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NTFS: Fix various bugs in the runlist merging code. (Based on libntfs
changes by Richard Russon.) Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
This commit is contained in:
Anton Altaparmakov
parent
065d9cac98
commit
5c9f6de3b8
2 changed files with 70 additions and 64 deletions
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@ -92,6 +92,8 @@ ToDo/Notes:
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an octal number to conform to how chmod(1) works, too. Thanks to
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Giuseppe Bilotta and Horst von Brand for pointing out the errors of
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my ways.
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- Fix various bugs in the runlist merging code. (Based on libntfs
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changes by Richard Russon.)
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2.1.23 - Implement extension of resident files and make writing safe as well as
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many bug fixes, cleanups, and enhancements...
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@ -2,7 +2,7 @@
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* runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2001-2005 Anton Altaparmakov
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* Copyright (c) 2002 Richard Russon
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* Copyright (c) 2002-2005 Richard Russon
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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@ -214,8 +214,8 @@ static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
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static inline runlist_element *ntfs_rl_append(runlist_element *dst,
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int dsize, runlist_element *src, int ssize, int loc)
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{
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BOOL right;
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int magic;
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BOOL right; /* Right end of @src needs merging. */
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int marker; /* End of the inserted runs. */
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BUG_ON(!dst);
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BUG_ON(!src);
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@ -236,18 +236,19 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst,
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if (right)
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__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
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magic = loc + ssize;
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/* First run after the @src runs that have been inserted. */
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marker = loc + ssize + 1;
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/* Move the tail of @dst out of the way, then copy in @src. */
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ntfs_rl_mm(dst, magic + 1, loc + 1 + right, dsize - loc - 1 - right);
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ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right));
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ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
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/* Adjust the size of the preceding hole. */
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dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
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/* We may have changed the length of the file, so fix the end marker */
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if (dst[magic + 1].lcn == LCN_ENOENT)
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dst[magic + 1].vcn = dst[magic].vcn + dst[magic].length;
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if (dst[marker].lcn == LCN_ENOENT)
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dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
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return dst;
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}
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@ -279,18 +280,17 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst,
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static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
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int dsize, runlist_element *src, int ssize, int loc)
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{
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BOOL left = FALSE;
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BOOL disc = FALSE; /* Discontinuity */
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BOOL hole = FALSE; /* Following a hole */
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int magic;
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BOOL left = FALSE; /* Left end of @src needs merging. */
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BOOL disc = FALSE; /* Discontinuity between @dst and @src. */
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int marker; /* End of the inserted runs. */
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BUG_ON(!dst);
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BUG_ON(!src);
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/* disc => Discontinuity between the end of @dst and the start of @src.
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* This means we might need to insert a hole.
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* hole => @dst ends with a hole or an unmapped region which we can
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* extend to match the discontinuity. */
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/*
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* disc => Discontinuity between the end of @dst and the start of @src.
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* This means we might need to insert a "not mapped" run.
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*/
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if (loc == 0)
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disc = (src[0].vcn > 0);
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else {
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@ -303,58 +303,49 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
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merged_length += src->length;
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disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
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if (disc)
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hole = (dst[loc - 1].lcn == LCN_HOLE);
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}
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/* Space required: @dst size + @src size, less one if we merged, plus
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* one if there was a discontinuity, less one for a trailing hole. */
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dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole);
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/*
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* Space required: @dst size + @src size, less one if we merged, plus
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* one if there was a discontinuity.
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*/
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dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
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if (IS_ERR(dst))
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return dst;
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/*
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* We are guaranteed to succeed from here so can start modifying the
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* original runlist.
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*/
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if (left)
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__ntfs_rl_merge(dst + loc - 1, src);
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magic = loc + ssize - left + disc - hole;
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/*
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* First run after the @src runs that have been inserted.
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* Nominally, @marker equals @loc + @ssize, i.e. location + number of
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* runs in @src. However, if @left, then the first run in @src has
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* been merged with one in @dst. And if @disc, then @dst and @src do
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* not meet and we need an extra run to fill the gap.
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*/
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marker = loc + ssize - left + disc;
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/* Move the tail of @dst out of the way, then copy in @src. */
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ntfs_rl_mm(dst, magic, loc, dsize - loc);
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ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left);
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ntfs_rl_mm(dst, marker, loc, dsize - loc);
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ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
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/* Adjust the VCN of the last run ... */
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if (dst[magic].lcn <= LCN_HOLE)
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dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
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/* Adjust the VCN of the first run after the insertion... */
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dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
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/* ... and the length. */
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if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED)
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dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn;
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if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
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dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;
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/* Writing beyond the end of the file and there's a discontinuity. */
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/* Writing beyond the end of the file and there is a discontinuity. */
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if (disc) {
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if (hole)
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dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn;
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else {
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if (loc > 0) {
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dst[loc].vcn = dst[loc - 1].vcn +
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dst[loc - 1].length;
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dst[loc].length = dst[loc + 1].vcn -
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dst[loc].vcn;
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} else {
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dst[loc].vcn = 0;
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dst[loc].length = dst[loc + 1].vcn;
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}
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dst[loc].lcn = LCN_RL_NOT_MAPPED;
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if (loc > 0) {
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dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
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dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
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} else {
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dst[loc].vcn = 0;
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dst[loc].length = dst[loc + 1].vcn;
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}
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magic += hole;
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if (dst[magic].lcn == LCN_ENOENT)
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dst[magic].vcn = dst[magic - 1].vcn +
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dst[magic - 1].length;
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dst[loc].lcn = LCN_RL_NOT_MAPPED;
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}
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return dst;
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}
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@ -385,9 +376,10 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
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static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
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int dsize, runlist_element *src, int ssize, int loc)
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{
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BOOL left = FALSE;
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BOOL right;
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int magic;
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BOOL left = FALSE; /* Left end of @src needs merging. */
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BOOL right; /* Right end of @src needs merging. */
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int tail; /* Start of tail of @dst. */
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int marker; /* End of the inserted runs. */
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BUG_ON(!dst);
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BUG_ON(!src);
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@ -396,9 +388,10 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
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right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
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if (loc > 0)
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left = ntfs_are_rl_mergeable(dst + loc - 1, src);
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/* Allocate some space. We'll need less if the left, right, or both
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* ends were merged. */
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/*
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* Allocate some space. We will need less if the left, right, or both
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* ends were merged.
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*/
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dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);
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if (IS_ERR(dst))
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return dst;
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@ -410,17 +403,28 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
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__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
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if (left)
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__ntfs_rl_merge(dst + loc - 1, src);
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/* FIXME: What does this mean? (AIA) */
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magic = loc + ssize - left;
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/*
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* First run of @dst that needs to be moved out of the way to make
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* space for the runs to be copied from @src, i.e. the first run of the
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* tail of @dst.
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*/
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tail = loc + right + 1;
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/*
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* First run after the @src runs that have been inserted, i.e. where
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* the tail of @dst needs to be moved to.
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* Nominally, marker equals @loc + @ssize, i.e. location + number of
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* runs in @src). However, if @left, then the first run in @src has
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* been merged with one in @dst.
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*/
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marker = loc + ssize - left;
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/* Move the tail of @dst out of the way, then copy in @src. */
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ntfs_rl_mm(dst, magic, loc + right + 1, dsize - loc - right - 1);
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ntfs_rl_mm(dst, marker, tail, dsize - tail);
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ntfs_rl_mc(dst, loc, src, left, ssize - left);
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/* We may have changed the length of the file, so fix the end marker */
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if (dst[magic].lcn == LCN_ENOENT)
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dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
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/* We may have changed the length of the file, so fix the end marker. */
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if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)
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dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
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return dst;
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}
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