super.c 50.8 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 initialization and VFS superblock operations. Some
 * initialization stuff which is rather large and complex is placed at
 * corresponding subsystems, but most of it is here.
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/kthread.h>
#include <linux/parser.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include "ubifs.h"

/* Slab cache for UBIFS inodes */
struct kmem_cache *ubifs_inode_slab;

/* UBIFS TNC shrinker description */
static struct shrinker ubifs_shrinker_info = {
	.shrink = ubifs_shrinker,
	.seeks = DEFAULT_SEEKS,
};

/**
 * validate_inode - validate inode.
 * @c: UBIFS file-system description object
 * @inode: the inode to validate
 *
 * This is a helper function for 'ubifs_iget()' which validates various fields
 * of a newly built inode to make sure they contain sane values and prevent
 * possible vulnerabilities. Returns zero if the inode is all right and
 * a non-zero error code if not.
 */
static int validate_inode(struct ubifs_info *c, const struct inode *inode)
{
	int err;
	const struct ubifs_inode *ui = ubifs_inode(inode);

	if (inode->i_size > c->max_inode_sz) {
		ubifs_err("inode is too large (%lld)",
			  (long long)inode->i_size);
		return 1;
	}

	if (ui->compr_type < 0 || ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
		ubifs_err("unknown compression type %d", ui->compr_type);
		return 2;
	}

	if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
		return 3;

	if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
		return 4;

	if (ui->xattr && (inode->i_mode & S_IFMT) != S_IFREG)
		return 5;

	if (!ubifs_compr_present(ui->compr_type)) {
		ubifs_warn("inode %lu uses '%s' compression, but it was not "
			   "compiled in", inode->i_ino,
			   ubifs_compr_name(ui->compr_type));
	}

	err = dbg_check_dir_size(c, inode);
	return err;
}

struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
{
	int err;
	union ubifs_key key;
	struct ubifs_ino_node *ino;
	struct ubifs_info *c = sb->s_fs_info;
	struct inode *inode;
	struct ubifs_inode *ui;

	dbg_gen("inode %lu", inum);

	inode = iget_locked(sb, inum);
	if (!inode)
		return ERR_PTR(-ENOMEM);
	if (!(inode->i_state & I_NEW))
		return inode;
	ui = ubifs_inode(inode);

	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
	if (!ino) {
		err = -ENOMEM;
		goto out;
	}

	ino_key_init(c, &key, inode->i_ino);

	err = ubifs_tnc_lookup(c, &key, ino);
	if (err)
		goto out_ino;

	inode->i_flags |= (S_NOCMTIME | S_NOATIME);
	inode->i_nlink = le32_to_cpu(ino->nlink);
	inode->i_uid   = le32_to_cpu(ino->uid);
	inode->i_gid   = le32_to_cpu(ino->gid);
	inode->i_atime.tv_sec  = (int64_t)le64_to_cpu(ino->atime_sec);
	inode->i_atime.tv_nsec = le32_to_cpu(ino->atime_nsec);
	inode->i_mtime.tv_sec  = (int64_t)le64_to_cpu(ino->mtime_sec);
	inode->i_mtime.tv_nsec = le32_to_cpu(ino->mtime_nsec);
	inode->i_ctime.tv_sec  = (int64_t)le64_to_cpu(ino->ctime_sec);
	inode->i_ctime.tv_nsec = le32_to_cpu(ino->ctime_nsec);
	inode->i_mode = le32_to_cpu(ino->mode);
	inode->i_size = le64_to_cpu(ino->size);

	ui->data_len    = le32_to_cpu(ino->data_len);
	ui->flags       = le32_to_cpu(ino->flags);
	ui->compr_type  = le16_to_cpu(ino->compr_type);
	ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
	ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
	ui->xattr_size  = le32_to_cpu(ino->xattr_size);
	ui->xattr_names = le32_to_cpu(ino->xattr_names);
	ui->synced_i_size = ui->ui_size = inode->i_size;

	ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;

	err = validate_inode(c, inode);
	if (err)
		goto out_invalid;

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	/* Disable read-ahead */
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	inode->i_mapping->backing_dev_info = &c->bdi;

	switch (inode->i_mode & S_IFMT) {
	case S_IFREG:
		inode->i_mapping->a_ops = &ubifs_file_address_operations;
		inode->i_op = &ubifs_file_inode_operations;
		inode->i_fop = &ubifs_file_operations;
		if (ui->xattr) {
			ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
			if (!ui->data) {
				err = -ENOMEM;
				goto out_ino;
			}
			memcpy(ui->data, ino->data, ui->data_len);
			((char *)ui->data)[ui->data_len] = '\0';
		} else if (ui->data_len != 0) {
			err = 10;
			goto out_invalid;
		}
		break;
	case S_IFDIR:
		inode->i_op  = &ubifs_dir_inode_operations;
		inode->i_fop = &ubifs_dir_operations;
		if (ui->data_len != 0) {
			err = 11;
			goto out_invalid;
		}
		break;
	case S_IFLNK:
		inode->i_op = &ubifs_symlink_inode_operations;
		if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
			err = 12;
			goto out_invalid;
		}
		ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
		if (!ui->data) {
			err = -ENOMEM;
			goto out_ino;
		}
		memcpy(ui->data, ino->data, ui->data_len);
		((char *)ui->data)[ui->data_len] = '\0';
		break;
	case S_IFBLK:
	case S_IFCHR:
	{
		dev_t rdev;
		union ubifs_dev_desc *dev;

		ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
		if (!ui->data) {
			err = -ENOMEM;
			goto out_ino;
		}

		dev = (union ubifs_dev_desc *)ino->data;
		if (ui->data_len == sizeof(dev->new))
			rdev = new_decode_dev(le32_to_cpu(dev->new));
		else if (ui->data_len == sizeof(dev->huge))
			rdev = huge_decode_dev(le64_to_cpu(dev->huge));
		else {
			err = 13;
			goto out_invalid;
		}
		memcpy(ui->data, ino->data, ui->data_len);
		inode->i_op = &ubifs_file_inode_operations;
		init_special_inode(inode, inode->i_mode, rdev);
		break;
	}
	case S_IFSOCK:
	case S_IFIFO:
		inode->i_op = &ubifs_file_inode_operations;
		init_special_inode(inode, inode->i_mode, 0);
		if (ui->data_len != 0) {
			err = 14;
			goto out_invalid;
		}
		break;
	default:
		err = 15;
		goto out_invalid;
	}

	kfree(ino);
	ubifs_set_inode_flags(inode);
	unlock_new_inode(inode);
	return inode;

out_invalid:
	ubifs_err("inode %lu validation failed, error %d", inode->i_ino, err);
	dbg_dump_node(c, ino);
	dbg_dump_inode(c, inode);
	err = -EINVAL;
out_ino:
	kfree(ino);
out:
	ubifs_err("failed to read inode %lu, error %d", inode->i_ino, err);
	iget_failed(inode);
	return ERR_PTR(err);
}

static struct inode *ubifs_alloc_inode(struct super_block *sb)
{
	struct ubifs_inode *ui;

	ui = kmem_cache_alloc(ubifs_inode_slab, GFP_NOFS);
	if (!ui)
		return NULL;

	memset((void *)ui + sizeof(struct inode), 0,
	       sizeof(struct ubifs_inode) - sizeof(struct inode));
	mutex_init(&ui->ui_mutex);
	spin_lock_init(&ui->ui_lock);
	return &ui->vfs_inode;
};

static void ubifs_destroy_inode(struct inode *inode)
{
	struct ubifs_inode *ui = ubifs_inode(inode);

	kfree(ui->data);
	kmem_cache_free(ubifs_inode_slab, inode);
}

/*
 * Note, Linux write-back code calls this without 'i_mutex'.
 */
static int ubifs_write_inode(struct inode *inode, int wait)
{
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	int err = 0;
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	struct ubifs_info *c = inode->i_sb->s_fs_info;
	struct ubifs_inode *ui = ubifs_inode(inode);

	ubifs_assert(!ui->xattr);
	if (is_bad_inode(inode))
		return 0;

	mutex_lock(&ui->ui_mutex);
	/*
	 * Due to races between write-back forced by budgeting
	 * (see 'sync_some_inodes()') and pdflush write-back, the inode may
	 * have already been synchronized, do not do this again. This might
	 * also happen if it was synchronized in an VFS operation, e.g.
	 * 'ubifs_link()'.
	 */
	if (!ui->dirty) {
		mutex_unlock(&ui->ui_mutex);
		return 0;
	}

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	/*
	 * As an optimization, do not write orphan inodes to the media just
	 * because this is not needed.
	 */
	dbg_gen("inode %lu, mode %#x, nlink %u",
		inode->i_ino, (int)inode->i_mode, inode->i_nlink);
	if (inode->i_nlink) {
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		err = ubifs_jnl_write_inode(c, inode);
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		if (err)
			ubifs_err("can't write inode %lu, error %d",
				  inode->i_ino, err);
	}
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	ui->dirty = 0;
	mutex_unlock(&ui->ui_mutex);
	ubifs_release_dirty_inode_budget(c, ui);
	return err;
}

static void ubifs_delete_inode(struct inode *inode)
{
	int err;
	struct ubifs_info *c = inode->i_sb->s_fs_info;
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	struct ubifs_inode *ui = ubifs_inode(inode);
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	if (ui->xattr)
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		/*
		 * Extended attribute inode deletions are fully handled in
		 * 'ubifs_removexattr()'. These inodes are special and have
		 * limited usage, so there is nothing to do here.
		 */
		goto out;

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	dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
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	ubifs_assert(!atomic_read(&inode->i_count));
	ubifs_assert(inode->i_nlink == 0);

	truncate_inode_pages(&inode->i_data, 0);
	if (is_bad_inode(inode))
		goto out;

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	ui->ui_size = inode->i_size = 0;
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	err = ubifs_jnl_delete_inode(c, inode);
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	if (err)
		/*
		 * Worst case we have a lost orphan inode wasting space, so a
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		 * simple error message is OK here.
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		 */
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		ubifs_err("can't delete inode %lu, error %d",
			  inode->i_ino, err);

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out:
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	if (ui->dirty)
		ubifs_release_dirty_inode_budget(c, ui);
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	clear_inode(inode);
}

static void ubifs_dirty_inode(struct inode *inode)
{
	struct ubifs_inode *ui = ubifs_inode(inode);

	ubifs_assert(mutex_is_locked(&ui->ui_mutex));
	if (!ui->dirty) {
		ui->dirty = 1;
		dbg_gen("inode %lu",  inode->i_ino);
	}
}

static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
	struct ubifs_info *c = dentry->d_sb->s_fs_info;
	unsigned long long free;
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	__le32 *uuid = (__le32 *)c->uuid;
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	free = ubifs_get_free_space(c);
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	dbg_gen("free space %lld bytes (%lld blocks)",
		free, free >> UBIFS_BLOCK_SHIFT);

	buf->f_type = UBIFS_SUPER_MAGIC;
	buf->f_bsize = UBIFS_BLOCK_SIZE;
	buf->f_blocks = c->block_cnt;
	buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
	if (free > c->report_rp_size)
		buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
	else
		buf->f_bavail = 0;
	buf->f_files = 0;
	buf->f_ffree = 0;
	buf->f_namelen = UBIFS_MAX_NLEN;
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	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
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	return 0;
}

static int ubifs_show_options(struct seq_file *s, struct vfsmount *mnt)
{
	struct ubifs_info *c = mnt->mnt_sb->s_fs_info;

	if (c->mount_opts.unmount_mode == 2)
		seq_printf(s, ",fast_unmount");
	else if (c->mount_opts.unmount_mode == 1)
		seq_printf(s, ",norm_unmount");

	return 0;
}

static int ubifs_sync_fs(struct super_block *sb, int wait)
{
	struct ubifs_info *c = sb->s_fs_info;
	int i, ret = 0, err;

	if (c->jheads)
		for (i = 0; i < c->jhead_cnt; i++) {
			err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
			if (err && !ret)
				ret = err;
		}
	/*
	 * We ought to call sync for c->ubi but it does not have one. If it had
	 * it would in turn call mtd->sync, however mtd operations are
	 * synchronous anyway, so we don't lose any sleep here.
	 */
	return ret;
}

/**
 * init_constants_early - initialize UBIFS constants.
 * @c: UBIFS file-system description object
 *
 * This function initialize UBIFS constants which do not need the superblock to
 * be read. It also checks that the UBI volume satisfies basic UBIFS
 * requirements. Returns zero in case of success and a negative error code in
 * case of failure.
 */
static int init_constants_early(struct ubifs_info *c)
{
	if (c->vi.corrupted) {
		ubifs_warn("UBI volume is corrupted - read-only mode");
		c->ro_media = 1;
	}

	if (c->di.ro_mode) {
		ubifs_msg("read-only UBI device");
		c->ro_media = 1;
	}

	if (c->vi.vol_type == UBI_STATIC_VOLUME) {
		ubifs_msg("static UBI volume - read-only mode");
		c->ro_media = 1;
	}

	c->leb_cnt = c->vi.size;
	c->leb_size = c->vi.usable_leb_size;
	c->half_leb_size = c->leb_size / 2;
	c->min_io_size = c->di.min_io_size;
	c->min_io_shift = fls(c->min_io_size) - 1;

	if (c->leb_size < UBIFS_MIN_LEB_SZ) {
		ubifs_err("too small LEBs (%d bytes), min. is %d bytes",
			  c->leb_size, UBIFS_MIN_LEB_SZ);
		return -EINVAL;
	}

	if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
		ubifs_err("too few LEBs (%d), min. is %d",
			  c->leb_cnt, UBIFS_MIN_LEB_CNT);
		return -EINVAL;
	}

	if (!is_power_of_2(c->min_io_size)) {
		ubifs_err("bad min. I/O size %d", c->min_io_size);
		return -EINVAL;
	}

	/*
	 * UBIFS aligns all node to 8-byte boundary, so to make function in
	 * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
	 * less than 8.
	 */
	if (c->min_io_size < 8) {
		c->min_io_size = 8;
		c->min_io_shift = 3;
	}

	c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
	c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);

	/*
	 * Initialize node length ranges which are mostly needed for node
	 * length validation.
	 */
	c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
	c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
	c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;

	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
	c->ranges[UBIFS_ORPH_NODE].min_len =
				UBIFS_ORPH_NODE_SZ + sizeof(__le64);
	c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
	c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
	c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
	c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
	c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
	c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
	c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
	/*
	 * Minimum indexing node size is amended later when superblock is
	 * read and the key length is known.
	 */
	c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
	/*
	 * Maximum indexing node size is amended later when superblock is
	 * read and the fanout is known.
	 */
	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;

	/*
	 * Initialize dead and dark LEB space watermarks.
	 *
	 * Dead space is the space which cannot be used. Its watermark is
	 * equivalent to min. I/O unit or minimum node size if it is greater
	 * then min. I/O unit.
	 *
	 * Dark space is the space which might be used, or might not, depending
	 * on which node should be written to the LEB. Its watermark is
	 * equivalent to maximum UBIFS node size.
	 */
	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);

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	/*
	 * Calculate how many bytes would be wasted at the end of LEB if it was
	 * fully filled with data nodes of maximum size. This is used in
	 * calculations when reporting free space.
	 */
	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
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	return 0;
}

/**
 * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
 * @c: UBIFS file-system description object
 * @lnum: LEB the write-buffer was synchronized to
 * @free: how many free bytes left in this LEB
 * @pad: how many bytes were padded
 *
 * This is a callback function which is called by the I/O unit when the
 * write-buffer is synchronized. We need this to correctly maintain space
 * accounting in bud logical eraseblocks. This function returns zero in case of
 * success and a negative error code in case of failure.
 *
 * This function actually belongs to the journal, but we keep it here because
 * we want to keep it static.
 */
static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
{
	return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
}

/*
 * init_constants_late - initialize UBIFS constants.
 * @c: UBIFS file-system description object
 *
 * This is a helper function which initializes various UBIFS constants after
 * the superblock has been read. It also checks various UBIFS parameters and
 * makes sure they are all right. Returns zero in case of success and a
 * negative error code in case of failure.
 */
static int init_constants_late(struct ubifs_info *c)
{
	int tmp, err;
	uint64_t tmp64;

	c->main_bytes = (long long)c->main_lebs * c->leb_size;
	c->max_znode_sz = sizeof(struct ubifs_znode) +
				c->fanout * sizeof(struct ubifs_zbranch);

	tmp = ubifs_idx_node_sz(c, 1);
	c->ranges[UBIFS_IDX_NODE].min_len = tmp;
	c->min_idx_node_sz = ALIGN(tmp, 8);

	tmp = ubifs_idx_node_sz(c, c->fanout);
	c->ranges[UBIFS_IDX_NODE].max_len = tmp;
	c->max_idx_node_sz = ALIGN(tmp, 8);

	/* Make sure LEB size is large enough to fit full commit */
	tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
	tmp = ALIGN(tmp, c->min_io_size);
	if (tmp > c->leb_size) {
		dbg_err("too small LEB size %d, at least %d needed",
			c->leb_size, tmp);
		return -EINVAL;
	}

	/*
	 * Make sure that the log is large enough to fit reference nodes for
	 * all buds plus one reserved LEB.
	 */
	tmp64 = c->max_bud_bytes;
	tmp = do_div(tmp64, c->leb_size);
	c->max_bud_cnt = tmp64 + !!tmp;
	tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
	tmp /= c->leb_size;
	tmp += 1;
	if (c->log_lebs < tmp) {
		dbg_err("too small log %d LEBs, required min. %d LEBs",
			c->log_lebs, tmp);
		return -EINVAL;
	}

	/*
	 * When budgeting we assume worst-case scenarios when the pages are not
	 * be compressed and direntries are of the maximum size.
	 *
	 * Note, data, which may be stored in inodes is budgeted separately, so
	 * it is not included into 'c->inode_budget'.
	 */
	c->page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
	c->inode_budget = UBIFS_INO_NODE_SZ;
	c->dent_budget = UBIFS_MAX_DENT_NODE_SZ;

	/*
	 * When the amount of flash space used by buds becomes
	 * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
	 * The writers are unblocked when the commit is finished. To avoid
	 * writers to be blocked UBIFS initiates background commit in advance,
	 * when number of bud bytes becomes above the limit defined below.
	 */
	c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;

	/*
	 * Ensure minimum journal size. All the bytes in the journal heads are
	 * considered to be used, when calculating the current journal usage.
	 * Consequently, if the journal is too small, UBIFS will treat it as
	 * always full.
	 */
	tmp64 = (uint64_t)(c->jhead_cnt + 1) * c->leb_size + 1;
	if (c->bg_bud_bytes < tmp64)
		c->bg_bud_bytes = tmp64;
	if (c->max_bud_bytes < tmp64 + c->leb_size)
		c->max_bud_bytes = tmp64 + c->leb_size;

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

	c->min_idx_lebs = ubifs_calc_min_idx_lebs(c);

	/*
	 * Calculate total amount of FS blocks. This number is not used
	 * internally because it does not make much sense for UBIFS, but it is
	 * necessary to report something for the 'statfs()' call.
	 *
658 659
	 * Subtract the LEB reserved for GC, the LEB which is reserved for
	 * deletions, and assume only one journal head is available.
660
	 */
661 662
	tmp64 = c->main_lebs - 2 - c->jhead_cnt + 1;
	tmp64 *= (uint64_t)c->leb_size - c->leb_overhead;
663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142
	tmp64 = ubifs_reported_space(c, tmp64);
	c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;

	return 0;
}

/**
 * take_gc_lnum - reserve GC LEB.
 * @c: UBIFS file-system description object
 *
 * This function ensures that the LEB reserved for garbage collection is
 * unmapped and is marked as "taken" in lprops. We also have to set free space
 * to LEB size and dirty space to zero, because lprops may contain out-of-date
 * information if the file-system was un-mounted before it has been committed.
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int take_gc_lnum(struct ubifs_info *c)
{
	int err;

	if (c->gc_lnum == -1) {
		ubifs_err("no LEB for GC");
		return -EINVAL;
	}

	err = ubifs_leb_unmap(c, c->gc_lnum);
	if (err)
		return err;

	/* And we have to tell lprops that this LEB is taken */
	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
				  LPROPS_TAKEN, 0, 0);
	return err;
}

/**
 * alloc_wbufs - allocate write-buffers.
 * @c: UBIFS file-system description object
 *
 * This helper function allocates and initializes UBIFS write-buffers. Returns
 * zero in case of success and %-ENOMEM in case of failure.
 */
static int alloc_wbufs(struct ubifs_info *c)
{
	int i, err;

	c->jheads = kzalloc(c->jhead_cnt * sizeof(struct ubifs_jhead),
			   GFP_KERNEL);
	if (!c->jheads)
		return -ENOMEM;

	/* Initialize journal heads */
	for (i = 0; i < c->jhead_cnt; i++) {
		INIT_LIST_HEAD(&c->jheads[i].buds_list);
		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
		if (err)
			return err;

		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
		c->jheads[i].wbuf.jhead = i;
	}

	c->jheads[BASEHD].wbuf.dtype = UBI_SHORTTERM;
	/*
	 * Garbage Collector head likely contains long-term data and
	 * does not need to be synchronized by timer.
	 */
	c->jheads[GCHD].wbuf.dtype = UBI_LONGTERM;
	c->jheads[GCHD].wbuf.timeout = 0;

	return 0;
}

/**
 * free_wbufs - free write-buffers.
 * @c: UBIFS file-system description object
 */
static void free_wbufs(struct ubifs_info *c)
{
	int i;

	if (c->jheads) {
		for (i = 0; i < c->jhead_cnt; i++) {
			kfree(c->jheads[i].wbuf.buf);
			kfree(c->jheads[i].wbuf.inodes);
		}
		kfree(c->jheads);
		c->jheads = NULL;
	}
}

/**
 * free_orphans - free orphans.
 * @c: UBIFS file-system description object
 */
static void free_orphans(struct ubifs_info *c)
{
	struct ubifs_orphan *orph;

	while (c->orph_dnext) {
		orph = c->orph_dnext;
		c->orph_dnext = orph->dnext;
		list_del(&orph->list);
		kfree(orph);
	}

	while (!list_empty(&c->orph_list)) {
		orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
		list_del(&orph->list);
		kfree(orph);
		dbg_err("orphan list not empty at unmount");
	}

	vfree(c->orph_buf);
	c->orph_buf = NULL;
}

/**
 * free_buds - free per-bud objects.
 * @c: UBIFS file-system description object
 */
static void free_buds(struct ubifs_info *c)
{
	struct rb_node *this = c->buds.rb_node;
	struct ubifs_bud *bud;

	while (this) {
		if (this->rb_left)
			this = this->rb_left;
		else if (this->rb_right)
			this = this->rb_right;
		else {
			bud = rb_entry(this, struct ubifs_bud, rb);
			this = rb_parent(this);
			if (this) {
				if (this->rb_left == &bud->rb)
					this->rb_left = NULL;
				else
					this->rb_right = NULL;
			}
			kfree(bud);
		}
	}
}

/**
 * check_volume_empty - check if the UBI volume is empty.
 * @c: UBIFS file-system description object
 *
 * This function checks if the UBIFS volume is empty by looking if its LEBs are
 * mapped or not. The result of checking is stored in the @c->empty variable.
 * Returns zero in case of success and a negative error code in case of
 * failure.
 */
static int check_volume_empty(struct ubifs_info *c)
{
	int lnum, err;

	c->empty = 1;
	for (lnum = 0; lnum < c->leb_cnt; lnum++) {
		err = ubi_is_mapped(c->ubi, lnum);
		if (unlikely(err < 0))
			return err;
		if (err == 1) {
			c->empty = 0;
			break;
		}

		cond_resched();
	}

	return 0;
}

/*
 * UBIFS mount options.
 *
 * Opt_fast_unmount: do not run a journal commit before un-mounting
 * Opt_norm_unmount: run a journal commit before un-mounting
 * Opt_err: just end of array marker
 */
enum {
	Opt_fast_unmount,
	Opt_norm_unmount,
	Opt_err,
};

static match_table_t tokens = {
	{Opt_fast_unmount, "fast_unmount"},
	{Opt_norm_unmount, "norm_unmount"},
	{Opt_err, NULL},
};

/**
 * ubifs_parse_options - parse mount parameters.
 * @c: UBIFS file-system description object
 * @options: parameters to parse
 * @is_remount: non-zero if this is FS re-mount
 *
 * This function parses UBIFS mount options and returns zero in case success
 * and a negative error code in case of failure.
 */
static int ubifs_parse_options(struct ubifs_info *c, char *options,
			       int is_remount)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];

	if (!options)
		return 0;

	while ((p = strsep(&options, ","))) {
		int token;

		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_fast_unmount:
			c->mount_opts.unmount_mode = 2;
			c->fast_unmount = 1;
			break;
		case Opt_norm_unmount:
			c->mount_opts.unmount_mode = 1;
			c->fast_unmount = 0;
			break;
		default:
			ubifs_err("unrecognized mount option \"%s\" "
				  "or missing value", p);
			return -EINVAL;
		}
	}

	return 0;
}

/**
 * destroy_journal - destroy journal data structures.
 * @c: UBIFS file-system description object
 *
 * This function destroys journal data structures including those that may have
 * been created by recovery functions.
 */
static void destroy_journal(struct ubifs_info *c)
{
	while (!list_empty(&c->unclean_leb_list)) {
		struct ubifs_unclean_leb *ucleb;

		ucleb = list_entry(c->unclean_leb_list.next,
				   struct ubifs_unclean_leb, list);
		list_del(&ucleb->list);
		kfree(ucleb);
	}
	while (!list_empty(&c->old_buds)) {
		struct ubifs_bud *bud;

		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
		list_del(&bud->list);
		kfree(bud);
	}
	ubifs_destroy_idx_gc(c);
	ubifs_destroy_size_tree(c);
	ubifs_tnc_close(c);
	free_buds(c);
}

/**
 * mount_ubifs - mount UBIFS file-system.
 * @c: UBIFS file-system description object
 *
 * This function mounts UBIFS file system. Returns zero in case of success and
 * a negative error code in case of failure.
 *
 * Note, the function does not de-allocate resources it it fails half way
 * through, and the caller has to do this instead.
 */
static int mount_ubifs(struct ubifs_info *c)
{
	struct super_block *sb = c->vfs_sb;
	int err, mounted_read_only = (sb->s_flags & MS_RDONLY);
	long long x;
	size_t sz;

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

#ifdef CONFIG_UBIFS_FS_DEBUG
	c->dbg_buf = vmalloc(c->leb_size);
	if (!c->dbg_buf)
		return -ENOMEM;
#endif

	err = check_volume_empty(c);
	if (err)
		goto out_free;

	if (c->empty && (mounted_read_only || c->ro_media)) {
		/*
		 * This UBI volume is empty, and read-only, or the file system
		 * is mounted read-only - we cannot format it.
		 */
		ubifs_err("can't format empty UBI volume: read-only %s",
			  c->ro_media ? "UBI volume" : "mount");
		err = -EROFS;
		goto out_free;
	}

	if (c->ro_media && !mounted_read_only) {
		ubifs_err("cannot mount read-write - read-only media");
		err = -EROFS;
		goto out_free;
	}

	/*
	 * The requirement for the buffer is that it should fit indexing B-tree
	 * height amount of integers. We assume the height if the TNC tree will
	 * never exceed 64.
	 */
	err = -ENOMEM;
	c->bottom_up_buf = kmalloc(BOTTOM_UP_HEIGHT * sizeof(int), GFP_KERNEL);
	if (!c->bottom_up_buf)
		goto out_free;

	c->sbuf = vmalloc(c->leb_size);
	if (!c->sbuf)
		goto out_free;

	if (!mounted_read_only) {
		c->ileb_buf = vmalloc(c->leb_size);
		if (!c->ileb_buf)
			goto out_free;
	}

	err = ubifs_read_superblock(c);
	if (err)
		goto out_free;

	/*
	 * Make sure the compressor which is set as the default on in the
	 * superblock was actually compiled in.
	 */
	if (!ubifs_compr_present(c->default_compr)) {
		ubifs_warn("'%s' compressor is set by superblock, but not "
			   "compiled in", ubifs_compr_name(c->default_compr));
		c->default_compr = UBIFS_COMPR_NONE;
	}

	dbg_failure_mode_registration(c);

	err = init_constants_late(c);
	if (err)
		goto out_dereg;

	sz = ALIGN(c->max_idx_node_sz, c->min_io_size);
	sz = ALIGN(sz + c->max_idx_node_sz, c->min_io_size);
	c->cbuf = kmalloc(sz, GFP_NOFS);
	if (!c->cbuf) {
		err = -ENOMEM;
		goto out_dereg;
	}

	if (!mounted_read_only) {
		err = alloc_wbufs(c);
		if (err)
			goto out_cbuf;

		/* Create background thread */
		sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num,
			c->vi.vol_id);
		c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
		if (!c->bgt)
			c->bgt = ERR_PTR(-EINVAL);
		if (IS_ERR(c->bgt)) {
			err = PTR_ERR(c->bgt);
			c->bgt = NULL;
			ubifs_err("cannot spawn \"%s\", error %d",
				  c->bgt_name, err);
			goto out_wbufs;
		}
		wake_up_process(c->bgt);
	}

	err = ubifs_read_master(c);
	if (err)
		goto out_master;

	if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
		ubifs_msg("recovery needed");
		c->need_recovery = 1;
		if (!mounted_read_only) {
			err = ubifs_recover_inl_heads(c, c->sbuf);
			if (err)
				goto out_master;
		}
	} else if (!mounted_read_only) {
		/*
		 * Set the "dirty" flag so that if we reboot uncleanly we
		 * will notice this immediately on the next mount.
		 */
		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
		err = ubifs_write_master(c);
		if (err)
			goto out_master;
	}

	err = ubifs_lpt_init(c, 1, !mounted_read_only);
	if (err)
		goto out_lpt;

	err = dbg_check_idx_size(c, c->old_idx_sz);
	if (err)
		goto out_lpt;

	err = ubifs_replay_journal(c);
	if (err)
		goto out_journal;

	err = ubifs_mount_orphans(c, c->need_recovery, mounted_read_only);
	if (err)
		goto out_orphans;

	if (!mounted_read_only) {
		int lnum;

		/* Check for enough free space */
		if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
			ubifs_err("insufficient available space");
			err = -EINVAL;
			goto out_orphans;
		}

		/* Check for enough log space */
		lnum = c->lhead_lnum + 1;
		if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
			lnum = UBIFS_LOG_LNUM;
		if (lnum == c->ltail_lnum) {
			err = ubifs_consolidate_log(c);
			if (err)
				goto out_orphans;
		}

		if (c->need_recovery) {
			err = ubifs_recover_size(c);
			if (err)
				goto out_orphans;
			err = ubifs_rcvry_gc_commit(c);
		} else
			err = take_gc_lnum(c);
		if (err)
			goto out_orphans;

		err = dbg_check_lprops(c);
		if (err)
			goto out_orphans;
	} else if (c->need_recovery) {
		err = ubifs_recover_size(c);
		if (err)
			goto out_orphans;
	}

	spin_lock(&ubifs_infos_lock);
	list_add_tail(&c->infos_list, &ubifs_infos);
	spin_unlock(&ubifs_infos_lock);

	if (c->need_recovery) {
		if (mounted_read_only)
			ubifs_msg("recovery deferred");
		else {
			c->need_recovery = 0;
			ubifs_msg("recovery completed");
		}
	}

	err = dbg_check_filesystem(c);
	if (err)
		goto out_infos;

1143 1144
	ubifs_msg("mounted UBI device %d, volume %d, name \"%s\"",
		  c->vi.ubi_num, c->vi.vol_id, c->vi.name);
1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489
	if (mounted_read_only)
		ubifs_msg("mounted read-only");
	x = (long long)c->main_lebs * c->leb_size;
	ubifs_msg("file system size: %lld bytes (%lld KiB, %lld MiB, %d LEBs)",
		  x, x >> 10, x >> 20, c->main_lebs);
	x = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
	ubifs_msg("journal size: %lld bytes (%lld KiB, %lld MiB, %d LEBs)",
		  x, x >> 10, x >> 20, c->log_lebs + c->max_bud_cnt);
	ubifs_msg("default compressor: %s", ubifs_compr_name(c->default_compr));
	ubifs_msg("media format %d, latest format %d",
		  c->fmt_version, UBIFS_FORMAT_VERSION);

	dbg_msg("compiled on:         " __DATE__ " at " __TIME__);
	dbg_msg("min. I/O unit size:  %d bytes", c->min_io_size);
	dbg_msg("LEB size:            %d bytes (%d KiB)",
		c->leb_size, c->leb_size / 1024);
	dbg_msg("data journal heads:  %d",
		c->jhead_cnt - NONDATA_JHEADS_CNT);
	dbg_msg("UUID:                %02X%02X%02X%02X-%02X%02X"
	       "-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
	       c->uuid[0], c->uuid[1], c->uuid[2], c->uuid[3],
	       c->uuid[4], c->uuid[5], c->uuid[6], c->uuid[7],
	       c->uuid[8], c->uuid[9], c->uuid[10], c->uuid[11],
	       c->uuid[12], c->uuid[13], c->uuid[14], c->uuid[15]);
	dbg_msg("fast unmount:        %d", c->fast_unmount);
	dbg_msg("big_lpt              %d", c->big_lpt);
	dbg_msg("log LEBs:            %d (%d - %d)",
		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
	dbg_msg("LPT area LEBs:       %d (%d - %d)",
		c->lpt_lebs, c->lpt_first, c->lpt_last);
	dbg_msg("orphan area LEBs:    %d (%d - %d)",
		c->orph_lebs, c->orph_first, c->orph_last);
	dbg_msg("main area LEBs:      %d (%d - %d)",
		c->main_lebs, c->main_first, c->leb_cnt - 1);
	dbg_msg("index LEBs:          %d", c->lst.idx_lebs);
	dbg_msg("total index bytes:   %lld (%lld KiB, %lld MiB)",
		c->old_idx_sz, c->old_idx_sz >> 10, c->old_idx_sz >> 20);
	dbg_msg("key hash type:       %d", c->key_hash_type);
	dbg_msg("tree fanout:         %d", c->fanout);
	dbg_msg("reserved GC LEB:     %d", c->gc_lnum);
	dbg_msg("first main LEB:      %d", c->main_first);
	dbg_msg("dead watermark:      %d", c->dead_wm);
	dbg_msg("dark watermark:      %d", c->dark_wm);
	x = (long long)c->main_lebs * c->dark_wm;
	dbg_msg("max. dark space:     %lld (%lld KiB, %lld MiB)",
		x, x >> 10, x >> 20);
	dbg_msg("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
		c->max_bud_bytes, c->max_bud_bytes >> 10,
		c->max_bud_bytes >> 20);
	dbg_msg("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
		c->bg_bud_bytes, c->bg_bud_bytes >> 10,
		c->bg_bud_bytes >> 20);
	dbg_msg("current bud bytes    %lld (%lld KiB, %lld MiB)",
		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
	dbg_msg("max. seq. number:    %llu", c->max_sqnum);
	dbg_msg("commit number:       %llu", c->cmt_no);

	return 0;

out_infos:
	spin_lock(&ubifs_infos_lock);
	list_del(&c->infos_list);
	spin_unlock(&ubifs_infos_lock);
out_orphans:
	free_orphans(c);
out_journal:
	destroy_journal(c);
out_lpt:
	ubifs_lpt_free(c, 0);
out_master:
	kfree(c->mst_node);
	kfree(c->rcvrd_mst_node);
	if (c->bgt)
		kthread_stop(c->bgt);
out_wbufs:
	free_wbufs(c);
out_cbuf:
	kfree(c->cbuf);
out_dereg:
	dbg_failure_mode_deregistration(c);
out_free:
	vfree(c->ileb_buf);
	vfree(c->sbuf);
	kfree(c->bottom_up_buf);
	UBIFS_DBG(vfree(c->dbg_buf));
	return err;
}

/**
 * ubifs_umount - un-mount UBIFS file-system.
 * @c: UBIFS file-system description object
 *
 * Note, this function is called to free allocated resourced when un-mounting,
 * as well as free resources when an error occurred while we were half way
 * through mounting (error path cleanup function). So it has to make sure the
 * resource was actually allocated before freeing it.
 */
static void ubifs_umount(struct ubifs_info *c)
{
	dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
		c->vi.vol_id);

	spin_lock(&ubifs_infos_lock);
	list_del(&c->infos_list);
	spin_unlock(&ubifs_infos_lock);

	if (c->bgt)
		kthread_stop(c->bgt);

	destroy_journal(c);
	free_wbufs(c);
	free_orphans(c);
	ubifs_lpt_free(c, 0);

	kfree(c->cbuf);
	kfree(c->rcvrd_mst_node);
	kfree(c->mst_node);
	vfree(c->sbuf);
	kfree(c->bottom_up_buf);
	UBIFS_DBG(vfree(c->dbg_buf));
	vfree(c->ileb_buf);
	dbg_failure_mode_deregistration(c);
}

/**
 * ubifs_remount_rw - re-mount in read-write mode.
 * @c: UBIFS file-system description object
 *
 * UBIFS avoids allocating many unnecessary resources when mounted in read-only
 * mode. This function allocates the needed resources and re-mounts UBIFS in
 * read-write mode.
 */
static int ubifs_remount_rw(struct ubifs_info *c)
{
	int err, lnum;

	if (c->ro_media)
		return -EINVAL;

	mutex_lock(&c->umount_mutex);
	c->remounting_rw = 1;

	/* Check for enough free space */
	if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
		ubifs_err("insufficient available space");
		err = -EINVAL;
		goto out;
	}

	if (c->old_leb_cnt != c->leb_cnt) {
		struct ubifs_sb_node *sup;

		sup = ubifs_read_sb_node(c);
		if (IS_ERR(sup)) {
			err = PTR_ERR(sup);
			goto out;
		}
		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
		err = ubifs_write_sb_node(c, sup);
		if (err)
			goto out;
	}

	if (c->need_recovery) {
		ubifs_msg("completing deferred recovery");
		err = ubifs_write_rcvrd_mst_node(c);
		if (err)
			goto out;
		err = ubifs_recover_size(c);
		if (err)
			goto out;
		err = ubifs_clean_lebs(c, c->sbuf);
		if (err)
			goto out;
		err = ubifs_recover_inl_heads(c, c->sbuf);
		if (err)
			goto out;
	}

	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
		err = ubifs_write_master(c);
		if (err)
			goto out;
	}

	c->ileb_buf = vmalloc(c->leb_size);
	if (!c->ileb_buf) {
		err = -ENOMEM;
		goto out;
	}

	err = ubifs_lpt_init(c, 0, 1);
	if (err)
		goto out;

	err = alloc_wbufs(c);
	if (err)
		goto out;

	ubifs_create_buds_lists(c);

	/* Create background thread */
	c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
	if (!c->bgt)
		c->bgt = ERR_PTR(-EINVAL);
	if (IS_ERR(c->bgt)) {
		err = PTR_ERR(c->bgt);
		c->bgt = NULL;
		ubifs_err("cannot spawn \"%s\", error %d",
			  c->bgt_name, err);
		return err;
	}
	wake_up_process(c->bgt);

	c->orph_buf = vmalloc(c->leb_size);
	if (!c->orph_buf)
		return -ENOMEM;

	/* Check for enough log space */
	lnum = c->lhead_lnum + 1;
	if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
		lnum = UBIFS_LOG_LNUM;
	if (lnum == c->ltail_lnum) {
		err = ubifs_consolidate_log(c);
		if (err)
			goto out;
	}

	if (c->need_recovery)
		err = ubifs_rcvry_gc_commit(c);
	else
		err = take_gc_lnum(c);
	if (err)
		goto out;

	if (c->need_recovery) {
		c->need_recovery = 0;
		ubifs_msg("deferred recovery completed");
	}

	dbg_gen("re-mounted read-write");
	c->vfs_sb->s_flags &= ~MS_RDONLY;
	c->remounting_rw = 0;
	mutex_unlock(&c->umount_mutex);
	return 0;

out:
	vfree(c->orph_buf);
	c->orph_buf = NULL;
	if (c->bgt) {
		kthread_stop(c->bgt);
		c->bgt = NULL;
	}
	free_wbufs(c);
	vfree(c->ileb_buf);
	c->ileb_buf = NULL;
	ubifs_lpt_free(c, 1);
	c->remounting_rw = 0;
	mutex_unlock(&c->umount_mutex);
	return err;
}

/**
 * commit_on_unmount - commit the journal when un-mounting.
 * @c: UBIFS file-system description object
 *
 * This function is called during un-mounting and it commits the journal unless
 * the "fast unmount" mode is enabled. It also avoids committing the journal if
 * it contains too few data.
 *
 * Sometimes recovery requires the journal to be committed at least once, and
 * this function takes care about this.
 */
static void commit_on_unmount(struct ubifs_info *c)
{
	if (!c->fast_unmount) {
		long long bud_bytes;

		spin_lock(&c->buds_lock);
		bud_bytes = c->bud_bytes;
		spin_unlock(&c->buds_lock);
		if (bud_bytes > c->leb_size)
			ubifs_run_commit(c);
	}
}

/**
 * ubifs_remount_ro - re-mount in read-only mode.
 * @c: UBIFS file-system description object
 *
 * We rely on VFS to have stopped writing. Possibly the background thread could
 * be running a commit, however kthread_stop will wait in that case.
 */
static void ubifs_remount_ro(struct ubifs_info *c)
{
	int i, err;

	ubifs_assert(!c->need_recovery);
	commit_on_unmount(c);

	mutex_lock(&c->umount_mutex);
	if (c->bgt) {
		kthread_stop(c->bgt);
		c->bgt = NULL;
	}

	for (i = 0; i < c->jhead_cnt; i++) {
		ubifs_wbuf_sync(&c->jheads[i].wbuf);
		del_timer_sync(&c->jheads[i].wbuf.timer);
	}

	if (!c->ro_media) {
		c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
		c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
		err = ubifs_write_master(c);
		if (err)
			ubifs_ro_mode(c, err);
	}

	ubifs_destroy_idx_gc(c);
	free_wbufs(c);
	vfree(c->orph_buf);
	c->orph_buf = NULL;
	vfree(c->ileb_buf);
	c->ileb_buf = NULL;
	ubifs_lpt_free(c, 1);
	mutex_unlock(&c->umount_mutex);
}

static void ubifs_put_super(struct super_block *sb)
{
	int i;
	struct ubifs_info *c = sb->s_fs_info;

	ubifs_msg("un-mount UBI device %d, volume %d", c->vi.ubi_num,
		  c->vi.vol_id);
	/*
	 * The following asserts are only valid if there has not been a failure
	 * of the media. For example, there will be dirty inodes if we failed
	 * to write them back because of I/O errors.
	 */
	ubifs_assert(atomic_long_read(&c->dirty_pg_cnt) == 0);
	ubifs_assert(c->budg_idx_growth == 0);
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	ubifs_assert(c->budg_dd_growth == 0);
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	ubifs_assert(c->budg_data_growth == 0);

	/*
	 * The 'c->umount_lock' prevents races between UBIFS memory shrinker
	 * and file system un-mount. Namely, it prevents the shrinker from
	 * picking this superblock for shrinking - it will be just skipped if
	 * the mutex is locked.
	 */
	mutex_lock(&c->umount_mutex);
	if (!(c->vfs_sb->s_flags & MS_RDONLY)) {
		/*
		 * First of all kill the background thread to make sure it does
		 * not interfere with un-mounting and freeing resources.
		 */
		if (c->bgt) {
			kthread_stop(c->bgt);
			c->bgt = NULL;
		}

		/* Synchronize write-buffers */
		if (c->jheads)
			for (i = 0; i < c->jhead_cnt; i++) {
				ubifs_wbuf_sync(&c->jheads[i].wbuf);
				del_timer_sync(&c->jheads[i].wbuf.timer);
			}

		/*
		 * On fatal errors c->ro_media is set to 1, in which case we do
		 * not write the master node.
		 */
		if (!c->ro_media) {
			/*
			 * We are being cleanly unmounted which means the
			 * orphans were killed - indicate this in the master
			 * node. Also save the reserved GC LEB number.
			 */
			int err;

			c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
			c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
			c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
			err = ubifs_write_master(c);
			if (err)
				/*
				 * Recovery will attempt to fix the master area
				 * next mount, so we just print a message and
				 * continue to unmount normally.
				 */
				ubifs_err("failed to write master node, "
					  "error %d", err);
		}
	}

	ubifs_umount(c);
	bdi_destroy(&c->bdi);
	ubi_close_volume(c->ubi);
	mutex_unlock(&c->umount_mutex);
	kfree(c);
}

static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
{
	int err;
	struct ubifs_info *c = sb->s_fs_info;

	dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);

	err = ubifs_parse_options(c, data, 1);
	if (err) {
		ubifs_err("invalid or unknown remount parameter");
		return err;
	}
	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
		err = ubifs_remount_rw(c);
		if (err)
			return err;
	} else if (!(sb->s_flags & MS_RDONLY) && (*flags & MS_RDONLY))
		ubifs_remount_ro(c);

	return 0;
}

struct super_operations ubifs_super_operations = {
	.alloc_inode   = ubifs_alloc_inode,
	.destroy_inode = ubifs_destroy_inode,
	.put_super     = ubifs_put_super,
	.write_inode   = ubifs_write_inode,
	.delete_inode  = ubifs_delete_inode,
	.statfs        = ubifs_statfs,
	.dirty_inode   = ubifs_dirty_inode,
	.remount_fs    = ubifs_remount_fs,
	.show_options  = ubifs_show_options,
	.sync_fs       = ubifs_sync_fs,
};

/**
 * open_ubi - parse UBI device name string and open the UBI device.
 * @name: UBI volume name
 * @mode: UBI volume open mode
 *
 * There are several ways to specify UBI volumes when mounting UBIFS:
 * o ubiX_Y    - UBI device number X, volume Y;
 * o ubiY      - UBI device number 0, volume Y;
 * o ubiX:NAME - mount UBI device X, volume with name NAME;
 * o ubi:NAME  - mount UBI device 0, volume with name NAME.
 *
 * Alternative '!' separator may be used instead of ':' (because some shells
 * like busybox may interpret ':' as an NFS host name separator). This function
 * returns ubi volume object in case of success and a negative error code in
 * case of failure.
 */
static struct ubi_volume_desc *open_ubi(const char *name, int mode)
{
	int dev, vol;
	char *endptr;

	if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
		return ERR_PTR(-EINVAL);

	/* ubi:NAME method */
	if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
		return ubi_open_volume_nm(0, name + 4, mode);

	if (!isdigit(name[3]))
		return ERR_PTR(-EINVAL);

	dev = simple_strtoul(name + 3, &endptr, 0);

	/* ubiY method */
	if (*endptr == '\0')
		return ubi_open_volume(0, dev, mode);

	/* ubiX_Y method */
	if (*endptr == '_' && isdigit(endptr[1])) {
		vol = simple_strtoul(endptr + 1, &endptr, 0);
		if (*endptr != '\0')
			return ERR_PTR(-EINVAL);
		return ubi_open_volume(dev, vol, mode);
	}

	/* ubiX:NAME method */
	if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
		return ubi_open_volume_nm(dev, ++endptr, mode);

	return ERR_PTR(-EINVAL);
}

static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct ubi_volume_desc *ubi = sb->s_fs_info;
	struct ubifs_info *c;
	struct inode *root;
	int err;

	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
	if (!c)
		return -ENOMEM;

	spin_lock_init(&c->cnt_lock);
	spin_lock_init(&c->cs_lock);
	spin_lock_init(&c->buds_lock);
	spin_lock_init(&c->space_lock);
	spin_lock_init(&c->orphan_lock);
	init_rwsem(&c->commit_sem);
	mutex_init(&c->lp_mutex);
	mutex_init(&c->tnc_mutex);
	mutex_init(&c->log_mutex);
	mutex_init(&c->mst_mutex);
	mutex_init(&c->umount_mutex);
	init_waitqueue_head(&c->cmt_wq);
	c->buds = RB_ROOT;
	c->old_idx = RB_ROOT;
	c->size_tree = RB_ROOT;
	c->orph_tree = RB_ROOT;
	INIT_LIST_HEAD(&c->infos_list);
	INIT_LIST_HEAD(&c->idx_gc);
	INIT_LIST_HEAD(&c->replay_list);
	INIT_LIST_HEAD(&c->replay_buds);
	INIT_LIST_HEAD(&c->uncat_list);
	INIT_LIST_HEAD(&c->empty_list);
	INIT_LIST_HEAD(&c->freeable_list);
	INIT_LIST_HEAD(&c->frdi_idx_list);
	INIT_LIST_HEAD(&c->unclean_leb_list);
	INIT_LIST_HEAD(&c->old_buds);
	INIT_LIST_HEAD(&c->orph_list);
	INIT_LIST_HEAD(&c->orph_new);

	c->highest_inum = UBIFS_FIRST_INO;
	c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;

	ubi_get_volume_info(ubi, &c->vi);
	ubi_get_device_info(c->vi.ubi_num, &c->di);

	/* Re-open the UBI device in read-write mode */
	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
	if (IS_ERR(c->ubi)) {
		err = PTR_ERR(c->ubi);
		goto out_free;
	}

	/*
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	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
1693 1694
	 * UBIFS, I/O is not deferred, it is done immediately in readpage,
	 * which means the user would have to wait not just for their own I/O
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Artem Bityutskiy 已提交
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	 * but the read-ahead I/O as well i.e. completely pointless.
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	 *
	 * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
	 */
	c->bdi.capabilities = BDI_CAP_MAP_COPY;
	c->bdi.unplug_io_fn = default_unplug_io_fn;
	err  = bdi_init(&c->bdi);
	if (err)
		goto out_close;

	err = ubifs_parse_options(c, data, 0);
	if (err)
		goto out_bdi;

	c->vfs_sb = sb;

	sb->s_fs_info = c;
	sb->s_magic = UBIFS_SUPER_MAGIC;
	sb->s_blocksize = UBIFS_BLOCK_SIZE;
	sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
	sb->s_dev = c->vi.cdev;
	sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
	if (c->max_inode_sz > MAX_LFS_FILESIZE)
		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
	sb->s_op = &ubifs_super_operations;

	mutex_lock(&c->umount_mutex);
	err = mount_ubifs(c);
	if (err) {
		ubifs_assert(err < 0);
		goto out_unlock;
	}

	/* Read the root inode */
	root = ubifs_iget(sb, UBIFS_ROOT_INO);
	if (IS_ERR(root)) {
		err = PTR_ERR(root);
		goto out_umount;
	}

	sb->s_root = d_alloc_root(root);
	if (!sb->s_root)
		goto out_iput;

	mutex_unlock(&c->umount_mutex);

	return 0;

out_iput:
	iput(root);
out_umount:
	ubifs_umount(c);
out_unlock:
	mutex_unlock(&c->umount_mutex);
out_bdi:
	bdi_destroy(&c->bdi);
out_close:
	ubi_close_volume(c->ubi);
out_free:
	kfree(c);
	return err;
}

static int sb_test(struct super_block *sb, void *data)
{
	dev_t *dev = data;

	return sb->s_dev == *dev;
}

static int sb_set(struct super_block *sb, void *data)
{
	dev_t *dev = data;

	sb->s_dev = *dev;
	return 0;
}

static int ubifs_get_sb(struct file_system_type *fs_type, int flags,
			const char *name, void *data, struct vfsmount *mnt)
{
	struct ubi_volume_desc *ubi;
	struct ubi_volume_info vi;
	struct super_block *sb;
	int err;

	dbg_gen("name %s, flags %#x", name, flags);

	/*
	 * Get UBI device number and volume ID. Mount it read-only so far
	 * because this might be a new mount point, and UBI allows only one
	 * read-write user at a time.
	 */
	ubi = open_ubi(name, UBI_READONLY);
	if (IS_ERR(ubi)) {
		ubifs_err("cannot open \"%s\", error %d",
			  name, (int)PTR_ERR(ubi));
		return PTR_ERR(ubi);
	}
	ubi_get_volume_info(ubi, &vi);

	dbg_gen("opened ubi%d_%d", vi.ubi_num, vi.vol_id);

	sb = sget(fs_type, &sb_test, &sb_set, &vi.cdev);
	if (IS_ERR(sb)) {
		err = PTR_ERR(sb);
		goto out_close;
	}

	if (sb->s_root) {
		/* A new mount point for already mounted UBIFS */
		dbg_gen("this ubi volume is already mounted");
		if ((flags ^ sb->s_flags) & MS_RDONLY) {
			err = -EBUSY;
			goto out_deact;
		}
	} else {
		sb->s_flags = flags;
		/*
		 * Pass 'ubi' to 'fill_super()' in sb->s_fs_info where it is
		 * replaced by 'c'.
		 */
		sb->s_fs_info = ubi;
		err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
		if (err)
			goto out_deact;
		/* We do not support atime */
		sb->s_flags |= MS_ACTIVE | MS_NOATIME;
	}

	/* 'fill_super()' opens ubi again so we must close it here */
	ubi_close_volume(ubi);

	return simple_set_mnt(mnt, sb);

out_deact:
	up_write(&sb->s_umount);
	deactivate_super(sb);
out_close:
	ubi_close_volume(ubi);
	return err;
}

static void ubifs_kill_sb(struct super_block *sb)
{
	struct ubifs_info *c = sb->s_fs_info;

	/*
	 * We do 'commit_on_unmount()' here instead of 'ubifs_put_super()'
	 * in order to be outside BKL.
	 */
	if (sb->s_root && !(sb->s_flags & MS_RDONLY))
		commit_on_unmount(c);
	/* The un-mount routine is actually done in put_super() */
	generic_shutdown_super(sb);
}

static struct file_system_type ubifs_fs_type = {
	.name    = "ubifs",
	.owner   = THIS_MODULE,
	.get_sb  = ubifs_get_sb,
	.kill_sb = ubifs_kill_sb
};

/*
 * Inode slab cache constructor.
 */
1862
static void inode_slab_ctor(void *obj)
1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969
{
	struct ubifs_inode *ui = obj;
	inode_init_once(&ui->vfs_inode);
}

static int __init ubifs_init(void)
{
	int err;

	BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);

	/* Make sure node sizes are 8-byte aligned */
	BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
	BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
	BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
	BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
	BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);

	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
	BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
	BUILD_BUG_ON(MIN_WRITE_SZ           & 7);

	/* Check min. node size */
	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);

	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);

	/* Defined node sizes */
	BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
	BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);

	/*
	 * We require that PAGE_CACHE_SIZE is greater-than-or-equal-to
	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
	 */
	if (PAGE_CACHE_SIZE < UBIFS_BLOCK_SIZE) {
		ubifs_err("VFS page cache size is %u bytes, but UBIFS requires"
			  " at least 4096 bytes",
			  (unsigned int)PAGE_CACHE_SIZE);
		return -EINVAL;
	}

	err = register_filesystem(&ubifs_fs_type);
	if (err) {
		ubifs_err("cannot register file system, error %d", err);
		return err;
	}

	err = -ENOMEM;
	ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
				sizeof(struct ubifs_inode), 0,
				SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT,
				&inode_slab_ctor);
	if (!ubifs_inode_slab)
		goto out_reg;

	register_shrinker(&ubifs_shrinker_info);

	err = ubifs_compressors_init();
	if (err)
		goto out_compr;

	return 0;

out_compr:
	unregister_shrinker(&ubifs_shrinker_info);
	kmem_cache_destroy(ubifs_inode_slab);
out_reg:
	unregister_filesystem(&ubifs_fs_type);
	return err;
}
/* late_initcall to let compressors initialize first */
late_initcall(ubifs_init);

static void __exit ubifs_exit(void)
{
	ubifs_assert(list_empty(&ubifs_infos));
	ubifs_assert(atomic_long_read(&ubifs_clean_zn_cnt) == 0);

	ubifs_compressors_exit();
	unregister_shrinker(&ubifs_shrinker_info);
	kmem_cache_destroy(ubifs_inode_slab);
	unregister_filesystem(&ubifs_fs_type);
}
module_exit(ubifs_exit);

MODULE_LICENSE("GPL");
MODULE_VERSION(__stringify(UBIFS_VERSION));
MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
MODULE_DESCRIPTION("UBIFS - UBI File System");