fs/udf/truncate.c - 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 "udf_i.h"
 #include "udf_sb.h"

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

 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 	    inode->i_size == iinfo->i_lenExtents)
 		return;
 	/* Are we going to delete the file anyway? */
 	if (inode->i_nlink == 0)
 		return;

 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct 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)
 				udf_warn(inode->i_sb,
 					 "Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld 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)
 				udf_err(inode->i_sb,
 					"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 */
 	iinfo->i_lenExtents = inode->i_size;
 	brelse(epos.bh);
 }

 void udf_discard_prealloc(struct inode *inode)
 {
 	struct extent_position epos = {};
 	struct extent_position prev_epos = {};
 	struct kernel_lb_addr eloc;
 	uint32_t elen;
 	uint64_t lbcount = 0;
 	int8_t etype = -1, netype;
 	struct udf_inode_info *iinfo = UDF_I(inode);
 	int bsize = 1 << inode->i_blkbits;

 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
 	    ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
 		return;

 	epos.block = iinfo->i_location;

 	/* Find the last extent in the file */
 	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 0)) != -1) {
 		brelse(prev_epos.bh);
 		prev_epos = epos;
 		if (prev_epos.bh)
 			get_bh(prev_epos.bh);

 		etype = udf_next_aext(inode, &epos, &eloc, &elen, 1);
 		lbcount += elen;
 	}
 	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
 		lbcount -= elen;
 		udf_delete_aext(inode, prev_epos);
 		udf_free_blocks(inode->i_sb, inode, &eloc, 0,
 				DIV_ROUND_UP(elen, 1 << inode->i_blkbits));
 	}
 	/* This inode entry is in-memory only and thus we don't have to mark
 	 * the inode dirty */
 	iinfo->i_lenExtents = lbcount;
 	brelse(epos.bh);
 	brelse(prev_epos.bh);
 }

 static void udf_update_alloc_ext_desc(struct inode *inode,
 				      struct extent_position *epos,
 				      u32 lenalloc)
 {
 	struct super_block *sb = inode->i_sb;
 	struct udf_sb_info *sbi = UDF_SB(sb);

 	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);
 }

 /*
  * Truncate extents of inode to inode->i_size. This function can be used only
  * for making file shorter. For making file longer, udf_extend_file() has to
  * be used.
  */
 int udf_truncate_extents(struct inode *inode)
 {
 	struct extent_position epos;
 	struct 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;
 	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
 	loff_t byte_offset;
 	int adsize;
 	struct udf_inode_info *iinfo = UDF_I(inode);

 	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
 		adsize = sizeof(struct short_ad);
 	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
 		adsize = sizeof(struct 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) {
 		/* We should extend the file? */
 		WARN_ON(byte_offset);
 		return 0;
 	}
 	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_ALLOCDESCS >> 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 */
 				BUG_ON(!epos.bh);
 				udf_free_blocks(sb, NULL, &epos.block,
 						0, indirect_ext_len);
 			} else if (!epos.bh) {
 				iinfo->i_lenAlloc = lenalloc;
 				mark_inode_dirty(inode);
 			} else
 				udf_update_alloc_ext_desc(inode,
 						&epos, lenalloc);
 			brelse(epos.bh);
 			epos.offset = sizeof(struct allocExtDesc);
 			epos.block = eloc;
 			epos.bh = udf_tread(sb,
 					udf_get_lb_pblock(sb, &eloc, 0));
 			/* Error reading indirect block? */
 			if (!epos.bh)
 				return -EIO;
 			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) {
 		BUG_ON(!epos.bh);
 		udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
 	} else if (!epos.bh) {
 		iinfo->i_lenAlloc = lenalloc;
 		mark_inode_dirty(inode);
 	} else
 		udf_update_alloc_ext_desc(inode, &epos, lenalloc);
 	iinfo->i_lenExtents = inode->i_size;

 	brelse(epos.bh);
 	return 0;
 }
	/*
	* 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 "udf_i.h"
	#include "udf_sb.h"

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

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB \|\|
	inode->i_size == iinfo->i_lenExtents)
	return;
	/* Are we going to delete the file anyway? */
	if (inode->i_nlink == 0)
	return;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(struct 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)
	udf_warn(inode->i_sb,
	"Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld 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)
	udf_err(inode->i_sb,
	"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 */
	iinfo->i_lenExtents = inode->i_size;
	brelse(epos.bh);
	}

	void udf_discard_prealloc(struct inode *inode)
	{
	struct extent_position epos = {};
	struct extent_position prev_epos = {};
	struct kernel_lb_addr eloc;
	uint32_t elen;
	uint64_t lbcount = 0;
	int8_t etype = -1, netype;
	struct udf_inode_info *iinfo = UDF_I(inode);
	int bsize = 1 << inode->i_blkbits;

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB \|\|
	ALIGN(inode->i_size, bsize) == ALIGN(iinfo->i_lenExtents, bsize))
	return;

	epos.block = iinfo->i_location;

	/* Find the last extent in the file */
	while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 0)) != -1) {
	brelse(prev_epos.bh);
	prev_epos = epos;
	if (prev_epos.bh)
	get_bh(prev_epos.bh);

	etype = udf_next_aext(inode, &epos, &eloc, &elen, 1);
	lbcount += elen;
	}
	if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
	lbcount -= elen;
	udf_delete_aext(inode, prev_epos);
	udf_free_blocks(inode->i_sb, inode, &eloc, 0,
	DIV_ROUND_UP(elen, 1 << inode->i_blkbits));
	}
	/* This inode entry is in-memory only and thus we don't have to mark
	* the inode dirty */
	iinfo->i_lenExtents = lbcount;
	brelse(epos.bh);
	brelse(prev_epos.bh);
	}

	static void udf_update_alloc_ext_desc(struct inode *inode,
	struct extent_position *epos,
	u32 lenalloc)
	{
	struct super_block *sb = inode->i_sb;
	struct udf_sb_info *sbi = UDF_SB(sb);

	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);
	}

	/*
	* Truncate extents of inode to inode->i_size. This function can be used only
	* for making file shorter. For making file longer, udf_extend_file() has to
	* be used.
	*/
	int udf_truncate_extents(struct inode *inode)
	{
	struct extent_position epos;
	struct 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;
	sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
	loff_t byte_offset;
	int adsize;
	struct udf_inode_info *iinfo = UDF_I(inode);

	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
	adsize = sizeof(struct short_ad);
	else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
	adsize = sizeof(struct 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) {
	/* We should extend the file? */
	WARN_ON(byte_offset);
	return 0;
	}
	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_ALLOCDESCS >> 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 */
	BUG_ON(!epos.bh);
	udf_free_blocks(sb, NULL, &epos.block,
	0, indirect_ext_len);
	} else if (!epos.bh) {
	iinfo->i_lenAlloc = lenalloc;
	mark_inode_dirty(inode);
	} else
	udf_update_alloc_ext_desc(inode,
	&epos, lenalloc);
	brelse(epos.bh);
	epos.offset = sizeof(struct allocExtDesc);
	epos.block = eloc;
	epos.bh = udf_tread(sb,
	udf_get_lb_pblock(sb, &eloc, 0));
	/* Error reading indirect block? */
	if (!epos.bh)
	return -EIO;
	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) {
	BUG_ON(!epos.bh);
	udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
	} else if (!epos.bh) {
	iinfo->i_lenAlloc = lenalloc;
	mark_inode_dirty(inode);
	} else
	udf_update_alloc_ext_desc(inode, &epos, lenalloc);
	iinfo->i_lenExtents = inode->i_size;

	brelse(epos.bh);
	return 0;
	}