linux/drivers/mtd/mtdsuper.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

221 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* MTD-based superblock management
*
* Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved.
* Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
*
* Written by: David Howells <dhowells@redhat.com>
* David Woodhouse <dwmw2@infradead.org>
*/
#include <linux/mtd/super.h>
#include <linux/namei.h>
#include <linux/export.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/major.h>
#include <linux/backing-dev.h>
/*
* compare superblocks to see if they're equivalent
* - they are if the underlying MTD device is the same
*/
static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
if (sb->s_mtd == mtd) {
pr_debug("MTDSB: Match on device %d (\"%s\")\n",
mtd->index, mtd->name);
return 1;
}
pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n",
sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name);
return 0;
}
extern struct backing_dev_info *mtd_bdi;
/*
* mark the superblock by the MTD device it is using
* - set the device number to be the correct MTD block device for pesuperstence
* of NFS exports
*/
static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
{
struct mtd_info *mtd = _mtd;
sb->s_mtd = mtd;
sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
sb->s_bdi = bdi_get(mtd_bdi);
return 0;
}
/*
* get a superblock on an MTD-backed filesystem
*/
static struct dentry *mount_mtd_aux(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
struct mtd_info *mtd,
int (*fill_super)(struct super_block *, void *, int))
{
struct super_block *sb;
int ret;
sb = sget(fs_type, get_sb_mtd_compare, get_sb_mtd_set, flags, mtd);
if (IS_ERR(sb))
goto out_error;
if (sb->s_root)
goto already_mounted;
/* fresh new superblock */
pr_debug("MTDSB: New superblock for device %d (\"%s\")\n",
mtd->index, mtd->name);
ret = fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
if (ret < 0) {
deactivate_locked_super(sb);
return ERR_PTR(ret);
}
/* go */
sb->s_flags |= SB_ACTIVE;
return dget(sb->s_root);
/* new mountpoint for an already mounted superblock */
already_mounted:
pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n",
mtd->index, mtd->name);
put_mtd_device(mtd);
return dget(sb->s_root);
out_error:
put_mtd_device(mtd);
return ERR_CAST(sb);
}
/*
* get a superblock on an MTD-backed filesystem by MTD device number
*/
static struct dentry *mount_mtd_nr(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, int mtdnr,
int (*fill_super)(struct super_block *, void *, int))
{
struct mtd_info *mtd;
mtd = get_mtd_device(NULL, mtdnr);
if (IS_ERR(mtd)) {
pr_debug("MTDSB: Device #%u doesn't appear to exist\n", mtdnr);
return ERR_CAST(mtd);
}
return mount_mtd_aux(fs_type, flags, dev_name, data, mtd, fill_super);
}
/*
* set up an MTD-based superblock
*/
struct dentry *mount_mtd(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
int ret, major;
#endif
int mtdnr;
if (!dev_name)
return ERR_PTR(-EINVAL);
pr_debug("MTDSB: dev_name \"%s\"\n", dev_name);
/* the preferred way of mounting in future; especially when
* CONFIG_BLOCK=n - we specify the underlying MTD device by number or
* by name, so that we don't require block device support to be present
* in the kernel. */
if (dev_name[0] == 'm' && dev_name[1] == 't' && dev_name[2] == 'd') {
if (dev_name[3] == ':') {
struct mtd_info *mtd;
/* mount by MTD device name */
pr_debug("MTDSB: mtd:%%s, name \"%s\"\n",
dev_name + 4);
mtd = get_mtd_device_nm(dev_name + 4);
if (!IS_ERR(mtd))
return mount_mtd_aux(
fs_type, flags,
dev_name, data, mtd,
fill_super);
printk(KERN_NOTICE "MTD:"
" MTD device with name \"%s\" not found.\n",
dev_name + 4);
} else if (isdigit(dev_name[3])) {
/* mount by MTD device number name */
char *endptr;
mtdnr = simple_strtoul(dev_name + 3, &endptr, 0);
if (!*endptr) {
/* It was a valid number */
pr_debug("MTDSB: mtd%%d, mtdnr %d\n",
mtdnr);
return mount_mtd_nr(fs_type, flags,
dev_name, data,
mtdnr, fill_super);
}
}
}
#ifdef CONFIG_BLOCK
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
bdev = lookup_bdev(dev_name);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
pr_debug("MTDSB: lookup_bdev() returned %d\n", ret);
return ERR_PTR(ret);
}
pr_debug("MTDSB: lookup_bdev() returned 0\n");
ret = -EINVAL;
major = MAJOR(bdev->bd_dev);
mtdnr = MINOR(bdev->bd_dev);
bdput(bdev);
if (major != MTD_BLOCK_MAJOR)
goto not_an_MTD_device;
return mount_mtd_nr(fs_type, flags, dev_name, data, mtdnr, fill_super);
not_an_MTD_device:
#endif /* CONFIG_BLOCK */
if (!(flags & SB_SILENT))
printk(KERN_NOTICE
"MTD: Attempt to mount non-MTD device \"%s\"\n",
dev_name);
return ERR_PTR(-EINVAL);
}
EXPORT_SYMBOL_GPL(mount_mtd);
/*
* destroy an MTD-based superblock
*/
void kill_mtd_super(struct super_block *sb)
{
generic_shutdown_super(sb);
put_mtd_device(sb->s_mtd);
sb->s_mtd = NULL;
}
EXPORT_SYMBOL_GPL(kill_mtd_super);