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acaebfd8 DH |
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 | */ | |
21 | static 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 | */ | |
41 | static 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 | */ | |
53 | static 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 | ||
48440e89 DH |
73 | sb->s_flags = flags; |
74 | ||
acaebfd8 DH |
75 | ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); |
76 | if (ret < 0) { | |
77 | up_write(&sb->s_umount); | |
78 | deactivate_super(sb); | |
79 | return ret; | |
80 | } | |
81 | ||
82 | /* go */ | |
83 | sb->s_flags |= MS_ACTIVE; | |
a3ec947c SB |
84 | simple_set_mnt(mnt, sb); |
85 | ||
86 | return 0; | |
acaebfd8 DH |
87 | |
88 | /* new mountpoint for an already mounted superblock */ | |
89 | already_mounted: | |
90 | DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n", | |
91 | mtd->index, mtd->name); | |
a3ec947c SB |
92 | simple_set_mnt(mnt, sb); |
93 | ret = 0; | |
acaebfd8 DH |
94 | goto out_put; |
95 | ||
96 | out_error: | |
97 | ret = PTR_ERR(sb); | |
98 | out_put: | |
99 | put_mtd_device(mtd); | |
100 | return ret; | |
101 | } | |
102 | ||
103 | /* | |
104 | * get a superblock on an MTD-backed filesystem by MTD device number | |
105 | */ | |
106 | static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags, | |
107 | const char *dev_name, void *data, int mtdnr, | |
108 | int (*fill_super)(struct super_block *, void *, int), | |
109 | struct vfsmount *mnt) | |
110 | { | |
111 | struct mtd_info *mtd; | |
112 | ||
113 | mtd = get_mtd_device(NULL, mtdnr); | |
718ea836 | 114 | if (IS_ERR(mtd)) { |
acaebfd8 | 115 | DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr); |
718ea836 | 116 | return PTR_ERR(mtd); |
acaebfd8 DH |
117 | } |
118 | ||
119 | return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super, | |
120 | mnt); | |
121 | } | |
122 | ||
123 | /* | |
124 | * set up an MTD-based superblock | |
125 | */ | |
126 | int get_sb_mtd(struct file_system_type *fs_type, int flags, | |
127 | const char *dev_name, void *data, | |
128 | int (*fill_super)(struct super_block *, void *, int), | |
129 | struct vfsmount *mnt) | |
130 | { | |
f1136d02 | 131 | #ifdef CONFIG_BLOCK |
d5686b44 | 132 | struct block_device *bdev; |
f1136d02 DW |
133 | int ret, major; |
134 | #endif | |
135 | int mtdnr; | |
acaebfd8 DH |
136 | |
137 | if (!dev_name) | |
138 | return -EINVAL; | |
139 | ||
140 | DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name); | |
141 | ||
142 | /* the preferred way of mounting in future; especially when | |
143 | * CONFIG_BLOCK=n - we specify the underlying MTD device by number or | |
144 | * by name, so that we don't require block device support to be present | |
145 | * in the kernel. */ | |
146 | if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') { | |
147 | if (dev_name[3] == ':') { | |
148 | struct mtd_info *mtd; | |
149 | ||
150 | /* mount by MTD device name */ | |
151 | DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n", | |
152 | dev_name + 4); | |
153 | ||
154 | for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) { | |
155 | mtd = get_mtd_device(NULL, mtdnr); | |
718ea836 | 156 | if (!IS_ERR(mtd)) { |
acaebfd8 DH |
157 | if (!strcmp(mtd->name, dev_name + 4)) |
158 | return get_sb_mtd_aux( | |
159 | fs_type, flags, | |
160 | dev_name, data, mtd, | |
161 | fill_super, mnt); | |
162 | ||
163 | put_mtd_device(mtd); | |
164 | } | |
165 | } | |
166 | ||
167 | printk(KERN_NOTICE "MTD:" | |
168 | " MTD device with name \"%s\" not found.\n", | |
169 | dev_name + 4); | |
170 | ||
171 | } else if (isdigit(dev_name[3])) { | |
172 | /* mount by MTD device number name */ | |
173 | char *endptr; | |
174 | ||
175 | mtdnr = simple_strtoul(dev_name + 3, &endptr, 0); | |
176 | if (!*endptr) { | |
177 | /* It was a valid number */ | |
178 | DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n", | |
179 | mtdnr); | |
180 | return get_sb_mtd_nr(fs_type, flags, | |
181 | dev_name, data, | |
182 | mtdnr, fill_super, mnt); | |
183 | } | |
184 | } | |
185 | } | |
186 | ||
f1136d02 | 187 | #ifdef CONFIG_BLOCK |
acaebfd8 DH |
188 | /* try the old way - the hack where we allowed users to mount |
189 | * /dev/mtdblock$(n) but didn't actually _use_ the blockdev | |
190 | */ | |
d5686b44 AV |
191 | bdev = lookup_bdev(dev_name); |
192 | if (IS_ERR(bdev)) { | |
193 | ret = PTR_ERR(bdev); | |
194 | DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret); | |
acaebfd8 | 195 | return ret; |
acaebfd8 | 196 | } |
d5686b44 | 197 | DEBUG(1, "MTDSB: lookup_bdev() returned 0\n"); |
acaebfd8 | 198 | |
d5686b44 | 199 | ret = -EINVAL; |
acaebfd8 | 200 | |
f1136d02 | 201 | major = MAJOR(bdev->bd_dev); |
d5686b44 AV |
202 | mtdnr = MINOR(bdev->bd_dev); |
203 | bdput(bdev); | |
acaebfd8 | 204 | |
f1136d02 DW |
205 | if (major != MTD_BLOCK_MAJOR) |
206 | goto not_an_MTD_device; | |
207 | ||
acaebfd8 DH |
208 | return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super, |
209 | mnt); | |
210 | ||
211 | not_an_MTD_device: | |
f1136d02 DW |
212 | #endif /* CONFIG_BLOCK */ |
213 | ||
acaebfd8 DH |
214 | if (!(flags & MS_SILENT)) |
215 | printk(KERN_NOTICE | |
216 | "MTD: Attempt to mount non-MTD device \"%s\"\n", | |
217 | dev_name); | |
f1136d02 | 218 | return -EINVAL; |
acaebfd8 DH |
219 | } |
220 | ||
221 | EXPORT_SYMBOL_GPL(get_sb_mtd); | |
222 | ||
223 | /* | |
224 | * destroy an MTD-based superblock | |
225 | */ | |
226 | void kill_mtd_super(struct super_block *sb) | |
227 | { | |
228 | generic_shutdown_super(sb); | |
229 | put_mtd_device(sb->s_mtd); | |
230 | sb->s_mtd = NULL; | |
231 | } | |
232 | ||
233 | EXPORT_SYMBOL_GPL(kill_mtd_super); |