fs/udf/truncate.c - kernel/msm - Gitiles

 /*
  * truncate.c
  *
  * PURPOSE
  *	Truncate handling routines for the OSTA-UDF(tm) filesystem.
  *
  * COPYRIGHT
  *	This file is distributed under the terms of the GNU General Public
  *	License (GPL). Copies of the GPL can be obtained from:
  *		ftp://prep.ai.mit.edu/pub/gnu/GPL
  *	Each contributing author retains all rights to their own work.
  *
  *  (C) 1999-2004 Ben Fennema
  *  (C) 1999 Stelias Computing Inc
  *
  * HISTORY
  *
  *  02/24/99 blf  Created.
  *
  */

 #include "udfdecl.h"
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/udf_fs.h>
 #include <linux/buffer_head.h>

 #include "udf_i.h"
 #include "udf_sb.h"

 static void extent_trunc(struct inode * inode, struct extent_position *epos,
 	kernel_lb_addr eloc, int8_t etype, uint32_t elen, uint32_t nelen)
 {
 	kernel_lb_addr neloc = { 0, 0 };
 	int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
 	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;

 	if (nelen)
 	{
 		if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
 		{
 			udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
 			etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
 		}
 		else
 			neloc = eloc;
 		nelen = (etype << 30) | nelen;
 	}

 	if (elen != nelen)
 	{
 		udf_write_aext(inode, epos, neloc, nelen, 0);
 		if (last_block - first_block > 0)
 		{
 			if (etype == (EXT_RECORDED_ALLOCATED >> 30))
 				mark_inode_dirty(inode);

 			if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
 				udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
 		}
 	}
 }

 void udf_discard_prealloc(struct inode * inode)
 {
 	struct extent_position epos = { NULL, 0, {0, 0}};
 	kernel_lb_addr eloc;
 	uint32_t elen, nelen;
 	uint64_t lbcount = 0;
 	int8_t etype = -1, netype;
 	int adsize;

 	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB ||
 		inode->i_size == UDF_I_LENEXTENTS(inode))
 		return;

 	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(short_ad);
 	else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(long_ad);
 	else
 		adsize = 0;

 	epos.block = UDF_I_LOCATION(inode);

 	/* Find the last extent in the file */
 	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1)
 	{
 		etype = netype;
 		lbcount += elen;
 		if (lbcount > inode->i_size && lbcount - elen < inode->i_size)
 		{
 			WARN_ON(lbcount - inode->i_size >= inode->i_sb->s_blocksize);
 			nelen = elen - (lbcount - inode->i_size);
 			epos.offset -= adsize;
 			extent_trunc(inode, &epos, eloc, etype, elen, nelen);
 			epos.offset += adsize;
 			lbcount = inode->i_size;
 		}
 	}
 	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 		epos.offset -= adsize;
 		lbcount -= elen;
 		extent_trunc(inode, &epos, eloc, etype, elen, 0);
 		if (!epos.bh)
 		{
 			UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode);
 			mark_inode_dirty(inode);
 		}
 		else
 		{
 			struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 			aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc));
 			if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
 				udf_update_tag(epos.bh->b_data, epos.offset);
 			else
 				udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 			mark_buffer_dirty_inode(epos.bh, inode);
 		}
 	}
 	UDF_I_LENEXTENTS(inode) = lbcount;

 	WARN_ON(lbcount != inode->i_size);
 	brelse(epos.bh);
 }

 void udf_truncate_extents(struct inode * inode)
 {
 	struct extent_position epos;
 	kernel_lb_addr eloc, neloc = { 0, 0 };
 	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 	int8_t etype;
 	struct super_block *sb = inode->i_sb;
 	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 	loff_t byte_offset;
 	int adsize;

 	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(short_ad);
 	else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(long_ad);
 	else
 		BUG();

 	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
 	byte_offset = (offset << sb->s_blocksize_bits) + (inode->i_size & (sb->s_blocksize-1));
 	if (etype != -1)
 	{
 		epos.offset -= adsize;
 		extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
 		epos.offset += adsize;
 		if (byte_offset)
 			lenalloc = epos.offset;
 		else
 			lenalloc = epos.offset - adsize;

 		if (!epos.bh)
 			lenalloc -= udf_file_entry_alloc_offset(inode);
 		else
 			lenalloc -= sizeof(struct allocExtDesc);

 		while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1)
 		{
 			if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
 			{
 				udf_write_aext(inode, &epos, neloc, nelen, 0);
 				if (indirect_ext_len)
 				{
 					/* We managed to free all extents in the
 					 * indirect extent - free it too */
 					if (!epos.bh)
 						BUG();
 					udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
 				}
 				else
 				{
 					if (!epos.bh)
 					{
 						UDF_I_LENALLOC(inode) = lenalloc;
 						mark_inode_dirty(inode);
 					}
 					else
 					{
 						struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 						aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 						if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201)
 							udf_update_tag(epos.bh->b_data, lenalloc +
 								sizeof(struct allocExtDesc));
 						else
 							udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 						mark_buffer_dirty_inode(epos.bh, inode);
 					}
 				}
 				brelse(epos.bh);
 				epos.offset = sizeof(struct allocExtDesc);
 				epos.block = eloc;
 				epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0));
 				if (elen)
 					indirect_ext_len = (elen +
 						sb->s_blocksize - 1) >>
 						sb->s_blocksize_bits;
 				else
 					indirect_ext_len = 1;
 			}
 			else
 			{
 				extent_trunc(inode, &epos, eloc, etype, elen, 0);
 				epos.offset += adsize;
 			}
 		}

 		if (indirect_ext_len)
 		{
 			if (!epos.bh)
 				BUG();
 			udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
 		}
 		else
 		{
 			if (!epos.bh)
 			{
 				UDF_I_LENALLOC(inode) = lenalloc;
 				mark_inode_dirty(inode);
 			}
 			else
 			{
 				struct allocExtDesc *aed = (struct allocExtDesc *)(epos.bh->b_data);
 				aed->lengthAllocDescs = cpu_to_le32(lenalloc);
 				if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || UDF_SB_UDFREV(sb) >= 0x0201)
 					udf_update_tag(epos.bh->b_data, lenalloc +
 						sizeof(struct allocExtDesc));
 				else
 					udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
 				mark_buffer_dirty_inode(epos.bh, inode);
 			}
 		}
 	}
 	else if (inode->i_size)
 	{
 		if (byte_offset)
 		{
 			kernel_long_ad extent;

 			/*
 			 *  OK, there is not extent covering inode->i_size and
 			 *  no extent above inode->i_size => truncate is
 			 *  extending the file by 'offset' blocks.
 			 */
 			if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) ||
 			    (epos.bh && epos.offset == sizeof(struct allocExtDesc))) {
 				/* File has no extents at all or has empty last
 				 * indirect extent! Create a fake extent... */
 				extent.extLocation.logicalBlockNum = 0;
 				extent.extLocation.partitionReferenceNum = 0;
 				extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED;
 			}
 			else {
 				epos.offset -= adsize;
 				etype = udf_next_aext(inode, &epos,
 					&extent.extLocation, &extent.extLength, 0);
 				extent.extLength |= etype << 30;
 			}
 			udf_extend_file(inode, &epos, &extent, offset+((inode->i_size & (sb->s_blocksize-1)) != 0));
 		}
 	}
 	UDF_I_LENEXTENTS(inode) = inode->i_size;

 	brelse(epos.bh);
 }
	/*
	* truncate.c
	*
	* PURPOSE
	* Truncate handling routines for the OSTA-UDF(tm) filesystem.
	*
	* COPYRIGHT
	* This file is distributed under the terms of the GNU General Public
	* License (GPL). Copies of the GPL can be obtained from:
	* ftp://prep.ai.mit.edu/pub/gnu/GPL
	* Each contributing author retains all rights to their own work.
	*
	* (C) 1999-2004 Ben Fennema
	* (C) 1999 Stelias Computing Inc
	*
	* HISTORY
	*
	* 02/24/99 blf Created.
	*
	*/

	#include "udfdecl.h"
	#include <linux/fs.h>
	#include <linux/mm.h>
	#include <linux/udf_fs.h>
	#include <linux/buffer_head.h>

	#include "udf_i.h"
	#include "udf_sb.h"

	static void extent_trunc(struct inode * inode, struct extent_position *epos,
	kernel_lb_addr eloc, int8_t etype, uint32_t elen, uint32_t nelen)
	{
	kernel_lb_addr neloc = { 0, 0 };
	int last_block = (elen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;
	int first_block = (nelen + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits;

	if (nelen)
	{
	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30))
	{
	udf_free_blocks(inode->i_sb, inode, eloc, 0, last_block);
	etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
	}
	else
	neloc = eloc;
	nelen = (etype << 30) \| nelen;
	}

	if (elen != nelen)
	{
	udf_write_aext(inode, epos, neloc, nelen, 0);
	if (last_block - first_block > 0)
	{
	if (etype == (EXT_RECORDED_ALLOCATED >> 30))
	mark_inode_dirty(inode);

	if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
	udf_free_blocks(inode->i_sb, inode, eloc, first_block, last_block - first_block);
	}
	}
	}

	void udf_discard_prealloc(struct inode * inode)
	{
	struct extent_position epos = { NULL, 0, {0, 0}};
	kernel_lb_addr eloc;
	uint32_t elen, nelen;
	uint64_t lbcount = 0;
	int8_t etype = -1, netype;
	int adsize;

	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_IN_ICB \|\|
	inode->i_size == UDF_I_LENEXTENTS(inode))
	return;

	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(short_ad);
	else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(long_ad);
	else
	adsize = 0;

	epos.block = UDF_I_LOCATION(inode);

	/* Find the last extent in the file */
	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1)
	{
	etype = netype;
	lbcount += elen;
	if (lbcount > inode->i_size && lbcount - elen < inode->i_size)
	{
	WARN_ON(lbcount - inode->i_size >= inode->i_sb->s_blocksize);
	nelen = elen - (lbcount - inode->i_size);
	epos.offset -= adsize;
	extent_trunc(inode, &epos, eloc, etype, elen, nelen);
	epos.offset += adsize;
	lbcount = inode->i_size;
	}
	}
	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
	epos.offset -= adsize;
	lbcount -= elen;
	extent_trunc(inode, &epos, eloc, etype, elen, 0);
	if (!epos.bh)
	{
	UDF_I_LENALLOC(inode) = epos.offset - udf_file_entry_alloc_offset(inode);
	mark_inode_dirty(inode);
	}
	else
	{
	struct allocExtDesc aed = (struct allocExtDesc )(epos.bh->b_data);
	aed->lengthAllocDescs = cpu_to_le32(epos.offset - sizeof(struct allocExtDesc));
	if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) \|\| UDF_SB_UDFREV(inode->i_sb) >= 0x0201)
	udf_update_tag(epos.bh->b_data, epos.offset);
	else
	udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
	mark_buffer_dirty_inode(epos.bh, inode);
	}
	}
	UDF_I_LENEXTENTS(inode) = lbcount;

	WARN_ON(lbcount != inode->i_size);
	brelse(epos.bh);
	}

	void udf_truncate_extents(struct inode * inode)
	{
	struct extent_position epos;
	kernel_lb_addr eloc, neloc = { 0, 0 };
	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
	int8_t etype;
	struct super_block *sb = inode->i_sb;
	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
	loff_t byte_offset;
	int adsize;

	if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(short_ad);
	else if (UDF_I_ALLOCTYPE(inode) == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(long_ad);
	else
	BUG();

	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
	byte_offset = (offset << sb->s_blocksize_bits) + (inode->i_size & (sb->s_blocksize-1));
	if (etype != -1)
	{
	epos.offset -= adsize;
	extent_trunc(inode, &epos, eloc, etype, elen, byte_offset);
	epos.offset += adsize;
	if (byte_offset)
	lenalloc = epos.offset;
	else
	lenalloc = epos.offset - adsize;

	if (!epos.bh)
	lenalloc -= udf_file_entry_alloc_offset(inode);
	else
	lenalloc -= sizeof(struct allocExtDesc);

	while ((etype = udf_current_aext(inode, &epos, &eloc, &elen, 0)) != -1)
	{
	if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30))
	{
	udf_write_aext(inode, &epos, neloc, nelen, 0);
	if (indirect_ext_len)
	{
	/* We managed to free all extents in the
	* indirect extent - free it too */
	if (!epos.bh)
	BUG();
	udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
	}
	else
	{
	if (!epos.bh)
	{
	UDF_I_LENALLOC(inode) = lenalloc;
	mark_inode_dirty(inode);
	}
	else
	{
	struct allocExtDesc aed = (struct allocExtDesc )(epos.bh->b_data);
	aed->lengthAllocDescs = cpu_to_le32(lenalloc);
	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) \|\| UDF_SB_UDFREV(sb) >= 0x0201)
	udf_update_tag(epos.bh->b_data, lenalloc +
	sizeof(struct allocExtDesc));
	else
	udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
	mark_buffer_dirty_inode(epos.bh, inode);
	}
	}
	brelse(epos.bh);
	epos.offset = sizeof(struct allocExtDesc);
	epos.block = eloc;
	epos.bh = udf_tread(sb, udf_get_lb_pblock(sb, eloc, 0));
	if (elen)
	indirect_ext_len = (elen +
	sb->s_blocksize - 1) >>
	sb->s_blocksize_bits;
	else
	indirect_ext_len = 1;
	}
	else
	{
	extent_trunc(inode, &epos, eloc, etype, elen, 0);
	epos.offset += adsize;
	}
	}

	if (indirect_ext_len)
	{
	if (!epos.bh)
	BUG();
	udf_free_blocks(sb, inode, epos.block, 0, indirect_ext_len);
	}
	else
	{
	if (!epos.bh)
	{
	UDF_I_LENALLOC(inode) = lenalloc;
	mark_inode_dirty(inode);
	}
	else
	{
	struct allocExtDesc aed = (struct allocExtDesc )(epos.bh->b_data);
	aed->lengthAllocDescs = cpu_to_le32(lenalloc);
	if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) \|\| UDF_SB_UDFREV(sb) >= 0x0201)
	udf_update_tag(epos.bh->b_data, lenalloc +
	sizeof(struct allocExtDesc));
	else
	udf_update_tag(epos.bh->b_data, sizeof(struct allocExtDesc));
	mark_buffer_dirty_inode(epos.bh, inode);
	}
	}
	}
	else if (inode->i_size)
	{
	if (byte_offset)
	{
	kernel_long_ad extent;

	/*
	* OK, there is not extent covering inode->i_size and
	* no extent above inode->i_size => truncate is
	* extending the file by 'offset' blocks.
	*/
	if ((!epos.bh && epos.offset == udf_file_entry_alloc_offset(inode)) \|\|
	(epos.bh && epos.offset == sizeof(struct allocExtDesc))) {
	/* File has no extents at all or has empty last
	* indirect extent! Create a fake extent... */
	extent.extLocation.logicalBlockNum = 0;
	extent.extLocation.partitionReferenceNum = 0;
	extent.extLength = EXT_NOT_RECORDED_NOT_ALLOCATED;
	}
	else {
	epos.offset -= adsize;
	etype = udf_next_aext(inode, &epos,
	&extent.extLocation, &extent.extLength, 0);
	extent.extLength \|= etype << 30;
	}
	udf_extend_file(inode, &epos, &extent, offset+((inode->i_size & (sb->s_blocksize-1)) != 0));
	}
	}
	UDF_I_LENEXTENTS(inode) = inode->i_size;

	brelse(epos.bh);
	}