1 /* MTD-based superblock management
3 * Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
4 * Written by: David Howells <dhowells@redhat.com>
5 * David Woodhouse <dwmw2@infradead.org>
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.
13 #include <linux/mtd/super.h>
14 #include <linux/namei.h>
15 #include <linux/ctype.h>
16 #include <linux/slab.h>
19 * compare superblocks to see if they're equivalent
20 * - they are if the underlying MTD device is the same
22 static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
24 struct mtd_info *mtd = _mtd;
26 if (sb->s_mtd == mtd) {
27 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
28 mtd->index, mtd->name);
32 DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
33 sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
38 * mark the superblock by the MTD device it is using
39 * - set the device number to be the correct MTD block device for pesuperstence
42 static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
44 struct mtd_info *mtd = _mtd;
47 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
48 sb->s_bdi = mtd->backing_dev_info;
53 * get a superblock on an MTD-backed filesystem
55 static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
56 const char *dev_name, void *data,
58 int (*fill_super)(struct super_block *, void *, int),
61 struct super_block *sb;
64 sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
71 /* fresh new superblock */
72 DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
73 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 simple_set_mnt(mnt, sb);
89 /* new mountpoint for an already mounted superblock */
91 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
92 mtd->index, mtd->name);
93 simple_set_mnt(mnt, sb);
105 * get a superblock on an MTD-backed filesystem by MTD device number
107 static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
108 const char *dev_name, void *data, int mtdnr,
109 int (*fill_super)(struct super_block *, void *, int),
110 struct vfsmount *mnt)
112 struct mtd_info *mtd;
114 mtd = get_mtd_device(NULL, mtdnr);
116 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
120 return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
125 * set up an MTD-based superblock
127 int get_sb_mtd(struct file_system_type *fs_type, int flags,
128 const char *dev_name, void *data,
129 int (*fill_super)(struct super_block *, void *, int),
130 struct vfsmount *mnt)
133 struct block_device *bdev;
141 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
143 /* the preferred way of mounting in future; especially when
144 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
145 * by name, so that we don't require block device support to be present
147 if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
148 if (dev_name[3] == ':') {
149 struct mtd_info *mtd;
151 /* mount by MTD device name */
152 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
155 for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
156 mtd = get_mtd_device(NULL, mtdnr);
158 if (!strcmp(mtd->name, dev_name + 4))
159 return get_sb_mtd_aux(
168 printk(KERN_NOTICE "MTD:"
169 " MTD device with name \"%s\" not found.\n",
172 } else if (isdigit(dev_name[3])) {
173 /* mount by MTD device number name */
176 mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
178 /* It was a valid number */
179 DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
181 return get_sb_mtd_nr(fs_type, flags,
183 mtdnr, fill_super, mnt);
189 /* try the old way - the hack where we allowed users to mount
190 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
192 bdev = lookup_bdev(dev_name);
195 DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret);
198 DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
202 major = MAJOR(bdev->bd_dev);
203 mtdnr = MINOR(bdev->bd_dev);
206 if (major != MTD_BLOCK_MAJOR)
207 goto not_an_MTD_device;
209 return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
213 #endif /* CONFIG_BLOCK */
215 if (!(flags & MS_SILENT))
217 "MTD: Attempt to mount non-MTD device \"%s\"\n",
222 EXPORT_SYMBOL_GPL(get_sb_mtd);
225 * destroy an MTD-based superblock
227 void kill_mtd_super(struct super_block *sb)
229 generic_shutdown_super(sb);
230 put_mtd_device(sb->s_mtd);
234 EXPORT_SYMBOL_GPL(kill_mtd_super);