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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/mtd/mtdsuper.c
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 pr_debug("MTDSB: Match on device %d (\"%s\")\n",
31 mtd
->index
, mtd
->name
);
35 pr_debug("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
, flags
, mtd
);
73 /* fresh new superblock */
74 pr_debug("MTDSB: New superblock for device %d (\"%s\")\n",
75 mtd
->index
, mtd
->name
);
77 ret
= fill_super(sb
, data
, flags
& MS_SILENT
? 1 : 0);
79 deactivate_locked_super(sb
);
84 sb
->s_flags
|= MS_ACTIVE
;
85 return dget(sb
->s_root
);
87 /* new mountpoint for an already mounted superblock */
89 pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n",
90 mtd
->index
, mtd
->name
);
92 return dget(sb
->s_root
);
100 * get a superblock on an MTD-backed filesystem by MTD device number
102 static struct dentry
*mount_mtd_nr(struct file_system_type
*fs_type
, int flags
,
103 const char *dev_name
, void *data
, int mtdnr
,
104 int (*fill_super
)(struct super_block
*, void *, int))
106 struct mtd_info
*mtd
;
108 mtd
= get_mtd_device(NULL
, mtdnr
);
110 pr_debug("MTDSB: Device #%u doesn't appear to exist\n", mtdnr
);
111 return ERR_CAST(mtd
);
114 return mount_mtd_aux(fs_type
, flags
, dev_name
, data
, mtd
, fill_super
);
118 * set up an MTD-based superblock
120 struct dentry
*mount_mtd(struct file_system_type
*fs_type
, int flags
,
121 const char *dev_name
, void *data
,
122 int (*fill_super
)(struct super_block
*, void *, int))
125 struct block_device
*bdev
;
131 return ERR_PTR(-EINVAL
);
133 pr_debug("MTDSB: dev_name \"%s\"\n", dev_name
);
135 /* the preferred way of mounting in future; especially when
136 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
137 * by name, so that we don't require block device support to be present
139 if (dev_name
[0] == 'm' && dev_name
[1] == 't' && dev_name
[2] == 'd') {
140 if (dev_name
[3] == ':') {
141 struct mtd_info
*mtd
;
143 /* mount by MTD device name */
144 pr_debug("MTDSB: mtd:%%s, name \"%s\"\n",
147 mtd
= get_mtd_device_nm(dev_name
+ 4);
149 return mount_mtd_aux(
154 printk(KERN_NOTICE
"MTD:"
155 " MTD device with name \"%s\" not found.\n",
158 } else if (isdigit(dev_name
[3])) {
159 /* mount by MTD device number name */
162 mtdnr
= simple_strtoul(dev_name
+ 3, &endptr
, 0);
164 /* It was a valid number */
165 pr_debug("MTDSB: mtd%%d, mtdnr %d\n",
167 return mount_mtd_nr(fs_type
, flags
,
175 /* try the old way - the hack where we allowed users to mount
176 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
178 bdev
= lookup_bdev(dev_name
);
181 pr_debug("MTDSB: lookup_bdev() returned %d\n", ret
);
184 pr_debug("MTDSB: lookup_bdev() returned 0\n");
188 major
= MAJOR(bdev
->bd_dev
);
189 mtdnr
= MINOR(bdev
->bd_dev
);
192 if (major
!= MTD_BLOCK_MAJOR
)
193 goto not_an_MTD_device
;
195 return mount_mtd_nr(fs_type
, flags
, dev_name
, data
, mtdnr
, fill_super
);
198 #endif /* CONFIG_BLOCK */
200 if (!(flags
& MS_SILENT
))
202 "MTD: Attempt to mount non-MTD device \"%s\"\n",
204 return ERR_PTR(-EINVAL
);
207 EXPORT_SYMBOL_GPL(mount_mtd
);
210 * destroy an MTD-based superblock
212 void kill_mtd_super(struct super_block
*sb
)
214 generic_shutdown_super(sb
);
215 put_mtd_device(sb
->s_mtd
);
219 EXPORT_SYMBOL_GPL(kill_mtd_super
);