap.h>
37
38 #include "vxfs.h"
39 #include "vxfs_inode.h"
40
41
42 static int vxfs_immed_readlink(struct dentry *, char *, int);
43 static int vxfs_immed_follow_link(struct dentry *, struct nameidata *);
44
45 static int vxfs_immed_readpage(struct file *, struct page *);
46
47 /*
48 * Inode operations for immed symlinks.
49 *
50 * Unliked all other operations we do not go through the pagecache,
51 * but do all work directly on the inode.
52 */
53 struct inode_operations vxfs_immed_symlink_iops = {
54 .readlink = vxfs_immed_readlink,
55 .follow_link = vxfs_immed_follow_link,
56 };
57
58 /*
59 * Adress space operations for immed files and directories.
60 */
61 struct address_space_operations vxfs_immed_aops = {
62 .readpage = vxfs_immed_readpage,
63 };
64
65
66 /**
67 * vxfs_immed_readlink - read immed symlink
68 * @dp: dentry for the link
69 * @bp: output buffer
70 * @buflen: length of @bp
71 *
72 * Description:
73 * vxfs_immed_readlink calls vfs_readlink to read the link
74 * described by @dp into userspace.
75 *
76 * Returns:
77 * Number of bytes successfully copied to userspace.
78 */
79 static int
vxfs_immed_readlink(struct dentry * dp,char * bp,int buflen)80 vxfs_immed_readlink(struct dentry *dp, char *bp, int buflen)
81 {
82 struct vxfs_inode_info *vip = VXFS_INO(dp->d_inode);
83
84 return (vfs_readlink(dp, bp, buflen, vip->vii_immed.vi_immed));
85 }
86
87 /**
88 * vxfs_immed_follow_link - follow immed symlink
89 * @dp: dentry for the link
90 * @np: pathname lookup data for the current path walk
91 *
92 * Description:
93 * vxfs_immed_follow_link restarts the pathname lookup with
94 * the data obtained from @dp.
95 *
96 * Returns:
97 * Zero on success, else a negative error code.
98 */
99 static int
vxfs_immed_follow_link(struct dentry * dp,struct nameidata * np)100 vxfs_immed_follow_link(struct dentry *dp, struct nameidata *np)
101 {
102 struct vxfs_inode_info *vip = VXFS_INO(dp->d_inode);
103
104 return (vfs_follow_link(np, vip->vii_immed.vi_immed));
105 }
106
107 /**
108 * vxfs_immed_readpage - read part of an immed inode into pagecache
109 * @file: file context (unused)
110 * @page: page frame to fill in.
111 *
112 * Description:
113 * vxfs_immed_readpage reads a part of the immed area of the
114 * file that hosts @pp into the pagecache.
115 *
116 * Returns:
117 * Zero on success, else a negative error code.
118 *
119 * Locking status:
120 * @page is locked and will be unlocked.
121 */
122 static int
vxfs_immed_readpage(struct file * fp,struct page * pp)123 vxfs_immed_readpage(struct file *fp, struct page *pp)
124 {
125 struct vxfs_inode_info *vip = VXFS_INO(pp->mapping->host);
126 u_int64_t offset = pp->index << PAGE_CACHE_SHIFT;
127 caddr_t kaddr;
128
129 kaddr = kmap(pp);
130 memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
131 kunmap(pp);
132
133 flush_dcache_page(pp);
134 SetPageUptodate(pp);
135 UnlockPage(pp);
136
137 return 0;
138 }
139