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 /*
31 * Veritas filesystem driver - support for 'immed' inodes.
32 */
33 #include <linux/fs.h>
34 #include <linux/pagemap.h>
35 #include <linux/namei.h>
36
37 #include "vxfs.h"
38 #include "vxfs_extern.h"
39 #include "vxfs_inode.h"
40
41
42 static void * vxfs_immed_follow_link(struct dentry *, struct nameidata *);
43
44 static int vxfs_immed_readpage(struct file *, struct page *);
45
46 /*
47 * Inode operations for immed symlinks.
48 *
49 * Unliked all other operations we do not go through the pagecache,
50 * but do all work directly on the inode.
51 */
52 const struct inode_operations vxfs_immed_symlink_iops = {
53 .readlink = generic_readlink,
54 .follow_link = vxfs_immed_follow_link,
55 };
56
57 /*
58 * Address space operations for immed files and directories.
59 */
60 const struct address_space_operations vxfs_immed_aops = {
61 .readpage = vxfs_immed_readpage,
62 };
63
64 /**
65 * vxfs_immed_follow_link - follow immed symlink
66 * @dp: dentry for the link
67 * @np: pathname lookup data for the current path walk
68 *
69 * Description:
70 * vxfs_immed_follow_link restarts the pathname lookup with
71 * the data obtained from @dp.
72 *
73 * Returns:
74 * Zero on success, else a negative error code.
75 */
76 static void *
vxfs_immed_follow_link(struct dentry * dp,struct nameidata * np)77 vxfs_immed_follow_link(struct dentry *dp, struct nameidata *np)
78 {
79 struct vxfs_inode_info *vip = VXFS_INO(dp->d_inode);
80 nd_set_link(np, vip->vii_immed.vi_immed);
81 return NULL;
82 }
83
84 /**
85 * vxfs_immed_readpage - read part of an immed inode into pagecache
86 * @file: file context (unused)
87 * @page: page frame to fill in.
88 *
89 * Description:
90 * vxfs_immed_readpage reads a part of the immed area of the
91 * file that hosts @pp into the pagecache.
92 *
93 * Returns:
94 * Zero on success, else a negative error code.
95 *
96 * Locking status:
97 * @page is locked and will be unlocked.
98 */
99 static int
vxfs_immed_readpage(struct file * fp,struct page * pp)100 vxfs_immed_readpage(struct file *fp, struct page *pp)
101 {
102 struct vxfs_inode_info *vip = VXFS_INO(pp->mapping->host);
103 u_int64_t offset = (u_int64_t)pp->index << PAGE_CACHE_SHIFT;
104 caddr_t kaddr;
105
106 kaddr = kmap(pp);
107 memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
108 kunmap(pp);
109
110 flush_dcache_page(pp);
111 SetPageUptodate(pp);
112 unlock_page(pp);
113
114 return 0;
115 }
116