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authorDavid Howells <dhowells@redhat.com>2007-05-11 01:51:50 -0400
committerDavid Woodhouse <dwmw2@infradead.org>2007-05-11 07:14:15 -0400
commitacaebfd8a7af0019b2edfcf4045c56c3e18375c5 (patch)
tree312d91a96fbc6ed3672220e2c4087a196e5ab6cf /drivers/mtd/mtdsuper.c
parent33672f72b24191fb17c3666ec1c620f3fa617b50 (diff)
[MTD] generalise the handling of MTD-specific superblocks
Generalise the handling of MTD-specific superblocks so that JFFS2 and ROMFS can both share it. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Diffstat (limited to 'drivers/mtd/mtdsuper.c')
-rw-r--r--drivers/mtd/mtdsuper.c232
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
new file mode 100644
index 000000000000..a279540ba87a
--- /dev/null
+++ b/drivers/mtd/mtdsuper.c
@@ -0,0 +1,232 @@
1/* MTD-based superblock management
2 *
3 * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
4 * Written by: David Howells <dhowells@redhat.com>
5 * David Woodhouse <dwmw2@infradead.org>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/mtd/super.h>
14#include <linux/namei.h>
15#include <linux/ctype.h>
16
17/*
18 * compare superblocks to see if they're equivalent
19 * - they are if the underlying MTD device is the same
20 */
21static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
22{
23 struct mtd_info *mtd = _mtd;
24
25 if (sb->s_mtd == mtd) {
26 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
27 mtd->index, mtd->name);
28 return 1;
29 }
30
31 DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
32 sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
33 return 0;
34}
35
36/*
37 * mark the superblock by the MTD device it is using
38 * - set the device number to be the correct MTD block device for pesuperstence
39 * of NFS exports
40 */
41static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
42{
43 struct mtd_info *mtd = _mtd;
44
45 sb->s_mtd = mtd;
46 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
47 return 0;
48}
49
50/*
51 * get a superblock on an MTD-backed filesystem
52 */
53static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
54 const char *dev_name, void *data,
55 struct mtd_info *mtd,
56 int (*fill_super)(struct super_block *, void *, int),
57 struct vfsmount *mnt)
58{
59 struct super_block *sb;
60 int ret;
61
62 sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
63 if (IS_ERR(sb))
64 goto out_error;
65
66 if (sb->s_root)
67 goto already_mounted;
68
69 /* fresh new superblock */
70 DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
71 mtd->index, mtd->name);
72
73 ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
74 if (ret < 0) {
75 up_write(&sb->s_umount);
76 deactivate_super(sb);
77 return ret;
78 }
79
80 /* go */
81 sb->s_flags |= MS_ACTIVE;
82 return simple_set_mnt(mnt, sb);
83
84 /* new mountpoint for an already mounted superblock */
85already_mounted:
86 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
87 mtd->index, mtd->name);
88 ret = simple_set_mnt(mnt, sb);
89 goto out_put;
90
91out_error:
92 ret = PTR_ERR(sb);
93out_put:
94 put_mtd_device(mtd);
95 return ret;
96}
97
98/*
99 * get a superblock on an MTD-backed filesystem by MTD device number
100 */
101static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
102 const char *dev_name, void *data, int mtdnr,
103 int (*fill_super)(struct super_block *, void *, int),
104 struct vfsmount *mnt)
105{
106 struct mtd_info *mtd;
107
108 mtd = get_mtd_device(NULL, mtdnr);
109 if (!mtd) {
110 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
111 return -EINVAL;
112 }
113
114 return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
115 mnt);
116}
117
118/*
119 * set up an MTD-based superblock
120 */
121int get_sb_mtd(struct file_system_type *fs_type, int flags,
122 const char *dev_name, void *data,
123 int (*fill_super)(struct super_block *, void *, int),
124 struct vfsmount *mnt)
125{
126 struct nameidata nd;
127 int mtdnr, ret;
128
129 if (!dev_name)
130 return -EINVAL;
131
132 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
133
134 /* the preferred way of mounting in future; especially when
135 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
136 * by name, so that we don't require block device support to be present
137 * in the kernel. */
138 if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
139 if (dev_name[3] == ':') {
140 struct mtd_info *mtd;
141
142 /* mount by MTD device name */
143 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
144 dev_name + 4);
145
146 for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
147 mtd = get_mtd_device(NULL, mtdnr);
148 if (mtd) {
149 if (!strcmp(mtd->name, dev_name + 4))
150 return get_sb_mtd_aux(
151 fs_type, flags,
152 dev_name, data, mtd,
153 fill_super, mnt);
154
155 put_mtd_device(mtd);
156 }
157 }
158
159 printk(KERN_NOTICE "MTD:"
160 " MTD device with name \"%s\" not found.\n",
161 dev_name + 4);
162
163 } else if (isdigit(dev_name[3])) {
164 /* mount by MTD device number name */
165 char *endptr;
166
167 mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
168 if (!*endptr) {
169 /* It was a valid number */
170 DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
171 mtdnr);
172 return get_sb_mtd_nr(fs_type, flags,
173 dev_name, data,
174 mtdnr, fill_super, mnt);
175 }
176 }
177 }
178
179 /* try the old way - the hack where we allowed users to mount
180 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
181 */
182 ret = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
183
184 DEBUG(1, "MTDSB: path_lookup() returned %d, inode %p\n",
185 ret, nd.dentry ? nd.dentry->d_inode : NULL);
186
187 if (ret)
188 return ret;
189
190 ret = -EINVAL;
191
192 if (!S_ISBLK(nd.dentry->d_inode->i_mode))
193 goto out;
194
195 if (nd.mnt->mnt_flags & MNT_NODEV) {
196 ret = -EACCES;
197 goto out;
198 }
199
200 if (imajor(nd.dentry->d_inode) != MTD_BLOCK_MAJOR)
201 goto not_an_MTD_device;
202
203 mtdnr = iminor(nd.dentry->d_inode);
204 path_release(&nd);
205
206 return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
207 mnt);
208
209not_an_MTD_device:
210 if (!(flags & MS_SILENT))
211 printk(KERN_NOTICE
212 "MTD: Attempt to mount non-MTD device \"%s\"\n",
213 dev_name);
214out:
215 path_release(&nd);
216 return ret;
217
218}
219
220EXPORT_SYMBOL_GPL(get_sb_mtd);
221
222/*
223 * destroy an MTD-based superblock
224 */
225void kill_mtd_super(struct super_block *sb)
226{
227 generic_shutdown_super(sb);
228 put_mtd_device(sb->s_mtd);
229 sb->s_mtd = NULL;
230}
231
232EXPORT_SYMBOL_GPL(kill_mtd_super);