inode.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 604 行 · 第 1/2 页

/*
 * QNX4 file system, Linux implementation.
 *
 * Version : 0.2.1
 *
 * Using parts of the xiafs filesystem.
 *
 * History :
 *
 * 01-06-1998 by Richard Frowijn : first release.
 * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
 * 30-06-1998 by Frank Denis : first step to write inodes.
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/qnx4_fs.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/smp_lock.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
#include <asm/uaccess.h>

#define QNX4_VERSION  4
#define QNX4_BMNAME   ".bitmap"

static struct super_operations qnx4_sops;

#ifdef CONFIG_QNX4FS_RW

int qnx4_sync_inode(struct inode *inode)
{
	int err = 0;
# if 0
	struct buffer_head *bh;

   	bh = qnx4_update_inode(inode);
	if (bh && buffer_dirty(bh))
	{
		sync_dirty_buffer(bh);
		if (buffer_req(bh) && !buffer_uptodate(bh))
		{
			printk ("IO error syncing qnx4 inode [%s:%08lx]\n",
				inode->i_sb->s_id, inode->i_ino);
			err = -1;
		}
	        brelse (bh);
	} else if (!bh) {
		err = -1;
	}
# endif

	return err;
}

static void qnx4_delete_inode(struct inode *inode)
{
	QNX4DEBUG(("qnx4: deleting inode [%lu]\n", (unsigned long) inode->i_ino));
	inode->i_size = 0;
	qnx4_truncate(inode);
	lock_kernel();
	qnx4_free_inode(inode);
	unlock_kernel();
}

static void qnx4_write_super(struct super_block *sb)
{
	lock_kernel();
	QNX4DEBUG(("qnx4: write_super\n"));
	sb->s_dirt = 0;
	unlock_kernel();
}

static int qnx4_write_inode(struct inode *inode, int unused)
{
	struct qnx4_inode_entry *raw_inode;
	int block, ino;
	struct buffer_head *bh;
	ino = inode->i_ino;

	QNX4DEBUG(("qnx4: write inode 1.\n"));
	if (inode->i_nlink == 0) {
		return 0;
	}
	if (!ino) {
		printk("qnx4: bad inode number on dev %s: %d is out of range\n",
		       inode->i_sb->s_id, ino);
		return -EIO;
	}
	QNX4DEBUG(("qnx4: write inode 2.\n"));
	block = ino / QNX4_INODES_PER_BLOCK;
	lock_kernel();
	if (!(bh = sb_bread(inode->i_sb, block))) {
		printk("qnx4: major problem: unable to read inode from dev "
		       "%s\n", inode->i_sb->s_id);
		unlock_kernel();
		return -EIO;
	}
	raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
	    (ino % QNX4_INODES_PER_BLOCK);
	raw_inode->di_mode  = cpu_to_le16(inode->i_mode);
	raw_inode->di_uid   = cpu_to_le16(fs_high2lowuid(inode->i_uid));
	raw_inode->di_gid   = cpu_to_le16(fs_high2lowgid(inode->i_gid));
	raw_inode->di_nlink = cpu_to_le16(inode->i_nlink);
	raw_inode->di_size  = cpu_to_le32(inode->i_size);
	raw_inode->di_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
	raw_inode->di_atime = cpu_to_le32(inode->i_atime.tv_sec);
	raw_inode->di_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
	raw_inode->di_first_xtnt.xtnt_size = cpu_to_le32(inode->i_blocks);
	mark_buffer_dirty(bh);
	brelse(bh);
	unlock_kernel();
	return 0;
}

#endif

static void qnx4_put_super(struct super_block *sb);
static struct inode *qnx4_alloc_inode(struct super_block *sb);
static void qnx4_destroy_inode(struct inode *inode);
static void qnx4_read_inode(struct inode *);
static int qnx4_remount(struct super_block *sb, int *flags, char *data);
static int qnx4_statfs(struct super_block *, struct kstatfs *);

static struct super_operations qnx4_sops =
{
	.alloc_inode	= qnx4_alloc_inode,
	.destroy_inode	= qnx4_destroy_inode,
	.read_inode	= qnx4_read_inode,
	.put_super	= qnx4_put_super,
	.statfs		= qnx4_statfs,
	.remount_fs	= qnx4_remount,
#ifdef CONFIG_QNX4FS_RW
	.write_inode	= qnx4_write_inode,
	.delete_inode	= qnx4_delete_inode,
	.write_super	= qnx4_write_super,
#endif
};

static int qnx4_remount(struct super_block *sb, int *flags, char *data)
{
	struct qnx4_sb_info *qs;

	qs = qnx4_sb(sb);
	qs->Version = QNX4_VERSION;
#ifndef CONFIG_QNX4FS_RW
	*flags |= MS_RDONLY;
#endif
	if (*flags & MS_RDONLY) {
		return 0;
	}

	mark_buffer_dirty(qs->sb_buf);

	return 0;
}

struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
				 int create)
{
	struct buffer_head *result = NULL;

	if ( nr >= 0 )
		nr = qnx4_block_map( inode, nr );
	if (nr) {
		result = sb_getblk(inode->i_sb, nr);
		return result;
	}
	if (!create) {
		return NULL;
	}
#if 0
	tmp = qnx4_new_block(inode->i_sb);
	if (!tmp) {
		return NULL;
	}
	result = sb_getblk(inode->i_sb, tmp);
	if (tst) {
		qnx4_free_block(inode->i_sb, tmp);
		brelse(result);
		goto repeat;
	}
	tst = tmp;
#endif
	inode->i_ctime = CURRENT_TIME;
	mark_inode_dirty(inode);
	return result;
}

struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
{
	struct buffer_head *bh;

	bh = qnx4_getblk(inode, block, create);
	if (!bh || buffer_uptodate(bh)) {
		return bh;
	}
	ll_rw_block(READ, 1, &bh);
	wait_on_buffer(bh);
	if (buffer_uptodate(bh)) {
		return bh;
	}
	brelse(bh);

	return NULL;
}

int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
{
	unsigned long phys;

	QNX4DEBUG(("qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));

	phys = qnx4_block_map( inode, iblock );
	if ( phys ) {
		// logical block is before EOF
		map_bh(bh, inode->i_sb, phys);
	} else if ( create ) {
		// to be done.
	}
	return 0;
}

unsigned long qnx4_block_map( struct inode *inode, long iblock )
{
	int ix;
	long offset, i_xblk;
	unsigned long block = 0;
	struct buffer_head *bh = NULL;
	struct qnx4_xblk *xblk = NULL;
	struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
	qnx4_nxtnt_t nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);

	if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
		// iblock is in the first extent. This is easy.
		block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
	} else {
		// iblock is beyond first extent. We have to follow the extent chain.
		i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
		offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
		ix = 0;
		while ( --nxtnt > 0 ) {
			if ( ix == 0 ) {
				// read next xtnt block.
				bh = sb_bread(inode->i_sb, i_xblk - 1);
				if ( !bh ) {
					QNX4DEBUG(("qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
					return -EIO;
				}
				xblk = (struct qnx4_xblk*)bh->b_data;
				if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
					QNX4DEBUG(("qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
					return -EIO;
				}
			}
			if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
				// got it!
				block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
				break;
			}
			offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
			if ( ++ix >= xblk->xblk_num_xtnts ) {
				i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
				ix = 0;
				brelse( bh );
				bh = NULL;
			}
		}
		if ( bh )
			brelse( bh );
	}

	QNX4DEBUG(("qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
	return block;
}

static int qnx4_statfs(struct super_block *sb, struct kstatfs *buf)
{
	lock_kernel();

	buf->f_type    = sb->s_magic;
	buf->f_bsize   = sb->s_blocksize;
	buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
	buf->f_bfree   = qnx4_count_free_blocks(sb);
	buf->f_bavail  = buf->f_bfree;
	buf->f_namelen = QNX4_NAME_MAX;

	unlock_kernel();

	return 0;
}

/*
 * Check the root directory of the filesystem to make sure
 * it really _is_ a qnx4 filesystem, and to check the size