- 根目录:
- fs
- ubifs
- sb.c
/*
* 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"
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/math64.h>
/*
* 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
/**
* 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);
ubifs_msg("default file-system created");
return 0;
}
/**
* 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) {
ubifs_err("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",
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) {
ubifs_err("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",
c->max_leb_cnt, c->leb_cnt);
goto failed;
}
if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
ubifs_err("too few main LEBs count %d, must be at least %d",
c->main_lebs, UBIFS_MIN_MAIN_LEBS);
goto failed;
}
max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
if (c->max_bud_bytes < max_bytes) {
ubifs_err("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("too large journal size (%lld bytes), only %lld bytes available in the main area",
c->max_bud_bytes, max_bytes);
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;
}
if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
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;
}
return 0;
failed:
ubifs_err("bad superblock, error %d", err);
ubifs_dump_node(c, sup);
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
* 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)
{
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;
}
/**
* 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
*
* 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);
c->fmt_version = le32_to_cpu(sup->fmt_version);
c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
/*
* 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) {
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_RO_COMPAT_VERSION);
if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
ubifs_msg("only R/O mounting is possible");
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;
}
if (c->fmt_version < 3) {
ubifs_err("on-flash format version %d is not supported",
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;
};
c->key_fmt = sup->key_fmt;
switch (c->key_fmt) {
case UBIFS_SIMPLE_KEY_FMT:
c->key_len = UBIFS_SK_LEN;
break;
default:
ubifs_err("unsupported key format");
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);
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));
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);
if (c->ro_mount)
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:
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("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("free space fixup complete");
return err;
}