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David Howellsacaebfd2007-05-10 22:51:50 -07001/* MTD-based superblock management
2 *
3 * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
David Woodhousea1452a32010-08-08 20:58:20 +01004 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
5 *
David Howellsacaebfd2007-05-10 22:51:50 -07006 * 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>
17#include <linux/ctype.h>
Jörn Engel6de94002010-04-22 14:11:43 +020018#include <linux/slab.h>
David Howellsacaebfd2007-05-10 22:51:50 -070019
20/*
21 * compare superblocks to see if they're equivalent
22 * - they are if the underlying MTD device is the same
23 */
24static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
25{
26 struct mtd_info *mtd = _mtd;
27
28 if (sb->s_mtd == mtd) {
29 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
30 mtd->index, mtd->name);
31 return 1;
32 }
33
34 DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
35 sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
36 return 0;
37}
38
39/*
40 * mark the superblock by the MTD device it is using
41 * - set the device number to be the correct MTD block device for pesuperstence
42 * of NFS exports
43 */
44static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
45{
46 struct mtd_info *mtd = _mtd;
47
48 sb->s_mtd = mtd;
49 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
Jörn Engel6de94002010-04-22 14:11:43 +020050 sb->s_bdi = mtd->backing_dev_info;
David Howellsacaebfd2007-05-10 22:51:50 -070051 return 0;
52}
53
54/*
55 * get a superblock on an MTD-backed filesystem
56 */
57static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
58 const char *dev_name, void *data,
59 struct mtd_info *mtd,
60 int (*fill_super)(struct super_block *, void *, int),
61 struct vfsmount *mnt)
62{
63 struct super_block *sb;
64 int ret;
65
66 sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
67 if (IS_ERR(sb))
68 goto out_error;
69
70 if (sb->s_root)
71 goto already_mounted;
72
73 /* fresh new superblock */
74 DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
75 mtd->index, mtd->name);
76
David Howells48440e82007-08-30 17:21:19 +010077 sb->s_flags = flags;
78
David Howellsacaebfd2007-05-10 22:51:50 -070079 ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
80 if (ret < 0) {
Al Viro6f5bbff2009-05-06 01:34:22 -040081 deactivate_locked_super(sb);
David Howellsacaebfd2007-05-10 22:51:50 -070082 return ret;
83 }
84
85 /* go */
86 sb->s_flags |= MS_ACTIVE;
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -080087 simple_set_mnt(mnt, sb);
88
89 return 0;
David Howellsacaebfd2007-05-10 22:51:50 -070090
91 /* new mountpoint for an already mounted superblock */
92already_mounted:
93 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
94 mtd->index, mtd->name);
Sukadev Bhattiprolua3ec9472009-03-04 12:06:34 -080095 simple_set_mnt(mnt, sb);
96 ret = 0;
David Howellsacaebfd2007-05-10 22:51:50 -070097 goto out_put;
98
99out_error:
100 ret = PTR_ERR(sb);
101out_put:
102 put_mtd_device(mtd);
103 return ret;
104}
105
106/*
107 * get a superblock on an MTD-backed filesystem by MTD device number
108 */
109static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
110 const char *dev_name, void *data, int mtdnr,
111 int (*fill_super)(struct super_block *, void *, int),
112 struct vfsmount *mnt)
113{
114 struct mtd_info *mtd;
115
116 mtd = get_mtd_device(NULL, mtdnr);
David Woodhouse718ea832007-06-01 19:21:59 +0100117 if (IS_ERR(mtd)) {
David Howellsacaebfd2007-05-10 22:51:50 -0700118 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
David Woodhouse718ea832007-06-01 19:21:59 +0100119 return PTR_ERR(mtd);
David Howellsacaebfd2007-05-10 22:51:50 -0700120 }
121
122 return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
123 mnt);
124}
125
126/*
127 * set up an MTD-based superblock
128 */
129int get_sb_mtd(struct file_system_type *fs_type, int flags,
130 const char *dev_name, void *data,
131 int (*fill_super)(struct super_block *, void *, int),
132 struct vfsmount *mnt)
133{
David Woodhousef1136d02008-08-02 00:01:21 +0100134#ifdef CONFIG_BLOCK
Al Virod5686b42008-08-01 05:00:11 -0400135 struct block_device *bdev;
David Woodhousef1136d02008-08-02 00:01:21 +0100136 int ret, major;
137#endif
138 int mtdnr;
David Howellsacaebfd2007-05-10 22:51:50 -0700139
140 if (!dev_name)
141 return -EINVAL;
142
143 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
144
145 /* the preferred way of mounting in future; especially when
146 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
147 * by name, so that we don't require block device support to be present
148 * in the kernel. */
149 if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
150 if (dev_name[3] == ':') {
151 struct mtd_info *mtd;
152
153 /* mount by MTD device name */
154 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
155 dev_name + 4);
156
Ben Hutchings677c2ae2010-01-29 20:57:18 +0000157 mtd = get_mtd_device_nm(dev_name + 4);
158 if (!IS_ERR(mtd))
159 return get_sb_mtd_aux(
160 fs_type, flags,
161 dev_name, data, mtd,
162 fill_super, mnt);
David Howellsacaebfd2007-05-10 22:51:50 -0700163
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
David Woodhousef1136d02008-08-02 00:01:21 +0100184#ifdef CONFIG_BLOCK
David Howellsacaebfd2007-05-10 22:51:50 -0700185 /* try the old way - the hack where we allowed users to mount
186 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
187 */
Al Virod5686b42008-08-01 05:00:11 -0400188 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);
David Howellsacaebfd2007-05-10 22:51:50 -0700192 return ret;
Al Virod5686b42008-08-01 05:00:11 -0400193 }
194 DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
David Howellsacaebfd2007-05-10 22:51:50 -0700195
196 ret = -EINVAL;
David Howellsacaebfd2007-05-10 22:51:50 -0700197
David Woodhousef1136d02008-08-02 00:01:21 +0100198 major = MAJOR(bdev->bd_dev);
Al Virod5686b42008-08-01 05:00:11 -0400199 mtdnr = MINOR(bdev->bd_dev);
200 bdput(bdev);
David Howellsacaebfd2007-05-10 22:51:50 -0700201
David Woodhousef1136d02008-08-02 00:01:21 +0100202 if (major != MTD_BLOCK_MAJOR)
203 goto not_an_MTD_device;
204
David Howellsacaebfd2007-05-10 22:51:50 -0700205 return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
206 mnt);
207
208not_an_MTD_device:
David Woodhousef1136d02008-08-02 00:01:21 +0100209#endif /* CONFIG_BLOCK */
210
David Howellsacaebfd2007-05-10 22:51:50 -0700211 if (!(flags & MS_SILENT))
212 printk(KERN_NOTICE
213 "MTD: Attempt to mount non-MTD device \"%s\"\n",
214 dev_name);
David Woodhousef1136d02008-08-02 00:01:21 +0100215 return -EINVAL;
David Howellsacaebfd2007-05-10 22:51:50 -0700216}
217
218EXPORT_SYMBOL_GPL(get_sb_mtd);
219
220/*
221 * destroy an MTD-based superblock
222 */
223void 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
230EXPORT_SYMBOL_GPL(kill_mtd_super);