ubifs: update implementation from u-boot v2016.03

This updated code supports recovering from unclean unmounts when write
buffer size is larger than 8. Linux uses takes information into
consideration when checking for writes.
The following list shows the changes for each file done compared to
u-boot v2016.03 code.

Makefile
* Add gc.o, do not include header as in u-boot

budget.c:
* Replace __UBOOT__ with __BAREBOX__

debug.c:
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Replace current->pid with 0

debug.h
* Replace __UBOOT__ with __BAREBOX__
* Add "0 &&" to ubifs_assert condition check
  U-Boot essentially disabled pr_crit output and dump_stack() is defined
  to do { } while (0), so ubifs_assert does nothing despite condition.

gc.c:
* Replace __UBOOT__ with __BAREBOX__

io.c:
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

key.h:
* No changes

log.c:
* No changes

lprops.c:
* Replace __UBOOT__ with __BAREBOX__

lpt.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>

lpt_commit.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

master.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>

misc.h
* Replace __UBOOT__ with __BAREBOX__
* Add #ifndef __BAREBOX__ around unneeded ubifs_current_time

orphan.c
* No changes

recovery.c
* Replace __UBOOT__ with __BAREBOX__

replay.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

sb.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>
* Remove #include <ubi_uboot.h>
* rp_uid and rp_gid are still uid_t, not kuid_t, so remove .val

scan.c
* Replace __UBOOT__ with __BAREBOX__

super.c:
* Replaced current->pid with 0
* Replaced __UBOOT__ with __BAREBOX__
* Removed #include <ubi_uboot.h>
* Removed #include <memalign.h>
* Added #include <init.h>
* Replaced malloc_cache_aligned with kzalloc
* Replaced I_LOCK with I_SYNC
* i_uid and i_gid are still uid_t, not kuid_t, so remove .val
* Replaced string "U-Boot" with "Barebox"
* Add #ifndef __BAREBOX__ around open_ubi, sb_test, sb_set, ubifs_mount,
  kill_ubifs_super, ubifs_fs_type
* Do not call ubi_open_volume or ubi_close_volume in ubifs_fill_super
  Those will already be handled in ubifs_probe
* Replaced uboot_ubifs_mount with new ubifs_get_super implementation using
  existing functions alloc_super, alloc_ubifs_info

tnc.c
* Replace __UBOOT__ with __BAREBOX__
* Remove #include <linux/compat.h>

tnc_misc.c
* Replace __UBOOT__ with __BAREBOX__

ubifs-media.h
* Replace __UBOOT__ with __BAREBOX__

ubifs.c:
* Replaced __UBOOT__ with __BAREBOX__
* Adjusted header includes
* Removed DECLARE_GLOBAL_DATA_PTR
* Add static struct z_stream_s variable
* Add struct ubifs_priv delcaration
* Replaced zunzip with deflate_decompress call
* Add ifdef for disabling ZLIB and/or LZO support
* Replaced malloc_cache_aligned with kzalloc
* Added #ifndef __BAREBOX__ around filldir, ubifs_printdir,
  ubifs_set_blk_dev, ubifs_ls, ubifs_exists, ubifs_size, do_readpage,
  ubifs_read, ubifs_close, ubifs_load
* Make parameter filename const char* in ubifs_findfile
* Add UBIFS fs_driver_d implementation
* Add zlib_decomp_init, ubifs_init

ubifs.h:
* Replaced __UBOOT__ with __BAREBOX__
* Adjusted header includes
* Added old #define crc32
* Added helper around kmem*
* Added XATTR_LIST_MAX define
* Added #ifndef __BAREBOX__ around current_fs_time struct inode,
  struct super_block, file_system_type, dentry and friends which barebox
  already has
* Added #ifndef __BAREBOX__ around write_inode in super_operations to avoid
  declaration of writeback_control
* Change rp_uid and rp_gid to uid_t and gui_t
* Added struct device_d to struct ubifs_info
* Added forward declaration of ubifs_get_super

linux/fs.h:
* Make struct inode's i_nlink a union containing a non-const int __i_nlink
  while making i_nlink a const int

linux/fs.h:
* Add s_remove_count

linux/fs.h:
* Convert struct super_block.s_instances and
  struct file_system_type.fs_supers to hlist_head

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 515 insertions, 43 deletions

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 00c9cd31a0..05655841e4 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -3,18 +3,7 @@
  *
  * 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
+ * SPDX-License-Identifier:	GPL-2.0+
  *
  * Authors: Artem Bityutskiy (Битюцкий Артём)
  *          Adrian Hunter
@@ -27,6 +16,15 @@
  */
 
 #include "ubifs.h"
+#ifndef __BAREBOX__
+#include <linux/slab.h>
+#include <linux/random.h>
+#include <linux/math64.h>
+#else
+
+#include <linux/err.h>
+#include <linux/stat.h>
+#endif
 
 /*
  * Default journal size in logical eraseblocks as a percent of total
@@ -60,6 +58,284 @@
 /* Default time granularity in nanoseconds */
 #define DEFAULT_TIME_GRAN 1000000000
 
+#ifndef __BAREBOX__
+/**
+ * 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;
+	long long tmp64, main_bytes;
+	__le64 tmp_le64;
+
+	/* 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,
+				    &big_lpt);
+	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;
+
+	/* Create default superblock */
+	tmp = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
+	sup = kzalloc(tmp, GFP_KERNEL);
+	if (!sup)
+		return -ENOMEM;
+
+	tmp64 = (long long)max_buds * c->leb_size;
+	if (big_lpt)
+		sup_flags |= UBIFS_FLG_BIGLPT;
+
+	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);
+	if (c->mount_opts.override_compr)
+		sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
+	else
+		sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
+
+	generate_random_uuid(sup->uuid);
+
+	main_bytes = (long long)main_lebs * c->leb_size;
+	tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
+	if (tmp64 > DEFAULT_MAX_RP_SIZE)
+		tmp64 = DEFAULT_MAX_RP_SIZE;
+	sup->rp_size = cpu_to_le64(tmp64);
+	sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
+
+	err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
+	kfree(sup);
+	if (err)
+		return err;
+
+	dbg_gen("default superblock created at LEB 0:0");
+
+	/* Create default master node */
+	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
+	if (!mst)
+		return -ENOMEM;
+
+	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);
+
+	/* 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 */
+	tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
+	mst->total_dark = cpu_to_le64(tmp64);
+
+	mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
+
+	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
+	if (err) {
+		kfree(mst);
+		return err;
+	}
+	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
+			       0);
+	kfree(mst);
+	if (err)
+		return err;
+
+	dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
+
+	/* Create the root indexing node */
+	tmp = ubifs_idx_node_sz(c, 1);
+	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
+	if (!idx)
+		return -ENOMEM;
+
+	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);
+	err = ubifs_write_node(c, idx, tmp, main_first + DEFAULT_IDX_LEB, 0);
+	kfree(idx);
+	if (err)
+		return err;
+
+	dbg_gen("default root indexing node created LEB %d:0",
+		main_first + DEFAULT_IDX_LEB);
+
+	/* Create default root inode */
+	tmp = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
+	ino = kzalloc(tmp, GFP_KERNEL);
+	if (!ino)
+		return -ENOMEM;
+
+	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);
+	tmp_le64 = cpu_to_le64(CURRENT_TIME_SEC.tv_sec);
+	ino->atime_sec   = tmp_le64;
+	ino->ctime_sec   = tmp_le64;
+	ino->mtime_sec   = tmp_le64;
+	ino->atime_nsec  = 0;
+	ino->ctime_nsec  = 0;
+	ino->mtime_nsec  = 0;
+	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);
+
+	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
+			       main_first + DEFAULT_DATA_LEB, 0);
+	kfree(ino);
+	if (err)
+		return err;
+
+	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.
+	 */
+	tmp = ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size);
+	cs = kzalloc(tmp, GFP_KERNEL);
+	if (!cs)
+		return -ENOMEM;
+
+	cs->ch.node_type = UBIFS_CS_NODE;
+	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
+	kfree(cs);
+	if (err)
+		return err;
+
+	ubifs_msg(c, "default file-system created");
+	return 0;
+}
+#endif
+
 /**
  * validate_sb - validate superblock node.
  * @c: UBIFS file-system description object
@@ -86,13 +362,13 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 	}
 
 	if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
-		ubifs_err("min. I/O unit mismatch: %d in superblock, %d real",
+		ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
 			  le32_to_cpu(sup->min_io_size), c->min_io_size);
 		goto failed;
 	}
 
 	if (le32_to_cpu(sup->leb_size) != c->leb_size) {
-		ubifs_err("LEB size mismatch: %d in superblock, %d real",
+		ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
 			  le32_to_cpu(sup->leb_size), c->leb_size);
 		goto failed;
 	}
@@ -114,26 +390,34 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 	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) {
-		ubifs_err("bad LEB count: %d in superblock, %d on UBI volume, "
-			  "%d minimum required", c->leb_cnt, c->vi.size,
-			  min_leb_cnt);
+		ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
+			  c->leb_cnt, c->vi.size, min_leb_cnt);
 		goto failed;
 	}
 
 	if (c->max_leb_cnt < c->leb_cnt) {
-		ubifs_err("max. LEB count %d less than LEB count %d",
+		ubifs_err(c, "max. LEB count %d less than LEB count %d",
 			  c->max_leb_cnt, c->leb_cnt);
 		goto failed;
 	}
 
 	if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
-		err = 7;
+		ubifs_err(c, "too few main LEBs count %d, must be at least %d",
+			  c->main_lebs, UBIFS_MIN_MAIN_LEBS);
 		goto failed;
 	}
 
-	if (c->max_bud_bytes < (long long)c->leb_size * UBIFS_MIN_BUD_LEBS ||
-	    c->max_bud_bytes > (long long)c->leb_size * c->main_lebs) {
-		err = 8;
+	max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
+	if (c->max_bud_bytes < max_bytes) {
+		ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
+			  c->max_bud_bytes, max_bytes);
+		goto failed;
+	}
+
+	max_bytes = (long long)c->leb_size * c->main_lebs;
+	if (c->max_bud_bytes > max_bytes) {
+		ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
+			  c->max_bud_bytes, max_bytes);
 		goto failed;
 	}
 
@@ -162,12 +446,11 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 		goto failed;
 	}
 
-	if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
+	if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
 		err = 13;
 		goto failed;
 	}
 
-	max_bytes = c->main_lebs * (long long)c->leb_size;
 	if (c->rp_size < 0 || max_bytes < c->rp_size) {
 		err = 14;
 		goto failed;
@@ -182,8 +465,8 @@ static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
 	return 0;
 
 failed:
-	ubifs_err("bad superblock, error %d", err);
-	dbg_dump_node(c, sup);
+	ubifs_err(c, "bad superblock, error %d", err);
+	ubifs_dump_node(c, sup);
 	return -EINVAL;
 }
 
@@ -192,7 +475,8 @@ failed:
  * @c: UBIFS file-system description object
  *
  * This function returns a pointer to the superblock node or a negative error
- * code.
+ * code. Note, the user of this function is responsible of kfree()'ing the
+ * returned superblock buffer.
  */
 struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
 {
@@ -214,6 +498,21 @@ struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
 }
 
 /**
+ * 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);
+
+	ubifs_prepare_node(c, sup, UBIFS_SB_NODE_SZ, 1);
+	return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
+}
+
+/**
  * ubifs_read_superblock - read superblock.
  * @c: UBIFS file-system description object
  *
@@ -227,8 +526,14 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	struct ubifs_sb_node *sup;
 
 	if (c->empty) {
+#ifndef __BAREBOX__
+		err = create_default_filesystem(c);
+		if (err)
+			return err;
+#else
 		printf("No UBIFS filesystem found!\n");
 		return -1;
+#endif
 	}
 
 	sup = ubifs_read_sb_node(c);
@@ -243,19 +548,15 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	 * due to the unavailability of time-travelling equipment.
 	 */
 	if (c->fmt_version > UBIFS_FORMAT_VERSION) {
-		struct super_block *sb = c->vfs_sb;
-		int mounting_ro = sb->s_flags & MS_RDONLY;
-
-		ubifs_assert(!c->ro_media || mounting_ro);
-		if (!mounting_ro ||
+		ubifs_assert(!c->ro_media || c->ro_mount);
+		if (!c->ro_mount ||
 		    c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
-			ubifs_err("on-flash format version is w%d/r%d, but "
-				  "software only supports up to version "
-				  "w%d/r%d", c->fmt_version,
-				  c->ro_compat_version, UBIFS_FORMAT_VERSION,
+			ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
+				  c->fmt_version, c->ro_compat_version,
+				  UBIFS_FORMAT_VERSION,
 				  UBIFS_RO_COMPAT_VERSION);
 			if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
-				ubifs_msg("only R/O mounting is possible");
+				ubifs_msg(c, "only R/O mounting is possible");
 				err = -EROFS;
 			} else
 				err = -EINVAL;
@@ -271,7 +572,7 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	}
 
 	if (c->fmt_version < 3) {
-		ubifs_err("on-flash format version %d is not supported",
+		ubifs_err(c, "on-flash format version %d is not supported",
 			  c->fmt_version);
 		err = -EINVAL;
 		goto out;
@@ -296,7 +597,7 @@ int ubifs_read_superblock(struct ubifs_info *c)
 		c->key_len = UBIFS_SK_LEN;
 		break;
 	default:
-		ubifs_err("unsupported key format");
+		ubifs_err(c, "unsupported key format");
 		err = -EINVAL;
 		goto out;
 	}
@@ -310,22 +611,41 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	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->default_compr = le16_to_cpu(sup->default_compr);
 	c->rp_size       = le64_to_cpu(sup->rp_size);
+#ifndef __BAREBOX__
+	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));
+#else
 	c->rp_uid        = le32_to_cpu(sup->rp_uid);
 	c->rp_gid        = le32_to_cpu(sup->rp_gid);
+#endif
 	sup_flags        = le32_to_cpu(sup->flags);
+	if (!c->mount_opts.override_compr)
+		c->default_compr = le16_to_cpu(sup->default_compr);
 
 	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);
+	c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
 
 	/* 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);
-		dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
-			c->old_leb_cnt,	c->leb_cnt);
+		if (c->ro_mount)
+			dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
+				c->old_leb_cnt,	c->leb_cnt);
+#ifndef __BAREBOX__
+		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;
+		}
+#endif
 	}
 
 	c->log_bytes = (long long)c->log_lebs * c->leb_size;
@@ -337,10 +657,162 @@ int ubifs_read_superblock(struct ubifs_info *c)
 	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;
-	c->report_rp_size = ubifs_reported_space(c, c->rp_size);
 
 	err = validate_sb(c, sup);
 out:
 	kfree(sup);
 	return err;
 }
+
+/**
+ * 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;
+
+	ubifs_assert(len >= 0);
+	ubifs_assert(len % c->min_io_size == 0);
+	ubifs_assert(len < c->leb_size);
+
+	if (len == 0) {
+		dbg_mnt("unmap empty LEB %d", lnum);
+		return ubifs_leb_unmap(c, lnum);
+	}
+
+	dbg_mnt("fixup LEB %d, data len %d", lnum, len);
+	err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
+	if (err)
+		return err;
+
+	return ubifs_leb_change(c, lnum, c->sbuf, len);
+}
+
+/**
+ * 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);
+	}
+
+	/*
+	 * 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));
+	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;
+	struct ubifs_sb_node *sup;
+
+	ubifs_assert(c->space_fixup);
+	ubifs_assert(!c->ro_mount);
+
+	ubifs_msg(c, "start fixing up free space");
+
+	err = fixup_free_space(c);
+	if (err)
+		return err;
+
+	sup = ubifs_read_sb_node(c);
+	if (IS_ERR(sup))
+		return PTR_ERR(sup);
+
+	/* 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);
+	kfree(sup);
+	if (err)
+		return err;
+
+	ubifs_msg(c, "free space fixup complete");
+	return err;
+}