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>
18 * compare superblocks to see if they're equivalent
19 * - they are if the underlying MTD device is the same
21 static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
23 struct mtd_info *mtd = _mtd;
25 if (sb->s_mtd == mtd) {
26 DEBUG(2, "MTDSB: Match on device %d (\"%s\")\n",
27 mtd->index, mtd->name);
31 DEBUG(2, "MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
32 sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
37 * mark the superblock by the MTD device it is using
38 * - set the device number to be the correct MTD block device for pesuperstence
41 static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
43 struct mtd_info *mtd = _mtd;
46 sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
51 * get a superblock on an MTD-backed filesystem
53 static int get_sb_mtd_aux(struct file_system_type *fs_type, int flags,
54 const char *dev_name, void *data,
56 int (*fill_super)(struct super_block *, void *, int),
59 struct super_block *sb;
62 sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, mtd);
69 /* fresh new superblock */
70 DEBUG(1, "MTDSB: New superblock for device %d (\"%s\")\n",
71 mtd->index, mtd->name);
75 ret = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
77 deactivate_locked_super(sb);
82 sb->s_flags |= MS_ACTIVE;
83 simple_set_mnt(mnt, sb);
87 /* new mountpoint for an already mounted superblock */
89 DEBUG(1, "MTDSB: Device %d (\"%s\") is already mounted\n",
90 mtd->index, mtd->name);
91 simple_set_mnt(mnt, sb);
103 * get a superblock on an MTD-backed filesystem by MTD device number
105 static int get_sb_mtd_nr(struct file_system_type *fs_type, int flags,
106 const char *dev_name, void *data, int mtdnr,
107 int (*fill_super)(struct super_block *, void *, int),
108 struct vfsmount *mnt)
110 struct mtd_info *mtd;
112 mtd = get_mtd_device(NULL, mtdnr);
114 DEBUG(0, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
118 return get_sb_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super,
123 * set up an MTD-based superblock
125 int get_sb_mtd(struct file_system_type *fs_type, int flags,
126 const char *dev_name, void *data,
127 int (*fill_super)(struct super_block *, void *, int),
128 struct vfsmount *mnt)
131 struct block_device *bdev;
139 DEBUG(2, "MTDSB: dev_name \"%s\"\n", dev_name);
141 /* the preferred way of mounting in future; especially when
142 * CONFIG_BLOCK=n - we specify the underlying MTD device by number or
143 * by name, so that we don't require block device support to be present
145 if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
146 if (dev_name[3] == ':') {
147 struct mtd_info *mtd;
149 /* mount by MTD device name */
150 DEBUG(1, "MTDSB: mtd:%%s, name \"%s\"\n",
153 for (mtdnr = 0; mtdnr < MAX_MTD_DEVICES; mtdnr++) {
154 mtd = get_mtd_device(NULL, mtdnr);
156 if (!strcmp(mtd->name, dev_name + 4))
157 return get_sb_mtd_aux(
166 printk(KERN_NOTICE "MTD:"
167 " MTD device with name \"%s\" not found.\n",
170 } else if (isdigit(dev_name[3])) {
171 /* mount by MTD device number name */
174 mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
176 /* It was a valid number */
177 DEBUG(1, "MTDSB: mtd%%d, mtdnr %d\n",
179 return get_sb_mtd_nr(fs_type, flags,
181 mtdnr, fill_super, mnt);
187 /* try the old way - the hack where we allowed users to mount
188 * /dev/mtdblock$(n) but didn't actually _use_ the blockdev
190 bdev = lookup_bdev(dev_name);
193 DEBUG(1, "MTDSB: lookup_bdev() returned %d\n", ret);
196 DEBUG(1, "MTDSB: lookup_bdev() returned 0\n");
200 major = MAJOR(bdev->bd_dev);
201 mtdnr = MINOR(bdev->bd_dev);
204 if (major != MTD_BLOCK_MAJOR)
205 goto not_an_MTD_device;
207 return get_sb_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super,
211 #endif /* CONFIG_BLOCK */
213 if (!(flags & MS_SILENT))
215 "MTD: Attempt to mount non-MTD device \"%s\"\n",
220 EXPORT_SYMBOL_GPL(get_sb_mtd);
223 * destroy an MTD-based superblock
225 void kill_mtd_super(struct super_block *sb)
227 generic_shutdown_super(sb);
228 put_mtd_device(sb->s_mtd);
232 EXPORT_SYMBOL_GPL(kill_mtd_super);