1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
/* MTD-based superblock management
*
* Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
* Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
*
* Written by: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@infradead.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/mtd/super.h>
#include <linux/namei.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/backing-dev.h>
/*
* compare superblocks to see if they're equivalent
* - they are if the underlying MTD device is the same
*/
static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
if (sb->s_mtd == mtd) {
pr_debug("MTDSB: Match on device %d (\"%s\")\n",
mtd->index, mtd->name);
return 1;
}
pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
return 0;
}
extern struct backing_dev_info *mtd_bdi;
/*
* mark the superblock by the MTD device it is using
* - set the device number to be the correct MTD block device for pesuperstence
* of NFS exports
*/
static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
sb->s_mtd = mtd;
sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
sb->s_bdi = bdi_get(mtd_bdi);
return 0;
}
/*
* get a superblock on an MTD-backed filesystem
*/
static struct dentry *mount_mtd_aux(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
struct mtd_info *mtd,
int (*fill_super)(struct super_block *, void *, int))
{
struct super_block *sb;
int ret;
sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, flags, mtd);
if (IS_ERR(sb))
goto out_error;
if (sb->s_root)
goto already_mounted;
/* fresh new superblock */
pr_debug("MTDSB: New superblock for device %d (\"%s\")\n",
mtd->index, mtd->name);
ret = fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
if (ret < 0) {
deactivate_locked_super(sb);
return ERR_PTR(ret);
}
/* go */
sb->s_flags |= SB_ACTIVE;
return dget(sb->s_root);
/* new mountpoint for an already mounted superblock */
already_mounted:
pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n",
mtd->index, mtd->name);
put_mtd_device(mtd);
return dget(sb->s_root);
out_error:
put_mtd_device(mtd);
return ERR_CAST(sb);
}
/*
* get a superblock on an MTD-backed filesystem by MTD device number
*/
static struct dentry *mount_mtd_nr(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, int mtdnr,
int (*fill_super)(struct super_block *, void *, int))
{
struct mtd_info *mtd;
mtd = get_mtd_device(NULL, mtdnr);
if (IS_ERR(mtd)) {
pr_debug("MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
return ERR_CAST(mtd);
}
return mount_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super);
}
/*
* set up an MTD-based superblock
*/
struct dentry *mount_mtd(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
int ret, major;
#endif
int mtdnr;
if (!dev_name)
return ERR_PTR(-EINVAL);
pr_debug("MTDSB: dev_name \"%s\"\n", dev_name);
/* the preferred way of mounting in future; especially when
* CONFIG_BLOCK=n - we specify the underlying MTD device by number or
* by name, so that we don't require block device support to be present
* in the kernel. */
if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
if (dev_name[3] == ':') {
struct mtd_info *mtd;
/* mount by MTD device name */
pr_debug("MTDSB: mtd:%%s, name \"%s\"\n",
dev_name + 4);
mtd = get_mtd_device_nm(dev_name + 4);
if (!IS_ERR(mtd))
return mount_mtd_aux(
fs_type, flags,
dev_name, data, mtd,
fill_super);
printk(KERN_NOTICE "MTD:"
" MTD device with name \"%s\" not found.\n",
dev_name + 4);
} else if (isdigit(dev_name[3])) {
/* mount by MTD device number name */
char *endptr;
mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
if (!*endptr) {
/* It was a valid number */
pr_debug("MTDSB: mtd%%d, mtdnr %d\n",
mtdnr);
return mount_mtd_nr(fs_type, flags,
dev_name, data,
mtdnr, fill_super);
}
}
}
#ifdef CONFIG_BLOCK
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
bdev = lookup_bdev(dev_name);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
pr_debug("MTDSB: lookup_bdev() returned %d\n", ret);
return ERR_PTR(ret);
}
pr_debug("MTDSB: lookup_bdev() returned 0\n");
ret = -EINVAL;
major = MAJOR(bdev->bd_dev);
mtdnr = MINOR(bdev->bd_dev);
bdput(bdev);
if (major != MTD_BLOCK_MAJOR)
goto not_an_MTD_device;
return mount_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super);
not_an_MTD_device:
#endif /* CONFIG_BLOCK */
if (!(flags & SB_SILENT))
printk(KERN_NOTICE
"MTD: Attempt to mount non-MTD device \"%s\"\n",
dev_name);
return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(mount_mtd);
/*
* destroy an MTD-based superblock
*/
void kill_mtd_super(struct super_block *sb)
{
generic_shutdown_super(sb);
put_mtd_device(sb->s_mtd);
sb->s_mtd = NULL;
}
EXPORT_SYMBOL_GPL(kill_mtd_super);
|
