Commit fa33cdbf authored by Steven J. Magnani's avatar Steven J. Magnani Committed by Jan Kara
Browse files

udf: Fix incorrect final NOT_ALLOCATED (hole) extent length 



In some cases, using the 'truncate' command to extend a UDF file results
in a mismatch between the length of the file's extents (specifically, due
to incorrect length of the final NOT_ALLOCATED extent) and the information
(file) length. The discrepancy can prevent other operating systems
(i.e., Windows 10) from opening the file.

Two particular errors have been observed when extending a file:

1. The final extent is larger than it should be, having been rounded up
   to a multiple of the block size.

B. The final extent is not shorter than it should be, due to not having
   been updated when the file's information length was increased.

[JK: simplified udf_do_extend_final_block(), fixed up some types]

Fixes: 2c948b3f ("udf: Avoid IO in udf_clear_inode")
CC: stable@vger.kernel.org
Signed-off-by: default avatarSteven J. Magnani <steve@digidescorp.com>
Link: https://lore.kernel.org/r/1561948775-5878-1-git-send-email-steve@digidescorp.com


Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 90f15ac9

fs/udf/inode.c

+60 −33
Original line number Diff line number Diff line
@@ -470,13 +470,15 @@ static struct buffer_head *udf_getblk(struct inode *inode, udf_pblk_t block, 
	return NULL;

}



/* Extend the file by 'blocks' blocks, return the number of extents added */

/* Extend the file with new blocks totaling 'new_block_bytes',

 * return the number of extents added

 */

static int udf_do_extend_file(struct inode *inode,

			      struct extent_position *last_pos,

			      struct kernel_long_ad *last_ext,

			      sector_t blocks)

			      loff_t new_block_bytes)

{

	sector_t add;

	uint32_t add;

	int count = 0, fake = !(last_ext->extLength & UDF_EXTENT_LENGTH_MASK);

	struct super_block *sb = inode->i_sb;

	struct kernel_lb_addr prealloc_loc = {};
@@ -486,7 +488,7 @@ static int udf_do_extend_file(struct inode *inode, 


	/* The previous extent is fake and we should not extend by anything

	 * - there's nothing to do... */

	if (!blocks && fake)

	if (!new_block_bytes && fake)

		return 0;



	iinfo = UDF_I(inode);
@@ -517,13 +519,12 @@ static int udf_do_extend_file(struct inode *inode, 
	/* Can we merge with the previous extent? */

	if ((last_ext->extLength & UDF_EXTENT_FLAG_MASK) ==

					EXT_NOT_RECORDED_NOT_ALLOCATED) {

		add = ((1 << 30) - sb->s_blocksize -

			(last_ext->extLength & UDF_EXTENT_LENGTH_MASK)) >>

			sb->s_blocksize_bits;

		if (add > blocks)

			add = blocks;

		blocks -= add;

		last_ext->extLength += add << sb->s_blocksize_bits;

		add = (1 << 30) - sb->s_blocksize -

			(last_ext->extLength & UDF_EXTENT_LENGTH_MASK);

		if (add > new_block_bytes)

			add = new_block_bytes;

		new_block_bytes -= add;

		last_ext->extLength += add;

	}



	if (fake) {
@@ -544,28 +545,27 @@ static int udf_do_extend_file(struct inode *inode, 
	}



	/* Managed to do everything necessary? */

	if (!blocks)

	if (!new_block_bytes)

		goto out;



	/* All further extents will be NOT_RECORDED_NOT_ALLOCATED */

	last_ext->extLocation.logicalBlockNum = 0;

	last_ext->extLocation.partitionReferenceNum = 0;

	add = (1 << (30-sb->s_blocksize_bits)) - 1;

	last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |

				(add << sb->s_blocksize_bits);

	add = (1 << 30) - sb->s_blocksize;

	last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED | add;



	/* Create enough extents to cover the whole hole */

	while (blocks > add) {

		blocks -= add;

	while (new_block_bytes > add) {

		new_block_bytes -= add;

		err = udf_add_aext(inode, last_pos, &last_ext->extLocation,

				   last_ext->extLength, 1);

		if (err)

			return err;

		count++;

	}

	if (blocks) {

	if (new_block_bytes) {

		last_ext->extLength = EXT_NOT_RECORDED_NOT_ALLOCATED |

			(blocks << sb->s_blocksize_bits);

			new_block_bytes;

		err = udf_add_aext(inode, last_pos, &last_ext->extLocation,

				   last_ext->extLength, 1);

		if (err)
@@ -596,6 +596,24 @@ out: 
	return count;

}



/* Extend the final block of the file to final_block_len bytes */

static void udf_do_extend_final_block(struct inode *inode,

				      struct extent_position *last_pos,

				      struct kernel_long_ad *last_ext,

				      uint32_t final_block_len)

{

	struct super_block *sb = inode->i_sb;

	uint32_t added_bytes;



	added_bytes = final_block_len -

		      (last_ext->extLength & (sb->s_blocksize - 1));

	last_ext->extLength += added_bytes;

	UDF_I(inode)->i_lenExtents += added_bytes;



	udf_write_aext(inode, last_pos, &last_ext->extLocation,

			last_ext->extLength, 1);

}



static int udf_extend_file(struct inode *inode, loff_t newsize)

{
@@ -605,10 +623,12 @@ static int udf_extend_file(struct inode *inode, loff_t newsize) 
	int8_t etype;

	struct super_block *sb = inode->i_sb;

	sector_t first_block = newsize >> sb->s_blocksize_bits, offset;

	unsigned long partial_final_block;

	int adsize;

	struct udf_inode_info *iinfo = UDF_I(inode);

	struct kernel_long_ad extent;

	int err;

	int err = 0;

	int within_final_block;



	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)

		adsize = sizeof(struct short_ad);
@@ -618,18 +638,8 @@ static int udf_extend_file(struct inode *inode, loff_t newsize) 
		BUG();



	etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);

	within_final_block = (etype != -1);



	/* File has extent covering the new size (could happen when extending

	 * inside a block)? */

	if (etype != -1)

		return 0;

	if (newsize & (sb->s_blocksize - 1))

		offset++;

	/* Extended file just to the boundary of the last file block? */

	if (offset == 0)

		return 0;



	/* 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
@@ -643,7 +653,22 @@ static int udf_extend_file(struct inode *inode, loff_t newsize) 
				      &extent.extLength, 0);

		extent.extLength |= etype << 30;

	}

	err = udf_do_extend_file(inode, &epos, &extent, offset);



	partial_final_block = newsize & (sb->s_blocksize - 1);



	/* File has extent covering the new size (could happen when extending

	 * inside a block)?

	 */

	if (within_final_block) {

		/* Extending file within the last file block */

		udf_do_extend_final_block(inode, &epos, &extent,

					  partial_final_block);

	} else {

		loff_t add = ((loff_t)offset << sb->s_blocksize_bits) |

			     partial_final_block;

		err = udf_do_extend_file(inode, &epos, &extent, add);

	}



	if (err < 0)

		goto out;

	err = 0;
@@ -745,6 +770,7 @@ static sector_t inode_getblk(struct inode *inode, sector_t block, 
	/* Are we beyond EOF? */

	if (etype == -1) {

		int ret;

		loff_t hole_len;

		isBeyondEOF = true;

		if (count) {

			if (c)
@@ -760,7 +786,8 @@ static sector_t inode_getblk(struct inode *inode, sector_t block, 
			startnum = (offset > 0);

		}

		/* Create extents for the hole between EOF and offset */

		ret = udf_do_extend_file(inode, &prev_epos, laarr, offset);

		hole_len = (loff_t)offset << inode->i_blkbits;

		ret = udf_do_extend_file(inode, &prev_epos, laarr, hole_len);

		if (ret < 0) {

			*err = ret;

			newblock = 0;

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