fs/udf/truncate.c - maze/linux - Git at Google

 /*
  * 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 = {};
 	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);
 		}
 	}
 }

 /*
  * Truncate the last extent to match i_size. This function assumes
  * that preallocation extent is already truncated.
  */
 void udf_truncate_tail_extent(struct inode *inode)
 {
 	struct extent_position epos = {};
 	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;
 	/* Are we going to delete the file anyway? */
 	if (inode->i_nlink == 0)
 		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
 		BUG();

 	/* 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) {
 			if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
 				printk(KERN_WARNING
 				       "udf_truncate_tail_extent(): Too long "
 				       "extent after EOF in inode %u: i_size: "
 				       "%Ld lbcount: %Ld extent %u+%u\n",
 				       (unsigned)inode->i_ino,
 				       (long long)inode->i_size,
 				       (long long)lbcount,
 				       (unsigned)eloc.logicalBlockNum,
 				       (unsigned)elen);
 			nelen = elen - (lbcount - inode->i_size);
 			epos.offset -= adsize;
 			extent_trunc(inode, &epos, eloc, etype, elen, nelen);
 			epos.offset += adsize;
 			if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
 				printk(KERN_ERR "udf_truncate_tail_extent(): "
 				       "Extent after EOF in inode %u.\n",
 				       (unsigned)inode->i_ino);
 			break;
 		}
 	}
 	/* This inode entry is in-memory only and thus we don't have to mark
 	 * the inode dirty */
 	UDF_I_LENEXTENTS(inode) = inode->i_size;
 	brelse(epos.bh);
 }

 void udf_discard_prealloc(struct inode *inode)
 {
 	struct extent_position epos = { NULL, 0, {0, 0} };
 	kernel_lb_addr eloc;
 	uint32_t elen;
 	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 (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(inode->i_sb)->s_udfrev >= 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);
 		}
 	}
 	/* This inode entry is in-memory only and thus we don't have to mark
 	 * the inode dirty */
 	UDF_I_LENEXTENTS(inode) = lbcount;
 	brelse(epos.bh);
 }

 void udf_truncate_extents(struct inode *inode)
 {
 	struct extent_position epos;
 	kernel_lb_addr eloc, neloc = {};
 	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
 	int8_t etype;
 	struct super_block *sb = inode->i_sb;
 	struct udf_sb_info *sbi = UDF_SB(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);
 						int len =
 						    sizeof(struct allocExtDesc);

 						aed->lengthAllocDescs =
 						    cpu_to_le32(lenalloc);
 						if (!UDF_QUERY_FLAG(sb,
 							UDF_FLAG_STRICT) ||
 						    sbi->s_udfrev >= 0x0201)
 							len += lenalloc;

 						udf_update_tag(epos.bh->b_data,
 								len);
 						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) ||
 				    sbi->s_udfrev >= 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 = {};
	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);
	}
	}
	}

	/*
	* Truncate the last extent to match i_size. This function assumes
	* that preallocation extent is already truncated.
	*/
	void udf_truncate_tail_extent(struct inode *inode)
	{
	struct extent_position epos = {};
	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;
	/* Are we going to delete the file anyway? */
	if (inode->i_nlink == 0)
	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
	BUG();

	/* 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) {
	if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
	printk(KERN_WARNING
	"udf_truncate_tail_extent(): Too long "
	"extent after EOF in inode %u: i_size: "
	"%Ld lbcount: %Ld extent %u+%u\n",
	(unsigned)inode->i_ino,
	(long long)inode->i_size,
	(long long)lbcount,
	(unsigned)eloc.logicalBlockNum,
	(unsigned)elen);
	nelen = elen - (lbcount - inode->i_size);
	epos.offset -= adsize;
	extent_trunc(inode, &epos, eloc, etype, elen, nelen);
	epos.offset += adsize;
	if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
	printk(KERN_ERR "udf_truncate_tail_extent(): "
	"Extent after EOF in inode %u.\n",
	(unsigned)inode->i_ino);
	break;
	}
	}
	/* This inode entry is in-memory only and thus we don't have to mark
	* the inode dirty */
	UDF_I_LENEXTENTS(inode) = inode->i_size;
	brelse(epos.bh);
	}

	void udf_discard_prealloc(struct inode *inode)
	{
	struct extent_position epos = { NULL, 0, {0, 0} };
	kernel_lb_addr eloc;
	uint32_t elen;
	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 (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(inode->i_sb)->s_udfrev >= 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);
	}
	}
	/* This inode entry is in-memory only and thus we don't have to mark
	* the inode dirty */
	UDF_I_LENEXTENTS(inode) = lbcount;
	brelse(epos.bh);
	}

	void udf_truncate_extents(struct inode *inode)
	{
	struct extent_position epos;
	kernel_lb_addr eloc, neloc = {};
	uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
	int8_t etype;
	struct super_block *sb = inode->i_sb;
	struct udf_sb_info *sbi = UDF_SB(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);
	int len =
	sizeof(struct allocExtDesc);

	aed->lengthAllocDescs =
	cpu_to_le32(lenalloc);
	if (!UDF_QUERY_FLAG(sb,
	UDF_FLAG_STRICT) \|\|
	sbi->s_udfrev >= 0x0201)
	len += lenalloc;

	udf_update_tag(epos.bh->b_data,
	len);
	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) \|\|
	sbi->s_udfrev >= 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);
	}