fs/jfs/inode.c - kernel/msm-5.4 - Gitiles

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *   Copyright (C) International Business Machines Corp., 2000-2004
  *   Portions Copyright (C) Christoph Hellwig, 2001-2002
  */

 #include <linux/fs.h>
 #include <linux/mpage.h>
 #include <linux/buffer_head.h>
 #include <linux/pagemap.h>
 #include <linux/quotaops.h>
 #include <linux/uio.h>
 #include <linux/writeback.h>
 #include "jfs_incore.h"
 #include "jfs_inode.h"
 #include "jfs_filsys.h"
 #include "jfs_imap.h"
 #include "jfs_extent.h"
 #include "jfs_unicode.h"
 #include "jfs_debug.h"
 #include "jfs_dmap.h"


 struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
 {
 	struct inode *inode;
 	int ret;

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

 	ret = diRead(inode);
 	if (ret < 0) {
 		iget_failed(inode);
 		return ERR_PTR(ret);
 	}

 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &jfs_file_inode_operations;
 		inode->i_fop = &jfs_file_operations;
 		inode->i_mapping->a_ops = &jfs_aops;
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = &jfs_dir_inode_operations;
 		inode->i_fop = &jfs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (inode->i_size >= IDATASIZE) {
 			inode->i_op = &page_symlink_inode_operations;
 			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &jfs_aops;
 		} else {
 			inode->i_op = &jfs_fast_symlink_inode_operations;
 			inode->i_link = JFS_IP(inode)->i_inline;
 			/*
 			 * The inline data should be null-terminated, but
 			 * don't let on-disk corruption crash the kernel
 			 */
 			inode->i_link[inode->i_size] = '\0';
 		}
 	} else {
 		inode->i_op = &jfs_file_inode_operations;
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
 	}
 	unlock_new_inode(inode);
 	return inode;
 }

 /*
  * Workhorse of both fsync & write_inode
  */
 int jfs_commit_inode(struct inode *inode, int wait)
 {
 	int rc = 0;
 	tid_t tid;
 	static int noisy = 5;

 	jfs_info("In jfs_commit_inode, inode = 0x%p", inode);

 	/*
 	 * Don't commit if inode has been committed since last being
 	 * marked dirty, or if it has been deleted.
 	 */
 	if (inode->i_nlink == 0 || !test_cflag(COMMIT_Dirty, inode))
 		return 0;

 	if (isReadOnly(inode)) {
 		/* kernel allows writes to devices on read-only
 		 * partitions and may think inode is dirty
 		 */
 		if (!special_file(inode->i_mode) && noisy) {
 			jfs_err("jfs_commit_inode(0x%p) called on read-only volume",
 				inode);
 			jfs_err("Is remount racy?");
 			noisy--;
 		}
 		return 0;
 	}

 	tid = txBegin(inode->i_sb, COMMIT_INODE);
 	mutex_lock(&JFS_IP(inode)->commit_mutex);

 	/*
 	 * Retest inode state after taking commit_mutex
 	 */
 	if (inode->i_nlink && test_cflag(COMMIT_Dirty, inode))
 		rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);

 	txEnd(tid);
 	mutex_unlock(&JFS_IP(inode)->commit_mutex);
 	return rc;
 }

 int jfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
 	int wait = wbc->sync_mode == WB_SYNC_ALL;

 	if (inode->i_nlink == 0)
 		return 0;
 	/*
 	 * If COMMIT_DIRTY is not set, the inode isn't really dirty.
 	 * It has been committed since the last change, but was still
 	 * on the dirty inode list.
 	 */
 	if (!test_cflag(COMMIT_Dirty, inode)) {
 		/* Make sure committed changes hit the disk */
 		jfs_flush_journal(JFS_SBI(inode->i_sb)->log, wait);
 		return 0;
 	}

 	if (jfs_commit_inode(inode, wait)) {
 		jfs_err("jfs_write_inode: jfs_commit_inode failed!");
 		return -EIO;
 	} else
 		return 0;
 }

 void jfs_evict_inode(struct inode *inode)
 {
 	struct jfs_inode_info *ji = JFS_IP(inode);

 	jfs_info("In jfs_evict_inode, inode = 0x%p", inode);

 	if (!inode->i_nlink && !is_bad_inode(inode)) {
 		dquot_initialize(inode);

 		if (JFS_IP(inode)->fileset == FILESYSTEM_I) {
 			truncate_inode_pages_final(&inode->i_data);

 			if (test_cflag(COMMIT_Freewmap, inode))
 				jfs_free_zero_link(inode);

 			diFree(inode);

 			/*
 			 * Free the inode from the quota allocation.
 			 */
 			dquot_free_inode(inode);
 		}
 	} else {
 		truncate_inode_pages_final(&inode->i_data);
 	}
 	clear_inode(inode);
 	dquot_drop(inode);

 	BUG_ON(!list_empty(&ji->anon_inode_list));

 	spin_lock_irq(&ji->ag_lock);
 	if (ji->active_ag != -1) {
 		struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
 		atomic_dec(&bmap->db_active[ji->active_ag]);
 		ji->active_ag = -1;
 	}
 	spin_unlock_irq(&ji->ag_lock);
 }

 void jfs_dirty_inode(struct inode *inode, int flags)
 {
 	static int noisy = 5;

 	if (isReadOnly(inode)) {
 		if (!special_file(inode->i_mode) && noisy) {
 			/* kernel allows writes to devices on read-only
 			 * partitions and may try to mark inode dirty
 			 */
 			jfs_err("jfs_dirty_inode called on read-only volume");
 			jfs_err("Is remount racy?");
 			noisy--;
 		}
 		return;
 	}

 	set_cflag(COMMIT_Dirty, inode);
 }

 int jfs_get_block(struct inode *ip, sector_t lblock,
 		  struct buffer_head *bh_result, int create)
 {
 	s64 lblock64 = lblock;
 	int rc = 0;
 	xad_t xad;
 	s64 xaddr;
 	int xflag;
 	s32 xlen = bh_result->b_size >> ip->i_blkbits;

 	/*
 	 * Take appropriate lock on inode
 	 */
 	if (create)
 		IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
 	else
 		IREAD_LOCK(ip, RDWRLOCK_NORMAL);

 	if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
 	    (!xtLookup(ip, lblock64, xlen, &xflag, &xaddr, &xlen, 0)) &&
 	    xaddr) {
 		if (xflag & XAD_NOTRECORDED) {
 			if (!create)
 				/*
 				 * Allocated but not recorded, read treats
 				 * this as a hole
 				 */
 				goto unlock;
 #ifdef _JFS_4K
 			XADoffset(&xad, lblock64);
 			XADlength(&xad, xlen);
 			XADaddress(&xad, xaddr);
 #else				/* _JFS_4K */
 			/*
 			 * As long as block size = 4K, this isn't a problem.
 			 * We should mark the whole page not ABNR, but how
 			 * will we know to mark the other blocks BH_New?
 			 */
 			BUG();
 #endif				/* _JFS_4K */
 			rc = extRecord(ip, &xad);
 			if (rc)
 				goto unlock;
 			set_buffer_new(bh_result);
 		}

 		map_bh(bh_result, ip->i_sb, xaddr);
 		bh_result->b_size = xlen << ip->i_blkbits;
 		goto unlock;
 	}
 	if (!create)
 		goto unlock;

 	/*
 	 * Allocate a new block
 	 */
 #ifdef _JFS_4K
 	if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
 		goto unlock;
 	rc = extAlloc(ip, xlen, lblock64, &xad, false);
 	if (rc)
 		goto unlock;

 	set_buffer_new(bh_result);
 	map_bh(bh_result, ip->i_sb, addressXAD(&xad));
 	bh_result->b_size = lengthXAD(&xad) << ip->i_blkbits;

 #else				/* _JFS_4K */
 	/*
 	 * We need to do whatever it takes to keep all but the last buffers
 	 * in 4K pages - see jfs_write.c
 	 */
 	BUG();
 #endif				/* _JFS_4K */

       unlock:
 	/*
 	 * Release lock on inode
 	 */
 	if (create)
 		IWRITE_UNLOCK(ip);
 	else
 		IREAD_UNLOCK(ip);
 	return rc;
 }

 static int jfs_writepage(struct page *page, struct writeback_control *wbc)
 {
 	return block_write_full_page(page, jfs_get_block, wbc);
 }

 static int jfs_writepages(struct address_space *mapping,
 			struct writeback_control *wbc)
 {
 	return mpage_writepages(mapping, wbc, jfs_get_block);
 }

 static int jfs_readpage(struct file *file, struct page *page)
 {
 	return mpage_readpage(page, jfs_get_block);
 }

 static int jfs_readpages(struct file *file, struct address_space *mapping,
 		struct list_head *pages, unsigned nr_pages)
 {
 	return mpage_readpages(mapping, pages, nr_pages, jfs_get_block);
 }

 static void jfs_write_failed(struct address_space *mapping, loff_t to)
 {
 	struct inode *inode = mapping->host;

 	if (to > inode->i_size) {
 		truncate_pagecache(inode, inode->i_size);
 		jfs_truncate(inode);
 	}
 }

 static int jfs_write_begin(struct file *file, struct address_space *mapping,
 				loff_t pos, unsigned len, unsigned flags,
 				struct page **pagep, void **fsdata)
 {
 	int ret;

 	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
 				jfs_get_block);
 	if (unlikely(ret))
 		jfs_write_failed(mapping, pos + len);

 	return ret;
 }

 static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
 {
 	return generic_block_bmap(mapping, block, jfs_get_block);
 }

 static ssize_t jfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
 	struct file *file = iocb->ki_filp;
 	struct address_space *mapping = file->f_mapping;
 	struct inode *inode = file->f_mapping->host;
 	size_t count = iov_iter_count(iter);
 	ssize_t ret;

 	ret = blockdev_direct_IO(iocb, inode, iter, jfs_get_block);

 	/*
 	 * In case of error extending write may have instantiated a few
 	 * blocks outside i_size. Trim these off again.
 	 */
 	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 		loff_t isize = i_size_read(inode);
 		loff_t end = iocb->ki_pos + count;

 		if (end > isize)
 			jfs_write_failed(mapping, end);
 	}

 	return ret;
 }

 const struct address_space_operations jfs_aops = {
 	.readpage	= jfs_readpage,
 	.readpages	= jfs_readpages,
 	.writepage	= jfs_writepage,
 	.writepages	= jfs_writepages,
 	.write_begin	= jfs_write_begin,
 	.write_end	= nobh_write_end,
 	.bmap		= jfs_bmap,
 	.direct_IO	= jfs_direct_IO,
 };

 /*
  * Guts of jfs_truncate.  Called with locks already held.  Can be called
  * with directory for truncating directory index table.
  */
 void jfs_truncate_nolock(struct inode *ip, loff_t length)
 {
 	loff_t newsize;
 	tid_t tid;

 	ASSERT(length >= 0);

 	if (test_cflag(COMMIT_Nolink, ip)) {
 		xtTruncate(0, ip, length, COMMIT_WMAP);
 		return;
 	}

 	do {
 		tid = txBegin(ip->i_sb, 0);

 		/*
 		 * The commit_mutex cannot be taken before txBegin.
 		 * txBegin may block and there is a chance the inode
 		 * could be marked dirty and need to be committed
 		 * before txBegin unblocks
 		 */
 		mutex_lock(&JFS_IP(ip)->commit_mutex);

 		newsize = xtTruncate(tid, ip, length,
 				     COMMIT_TRUNCATE | COMMIT_PWMAP);
 		if (newsize < 0) {
 			txEnd(tid);
 			mutex_unlock(&JFS_IP(ip)->commit_mutex);
 			break;
 		}

 		ip->i_mtime = ip->i_ctime = current_time(ip);
 		mark_inode_dirty(ip);

 		txCommit(tid, 1, &ip, 0);
 		txEnd(tid);
 		mutex_unlock(&JFS_IP(ip)->commit_mutex);
 	} while (newsize > length);	/* Truncate isn't always atomic */
 }

 void jfs_truncate(struct inode *ip)
 {
 	jfs_info("jfs_truncate: size = 0x%lx", (ulong) ip->i_size);

 	nobh_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);

 	IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
 	jfs_truncate_nolock(ip, ip->i_size);
 	IWRITE_UNLOCK(ip);
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) International Business Machines Corp., 2000-2004
	* Portions Copyright (C) Christoph Hellwig, 2001-2002
	*/

	#include <linux/fs.h>
	#include <linux/mpage.h>
	#include <linux/buffer_head.h>
	#include <linux/pagemap.h>
	#include <linux/quotaops.h>
	#include <linux/uio.h>
	#include <linux/writeback.h>
	#include "jfs_incore.h"
	#include "jfs_inode.h"
	#include "jfs_filsys.h"
	#include "jfs_imap.h"
	#include "jfs_extent.h"
	#include "jfs_unicode.h"
	#include "jfs_debug.h"
	#include "jfs_dmap.h"


	struct inode jfs_iget(struct super_block sb, unsigned long ino)
	{
	struct inode *inode;
	int ret;

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

	ret = diRead(inode);
	if (ret < 0) {
	iget_failed(inode);
	return ERR_PTR(ret);
	}

	if (S_ISREG(inode->i_mode)) {
	inode->i_op = &jfs_file_inode_operations;
	inode->i_fop = &jfs_file_operations;
	inode->i_mapping->a_ops = &jfs_aops;
	} else if (S_ISDIR(inode->i_mode)) {
	inode->i_op = &jfs_dir_inode_operations;
	inode->i_fop = &jfs_dir_operations;
	} else if (S_ISLNK(inode->i_mode)) {
	if (inode->i_size >= IDATASIZE) {
	inode->i_op = &page_symlink_inode_operations;
	inode_nohighmem(inode);
	inode->i_mapping->a_ops = &jfs_aops;
	} else {
	inode->i_op = &jfs_fast_symlink_inode_operations;
	inode->i_link = JFS_IP(inode)->i_inline;
	/*
	* The inline data should be null-terminated, but
	* don't let on-disk corruption crash the kernel
	*/
	inode->i_link[inode->i_size] = '\0';
	}
	} else {
	inode->i_op = &jfs_file_inode_operations;
	init_special_inode(inode, inode->i_mode, inode->i_rdev);
	}
	unlock_new_inode(inode);
	return inode;
	}

	/*
	* Workhorse of both fsync & write_inode
	*/
	int jfs_commit_inode(struct inode *inode, int wait)
	{
	int rc = 0;
	tid_t tid;
	static int noisy = 5;

	jfs_info("In jfs_commit_inode, inode = 0x%p", inode);

	/*
	* Don't commit if inode has been committed since last being
	* marked dirty, or if it has been deleted.
	*/
	if (inode->i_nlink == 0 \|\| !test_cflag(COMMIT_Dirty, inode))
	return 0;

	if (isReadOnly(inode)) {
	/* kernel allows writes to devices on read-only
	* partitions and may think inode is dirty
	*/
	if (!special_file(inode->i_mode) && noisy) {
	jfs_err("jfs_commit_inode(0x%p) called on read-only volume",
	inode);
	jfs_err("Is remount racy?");
	noisy--;
	}
	return 0;
	}

	tid = txBegin(inode->i_sb, COMMIT_INODE);
	mutex_lock(&JFS_IP(inode)->commit_mutex);

	/*
	* Retest inode state after taking commit_mutex
	*/
	if (inode->i_nlink && test_cflag(COMMIT_Dirty, inode))
	rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);

	txEnd(tid);
	mutex_unlock(&JFS_IP(inode)->commit_mutex);
	return rc;
	}

	int jfs_write_inode(struct inode inode, struct writeback_control wbc)
	{
	int wait = wbc->sync_mode == WB_SYNC_ALL;

	if (inode->i_nlink == 0)
	return 0;
	/*
	* If COMMIT_DIRTY is not set, the inode isn't really dirty.
	* It has been committed since the last change, but was still
	* on the dirty inode list.
	*/
	if (!test_cflag(COMMIT_Dirty, inode)) {
	/* Make sure committed changes hit the disk */
	jfs_flush_journal(JFS_SBI(inode->i_sb)->log, wait);
	return 0;
	}

	if (jfs_commit_inode(inode, wait)) {
	jfs_err("jfs_write_inode: jfs_commit_inode failed!");
	return -EIO;
	} else
	return 0;
	}

	void jfs_evict_inode(struct inode *inode)
	{
	struct jfs_inode_info *ji = JFS_IP(inode);

	jfs_info("In jfs_evict_inode, inode = 0x%p", inode);

	if (!inode->i_nlink && !is_bad_inode(inode)) {
	dquot_initialize(inode);

	if (JFS_IP(inode)->fileset == FILESYSTEM_I) {
	truncate_inode_pages_final(&inode->i_data);

	if (test_cflag(COMMIT_Freewmap, inode))
	jfs_free_zero_link(inode);

	diFree(inode);

	/*
	* Free the inode from the quota allocation.
	*/
	dquot_free_inode(inode);
	}
	} else {
	truncate_inode_pages_final(&inode->i_data);
	}
	clear_inode(inode);
	dquot_drop(inode);

	BUG_ON(!list_empty(&ji->anon_inode_list));

	spin_lock_irq(&ji->ag_lock);
	if (ji->active_ag != -1) {
	struct bmap *bmap = JFS_SBI(inode->i_sb)->bmap;
	atomic_dec(&bmap->db_active[ji->active_ag]);
	ji->active_ag = -1;
	}
	spin_unlock_irq(&ji->ag_lock);
	}

	void jfs_dirty_inode(struct inode *inode, int flags)
	{
	static int noisy = 5;

	if (isReadOnly(inode)) {
	if (!special_file(inode->i_mode) && noisy) {
	/* kernel allows writes to devices on read-only
	* partitions and may try to mark inode dirty
	*/
	jfs_err("jfs_dirty_inode called on read-only volume");
	jfs_err("Is remount racy?");
	noisy--;
	}
	return;
	}

	set_cflag(COMMIT_Dirty, inode);
	}

	int jfs_get_block(struct inode *ip, sector_t lblock,
	struct buffer_head *bh_result, int create)
	{
	s64 lblock64 = lblock;
	int rc = 0;
	xad_t xad;
	s64 xaddr;
	int xflag;
	s32 xlen = bh_result->b_size >> ip->i_blkbits;

	/*
	* Take appropriate lock on inode
	*/
	if (create)
	IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
	else
	IREAD_LOCK(ip, RDWRLOCK_NORMAL);

	if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
	(!xtLookup(ip, lblock64, xlen, &xflag, &xaddr, &xlen, 0)) &&
	xaddr) {
	if (xflag & XAD_NOTRECORDED) {
	if (!create)
	/*
	* Allocated but not recorded, read treats
	* this as a hole
	*/
	goto unlock;
	#ifdef _JFS_4K
	XADoffset(&xad, lblock64);
	XADlength(&xad, xlen);
	XADaddress(&xad, xaddr);
	#else /* _JFS_4K */
	/*
	* As long as block size = 4K, this isn't a problem.
	* We should mark the whole page not ABNR, but how
	* will we know to mark the other blocks BH_New?
	*/
	BUG();
	#endif /* _JFS_4K */
	rc = extRecord(ip, &xad);
	if (rc)
	goto unlock;
	set_buffer_new(bh_result);
	}

	map_bh(bh_result, ip->i_sb, xaddr);
	bh_result->b_size = xlen << ip->i_blkbits;
	goto unlock;
	}
	if (!create)
	goto unlock;

	/*
	* Allocate a new block
	*/
	#ifdef _JFS_4K
	if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
	goto unlock;
	rc = extAlloc(ip, xlen, lblock64, &xad, false);
	if (rc)
	goto unlock;

	set_buffer_new(bh_result);
	map_bh(bh_result, ip->i_sb, addressXAD(&xad));
	bh_result->b_size = lengthXAD(&xad) << ip->i_blkbits;

	#else /* _JFS_4K */
	/*
	* We need to do whatever it takes to keep all but the last buffers
	* in 4K pages - see jfs_write.c
	*/
	BUG();
	#endif /* _JFS_4K */

	unlock:
	/*
	* Release lock on inode
	*/
	if (create)
	IWRITE_UNLOCK(ip);
	else
	IREAD_UNLOCK(ip);
	return rc;
	}

	static int jfs_writepage(struct page page, struct writeback_control wbc)
	{
	return block_write_full_page(page, jfs_get_block, wbc);
	}

	static int jfs_writepages(struct address_space *mapping,
	struct writeback_control *wbc)
	{
	return mpage_writepages(mapping, wbc, jfs_get_block);
	}

	static int jfs_readpage(struct file file, struct page page)
	{
	return mpage_readpage(page, jfs_get_block);
	}

	static int jfs_readpages(struct file file, struct address_space mapping,
	struct list_head *pages, unsigned nr_pages)
	{
	return mpage_readpages(mapping, pages, nr_pages, jfs_get_block);
	}

	static void jfs_write_failed(struct address_space *mapping, loff_t to)
	{
	struct inode *inode = mapping->host;

	if (to > inode->i_size) {
	truncate_pagecache(inode, inode->i_size);
	jfs_truncate(inode);
	}
	}

	static int jfs_write_begin(struct file file, struct address_space mapping,
	loff_t pos, unsigned len, unsigned flags,
	struct page pagep, void fsdata)
	{
	int ret;

	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
	jfs_get_block);
	if (unlikely(ret))
	jfs_write_failed(mapping, pos + len);

	return ret;
	}

	static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
	{
	return generic_block_bmap(mapping, block, jfs_get_block);
	}

	static ssize_t jfs_direct_IO(struct kiocb iocb, struct iov_iter iter)
	{
	struct file *file = iocb->ki_filp;
	struct address_space *mapping = file->f_mapping;
	struct inode *inode = file->f_mapping->host;
	size_t count = iov_iter_count(iter);
	ssize_t ret;

	ret = blockdev_direct_IO(iocb, inode, iter, jfs_get_block);

	/*
	* In case of error extending write may have instantiated a few
	* blocks outside i_size. Trim these off again.
	*/
	if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
	loff_t isize = i_size_read(inode);
	loff_t end = iocb->ki_pos + count;

	if (end > isize)
	jfs_write_failed(mapping, end);
	}

	return ret;
	}

	const struct address_space_operations jfs_aops = {
	.readpage = jfs_readpage,
	.readpages = jfs_readpages,
	.writepage = jfs_writepage,
	.writepages = jfs_writepages,
	.write_begin = jfs_write_begin,
	.write_end = nobh_write_end,
	.bmap = jfs_bmap,
	.direct_IO = jfs_direct_IO,
	};

	/*
	* Guts of jfs_truncate. Called with locks already held. Can be called
	* with directory for truncating directory index table.
	*/
	void jfs_truncate_nolock(struct inode *ip, loff_t length)
	{
	loff_t newsize;
	tid_t tid;

	ASSERT(length >= 0);

	if (test_cflag(COMMIT_Nolink, ip)) {
	xtTruncate(0, ip, length, COMMIT_WMAP);
	return;
	}

	do {
	tid = txBegin(ip->i_sb, 0);

	/*
	* The commit_mutex cannot be taken before txBegin.
	* txBegin may block and there is a chance the inode
	* could be marked dirty and need to be committed
	* before txBegin unblocks
	*/
	mutex_lock(&JFS_IP(ip)->commit_mutex);

	newsize = xtTruncate(tid, ip, length,
	COMMIT_TRUNCATE \| COMMIT_PWMAP);
	if (newsize < 0) {
	txEnd(tid);
	mutex_unlock(&JFS_IP(ip)->commit_mutex);
	break;
	}

	ip->i_mtime = ip->i_ctime = current_time(ip);
	mark_inode_dirty(ip);

	txCommit(tid, 1, &ip, 0);
	txEnd(tid);
	mutex_unlock(&JFS_IP(ip)->commit_mutex);
	} while (newsize > length); /* Truncate isn't always atomic */
	}

	void jfs_truncate(struct inode *ip)
	{
	jfs_info("jfs_truncate: size = 0x%lx", (ulong) ip->i_size);

	nobh_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);

	IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
	jfs_truncate_nolock(ip, ip->i_size);
	IWRITE_UNLOCK(ip);
	}