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git.proxmox.com Git - mirror_ubuntu-bionic-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/ctype.h>
18 #include <linux/slab.h>
21 * compare superblocks to see if they're equivalent
22 * - they are if the underlying MTD device is the same
24 static int get_sb_mtd_compare(struct super_block
*sb
, void *_mtd
)
26 struct mtd_info
*mtd
= _mtd
;
28 if (sb
->s_mtd
== mtd
) {
29 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
30 mtd
->index
, mtd
->name
);
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
);
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
44 static int get_sb_mtd_set(struct super_block
*sb
, void *_mtd
)
46 struct mtd_info
*mtd
= _mtd
;
49 sb
->s_dev
= MKDEV(MTD_BLOCK_MAJOR
, mtd
->index
);
50 sb
->s_bdi
= mtd
->backing_dev_info
;
55 * get a superblock on an MTD-backed filesystem
57 static int get_sb_mtd_aux(struct file_system_type
*fs_type
, int flags
,
58 const char *dev_name
, void *data
,
60 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 simple_set_mnt(mnt
, sb
);
91 /* new mountpoint for an already mounted superblock */
93 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
94 mtd
->index
, mtd
->name
);
95 simple_set_mnt(mnt
, sb
);
107 * get a superblock on an MTD-backed filesystem by MTD device number
109 static 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
)
114 struct mtd_info
*mtd
;
116 mtd
= get_mtd_device(NULL
, mtdnr
);
118 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr
);
122 return get_sb_mtd_aux(fs_type
, flags
, dev_name
, data
, mtd
, fill_super
,
127 * set up an MTD-based superblock
129 int 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
)
135 struct block_device
*bdev
;
143 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name
);
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
149 if (dev_name
[0] == 'm' && dev_name
[1] == 't' && dev_name
[2] == 'd') {
150 if (dev_name
[3] == ':') {
151 struct mtd_info
*mtd
;
153 /* mount by MTD device name */
154 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
157 mtd
= get_mtd_device_nm(dev_name
+ 4);
159 return get_sb_mtd_aux(
164 printk(KERN_NOTICE
"MTD:"
165 " MTD device with name \"%s\" not found.\n",
168 } else if (isdigit(dev_name
[3])) {
169 /* mount by MTD device number name */
172 mtdnr
= simple_strtoul(dev_name
+ 3, &endptr
, 0);
174 /* It was a valid number */
175 DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
177 return get_sb_mtd_nr(fs_type
, flags
,
179 mtdnr
, fill_super
, mnt
);
185 /* try the old way - the hack where we allowed users to mount
186 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
188 bdev
= lookup_bdev(dev_name
);
191 DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret
);
194 DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
198 major
= MAJOR(bdev
->bd_dev
);
199 mtdnr
= MINOR(bdev
->bd_dev
);
202 if (major
!= MTD_BLOCK_MAJOR
)
203 goto not_an_MTD_device
;
205 return get_sb_mtd_nr(fs_type
, flags
, dev_name
, data
, mtdnr
, fill_super
,
209 #endif /* CONFIG_BLOCK */
211 if (!(flags
& MS_SILENT
))
213 "MTD: Attempt to mount non-MTD device \"%s\"\n",
218 EXPORT_SYMBOL_GPL(get_sb_mtd
);
221 * destroy an MTD-based superblock
223 void kill_mtd_super(struct super_block
*sb
)
225 generic_shutdown_super(sb
);
226 put_mtd_device(sb
->s_mtd
);
230 EXPORT_SYMBOL_GPL(kill_mtd_super
);