1 /* MTD-based superblock management
3 * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
4 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
6 * Written by: David Howells <dhowells@redhat.com>
7 * David Woodhouse <dwmw2@infradead.org>
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.
15 #include <linux/mtd/super.h>
16 #include <linux/namei.h>
17 #include <linux/export.h>
18 #include <linux/ctype.h>
19 #include <linux/slab.h>
22 * compare superblocks to see if they're equivalent
23 * - they are if the underlying MTD device is the same
25 static int get_sb_mtd_compare(struct super_block
*sb
, void *_mtd
)
27 struct mtd_info
*mtd
= _mtd
;
29 if (sb
->s_mtd
== mtd
) {
30 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
31 mtd
->index
, mtd
->name
);
35 DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
36 sb
->s_mtd
->index
, sb
->s_mtd
->name
, mtd
->index
, mtd
->name
);
41 * mark the superblock by the MTD device it is using
42 * - set the device number to be the correct MTD block device for pesuperstence
45 static int get_sb_mtd_set(struct super_block
*sb
, void *_mtd
)
47 struct mtd_info
*mtd
= _mtd
;
50 sb
->s_dev
= MKDEV(MTD_BLOCK_MAJOR
, mtd
->index
);
51 sb
->s_bdi
= mtd
->backing_dev_info
;
56 * get a superblock on an MTD-backed filesystem
58 static struct dentry
*mount_mtd_aux(struct file_system_type
*fs_type
, int flags
,
59 const char *dev_name
, void *data
,
61 int (*fill_super
)(struct super_block
*, void *, int))
63 struct super_block
*sb
;
66 sb
= sget(fs_type
, get_sb_mtd_compare
, get_sb_mtd_set
, mtd
);
73 /* fresh new superblock */
74 DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
75 mtd
->index
, mtd
->name
);
79 ret
= fill_super(sb
, data
, flags
& MS_SILENT
? 1 : 0);
81 deactivate_locked_super(sb
);
86 sb
->s_flags
|= MS_ACTIVE
;
87 return dget(sb
->s_root
);
89 /* new mountpoint for an already mounted superblock */
91 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
92 mtd
->index
, mtd
->name
);
94 return dget(sb
->s_root
);
102 * get a superblock on an MTD-backed filesystem by MTD device number
104 static struct dentry
*mount_mtd_nr(struct file_system_type
*fs_type
, int flags
,
105 const char *dev_name
, void *data
, int mtdnr
,
106 int (*fill_super
)(struct super_block
*, void *, int))
108 struct mtd_info
*mtd
;
110 mtd
= get_mtd_device(NULL
, mtdnr
);
112 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr
);
113 return ERR_CAST(mtd
);
116 return mount_mtd_aux(fs_type
, flags
, dev_name
, data
, mtd
, fill_super
);
120 * set up an MTD-based superblock
122 struct dentry
*mount_mtd(struct file_system_type
*fs_type
, int flags
,
123 const char *dev_name
, void *data
,
124 int (*fill_super
)(struct super_block
*, void *, int))
127 struct block_device
*bdev
;
133 return ERR_PTR(-EINVAL
);
135 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name
);
137 /* the preferred way of mounting in future; especially when
138 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
139 * by name, so that we don't require block device support to be present
141 if (dev_name
[0] == 'm' && dev_name
[1] == 't' && dev_name
[2] == 'd') {
142 if (dev_name
[3] == ':') {
143 struct mtd_info
*mtd
;
145 /* mount by MTD device name */
146 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
149 mtd
= get_mtd_device_nm(dev_name
+ 4);
151 return mount_mtd_aux(
156 printk(KERN_NOTICE
"MTD:"
157 " MTD device with name \"%s\" not found.\n",
160 } else if (isdigit(dev_name
[3])) {
161 /* mount by MTD device number name */
164 mtdnr
= simple_strtoul(dev_name
+ 3, &endptr
, 0);
166 /* It was a valid number */
167 DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
169 return mount_mtd_nr(fs_type
, flags
,
177 /* try the old way - the hack where we allowed users to mount
178 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
180 bdev
= lookup_bdev(dev_name
);
183 DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret
);
186 DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
190 major
= MAJOR(bdev
->bd_dev
);
191 mtdnr
= MINOR(bdev
->bd_dev
);
194 if (major
!= MTD_BLOCK_MAJOR
)
195 goto not_an_MTD_device
;
197 return mount_mtd_nr(fs_type
, flags
, dev_name
, data
, mtdnr
, fill_super
);
200 #endif /* CONFIG_BLOCK */
202 if (!(flags
& MS_SILENT
))
204 "MTD: Attempt to mount non-MTD device \"%s\"\n",
206 return ERR_PTR(-EINVAL
);
209 EXPORT_SYMBOL_GPL(mount_mtd
);
212 * destroy an MTD-based superblock
214 void kill_mtd_super(struct super_block
*sb
)
216 generic_shutdown_super(sb
);
217 put_mtd_device(sb
->s_mtd
);
221 EXPORT_SYMBOL_GPL(kill_mtd_super
);