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