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Commit 5c9f6de3 authored by Anton Altaparmakov's avatar Anton Altaparmakov
Browse files

NTFS: Fix various bugs in the runlist merging code. (Based on libntfs 


      changes by Richard Russon.)

Signed-off-by: default avatarAnton Altaparmakov <aia21@cantab.net>
parent 065d9cac

fs/ntfs/ChangeLog

+2 −0
Original line number Diff line number Diff line
@@ -92,6 +92,8 @@ ToDo/Notes: 
	  an octal number to conform to how chmod(1) works, too.  Thanks to

	  Giuseppe Bilotta and Horst von Brand for pointing out the errors of

	  my ways.

	- Fix various bugs in the runlist merging code.  (Based on libntfs

	  changes by Richard Russon.)



2.1.23 - Implement extension of resident files and make writing safe as well as

	 many bug fixes, cleanups, and enhancements...

fs/ntfs/runlist.c

+68 −64
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
 * runlist.c - NTFS runlist handling code.  Part of the Linux-NTFS project.

 *

 * Copyright (c) 2001-2005 Anton Altaparmakov

 * Copyright (c) 2002 Richard Russon

 * Copyright (c) 2002-2005 Richard Russon

 *

 * This program/include file is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as published
@@ -214,8 +214,8 @@ static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) 
static inline runlist_element *ntfs_rl_append(runlist_element *dst,

		int dsize, runlist_element *src, int ssize, int loc)

{

	BOOL right;

	int magic;

	BOOL right;	/* Right end of @src needs merging. */

	int marker;	/* End of the inserted runs. */



	BUG_ON(!dst);

	BUG_ON(!src);
@@ -236,18 +236,19 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst, 
	if (right)

		__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);



	magic = loc + ssize;

	/* First run after the @src runs that have been inserted. */

	marker = loc + ssize + 1;



	/* Move the tail of @dst out of the way, then copy in @src. */

	ntfs_rl_mm(dst, magic + 1, loc + 1 + right, dsize - loc - 1 - right);

	ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right));

	ntfs_rl_mc(dst, loc + 1, src, 0, ssize);



	/* Adjust the size of the preceding hole. */

	dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;



	/* We may have changed the length of the file, so fix the end marker */

	if (dst[magic + 1].lcn == LCN_ENOENT)

		dst[magic + 1].vcn = dst[magic].vcn + dst[magic].length;

	if (dst[marker].lcn == LCN_ENOENT)

		dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;



	return dst;

}
@@ -279,18 +280,17 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst, 
static inline runlist_element *ntfs_rl_insert(runlist_element *dst,

		int dsize, runlist_element *src, int ssize, int loc)

{

	BOOL left = FALSE;

	BOOL disc = FALSE;	/* Discontinuity */

	BOOL hole = FALSE;	/* Following a hole */

	int magic;

	BOOL left = FALSE;	/* Left end of @src needs merging. */

	BOOL disc = FALSE;	/* Discontinuity between @dst and @src. */

	int marker;		/* End of the inserted runs. */



	BUG_ON(!dst);

	BUG_ON(!src);



	/* disc => Discontinuity between the end of @dst and the start of @src.

	 *	   This means we might need to insert a hole.

	 * hole => @dst ends with a hole or an unmapped region which we can

	 *	   extend to match the discontinuity. */

	/*

	 * disc => Discontinuity between the end of @dst and the start of @src.

	 *	   This means we might need to insert a "not mapped" run.

	 */

	if (loc == 0)

		disc = (src[0].vcn > 0);

	else {
@@ -303,59 +303,50 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst, 
			merged_length += src->length;



		disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);

		if (disc)

			hole = (dst[loc - 1].lcn == LCN_HOLE);

	}



	/* Space required: @dst size + @src size, less one if we merged, plus

	 * one if there was a discontinuity, less one for a trailing hole. */

	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole);

	/*

	 * Space required: @dst size + @src size, less one if we merged, plus

	 * one if there was a discontinuity.

	 */

	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);

	if (IS_ERR(dst))

		return dst;

	/*

	 * We are guaranteed to succeed from here so can start modifying the

	 * original runlist.

	 */



	if (left)

		__ntfs_rl_merge(dst + loc - 1, src);



	magic = loc + ssize - left + disc - hole;

	/*

	 * First run after the @src runs that have been inserted.

	 * Nominally,  @marker equals @loc + @ssize, i.e. location + number of

	 * runs in @src.  However, if @left, then the first run in @src has

	 * been merged with one in @dst.  And if @disc, then @dst and @src do

	 * not meet and we need an extra run to fill the gap.

	 */

	marker = loc + ssize - left + disc;



	/* Move the tail of @dst out of the way, then copy in @src. */

	ntfs_rl_mm(dst, magic, loc, dsize - loc);

	ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left);

	ntfs_rl_mm(dst, marker, loc, dsize - loc);

	ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);



	/* Adjust the VCN of the last run ... */

	if (dst[magic].lcn <= LCN_HOLE)

		dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;

	/* Adjust the VCN of the first run after the insertion... */

	dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;

	/* ... and the length. */

	if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED)

		dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn;

	if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)

		dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;



	/* Writing beyond the end of the file and there's a discontinuity. */

	/* Writing beyond the end of the file and there is a discontinuity. */

	if (disc) {

		if (hole)

			dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn;

		else {

		if (loc > 0) {

				dst[loc].vcn = dst[loc - 1].vcn +

						dst[loc - 1].length;

				dst[loc].length = dst[loc + 1].vcn -

						dst[loc].vcn;

			dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;

			dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;

		} else {

			dst[loc].vcn = 0;

			dst[loc].length = dst[loc + 1].vcn;

		}

		dst[loc].lcn = LCN_RL_NOT_MAPPED;

	}



		magic += hole;



		if (dst[magic].lcn == LCN_ENOENT)

			dst[magic].vcn = dst[magic - 1].vcn +

					dst[magic - 1].length;

	}

	return dst;

}
@@ -385,9 +376,10 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst, 
static inline runlist_element *ntfs_rl_replace(runlist_element *dst,

		int dsize, runlist_element *src, int ssize, int loc)

{

	BOOL left = FALSE;

	BOOL right;

	int magic;

	BOOL left = FALSE;	/* Left end of @src needs merging. */

	BOOL right;		/* Right end of @src needs merging. */

	int tail;		/* Start of tail of @dst. */

	int marker;		/* End of the inserted runs. */



	BUG_ON(!dst);

	BUG_ON(!src);
@@ -396,9 +388,10 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, 
	right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);

	if (loc > 0)

		left = ntfs_are_rl_mergeable(dst + loc - 1, src);



	/* Allocate some space. We'll need less if the left, right, or both

	 * ends were merged. */

	/*

	 * Allocate some space.  We will need less if the left, right, or both

	 * ends were merged.

	 */

	dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);

	if (IS_ERR(dst))

		return dst;
@@ -410,17 +403,28 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, 
		__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);

	if (left)

		__ntfs_rl_merge(dst + loc - 1, src);



	/* FIXME: What does this mean? (AIA) */

	magic = loc + ssize - left;

	/*

	 * First run of @dst that needs to be moved out of the way to make

	 * space for the runs to be copied from @src, i.e. the first run of the

	 * tail of @dst.

	 */

	tail = loc + right + 1;

	/*

	 * First run after the @src runs that have been inserted, i.e. where

	 * the tail of @dst needs to be moved to.

	 * Nominally, marker equals @loc + @ssize, i.e. location + number of

	 * runs in @src).  However, if @left, then the first run in @src has

	 * been merged with one in @dst.

	 */

	marker = loc + ssize - left;



	/* Move the tail of @dst out of the way, then copy in @src. */

	ntfs_rl_mm(dst, magic, loc + right + 1, dsize - loc - right - 1);

	ntfs_rl_mm(dst, marker, tail, dsize - tail);

	ntfs_rl_mc(dst, loc, src, left, ssize - left);



	/* We may have changed the length of the file, so fix the end marker */

	if (dst[magic].lcn == LCN_ENOENT)

		dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;

	/* We may have changed the length of the file, so fix the end marker. */

	if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)

		dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;

	return dst;

}