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acaebfd8 DH |
1 | /* MTD-based superblock management |
2 | * | |
3 | * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved. | |
a1452a37 DW |
4 | * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org> |
5 | * | |
acaebfd8 DH |
6 | * Written by: David Howells <dhowells@redhat.com> |
7 | * David Woodhouse <dwmw2@infradead.org> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
15 | #include <linux/mtd/super.h> | |
16 | #include <linux/namei.h> | |
f3bcc017 | 17 | #include <linux/export.h> |
acaebfd8 | 18 | #include <linux/ctype.h> |
6de94002 | 19 | #include <linux/slab.h> |
f83c3838 | 20 | #include <linux/major.h> |
fa06052d | 21 | #include <linux/backing-dev.h> |
acaebfd8 DH |
22 | |
23 | /* | |
24 | * compare superblocks to see if they're equivalent | |
25 | * - they are if the underlying MTD device is the same | |
26 | */ | |
27 | static int get_sb_mtd_compare(struct super_block *sb, void *_mtd) | |
28 | { | |
29 | struct mtd_info *mtd = _mtd; | |
30 | ||
31 | if (sb->s_mtd == mtd) { | |
289c0522 | 32 | pr_debug("MTDSB: Match on device %d (\"%s\")\n", |
acaebfd8 DH |
33 | mtd->index, mtd->name); |
34 | return 1; | |
35 | } | |
36 | ||
289c0522 | 37 | pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n", |
acaebfd8 DH |
38 | sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name); |
39 | return 0; | |
40 | } | |
41 | ||
fa06052d JK |
42 | extern struct backing_dev_info *mtd_bdi; |
43 | ||
acaebfd8 DH |
44 | /* |
45 | * mark the superblock by the MTD device it is using | |
46 | * - set the device number to be the correct MTD block device for pesuperstence | |
47 | * of NFS exports | |
48 | */ | |
49 | static int get_sb_mtd_set(struct super_block *sb, void *_mtd) | |
50 | { | |
51 | struct mtd_info *mtd = _mtd; | |
52 | ||
53 | sb->s_mtd = mtd; | |
54 | sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index); | |
fa06052d | 55 | sb->s_bdi = bdi_get(mtd_bdi); |
fa06052d | 56 | |
acaebfd8 DH |
57 | return 0; |
58 | } | |
59 | ||
60 | /* | |
61 | * get a superblock on an MTD-backed filesystem | |
62 | */ | |
848b83a5 | 63 | static struct dentry *mount_mtd_aux(struct file_system_type *fs_type, int flags, |
acaebfd8 DH |
64 | const char *dev_name, void *data, |
65 | struct mtd_info *mtd, | |
848b83a5 | 66 | int (*fill_super)(struct super_block *, void *, int)) |
acaebfd8 DH |
67 | { |
68 | struct super_block *sb; | |
69 | int ret; | |
70 | ||
9249e17f | 71 | sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, flags, mtd); |
acaebfd8 DH |
72 | if (IS_ERR(sb)) |
73 | goto out_error; | |
74 | ||
75 | if (sb->s_root) | |
76 | goto already_mounted; | |
77 | ||
78 | /* fresh new superblock */ | |
289c0522 | 79 | pr_debug("MTDSB: New superblock for device %d (\"%s\")\n", |
acaebfd8 DH |
80 | mtd->index, mtd->name); |
81 | ||
82 | ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0); | |
83 | if (ret < 0) { | |
6f5bbff9 | 84 | deactivate_locked_super(sb); |
848b83a5 | 85 | return ERR_PTR(ret); |
acaebfd8 DH |
86 | } |
87 | ||
88 | /* go */ | |
89 | sb->s_flags |= MS_ACTIVE; | |
848b83a5 | 90 | return dget(sb->s_root); |
acaebfd8 DH |
91 | |
92 | /* new mountpoint for an already mounted superblock */ | |
93 | already_mounted: | |
289c0522 | 94 | pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n", |
acaebfd8 | 95 | mtd->index, mtd->name); |
848b83a5 AV |
96 | put_mtd_device(mtd); |
97 | return dget(sb->s_root); | |
acaebfd8 DH |
98 | |
99 | out_error: | |
acaebfd8 | 100 | put_mtd_device(mtd); |
848b83a5 | 101 | return ERR_CAST(sb); |
acaebfd8 DH |
102 | } |
103 | ||
104 | /* | |
105 | * get a superblock on an MTD-backed filesystem by MTD device number | |
106 | */ | |
848b83a5 | 107 | static struct dentry *mount_mtd_nr(struct file_system_type *fs_type, int flags, |
acaebfd8 | 108 | const char *dev_name, void *data, int mtdnr, |
848b83a5 | 109 | int (*fill_super)(struct super_block *, void *, int)) |
acaebfd8 DH |
110 | { |
111 | struct mtd_info *mtd; | |
112 | ||
113 | mtd = get_mtd_device(NULL, mtdnr); | |
718ea836 | 114 | if (IS_ERR(mtd)) { |
289c0522 | 115 | pr_debug("MTDSB: Device #%u doesn't appear to exist\n", mtdnr); |
848b83a5 | 116 | return ERR_CAST(mtd); |
acaebfd8 DH |
117 | } |
118 | ||
848b83a5 | 119 | return mount_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super); |
acaebfd8 DH |
120 | } |
121 | ||
122 | /* | |
123 | * set up an MTD-based superblock | |
124 | */ | |
848b83a5 | 125 | struct dentry *mount_mtd(struct file_system_type *fs_type, int flags, |
acaebfd8 | 126 | const char *dev_name, void *data, |
848b83a5 | 127 | int (*fill_super)(struct super_block *, void *, int)) |
acaebfd8 | 128 | { |
f1136d02 | 129 | #ifdef CONFIG_BLOCK |
d5686b44 | 130 | struct block_device *bdev; |
f1136d02 | 131 | int ret, major; |
06137c47 | 132 | int perm; |
f1136d02 DW |
133 | #endif |
134 | int mtdnr; | |
acaebfd8 DH |
135 | |
136 | if (!dev_name) | |
848b83a5 | 137 | return ERR_PTR(-EINVAL); |
acaebfd8 | 138 | |
289c0522 | 139 | pr_debug("MTDSB: dev_name \"%s\"\n", dev_name); |
acaebfd8 DH |
140 | |
141 | /* the preferred way of mounting in future; especially when | |
142 | * CONFIG_BLOCK=n - we specify the underlying MTD device by number or | |
143 | * by name, so that we don't require block device support to be present | |
144 | * in the kernel. */ | |
145 | if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') { | |
146 | if (dev_name[3] == ':') { | |
147 | struct mtd_info *mtd; | |
148 | ||
149 | /* mount by MTD device name */ | |
289c0522 | 150 | pr_debug("MTDSB: mtd:%%s, name \"%s\"\n", |
acaebfd8 DH |
151 | dev_name + 4); |
152 | ||
677c2aec BH |
153 | mtd = get_mtd_device_nm(dev_name + 4); |
154 | if (!IS_ERR(mtd)) | |
848b83a5 | 155 | return mount_mtd_aux( |
677c2aec BH |
156 | fs_type, flags, |
157 | dev_name, data, mtd, | |
848b83a5 | 158 | fill_super); |
acaebfd8 DH |
159 | |
160 | printk(KERN_NOTICE "MTD:" | |
161 | " MTD device with name \"%s\" not found.\n", | |
162 | dev_name + 4); | |
163 | ||
164 | } else if (isdigit(dev_name[3])) { | |
165 | /* mount by MTD device number name */ | |
166 | char *endptr; | |
167 | ||
168 | mtdnr = simple_strtoul(dev_name + 3, &endptr, 0); | |
169 | if (!*endptr) { | |
170 | /* It was a valid number */ | |
289c0522 | 171 | pr_debug("MTDSB: mtd%%d, mtdnr %d\n", |
acaebfd8 | 172 | mtdnr); |
848b83a5 | 173 | return mount_mtd_nr(fs_type, flags, |
acaebfd8 | 174 | dev_name, data, |
848b83a5 | 175 | mtdnr, fill_super); |
acaebfd8 DH |
176 | } |
177 | } | |
178 | } | |
179 | ||
f1136d02 | 180 | #ifdef CONFIG_BLOCK |
acaebfd8 DH |
181 | /* try the old way - the hack where we allowed users to mount |
182 | * /dev/mtdblock$(n) but didn't actually _use_ the blockdev | |
183 | */ | |
06137c47 SF |
184 | perm = MAY_READ; |
185 | if (!(flags & MS_RDONLY)) | |
186 | perm |= MAY_WRITE; | |
187 | bdev = lookup_bdev(dev_name, perm); | |
d5686b44 AV |
188 | if (IS_ERR(bdev)) { |
189 | ret = PTR_ERR(bdev); | |
289c0522 | 190 | pr_debug("MTDSB: lookup_bdev() returned %d\n", ret); |
848b83a5 | 191 | return ERR_PTR(ret); |
acaebfd8 | 192 | } |
289c0522 | 193 | pr_debug("MTDSB: lookup_bdev() returned 0\n"); |
acaebfd8 | 194 | |
d5686b44 | 195 | ret = -EINVAL; |
acaebfd8 | 196 | |
f1136d02 | 197 | major = MAJOR(bdev->bd_dev); |
d5686b44 AV |
198 | mtdnr = MINOR(bdev->bd_dev); |
199 | bdput(bdev); | |
acaebfd8 | 200 | |
f1136d02 DW |
201 | if (major != MTD_BLOCK_MAJOR) |
202 | goto not_an_MTD_device; | |
203 | ||
848b83a5 | 204 | return mount_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super); |
acaebfd8 DH |
205 | |
206 | not_an_MTD_device: | |
f1136d02 DW |
207 | #endif /* CONFIG_BLOCK */ |
208 | ||
acaebfd8 DH |
209 | if (!(flags & MS_SILENT)) |
210 | printk(KERN_NOTICE | |
211 | "MTD: Attempt to mount non-MTD device \"%s\"\n", | |
212 | dev_name); | |
848b83a5 | 213 | return ERR_PTR(-EINVAL); |
acaebfd8 DH |
214 | } |
215 | ||
848b83a5 | 216 | EXPORT_SYMBOL_GPL(mount_mtd); |
acaebfd8 DH |
217 | |
218 | /* | |
219 | * destroy an MTD-based superblock | |
220 | */ | |
221 | void kill_mtd_super(struct super_block *sb) | |
222 | { | |
223 | generic_shutdown_super(sb); | |
224 | put_mtd_device(sb->s_mtd); | |
225 | sb->s_mtd = NULL; | |
226 | } | |
227 | ||
228 | EXPORT_SYMBOL_GPL(kill_mtd_super); |