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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 | ||
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 */ | |
85 | already_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 | ||
91 | out_error: | |
92 | ret = PTR_ERR(sb); | |
93 | out_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 | */ | |
101 | static 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); | |
718ea836 | 109 | if (IS_ERR(mtd)) { |
acaebfd8 | 110 | DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr); |
718ea836 | 111 | return PTR_ERR(mtd); |
acaebfd8 DH |
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 | */ | |
121 | int 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); | |
718ea836 | 148 | if (!IS_ERR(mtd)) { |
acaebfd8 DH |
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 | ||
209 | not_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); | |
214 | out: | |
215 | path_release(&nd); | |
216 | return ret; | |
217 | ||
218 | } | |
219 | ||
220 | EXPORT_SYMBOL_GPL(get_sb_mtd); | |
221 | ||
222 | /* | |
223 | * destroy an MTD-based superblock | |
224 | */ | |
225 | void 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 | ||
232 | EXPORT_SYMBOL_GPL(kill_mtd_super); |