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201 lines
4.9 KiB
201 lines
4.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* MTD-based superblock management |
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* |
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* Copyright © 2001-2007 Red Hat, Inc. All Rights Reserved. |
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* Copyright © 2001-2010 David Woodhouse <[email protected]> |
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* |
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* Written by: David Howells <[email protected]> |
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* David Woodhouse <[email protected]> |
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*/ |
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#include <linux/mtd/super.h> |
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#include <linux/namei.h> |
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#include <linux/export.h> |
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#include <linux/ctype.h> |
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#include <linux/slab.h> |
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#include <linux/major.h> |
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#include <linux/backing-dev.h> |
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#include <linux/fs_context.h> |
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#include "mtdcore.h" |
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/* |
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* compare superblocks to see if they're equivalent |
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* - they are if the underlying MTD device is the same |
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*/ |
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static int mtd_test_super(struct super_block *sb, struct fs_context *fc) |
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{ |
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struct mtd_info *mtd = fc->sget_key; |
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if (sb->s_mtd == fc->sget_key) { |
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pr_debug("MTDSB: Match on device %d (\"%s\")\n", |
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mtd->index, mtd->name); |
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return 1; |
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} |
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pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n", |
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sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name); |
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return 0; |
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} |
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/* |
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* mark the superblock by the MTD device it is using |
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* - set the device number to be the correct MTD block device for pesuperstence |
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* of NFS exports |
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*/ |
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static int mtd_set_super(struct super_block *sb, struct fs_context *fc) |
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{ |
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sb->s_mtd = fc->sget_key; |
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sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, sb->s_mtd->index); |
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sb->s_bdi = bdi_get(mtd_bdi); |
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return 0; |
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} |
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/* |
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* get a superblock on an MTD-backed filesystem |
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*/ |
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static int mtd_get_sb(struct fs_context *fc, |
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struct mtd_info *mtd, |
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int (*fill_super)(struct super_block *, |
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struct fs_context *)) |
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{ |
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struct super_block *sb; |
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int ret; |
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fc->sget_key = mtd; |
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sb = sget_fc(fc, mtd_test_super, mtd_set_super); |
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if (IS_ERR(sb)) |
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return PTR_ERR(sb); |
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if (sb->s_root) { |
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/* new mountpoint for an already mounted superblock */ |
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pr_debug("MTDSB: Device %d (\"%s\") is already mounted\n", |
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mtd->index, mtd->name); |
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put_mtd_device(mtd); |
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} else { |
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/* fresh new superblock */ |
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pr_debug("MTDSB: New superblock for device %d (\"%s\")\n", |
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mtd->index, mtd->name); |
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ret = fill_super(sb, fc); |
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if (ret < 0) |
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goto error_sb; |
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sb->s_flags |= SB_ACTIVE; |
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} |
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BUG_ON(fc->root); |
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fc->root = dget(sb->s_root); |
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return 0; |
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error_sb: |
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deactivate_locked_super(sb); |
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return ret; |
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} |
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/* |
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* get a superblock on an MTD-backed filesystem by MTD device number |
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*/ |
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static int mtd_get_sb_by_nr(struct fs_context *fc, int mtdnr, |
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int (*fill_super)(struct super_block *, |
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struct fs_context *)) |
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{ |
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struct mtd_info *mtd; |
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mtd = get_mtd_device(NULL, mtdnr); |
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if (IS_ERR(mtd)) { |
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errorf(fc, "MTDSB: Device #%u doesn't appear to exist\n", mtdnr); |
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return PTR_ERR(mtd); |
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} |
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return mtd_get_sb(fc, mtd, fill_super); |
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} |
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/** |
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* get_tree_mtd - Get a superblock based on a single MTD device |
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* @fc: The filesystem context holding the parameters |
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* @fill_super: Helper to initialise a new superblock |
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*/ |
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int get_tree_mtd(struct fs_context *fc, |
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int (*fill_super)(struct super_block *sb, |
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struct fs_context *fc)) |
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{ |
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#ifdef CONFIG_BLOCK |
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dev_t dev; |
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int ret; |
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#endif |
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int mtdnr; |
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if (!fc->source) |
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return invalf(fc, "No source specified"); |
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pr_debug("MTDSB: dev_name \"%s\"\n", fc->source); |
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/* the preferred way of mounting in future; especially when |
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* CONFIG_BLOCK=n - we specify the underlying MTD device by number or |
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* by name, so that we don't require block device support to be present |
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* in the kernel. |
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*/ |
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if (fc->source[0] == 'm' && |
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fc->source[1] == 't' && |
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fc->source[2] == 'd') { |
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if (fc->source[3] == ':') { |
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struct mtd_info *mtd; |
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/* mount by MTD device name */ |
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pr_debug("MTDSB: mtd:%%s, name \"%s\"\n", |
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fc->source + 4); |
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mtd = get_mtd_device_nm(fc->source + 4); |
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if (!IS_ERR(mtd)) |
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return mtd_get_sb(fc, mtd, fill_super); |
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errorf(fc, "MTD: MTD device with name \"%s\" not found", |
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fc->source + 4); |
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} else if (isdigit(fc->source[3])) { |
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/* mount by MTD device number name */ |
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char *endptr; |
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mtdnr = simple_strtoul(fc->source + 3, &endptr, 0); |
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if (!*endptr) { |
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/* It was a valid number */ |
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pr_debug("MTDSB: mtd%%d, mtdnr %d\n", mtdnr); |
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return mtd_get_sb_by_nr(fc, mtdnr, fill_super); |
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} |
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} |
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} |
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#ifdef CONFIG_BLOCK |
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/* try the old way - the hack where we allowed users to mount |
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* /dev/mtdblock$(n) but didn't actually _use_ the blockdev |
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*/ |
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ret = lookup_bdev(fc->source, &dev); |
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if (ret) { |
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errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret); |
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return ret; |
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} |
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pr_debug("MTDSB: lookup_bdev() returned 0\n"); |
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if (MAJOR(dev) == MTD_BLOCK_MAJOR) |
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return mtd_get_sb_by_nr(fc, MINOR(dev), fill_super); |
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#endif /* CONFIG_BLOCK */ |
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if (!(fc->sb_flags & SB_SILENT)) |
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errorf(fc, "MTD: Attempt to mount non-MTD device \"%s\"", |
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fc->source); |
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return -EINVAL; |
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} |
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EXPORT_SYMBOL_GPL(get_tree_mtd); |
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/* |
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* destroy an MTD-based superblock |
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*/ |
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void kill_mtd_super(struct super_block *sb) |
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{ |
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generic_shutdown_super(sb); |
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put_mtd_device(sb->s_mtd); |
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sb->s_mtd = NULL; |
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} |
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EXPORT_SYMBOL_GPL(kill_mtd_super);
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