sb.c 26.7 KB
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/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This file implements UBIFS superblock. The superblock is stored at the first
 * LEB of the volume and is never changed by UBIFS. Only user-space tools may
 * change it. The superblock node mostly contains geometry information.
 */

#include "ubifs.h"
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#include <linux/slab.h>
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#include <linux/math64.h>
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#include <linux/uuid.h>
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/*
 * Default journal size in logical eraseblocks as a percent of total
 * flash size.
 */
#define DEFAULT_JNL_PERCENT 5

/* Default maximum journal size in bytes */
#define DEFAULT_MAX_JNL (32*1024*1024)

/* Default indexing tree fanout */
#define DEFAULT_FANOUT 8

/* Default number of data journal heads */
#define DEFAULT_JHEADS_CNT 1

/* Default positions of different LEBs in the main area */
#define DEFAULT_IDX_LEB  0
#define DEFAULT_DATA_LEB 1
#define DEFAULT_GC_LEB   2

/* Default number of LEB numbers in LPT's save table */
#define DEFAULT_LSAVE_CNT 256

/* Default reserved pool size as a percent of maximum free space */
#define DEFAULT_RP_PERCENT 5

/* The default maximum size of reserved pool in bytes */
#define DEFAULT_MAX_RP_SIZE (5*1024*1024)

/* Default time granularity in nanoseconds */
#define DEFAULT_TIME_GRAN 1000000000

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static int get_default_compressor(struct ubifs_info *c)
{
	if (ubifs_compr_present(c, UBIFS_COMPR_LZO))
		return UBIFS_COMPR_LZO;

	if (ubifs_compr_present(c, UBIFS_COMPR_ZLIB))
		return UBIFS_COMPR_ZLIB;

	return UBIFS_COMPR_NONE;
}

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/**
 * create_default_filesystem - format empty UBI volume.
 * @c: UBIFS file-system description object
 *
 * This function creates default empty file-system. Returns zero in case of
 * success and a negative error code in case of failure.
 */
static int create_default_filesystem(struct ubifs_info *c)
{
	struct ubifs_sb_node *sup;
	struct ubifs_mst_node *mst;
	struct ubifs_idx_node *idx;
	struct ubifs_branch *br;
	struct ubifs_ino_node *ino;
	struct ubifs_cs_node *cs;
	union ubifs_key key;
	int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
	int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
	int min_leb_cnt = UBIFS_MIN_LEB_CNT;
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	int idx_node_size;
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	long long tmp64, main_bytes;
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	__le64 tmp_le64;
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	__le32 tmp_le32;
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	struct timespec64 ts;
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	u8 hash[UBIFS_HASH_ARR_SZ];
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	u8 hash_lpt[UBIFS_HASH_ARR_SZ];
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	/* Some functions called from here depend on the @c->key_len filed */
	c->key_len = UBIFS_SK_LEN;

	/*
	 * First of all, we have to calculate default file-system geometry -
	 * log size, journal size, etc.
	 */
	if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
		/* We can first multiply then divide and have no overflow */
		jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
	else
		jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;

	if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
		jnl_lebs = UBIFS_MIN_JNL_LEBS;
	if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
		jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;

	/*
	 * The log should be large enough to fit reference nodes for all bud
	 * LEBs. Because buds do not have to start from the beginning of LEBs
	 * (half of the LEB may contain committed data), the log should
	 * generally be larger, make it twice as large.
	 */
	tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
	log_lebs = tmp / c->leb_size;
	/* Plus one LEB reserved for commit */
	log_lebs += 1;
	if (c->leb_cnt - min_leb_cnt > 8) {
		/* And some extra space to allow writes while committing */
		log_lebs += 1;
		min_leb_cnt += 1;
	}

	max_buds = jnl_lebs - log_lebs;
	if (max_buds < UBIFS_MIN_BUD_LEBS)
		max_buds = UBIFS_MIN_BUD_LEBS;

	/*
	 * Orphan nodes are stored in a separate area. One node can store a lot
	 * of orphan inode numbers, but when new orphan comes we just add a new
	 * orphan node. At some point the nodes are consolidated into one
	 * orphan node.
	 */
	orph_lebs = UBIFS_MIN_ORPH_LEBS;
	if (c->leb_cnt - min_leb_cnt > 1)
		/*
		 * For debugging purposes it is better to have at least 2
		 * orphan LEBs, because the orphan subsystem would need to do
		 * consolidations and would be stressed more.
		 */
		orph_lebs += 1;

	main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
	main_lebs -= orph_lebs;

	lpt_first = UBIFS_LOG_LNUM + log_lebs;
	c->lsave_cnt = DEFAULT_LSAVE_CNT;
	c->max_leb_cnt = c->leb_cnt;
	err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
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				    &big_lpt, hash_lpt);
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	if (err)
		return err;

	dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
		lpt_first + lpt_lebs - 1);

	main_first = c->leb_cnt - main_lebs;

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	sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
	idx_node_size = ubifs_idx_node_sz(c, 1);
	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
	ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
	cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);

	if (!sup || !mst || !idx || !ino || !cs) {
		err = -ENOMEM;
		goto out;
	}

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	/* Create default superblock */

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	tmp64 = (long long)max_buds * c->leb_size;
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	if (big_lpt)
		sup_flags |= UBIFS_FLG_BIGLPT;
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	sup_flags |= UBIFS_FLG_DOUBLE_HASH;
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	if (ubifs_authenticated(c)) {
		sup_flags |= UBIFS_FLG_AUTHENTICATION;
		sup->hash_algo = cpu_to_le16(c->auth_hash_algo);
		err = ubifs_hmac_wkm(c, sup->hmac_wkm);
		if (err)
			goto out;
	} else {
		sup->hash_algo = 0xffff;
	}

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	sup->ch.node_type  = UBIFS_SB_NODE;
	sup->key_hash      = UBIFS_KEY_HASH_R5;
	sup->flags         = cpu_to_le32(sup_flags);
	sup->min_io_size   = cpu_to_le32(c->min_io_size);
	sup->leb_size      = cpu_to_le32(c->leb_size);
	sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
	sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
	sup->max_bud_bytes = cpu_to_le64(tmp64);
	sup->log_lebs      = cpu_to_le32(log_lebs);
	sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
	sup->orph_lebs     = cpu_to_le32(orph_lebs);
	sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
	sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
	sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
	sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
	sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
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	if (c->mount_opts.override_compr)
		sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
	else
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		sup->default_compr = cpu_to_le16(get_default_compressor(c));
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	generate_random_uuid(sup->uuid);

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	main_bytes = (long long)main_lebs * c->leb_size;
	tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
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	if (tmp64 > DEFAULT_MAX_RP_SIZE)
		tmp64 = DEFAULT_MAX_RP_SIZE;
	sup->rp_size = cpu_to_le64(tmp64);
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	sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
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	dbg_gen("default superblock created at LEB 0:0");

	/* Create default master node */

	mst->ch.node_type = UBIFS_MST_NODE;
	mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
	mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
	mst->cmt_no       = 0;
	mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
	mst->root_offs    = 0;
	tmp = ubifs_idx_node_sz(c, 1);
	mst->root_len     = cpu_to_le32(tmp);
	mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
	mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
	mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
	mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
	mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
	mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
	mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
	mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
	mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
	mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
	mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
	mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
	mst->lscan_lnum   = cpu_to_le32(main_first);
	mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
	mst->idx_lebs     = cpu_to_le32(1);
	mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
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	ubifs_copy_hash(c, hash_lpt, mst->hash_lpt);
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	/* Calculate lprops statistics */
	tmp64 = main_bytes;
	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
	tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
	mst->total_free = cpu_to_le64(tmp64);

	tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
	ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
			  UBIFS_INO_NODE_SZ;
	tmp64 += ino_waste;
	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
	mst->total_dirty = cpu_to_le64(tmp64);

	/*  The indexing LEB does not contribute to dark space */
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	tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
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	mst->total_dark = cpu_to_le64(tmp64);

	mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);

	dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);

	/* Create the root indexing node */

	c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
	c->key_hash = key_r5_hash;

	idx->ch.node_type = UBIFS_IDX_NODE;
	idx->child_cnt = cpu_to_le16(1);
	ino_key_init(c, &key, UBIFS_ROOT_INO);
	br = ubifs_idx_branch(c, idx, 0);
	key_write_idx(c, &key, &br->key);
	br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
	br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);

	dbg_gen("default root indexing node created LEB %d:0",
		main_first + DEFAULT_IDX_LEB);

	/* Create default root inode */

	ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
	ino->ch.node_type = UBIFS_INO_NODE;
	ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
	ino->nlink = cpu_to_le32(2);
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	ktime_get_real_ts64(&ts);
	ts = timespec64_trunc(ts, DEFAULT_TIME_GRAN);
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	tmp_le64 = cpu_to_le64(ts.tv_sec);
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	ino->atime_sec   = tmp_le64;
	ino->ctime_sec   = tmp_le64;
	ino->mtime_sec   = tmp_le64;
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	tmp_le32 = cpu_to_le32(ts.tv_nsec);
	ino->atime_nsec  = tmp_le32;
	ino->ctime_nsec  = tmp_le32;
	ino->mtime_nsec  = tmp_le32;
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	ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
	ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);

	/* Set compression enabled by default */
	ino->flags = cpu_to_le32(UBIFS_COMPR_FL);

	dbg_gen("root inode created at LEB %d:0",
		main_first + DEFAULT_DATA_LEB);

	/*
	 * The first node in the log has to be the commit start node. This is
	 * always the case during normal file-system operation. Write a fake
	 * commit start node to the log.
	 */

	cs->ch.node_type = UBIFS_CS_NODE;
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	err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
				    offsetof(struct ubifs_sb_node, hmac));
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	if (err)
		goto out;

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	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
			       main_first + DEFAULT_DATA_LEB, 0);
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	if (err)
		goto out;

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	ubifs_node_calc_hash(c, ino, hash);
	ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));

	err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
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	if (err)
		goto out;

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	ubifs_node_calc_hash(c, idx, hash);
	ubifs_copy_hash(c, hash, mst->hash_root_idx);

	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
		offsetof(struct ubifs_mst_node, hmac));
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	if (err)
		goto out;

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	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
			       0, offsetof(struct ubifs_mst_node, hmac));
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	if (err)
		goto out;

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	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
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	if (err)
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		goto out;
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	ubifs_msg(c, "default file-system created");
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	err = 0;
out:
	kfree(sup);
	kfree(mst);
	kfree(idx);
	kfree(ino);
	kfree(cs);

	return err;
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}

/**
 * validate_sb - validate superblock node.
 * @c: UBIFS file-system description object
 * @sup: superblock node
 *
 * This function validates superblock node @sup. Since most of data was read
 * from the superblock and stored in @c, the function validates fields in @c
 * instead. Returns zero in case of success and %-EINVAL in case of validation
 * failure.
 */
static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
{
	long long max_bytes;
	int err = 1, min_leb_cnt;

	if (!c->key_hash) {
		err = 2;
		goto failed;
	}

	if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
		err = 3;
		goto failed;
	}

	if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
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		ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
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			  le32_to_cpu(sup->min_io_size), c->min_io_size);
		goto failed;
	}

	if (le32_to_cpu(sup->leb_size) != c->leb_size) {
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		ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
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			  le32_to_cpu(sup->leb_size), c->leb_size);
		goto failed;
	}

	if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
	    c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
	    c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
	    c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
		err = 4;
		goto failed;
	}

	/*
	 * Calculate minimum allowed amount of main area LEBs. This is very
	 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
	 * have just read from the superblock.
	 */
	min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
	min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;

	if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
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		ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
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			  c->leb_cnt, c->vi.size, min_leb_cnt);
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		goto failed;
	}

	if (c->max_leb_cnt < c->leb_cnt) {
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		ubifs_err(c, "max. LEB count %d less than LEB count %d",
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			  c->max_leb_cnt, c->leb_cnt);
		goto failed;
	}

	if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
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		ubifs_err(c, "too few main LEBs count %d, must be at least %d",
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			  c->main_lebs, UBIFS_MIN_MAIN_LEBS);
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		goto failed;
	}

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	max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
	if (c->max_bud_bytes < max_bytes) {
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		ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
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			  c->max_bud_bytes, max_bytes);
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		goto failed;
	}

	max_bytes = (long long)c->leb_size * c->main_lebs;
	if (c->max_bud_bytes > max_bytes) {
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		ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
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			  c->max_bud_bytes, max_bytes);
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		goto failed;
	}

	if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
	    c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
		err = 9;
		goto failed;
	}

	if (c->fanout < UBIFS_MIN_FANOUT ||
	    ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
		err = 10;
		goto failed;
	}

	if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
	    c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
	    c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
		err = 11;
		goto failed;
	}

	if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
	    c->orph_lebs + c->main_lebs != c->leb_cnt) {
		err = 12;
		goto failed;
	}

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	if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
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		err = 13;
		goto failed;
	}

	if (c->rp_size < 0 || max_bytes < c->rp_size) {
		err = 14;
		goto failed;
	}

	if (le32_to_cpu(sup->time_gran) > 1000000000 ||
	    le32_to_cpu(sup->time_gran) < 1) {
		err = 15;
		goto failed;
	}

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	if (!c->double_hash && c->fmt_version >= 5) {
		err = 16;
		goto failed;
	}

	if (c->encrypted && c->fmt_version < 5) {
		err = 17;
		goto failed;
	}

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	return 0;

failed:
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	ubifs_err(c, "bad superblock, error %d", err);
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	ubifs_dump_node(c, sup);
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	return -EINVAL;
}

/**
 * ubifs_read_sb_node - read superblock node.
 * @c: UBIFS file-system description object
 *
 * This function returns a pointer to the superblock node or a negative error
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 * code. Note, the user of this function is responsible of kfree()'ing the
 * returned superblock buffer.
531
 */
532
static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
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{
	struct ubifs_sb_node *sup;
	int err;

	sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
	if (!sup)
		return ERR_PTR(-ENOMEM);

	err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
			      UBIFS_SB_LNUM, 0);
	if (err) {
		kfree(sup);
		return ERR_PTR(err);
	}

	return sup;
}

551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609
static int authenticate_sb_node(struct ubifs_info *c,
				const struct ubifs_sb_node *sup)
{
	unsigned int sup_flags = le32_to_cpu(sup->flags);
	u8 hmac_wkm[UBIFS_HMAC_ARR_SZ];
	int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
	int hash_algo;
	int err;

	if (c->authenticated && !authenticated) {
		ubifs_err(c, "authenticated FS forced, but found FS without authentication");
		return -EINVAL;
	}

	if (!c->authenticated && authenticated) {
		ubifs_err(c, "authenticated FS found, but no key given");
		return -EINVAL;
	}

	ubifs_msg(c, "Mounting in %sauthenticated mode",
		  c->authenticated ? "" : "un");

	if (!c->authenticated)
		return 0;

	if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
		return -EOPNOTSUPP;

	hash_algo = le16_to_cpu(sup->hash_algo);
	if (hash_algo >= HASH_ALGO__LAST) {
		ubifs_err(c, "superblock uses unknown hash algo %d",
			  hash_algo);
		return -EINVAL;
	}

	if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
		ubifs_err(c, "This filesystem uses %s for hashing,"
			     " but %s is specified", hash_algo_name[hash_algo],
			     c->auth_hash_name);
		return -EINVAL;
	}

	err = ubifs_hmac_wkm(c, hmac_wkm);
	if (err)
		return err;

	if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
		ubifs_err(c, "provided key does not fit");
		return -ENOKEY;
	}

	err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
				     offsetof(struct ubifs_sb_node, hmac));
	if (err)
		ubifs_err(c, "Failed to authenticate superblock: %d", err);

	return err;
}

610 611 612 613 614 615 616 617 618 619
/**
 * ubifs_write_sb_node - write superblock node.
 * @c: UBIFS file-system description object
 * @sup: superblock node read with 'ubifs_read_sb_node()'
 *
 * This function returns %0 on success and a negative error code on failure.
 */
int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
{
	int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
620 621 622 623 624 625
	int err;

	err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
				      offsetof(struct ubifs_sb_node, hmac), 1);
	if (err)
		return err;
626

627
	return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652
}

/**
 * ubifs_read_superblock - read superblock.
 * @c: UBIFS file-system description object
 *
 * This function finds, reads and checks the superblock. If an empty UBI volume
 * is being mounted, this function creates default superblock. Returns zero in
 * case of success, and a negative error code in case of failure.
 */
int ubifs_read_superblock(struct ubifs_info *c)
{
	int err, sup_flags;
	struct ubifs_sb_node *sup;

	if (c->empty) {
		err = create_default_filesystem(c);
		if (err)
			return err;
	}

	sup = ubifs_read_sb_node(c);
	if (IS_ERR(sup))
		return PTR_ERR(sup);

653 654
	c->sup_node = sup;

655 656 657
	c->fmt_version = le32_to_cpu(sup->fmt_version);
	c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);

658 659 660 661 662
	/*
	 * The software supports all previous versions but not future versions,
	 * due to the unavailability of time-travelling equipment.
	 */
	if (c->fmt_version > UBIFS_FORMAT_VERSION) {
663
		ubifs_assert(c, !c->ro_media || c->ro_mount);
664
		if (!c->ro_mount ||
665
		    c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
666
			ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
667 668
				  c->fmt_version, c->ro_compat_version,
				  UBIFS_FORMAT_VERSION,
669 670
				  UBIFS_RO_COMPAT_VERSION);
			if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
671
				ubifs_msg(c, "only R/O mounting is possible");
672 673 674 675 676 677 678 679 680 681 682 683
				err = -EROFS;
			} else
				err = -EINVAL;
			goto out;
		}

		/*
		 * The FS is mounted R/O, and the media format is
		 * R/O-compatible with the UBIFS implementation, so we can
		 * mount.
		 */
		c->rw_incompat = 1;
684 685 686
	}

	if (c->fmt_version < 3) {
687
		ubifs_err(c, "on-flash format version %d is not supported",
688 689 690 691 692 693 694 695 696 697 698 699 700 701 702
			  c->fmt_version);
		err = -EINVAL;
		goto out;
	}

	switch (sup->key_hash) {
	case UBIFS_KEY_HASH_R5:
		c->key_hash = key_r5_hash;
		c->key_hash_type = UBIFS_KEY_HASH_R5;
		break;

	case UBIFS_KEY_HASH_TEST:
		c->key_hash = key_test_hash;
		c->key_hash_type = UBIFS_KEY_HASH_TEST;
		break;
703
	}
704 705 706 707 708 709 710 711

	c->key_fmt = sup->key_fmt;

	switch (c->key_fmt) {
	case UBIFS_SIMPLE_KEY_FMT:
		c->key_len = UBIFS_SK_LEN;
		break;
	default:
712
		ubifs_err(c, "unsupported key format");
713 714 715 716 717 718 719 720 721 722 723 724 725 726
		err = -EINVAL;
		goto out;
	}

	c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
	c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
	c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
	c->log_lebs      = le32_to_cpu(sup->log_lebs);
	c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
	c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
	c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
	c->fanout        = le32_to_cpu(sup->fanout);
	c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
	c->rp_size       = le64_to_cpu(sup->rp_size);
727 728
	c->rp_uid        = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
	c->rp_gid        = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
729
	sup_flags        = le32_to_cpu(sup->flags);
730 731
	if (!c->mount_opts.override_compr)
		c->default_compr = le16_to_cpu(sup->default_compr);
732 733 734 735

	c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
	memcpy(&c->uuid, &sup->uuid, 16);
	c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
736
	c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
737
	c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
738 739
	c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);

740 741 742 743
	err = authenticate_sb_node(c, sup);
	if (err)
		goto out;

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	if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
		ubifs_err(c, "Unknown feature flags found: %#x",
			  sup_flags & ~UBIFS_FLG_MASK);
		err = -EINVAL;
		goto out;
	}

751 752 753 754 755 756 757 758
#ifndef CONFIG_UBIFS_FS_ENCRYPTION
	if (c->encrypted) {
		ubifs_err(c, "file system contains encrypted files but UBIFS"
			     " was built without crypto support.");
		err = -EINVAL;
		goto out;
	}
#endif
759 760 761 762 763

	/* Automatically increase file system size to the maximum size */
	c->old_leb_cnt = c->leb_cnt;
	if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
		c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
764
		if (c->ro_mount)
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791
			dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
				c->old_leb_cnt,	c->leb_cnt);
		else {
			dbg_mnt("Auto resizing (sb) from %d LEBs to %d LEBs",
				c->old_leb_cnt, c->leb_cnt);
			sup->leb_cnt = cpu_to_le32(c->leb_cnt);
			err = ubifs_write_sb_node(c, sup);
			if (err)
				goto out;
			c->old_leb_cnt = c->leb_cnt;
		}
	}

	c->log_bytes = (long long)c->log_lebs * c->leb_size;
	c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
	c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
	c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
	c->orph_first = c->lpt_last + 1;
	c->orph_last = c->orph_first + c->orph_lebs - 1;
	c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
	c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
	c->main_first = c->leb_cnt - c->main_lebs;

	err = validate_sb(c, sup);
out:
	return err;
}
792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807

/**
 * fixup_leb - fixup/unmap an LEB containing free space.
 * @c: UBIFS file-system description object
 * @lnum: the LEB number to fix up
 * @len: number of used bytes in LEB (starting at offset 0)
 *
 * This function reads the contents of the given LEB number @lnum, then fixes
 * it up, so that empty min. I/O units in the end of LEB are actually erased on
 * flash (rather than being just all-0xff real data). If the LEB is completely
 * empty, it is simply unmapped.
 */
static int fixup_leb(struct ubifs_info *c, int lnum, int len)
{
	int err;

808 809 810
	ubifs_assert(c, len >= 0);
	ubifs_assert(c, len % c->min_io_size == 0);
	ubifs_assert(c, len < c->leb_size);
811 812 813

	if (len == 0) {
		dbg_mnt("unmap empty LEB %d", lnum);
814
		return ubifs_leb_unmap(c, lnum);
815 816 817
	}

	dbg_mnt("fixup LEB %d, data len %d", lnum, len);
818
	err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
819 820 821
	if (err)
		return err;

822
	return ubifs_leb_change(c, lnum, c->sbuf, len);
823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854
}

/**
 * fixup_free_space - find & remap all LEBs containing free space.
 * @c: UBIFS file-system description object
 *
 * This function walks through all LEBs in the filesystem and fiexes up those
 * containing free/empty space.
 */
static int fixup_free_space(struct ubifs_info *c)
{
	int lnum, err = 0;
	struct ubifs_lprops *lprops;

	ubifs_get_lprops(c);

	/* Fixup LEBs in the master area */
	for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
		err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
		if (err)
			goto out;
	}

	/* Unmap unused log LEBs */
	lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
	while (lnum != c->ltail_lnum) {
		err = fixup_leb(c, lnum, 0);
		if (err)
			goto out;
		lnum = ubifs_next_log_lnum(c, lnum);
	}

855 856 857 858 859 860
	/*
	 * Fixup the log head which contains the only a CS node at the
	 * beginning.
	 */
	err = fixup_leb(c, c->lhead_lnum,
			ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917
	if (err)
		goto out;

	/* Fixup LEBs in the LPT area */
	for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
		int free = c->ltab[lnum - c->lpt_first].free;

		if (free > 0) {
			err = fixup_leb(c, lnum, c->leb_size - free);
			if (err)
				goto out;
		}
	}

	/* Unmap LEBs in the orphans area */
	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
		err = fixup_leb(c, lnum, 0);
		if (err)
			goto out;
	}

	/* Fixup LEBs in the main area */
	for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
		lprops = ubifs_lpt_lookup(c, lnum);
		if (IS_ERR(lprops)) {
			err = PTR_ERR(lprops);
			goto out;
		}

		if (lprops->free > 0) {
			err = fixup_leb(c, lnum, c->leb_size - lprops->free);
			if (err)
				goto out;
		}
	}

out:
	ubifs_release_lprops(c);
	return err;
}

/**
 * ubifs_fixup_free_space - find & fix all LEBs with free space.
 * @c: UBIFS file-system description object
 *
 * This function fixes up LEBs containing free space on first mount, if the
 * appropriate flag was set when the FS was created. Each LEB with one or more
 * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
 * the free space is actually erased. E.g., this is necessary for some NAND
 * chips, since the free space may have been programmed like real "0xff" data
 * (generating a non-0xff ECC), causing future writes to the not-really-erased
 * NAND pages to behave badly. After the space is fixed up, the superblock flag
 * is cleared, so that this is skipped for all future mounts.
 */
int ubifs_fixup_free_space(struct ubifs_info *c)
{
	int err;
918
	struct ubifs_sb_node *sup = c->sup_node;
919

920 921
	ubifs_assert(c, c->space_fixup);
	ubifs_assert(c, !c->ro_mount);
922

923
	ubifs_msg(c, "start fixing up free space");
924 925 926 927 928 929 930 931 932 933 934 935 936

	err = fixup_free_space(c);
	if (err)
		return err;

	/* Free-space fixup is no longer required */
	c->space_fixup = 0;
	sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);

	err = ubifs_write_sb_node(c, sup);
	if (err)
		return err;

937
	ubifs_msg(c, "free space fixup complete");
938 939
	return err;
}
940 941 942 943

int ubifs_enable_encryption(struct ubifs_info *c)
{
	int err;
944
	struct ubifs_sb_node *sup = c->sup_node;
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964

	if (c->encrypted)
		return 0;

	if (c->ro_mount || c->ro_media)
		return -EROFS;

	if (c->fmt_version < 5) {
		ubifs_err(c, "on-flash format version 5 is needed for encryption");
		return -EINVAL;
	}

	sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);

	err = ubifs_write_sb_node(c, sup);
	if (!err)
		c->encrypted = 1;

	return err;
}