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

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
...@@ -92,6 +92,8 @@ ToDo/Notes: ...@@ -92,6 +92,8 @@ ToDo/Notes:
an octal number to conform to how chmod(1) works, too. Thanks to 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 Giuseppe Bilotta and Horst von Brand for pointing out the errors of
my ways. 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 2.1.23 - Implement extension of resident files and make writing safe as well as
many bug fixes, cleanups, and enhancements... many bug fixes, cleanups, and enhancements...
......
...@@ -2,7 +2,7 @@ ...@@ -2,7 +2,7 @@
* runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
* *
* Copyright (c) 2001-2005 Anton Altaparmakov * 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 * 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 * 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) ...@@ -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, static inline runlist_element *ntfs_rl_append(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc) int dsize, runlist_element *src, int ssize, int loc)
{ {
BOOL right; BOOL right; /* Right end of @src needs merging. */
int magic; int marker; /* End of the inserted runs. */
BUG_ON(!dst); BUG_ON(!dst);
BUG_ON(!src); BUG_ON(!src);
...@@ -236,18 +236,19 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst, ...@@ -236,18 +236,19 @@ static inline runlist_element *ntfs_rl_append(runlist_element *dst,
if (right) if (right)
__ntfs_rl_merge(src + ssize - 1, dst + loc + 1); __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. */ /* 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); ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
/* Adjust the size of the preceding hole. */ /* Adjust the size of the preceding hole. */
dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
/* We may have changed the length of the file, so fix the end marker */ /* We may have changed the length of the file, so fix the end marker */
if (dst[magic + 1].lcn == LCN_ENOENT) if (dst[marker].lcn == LCN_ENOENT)
dst[magic + 1].vcn = dst[magic].vcn + dst[magic].length; dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
return dst; return dst;
} }
...@@ -279,18 +280,17 @@ static inline runlist_element *ntfs_rl_append(runlist_element *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, static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc) int dsize, runlist_element *src, int ssize, int loc)
{ {
BOOL left = FALSE; BOOL left = FALSE; /* Left end of @src needs merging. */
BOOL disc = FALSE; /* Discontinuity */ BOOL disc = FALSE; /* Discontinuity between @dst and @src. */
BOOL hole = FALSE; /* Following a hole */ int marker; /* End of the inserted runs. */
int magic;
BUG_ON(!dst); BUG_ON(!dst);
BUG_ON(!src); BUG_ON(!src);
/* disc => Discontinuity between the end of @dst and the start of @src. /*
* This means we might need to insert a hole. * disc => Discontinuity between the end of @dst and the start of @src.
* hole => @dst ends with a hole or an unmapped region which we can * This means we might need to insert a "not mapped" run.
* extend to match the discontinuity. */ */
if (loc == 0) if (loc == 0)
disc = (src[0].vcn > 0); disc = (src[0].vcn > 0);
else { else {
...@@ -303,59 +303,50 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst, ...@@ -303,59 +303,50 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
merged_length += src->length; merged_length += src->length;
disc = (src[0].vcn > dst[loc - 1].vcn + merged_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 * Space required: @dst size + @src size, less one if we merged, plus
* one if there was a discontinuity, less one for a trailing hole. */ * one if there was a discontinuity.
dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole); */
dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
if (IS_ERR(dst)) if (IS_ERR(dst))
return dst; return dst;
/* /*
* We are guaranteed to succeed from here so can start modifying the * We are guaranteed to succeed from here so can start modifying the
* original runlist. * original runlist.
*/ */
if (left) if (left)
__ntfs_rl_merge(dst + loc - 1, src); __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. */ /* Move the tail of @dst out of the way, then copy in @src. */
ntfs_rl_mm(dst, magic, loc, dsize - loc); ntfs_rl_mm(dst, marker, loc, dsize - loc);
ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left); ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
/* Adjust the VCN of the last run ... */ /* Adjust the VCN of the first run after the insertion... */
if (dst[magic].lcn <= LCN_HOLE) dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
/* ... and the length. */ /* ... and the length. */
if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED) if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn; 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 (disc) {
if (hole)
dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn;
else {
if (loc > 0) { if (loc > 0) {
dst[loc].vcn = dst[loc - 1].vcn + dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
dst[loc - 1].length; dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
dst[loc].length = dst[loc + 1].vcn -
dst[loc].vcn;
} else { } else {
dst[loc].vcn = 0; dst[loc].vcn = 0;
dst[loc].length = dst[loc + 1].vcn; dst[loc].length = dst[loc + 1].vcn;
} }
dst[loc].lcn = LCN_RL_NOT_MAPPED; 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; return dst;
} }
...@@ -385,9 +376,10 @@ static inline runlist_element *ntfs_rl_insert(runlist_element *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, static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc) int dsize, runlist_element *src, int ssize, int loc)
{ {
BOOL left = FALSE; BOOL left = FALSE; /* Left end of @src needs merging. */
BOOL right; BOOL right; /* Right end of @src needs merging. */
int magic; int tail; /* Start of tail of @dst. */
int marker; /* End of the inserted runs. */
BUG_ON(!dst); BUG_ON(!dst);
BUG_ON(!src); BUG_ON(!src);
...@@ -396,9 +388,10 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, ...@@ -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); right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
if (loc > 0) if (loc > 0)
left = ntfs_are_rl_mergeable(dst + loc - 1, src); left = ntfs_are_rl_mergeable(dst + loc - 1, src);
/*
/* Allocate some space. We'll need less if the left, right, or both * Allocate some space. We will need less if the left, right, or both
* ends were merged. */ * ends were merged.
*/
dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right); dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);
if (IS_ERR(dst)) if (IS_ERR(dst))
return dst; return dst;
...@@ -410,17 +403,28 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst, ...@@ -410,17 +403,28 @@ static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
__ntfs_rl_merge(src + ssize - 1, dst + loc + 1); __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
if (left) if (left)
__ntfs_rl_merge(dst + loc - 1, src); __ntfs_rl_merge(dst + loc - 1, src);
/*
/* FIXME: What does this mean? (AIA) */ * First run of @dst that needs to be moved out of the way to make
magic = loc + ssize - left; * 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. */ /* 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); ntfs_rl_mc(dst, loc, src, left, ssize - left);
/* We may have changed the length of the file, so fix the end marker */ /* We may have changed the length of the file, so fix the end marker. */
if (dst[magic].lcn == LCN_ENOENT) if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)
dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length; dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
return dst; return dst;
} }
......
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