mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 03:10:12 +00:00
![Denis Efremov](/assets/img/avatar_default.png)
"likely(!IS_ERR(x))" is excessive. IS_ERR() already uses unlikely() internally. Link: http://lkml.kernel.org/r/20190829165025.15750-11-efremov@linux.com Signed-off-by: Denis Efremov <efremov@linux.com> Cc: Anton Altaparmakov <anton@tuxera.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1893 lines
59 KiB
C
1893 lines
59 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/**
|
|
* runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
|
|
*
|
|
* Copyright (c) 2001-2007 Anton Altaparmakov
|
|
* Copyright (c) 2002-2005 Richard Russon
|
|
*/
|
|
|
|
#include "debug.h"
|
|
#include "dir.h"
|
|
#include "endian.h"
|
|
#include "malloc.h"
|
|
#include "ntfs.h"
|
|
|
|
/**
|
|
* ntfs_rl_mm - runlist memmove
|
|
*
|
|
* It is up to the caller to serialize access to the runlist @base.
|
|
*/
|
|
static inline void ntfs_rl_mm(runlist_element *base, int dst, int src,
|
|
int size)
|
|
{
|
|
if (likely((dst != src) && (size > 0)))
|
|
memmove(base + dst, base + src, size * sizeof(*base));
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_mc - runlist memory copy
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dstbase and
|
|
* @srcbase.
|
|
*/
|
|
static inline void ntfs_rl_mc(runlist_element *dstbase, int dst,
|
|
runlist_element *srcbase, int src, int size)
|
|
{
|
|
if (likely(size > 0))
|
|
memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase));
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_realloc - Reallocate memory for runlists
|
|
* @rl: original runlist
|
|
* @old_size: number of runlist elements in the original runlist @rl
|
|
* @new_size: number of runlist elements we need space for
|
|
*
|
|
* As the runlists grow, more memory will be required. To prevent the
|
|
* kernel having to allocate and reallocate large numbers of small bits of
|
|
* memory, this function returns an entire page of memory.
|
|
*
|
|
* It is up to the caller to serialize access to the runlist @rl.
|
|
*
|
|
* N.B. If the new allocation doesn't require a different number of pages in
|
|
* memory, the function will return the original pointer.
|
|
*
|
|
* On success, return a pointer to the newly allocated, or recycled, memory.
|
|
* On error, return -errno. The following error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_realloc(runlist_element *rl,
|
|
int old_size, int new_size)
|
|
{
|
|
runlist_element *new_rl;
|
|
|
|
old_size = PAGE_ALIGN(old_size * sizeof(*rl));
|
|
new_size = PAGE_ALIGN(new_size * sizeof(*rl));
|
|
if (old_size == new_size)
|
|
return rl;
|
|
|
|
new_rl = ntfs_malloc_nofs(new_size);
|
|
if (unlikely(!new_rl))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (likely(rl != NULL)) {
|
|
if (unlikely(old_size > new_size))
|
|
old_size = new_size;
|
|
memcpy(new_rl, rl, old_size);
|
|
ntfs_free(rl);
|
|
}
|
|
return new_rl;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_realloc_nofail - Reallocate memory for runlists
|
|
* @rl: original runlist
|
|
* @old_size: number of runlist elements in the original runlist @rl
|
|
* @new_size: number of runlist elements we need space for
|
|
*
|
|
* As the runlists grow, more memory will be required. To prevent the
|
|
* kernel having to allocate and reallocate large numbers of small bits of
|
|
* memory, this function returns an entire page of memory.
|
|
*
|
|
* This function guarantees that the allocation will succeed. It will sleep
|
|
* for as long as it takes to complete the allocation.
|
|
*
|
|
* It is up to the caller to serialize access to the runlist @rl.
|
|
*
|
|
* N.B. If the new allocation doesn't require a different number of pages in
|
|
* memory, the function will return the original pointer.
|
|
*
|
|
* On success, return a pointer to the newly allocated, or recycled, memory.
|
|
* On error, return -errno. The following error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl,
|
|
int old_size, int new_size)
|
|
{
|
|
runlist_element *new_rl;
|
|
|
|
old_size = PAGE_ALIGN(old_size * sizeof(*rl));
|
|
new_size = PAGE_ALIGN(new_size * sizeof(*rl));
|
|
if (old_size == new_size)
|
|
return rl;
|
|
|
|
new_rl = ntfs_malloc_nofs_nofail(new_size);
|
|
BUG_ON(!new_rl);
|
|
|
|
if (likely(rl != NULL)) {
|
|
if (unlikely(old_size > new_size))
|
|
old_size = new_size;
|
|
memcpy(new_rl, rl, old_size);
|
|
ntfs_free(rl);
|
|
}
|
|
return new_rl;
|
|
}
|
|
|
|
/**
|
|
* ntfs_are_rl_mergeable - test if two runlists can be joined together
|
|
* @dst: original runlist
|
|
* @src: new runlist to test for mergeability with @dst
|
|
*
|
|
* Test if two runlists can be joined together. For this, their VCNs and LCNs
|
|
* must be adjacent.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*
|
|
* Return: true Success, the runlists can be merged.
|
|
* false Failure, the runlists cannot be merged.
|
|
*/
|
|
static inline bool ntfs_are_rl_mergeable(runlist_element *dst,
|
|
runlist_element *src)
|
|
{
|
|
BUG_ON(!dst);
|
|
BUG_ON(!src);
|
|
|
|
/* We can merge unmapped regions even if they are misaligned. */
|
|
if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED))
|
|
return true;
|
|
/* If the runs are misaligned, we cannot merge them. */
|
|
if ((dst->vcn + dst->length) != src->vcn)
|
|
return false;
|
|
/* If both runs are non-sparse and contiguous, we can merge them. */
|
|
if ((dst->lcn >= 0) && (src->lcn >= 0) &&
|
|
((dst->lcn + dst->length) == src->lcn))
|
|
return true;
|
|
/* If we are merging two holes, we can merge them. */
|
|
if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE))
|
|
return true;
|
|
/* Cannot merge. */
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* __ntfs_rl_merge - merge two runlists without testing if they can be merged
|
|
* @dst: original, destination runlist
|
|
* @src: new runlist to merge with @dst
|
|
*
|
|
* Merge the two runlists, writing into the destination runlist @dst. The
|
|
* caller must make sure the runlists can be merged or this will corrupt the
|
|
* destination runlist.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*/
|
|
static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
|
|
{
|
|
dst->length += src->length;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_append - append a runlist after a given element
|
|
* @dst: original runlist to be worked on
|
|
* @dsize: number of elements in @dst (including end marker)
|
|
* @src: runlist to be inserted into @dst
|
|
* @ssize: number of elements in @src (excluding end marker)
|
|
* @loc: append the new runlist @src after this element in @dst
|
|
*
|
|
* Append the runlist @src after element @loc in @dst. Merge the right end of
|
|
* the new runlist, if necessary. Adjust the size of the hole before the
|
|
* appended runlist.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*
|
|
* On success, return a pointer to the new, combined, runlist. Note, both
|
|
* runlists @dst and @src are deallocated before returning so you cannot use
|
|
* the pointers for anything any more. (Strictly speaking the returned runlist
|
|
* may be the same as @dst but this is irrelevant.)
|
|
*
|
|
* On error, return -errno. Both runlists are left unmodified. The following
|
|
* error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_append(runlist_element *dst,
|
|
int dsize, runlist_element *src, int ssize, int loc)
|
|
{
|
|
bool right = false; /* Right end of @src needs merging. */
|
|
int marker; /* End of the inserted runs. */
|
|
|
|
BUG_ON(!dst);
|
|
BUG_ON(!src);
|
|
|
|
/* First, check if the right hand end needs merging. */
|
|
if ((loc + 1) < dsize)
|
|
right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
|
|
|
|
/* Space required: @dst size + @src size, less one if we merged. */
|
|
dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right);
|
|
if (IS_ERR(dst))
|
|
return dst;
|
|
/*
|
|
* We are guaranteed to succeed from here so can start modifying the
|
|
* original runlists.
|
|
*/
|
|
|
|
/* First, merge the right hand end, if necessary. */
|
|
if (right)
|
|
__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
|
|
|
|
/* 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, 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[marker].lcn == LCN_ENOENT)
|
|
dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
|
|
|
|
return dst;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_insert - insert a runlist into another
|
|
* @dst: original runlist to be worked on
|
|
* @dsize: number of elements in @dst (including end marker)
|
|
* @src: new runlist to be inserted
|
|
* @ssize: number of elements in @src (excluding end marker)
|
|
* @loc: insert the new runlist @src before this element in @dst
|
|
*
|
|
* Insert the runlist @src before element @loc in the runlist @dst. Merge the
|
|
* left end of the new runlist, if necessary. Adjust the size of the hole
|
|
* after the inserted runlist.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*
|
|
* On success, return a pointer to the new, combined, runlist. Note, both
|
|
* runlists @dst and @src are deallocated before returning so you cannot use
|
|
* the pointers for anything any more. (Strictly speaking the returned runlist
|
|
* may be the same as @dst but this is irrelevant.)
|
|
*
|
|
* On error, return -errno. Both runlists are left unmodified. The following
|
|
* error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
|
|
int dsize, runlist_element *src, int ssize, int loc)
|
|
{
|
|
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 "not mapped" run.
|
|
*/
|
|
if (loc == 0)
|
|
disc = (src[0].vcn > 0);
|
|
else {
|
|
s64 merged_length;
|
|
|
|
left = ntfs_are_rl_mergeable(dst + loc - 1, src);
|
|
|
|
merged_length = dst[loc - 1].length;
|
|
if (left)
|
|
merged_length += src->length;
|
|
|
|
disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
|
|
}
|
|
/*
|
|
* 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);
|
|
/*
|
|
* 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, marker, loc, dsize - loc);
|
|
ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
|
|
|
|
/* 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[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 is a discontinuity. */
|
|
if (disc) {
|
|
if (loc > 0) {
|
|
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;
|
|
}
|
|
return dst;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_replace - overwrite a runlist element with another runlist
|
|
* @dst: original runlist to be worked on
|
|
* @dsize: number of elements in @dst (including end marker)
|
|
* @src: new runlist to be inserted
|
|
* @ssize: number of elements in @src (excluding end marker)
|
|
* @loc: index in runlist @dst to overwrite with @src
|
|
*
|
|
* Replace the runlist element @dst at @loc with @src. Merge the left and
|
|
* right ends of the inserted runlist, if necessary.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*
|
|
* On success, return a pointer to the new, combined, runlist. Note, both
|
|
* runlists @dst and @src are deallocated before returning so you cannot use
|
|
* the pointers for anything any more. (Strictly speaking the returned runlist
|
|
* may be the same as @dst but this is irrelevant.)
|
|
*
|
|
* On error, return -errno. Both runlists are left unmodified. The following
|
|
* error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
|
|
int dsize, runlist_element *src, int ssize, int loc)
|
|
{
|
|
signed delta;
|
|
bool left = false; /* Left end of @src needs merging. */
|
|
bool right = false; /* 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);
|
|
|
|
/* First, see if the left and right ends need merging. */
|
|
if ((loc + 1) < dsize)
|
|
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 will need less if the left, right, or both
|
|
* ends get merged. The -1 accounts for the run being replaced.
|
|
*/
|
|
delta = ssize - 1 - left - right;
|
|
if (delta > 0) {
|
|
dst = ntfs_rl_realloc(dst, dsize, dsize + delta);
|
|
if (IS_ERR(dst))
|
|
return dst;
|
|
}
|
|
/*
|
|
* We are guaranteed to succeed from here so can start modifying the
|
|
* original runlists.
|
|
*/
|
|
|
|
/* First, merge the left and right ends, if necessary. */
|
|
if (right)
|
|
__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
|
|
if (left)
|
|
__ntfs_rl_merge(dst + loc - 1, src);
|
|
/*
|
|
* Offset of the tail of @dst. This 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.
|
|
* Nominally, @tail equals @loc + 1, i.e. location, skipping the
|
|
* replaced run. However, if @right, then one of @dst's runs is
|
|
* already merged into @src.
|
|
*/
|
|
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, 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 (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)
|
|
dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
|
|
return dst;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_split - insert a runlist into the centre of a hole
|
|
* @dst: original runlist to be worked on
|
|
* @dsize: number of elements in @dst (including end marker)
|
|
* @src: new runlist to be inserted
|
|
* @ssize: number of elements in @src (excluding end marker)
|
|
* @loc: index in runlist @dst at which to split and insert @src
|
|
*
|
|
* Split the runlist @dst at @loc into two and insert @new in between the two
|
|
* fragments. No merging of runlists is necessary. Adjust the size of the
|
|
* holes either side.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @dst and @src.
|
|
*
|
|
* On success, return a pointer to the new, combined, runlist. Note, both
|
|
* runlists @dst and @src are deallocated before returning so you cannot use
|
|
* the pointers for anything any more. (Strictly speaking the returned runlist
|
|
* may be the same as @dst but this is irrelevant.)
|
|
*
|
|
* On error, return -errno. Both runlists are left unmodified. The following
|
|
* error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
*/
|
|
static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize,
|
|
runlist_element *src, int ssize, int loc)
|
|
{
|
|
BUG_ON(!dst);
|
|
BUG_ON(!src);
|
|
|
|
/* Space required: @dst size + @src size + one new hole. */
|
|
dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1);
|
|
if (IS_ERR(dst))
|
|
return dst;
|
|
/*
|
|
* We are guaranteed to succeed from here so can start modifying the
|
|
* original runlists.
|
|
*/
|
|
|
|
/* Move the tail of @dst out of the way, then copy in @src. */
|
|
ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc);
|
|
ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
|
|
|
|
/* Adjust the size of the holes either size of @src. */
|
|
dst[loc].length = dst[loc+1].vcn - dst[loc].vcn;
|
|
dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length;
|
|
dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;
|
|
|
|
return dst;
|
|
}
|
|
|
|
/**
|
|
* ntfs_runlists_merge - merge two runlists into one
|
|
* @drl: original runlist to be worked on
|
|
* @srl: new runlist to be merged into @drl
|
|
*
|
|
* First we sanity check the two runlists @srl and @drl to make sure that they
|
|
* are sensible and can be merged. The runlist @srl must be either after the
|
|
* runlist @drl or completely within a hole (or unmapped region) in @drl.
|
|
*
|
|
* It is up to the caller to serialize access to the runlists @drl and @srl.
|
|
*
|
|
* Merging of runlists is necessary in two cases:
|
|
* 1. When attribute lists are used and a further extent is being mapped.
|
|
* 2. When new clusters are allocated to fill a hole or extend a file.
|
|
*
|
|
* There are four possible ways @srl can be merged. It can:
|
|
* - be inserted at the beginning of a hole,
|
|
* - split the hole in two and be inserted between the two fragments,
|
|
* - be appended at the end of a hole, or it can
|
|
* - replace the whole hole.
|
|
* It can also be appended to the end of the runlist, which is just a variant
|
|
* of the insert case.
|
|
*
|
|
* On success, return a pointer to the new, combined, runlist. Note, both
|
|
* runlists @drl and @srl are deallocated before returning so you cannot use
|
|
* the pointers for anything any more. (Strictly speaking the returned runlist
|
|
* may be the same as @dst but this is irrelevant.)
|
|
*
|
|
* On error, return -errno. Both runlists are left unmodified. The following
|
|
* error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
* -ERANGE - The runlists overlap and cannot be merged.
|
|
*/
|
|
runlist_element *ntfs_runlists_merge(runlist_element *drl,
|
|
runlist_element *srl)
|
|
{
|
|
int di, si; /* Current index into @[ds]rl. */
|
|
int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */
|
|
int dins; /* Index into @drl at which to insert @srl. */
|
|
int dend, send; /* Last index into @[ds]rl. */
|
|
int dfinal, sfinal; /* The last index into @[ds]rl with
|
|
lcn >= LCN_HOLE. */
|
|
int marker = 0;
|
|
VCN marker_vcn = 0;
|
|
|
|
#ifdef DEBUG
|
|
ntfs_debug("dst:");
|
|
ntfs_debug_dump_runlist(drl);
|
|
ntfs_debug("src:");
|
|
ntfs_debug_dump_runlist(srl);
|
|
#endif
|
|
|
|
/* Check for silly calling... */
|
|
if (unlikely(!srl))
|
|
return drl;
|
|
if (IS_ERR(srl) || IS_ERR(drl))
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/* Check for the case where the first mapping is being done now. */
|
|
if (unlikely(!drl)) {
|
|
drl = srl;
|
|
/* Complete the source runlist if necessary. */
|
|
if (unlikely(drl[0].vcn)) {
|
|
/* Scan to the end of the source runlist. */
|
|
for (dend = 0; likely(drl[dend].length); dend++)
|
|
;
|
|
dend++;
|
|
drl = ntfs_rl_realloc(drl, dend, dend + 1);
|
|
if (IS_ERR(drl))
|
|
return drl;
|
|
/* Insert start element at the front of the runlist. */
|
|
ntfs_rl_mm(drl, 1, 0, dend);
|
|
drl[0].vcn = 0;
|
|
drl[0].lcn = LCN_RL_NOT_MAPPED;
|
|
drl[0].length = drl[1].vcn;
|
|
}
|
|
goto finished;
|
|
}
|
|
|
|
si = di = 0;
|
|
|
|
/* Skip any unmapped start element(s) in the source runlist. */
|
|
while (srl[si].length && srl[si].lcn < LCN_HOLE)
|
|
si++;
|
|
|
|
/* Can't have an entirely unmapped source runlist. */
|
|
BUG_ON(!srl[si].length);
|
|
|
|
/* Record the starting points. */
|
|
sstart = si;
|
|
|
|
/*
|
|
* Skip forward in @drl until we reach the position where @srl needs to
|
|
* be inserted. If we reach the end of @drl, @srl just needs to be
|
|
* appended to @drl.
|
|
*/
|
|
for (; drl[di].length; di++) {
|
|
if (drl[di].vcn + drl[di].length > srl[sstart].vcn)
|
|
break;
|
|
}
|
|
dins = di;
|
|
|
|
/* Sanity check for illegal overlaps. */
|
|
if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) &&
|
|
(srl[si].lcn >= 0)) {
|
|
ntfs_error(NULL, "Run lists overlap. Cannot merge!");
|
|
return ERR_PTR(-ERANGE);
|
|
}
|
|
|
|
/* Scan to the end of both runlists in order to know their sizes. */
|
|
for (send = si; srl[send].length; send++)
|
|
;
|
|
for (dend = di; drl[dend].length; dend++)
|
|
;
|
|
|
|
if (srl[send].lcn == LCN_ENOENT)
|
|
marker_vcn = srl[marker = send].vcn;
|
|
|
|
/* Scan to the last element with lcn >= LCN_HOLE. */
|
|
for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--)
|
|
;
|
|
for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--)
|
|
;
|
|
|
|
{
|
|
bool start;
|
|
bool finish;
|
|
int ds = dend + 1; /* Number of elements in drl & srl */
|
|
int ss = sfinal - sstart + 1;
|
|
|
|
start = ((drl[dins].lcn < LCN_RL_NOT_MAPPED) || /* End of file */
|
|
(drl[dins].vcn == srl[sstart].vcn)); /* Start of hole */
|
|
finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) && /* End of file */
|
|
((drl[dins].vcn + drl[dins].length) <= /* End of hole */
|
|
(srl[send - 1].vcn + srl[send - 1].length)));
|
|
|
|
/* Or we will lose an end marker. */
|
|
if (finish && !drl[dins].length)
|
|
ss++;
|
|
if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn))
|
|
finish = false;
|
|
#if 0
|
|
ntfs_debug("dfinal = %i, dend = %i", dfinal, dend);
|
|
ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart, sfinal, send);
|
|
ntfs_debug("start = %i, finish = %i", start, finish);
|
|
ntfs_debug("ds = %i, ss = %i, dins = %i", ds, ss, dins);
|
|
#endif
|
|
if (start) {
|
|
if (finish)
|
|
drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins);
|
|
else
|
|
drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins);
|
|
} else {
|
|
if (finish)
|
|
drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins);
|
|
else
|
|
drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins);
|
|
}
|
|
if (IS_ERR(drl)) {
|
|
ntfs_error(NULL, "Merge failed.");
|
|
return drl;
|
|
}
|
|
ntfs_free(srl);
|
|
if (marker) {
|
|
ntfs_debug("Triggering marker code.");
|
|
for (ds = dend; drl[ds].length; ds++)
|
|
;
|
|
/* We only need to care if @srl ended after @drl. */
|
|
if (drl[ds].vcn <= marker_vcn) {
|
|
int slots = 0;
|
|
|
|
if (drl[ds].vcn == marker_vcn) {
|
|
ntfs_debug("Old marker = 0x%llx, replacing "
|
|
"with LCN_ENOENT.",
|
|
(unsigned long long)
|
|
drl[ds].lcn);
|
|
drl[ds].lcn = LCN_ENOENT;
|
|
goto finished;
|
|
}
|
|
/*
|
|
* We need to create an unmapped runlist element in
|
|
* @drl or extend an existing one before adding the
|
|
* ENOENT terminator.
|
|
*/
|
|
if (drl[ds].lcn == LCN_ENOENT) {
|
|
ds--;
|
|
slots = 1;
|
|
}
|
|
if (drl[ds].lcn != LCN_RL_NOT_MAPPED) {
|
|
/* Add an unmapped runlist element. */
|
|
if (!slots) {
|
|
drl = ntfs_rl_realloc_nofail(drl, ds,
|
|
ds + 2);
|
|
slots = 2;
|
|
}
|
|
ds++;
|
|
/* Need to set vcn if it isn't set already. */
|
|
if (slots != 1)
|
|
drl[ds].vcn = drl[ds - 1].vcn +
|
|
drl[ds - 1].length;
|
|
drl[ds].lcn = LCN_RL_NOT_MAPPED;
|
|
/* We now used up a slot. */
|
|
slots--;
|
|
}
|
|
drl[ds].length = marker_vcn - drl[ds].vcn;
|
|
/* Finally add the ENOENT terminator. */
|
|
ds++;
|
|
if (!slots)
|
|
drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1);
|
|
drl[ds].vcn = marker_vcn;
|
|
drl[ds].lcn = LCN_ENOENT;
|
|
drl[ds].length = (s64)0;
|
|
}
|
|
}
|
|
}
|
|
|
|
finished:
|
|
/* The merge was completed successfully. */
|
|
ntfs_debug("Merged runlist:");
|
|
ntfs_debug_dump_runlist(drl);
|
|
return drl;
|
|
}
|
|
|
|
/**
|
|
* ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
|
|
* @vol: ntfs volume on which the attribute resides
|
|
* @attr: attribute record whose mapping pairs array to decompress
|
|
* @old_rl: optional runlist in which to insert @attr's runlist
|
|
*
|
|
* It is up to the caller to serialize access to the runlist @old_rl.
|
|
*
|
|
* Decompress the attribute @attr's mapping pairs array into a runlist. On
|
|
* success, return the decompressed runlist.
|
|
*
|
|
* If @old_rl is not NULL, decompressed runlist is inserted into the
|
|
* appropriate place in @old_rl and the resultant, combined runlist is
|
|
* returned. The original @old_rl is deallocated.
|
|
*
|
|
* On error, return -errno. @old_rl is left unmodified in that case.
|
|
*
|
|
* The following error codes are defined:
|
|
* -ENOMEM - Not enough memory to allocate runlist array.
|
|
* -EIO - Corrupt runlist.
|
|
* -EINVAL - Invalid parameters were passed in.
|
|
* -ERANGE - The two runlists overlap.
|
|
*
|
|
* FIXME: For now we take the conceptionally simplest approach of creating the
|
|
* new runlist disregarding the already existing one and then splicing the
|
|
* two into one, if that is possible (we check for overlap and discard the new
|
|
* runlist if overlap present before returning ERR_PTR(-ERANGE)).
|
|
*/
|
|
runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
|
|
const ATTR_RECORD *attr, runlist_element *old_rl)
|
|
{
|
|
VCN vcn; /* Current vcn. */
|
|
LCN lcn; /* Current lcn. */
|
|
s64 deltaxcn; /* Change in [vl]cn. */
|
|
runlist_element *rl; /* The output runlist. */
|
|
u8 *buf; /* Current position in mapping pairs array. */
|
|
u8 *attr_end; /* End of attribute. */
|
|
int rlsize; /* Size of runlist buffer. */
|
|
u16 rlpos; /* Current runlist position in units of
|
|
runlist_elements. */
|
|
u8 b; /* Current byte offset in buf. */
|
|
|
|
#ifdef DEBUG
|
|
/* Make sure attr exists and is non-resident. */
|
|
if (!attr || !attr->non_resident || sle64_to_cpu(
|
|
attr->data.non_resident.lowest_vcn) < (VCN)0) {
|
|
ntfs_error(vol->sb, "Invalid arguments.");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
#endif
|
|
/* Start at vcn = lowest_vcn and lcn 0. */
|
|
vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn);
|
|
lcn = 0;
|
|
/* Get start of the mapping pairs array. */
|
|
buf = (u8*)attr + le16_to_cpu(
|
|
attr->data.non_resident.mapping_pairs_offset);
|
|
attr_end = (u8*)attr + le32_to_cpu(attr->length);
|
|
if (unlikely(buf < (u8*)attr || buf > attr_end)) {
|
|
ntfs_error(vol->sb, "Corrupt attribute.");
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
/* If the mapping pairs array is valid but empty, nothing to do. */
|
|
if (!vcn && !*buf)
|
|
return old_rl;
|
|
/* Current position in runlist array. */
|
|
rlpos = 0;
|
|
/* Allocate first page and set current runlist size to one page. */
|
|
rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE);
|
|
if (unlikely(!rl))
|
|
return ERR_PTR(-ENOMEM);
|
|
/* Insert unmapped starting element if necessary. */
|
|
if (vcn) {
|
|
rl->vcn = 0;
|
|
rl->lcn = LCN_RL_NOT_MAPPED;
|
|
rl->length = vcn;
|
|
rlpos++;
|
|
}
|
|
while (buf < attr_end && *buf) {
|
|
/*
|
|
* Allocate more memory if needed, including space for the
|
|
* not-mapped and terminator elements. ntfs_malloc_nofs()
|
|
* operates on whole pages only.
|
|
*/
|
|
if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) {
|
|
runlist_element *rl2;
|
|
|
|
rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
|
|
if (unlikely(!rl2)) {
|
|
ntfs_free(rl);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
memcpy(rl2, rl, rlsize);
|
|
ntfs_free(rl);
|
|
rl = rl2;
|
|
rlsize += PAGE_SIZE;
|
|
}
|
|
/* Enter the current vcn into the current runlist element. */
|
|
rl[rlpos].vcn = vcn;
|
|
/*
|
|
* Get the change in vcn, i.e. the run length in clusters.
|
|
* Doing it this way ensures that we signextend negative values.
|
|
* A negative run length doesn't make any sense, but hey, I
|
|
* didn't make up the NTFS specs and Windows NT4 treats the run
|
|
* length as a signed value so that's how it is...
|
|
*/
|
|
b = *buf & 0xf;
|
|
if (b) {
|
|
if (unlikely(buf + b > attr_end))
|
|
goto io_error;
|
|
for (deltaxcn = (s8)buf[b--]; b; b--)
|
|
deltaxcn = (deltaxcn << 8) + buf[b];
|
|
} else { /* The length entry is compulsory. */
|
|
ntfs_error(vol->sb, "Missing length entry in mapping "
|
|
"pairs array.");
|
|
deltaxcn = (s64)-1;
|
|
}
|
|
/*
|
|
* Assume a negative length to indicate data corruption and
|
|
* hence clean-up and return NULL.
|
|
*/
|
|
if (unlikely(deltaxcn < 0)) {
|
|
ntfs_error(vol->sb, "Invalid length in mapping pairs "
|
|
"array.");
|
|
goto err_out;
|
|
}
|
|
/*
|
|
* Enter the current run length into the current runlist
|
|
* element.
|
|
*/
|
|
rl[rlpos].length = deltaxcn;
|
|
/* Increment the current vcn by the current run length. */
|
|
vcn += deltaxcn;
|
|
/*
|
|
* There might be no lcn change at all, as is the case for
|
|
* sparse clusters on NTFS 3.0+, in which case we set the lcn
|
|
* to LCN_HOLE.
|
|
*/
|
|
if (!(*buf & 0xf0))
|
|
rl[rlpos].lcn = LCN_HOLE;
|
|
else {
|
|
/* Get the lcn change which really can be negative. */
|
|
u8 b2 = *buf & 0xf;
|
|
b = b2 + ((*buf >> 4) & 0xf);
|
|
if (buf + b > attr_end)
|
|
goto io_error;
|
|
for (deltaxcn = (s8)buf[b--]; b > b2; b--)
|
|
deltaxcn = (deltaxcn << 8) + buf[b];
|
|
/* Change the current lcn to its new value. */
|
|
lcn += deltaxcn;
|
|
#ifdef DEBUG
|
|
/*
|
|
* On NTFS 1.2-, apparently can have lcn == -1 to
|
|
* indicate a hole. But we haven't verified ourselves
|
|
* whether it is really the lcn or the deltaxcn that is
|
|
* -1. So if either is found give us a message so we
|
|
* can investigate it further!
|
|
*/
|
|
if (vol->major_ver < 3) {
|
|
if (unlikely(deltaxcn == (LCN)-1))
|
|
ntfs_error(vol->sb, "lcn delta == -1");
|
|
if (unlikely(lcn == (LCN)-1))
|
|
ntfs_error(vol->sb, "lcn == -1");
|
|
}
|
|
#endif
|
|
/* Check lcn is not below -1. */
|
|
if (unlikely(lcn < (LCN)-1)) {
|
|
ntfs_error(vol->sb, "Invalid LCN < -1 in "
|
|
"mapping pairs array.");
|
|
goto err_out;
|
|
}
|
|
/* Enter the current lcn into the runlist element. */
|
|
rl[rlpos].lcn = lcn;
|
|
}
|
|
/* Get to the next runlist element. */
|
|
rlpos++;
|
|
/* Increment the buffer position to the next mapping pair. */
|
|
buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1;
|
|
}
|
|
if (unlikely(buf >= attr_end))
|
|
goto io_error;
|
|
/*
|
|
* If there is a highest_vcn specified, it must be equal to the final
|
|
* vcn in the runlist - 1, or something has gone badly wrong.
|
|
*/
|
|
deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn);
|
|
if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) {
|
|
mpa_err:
|
|
ntfs_error(vol->sb, "Corrupt mapping pairs array in "
|
|
"non-resident attribute.");
|
|
goto err_out;
|
|
}
|
|
/* Setup not mapped runlist element if this is the base extent. */
|
|
if (!attr->data.non_resident.lowest_vcn) {
|
|
VCN max_cluster;
|
|
|
|
max_cluster = ((sle64_to_cpu(
|
|
attr->data.non_resident.allocated_size) +
|
|
vol->cluster_size - 1) >>
|
|
vol->cluster_size_bits) - 1;
|
|
/*
|
|
* A highest_vcn of zero means this is a single extent
|
|
* attribute so simply terminate the runlist with LCN_ENOENT).
|
|
*/
|
|
if (deltaxcn) {
|
|
/*
|
|
* If there is a difference between the highest_vcn and
|
|
* the highest cluster, the runlist is either corrupt
|
|
* or, more likely, there are more extents following
|
|
* this one.
|
|
*/
|
|
if (deltaxcn < max_cluster) {
|
|
ntfs_debug("More extents to follow; deltaxcn "
|
|
"= 0x%llx, max_cluster = "
|
|
"0x%llx",
|
|
(unsigned long long)deltaxcn,
|
|
(unsigned long long)
|
|
max_cluster);
|
|
rl[rlpos].vcn = vcn;
|
|
vcn += rl[rlpos].length = max_cluster -
|
|
deltaxcn;
|
|
rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
|
|
rlpos++;
|
|
} else if (unlikely(deltaxcn > max_cluster)) {
|
|
ntfs_error(vol->sb, "Corrupt attribute. "
|
|
"deltaxcn = 0x%llx, "
|
|
"max_cluster = 0x%llx",
|
|
(unsigned long long)deltaxcn,
|
|
(unsigned long long)
|
|
max_cluster);
|
|
goto mpa_err;
|
|
}
|
|
}
|
|
rl[rlpos].lcn = LCN_ENOENT;
|
|
} else /* Not the base extent. There may be more extents to follow. */
|
|
rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
|
|
|
|
/* Setup terminating runlist element. */
|
|
rl[rlpos].vcn = vcn;
|
|
rl[rlpos].length = (s64)0;
|
|
/* If no existing runlist was specified, we are done. */
|
|
if (!old_rl) {
|
|
ntfs_debug("Mapping pairs array successfully decompressed:");
|
|
ntfs_debug_dump_runlist(rl);
|
|
return rl;
|
|
}
|
|
/* Now combine the new and old runlists checking for overlaps. */
|
|
old_rl = ntfs_runlists_merge(old_rl, rl);
|
|
if (!IS_ERR(old_rl))
|
|
return old_rl;
|
|
ntfs_free(rl);
|
|
ntfs_error(vol->sb, "Failed to merge runlists.");
|
|
return old_rl;
|
|
io_error:
|
|
ntfs_error(vol->sb, "Corrupt attribute.");
|
|
err_out:
|
|
ntfs_free(rl);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
|
|
* @rl: runlist to use for conversion
|
|
* @vcn: vcn to convert
|
|
*
|
|
* Convert the virtual cluster number @vcn of an attribute into a logical
|
|
* cluster number (lcn) of a device using the runlist @rl to map vcns to their
|
|
* corresponding lcns.
|
|
*
|
|
* It is up to the caller to serialize access to the runlist @rl.
|
|
*
|
|
* Since lcns must be >= 0, we use negative return codes with special meaning:
|
|
*
|
|
* Return code Meaning / Description
|
|
* ==================================================
|
|
* LCN_HOLE Hole / not allocated on disk.
|
|
* LCN_RL_NOT_MAPPED This is part of the runlist which has not been
|
|
* inserted into the runlist yet.
|
|
* LCN_ENOENT There is no such vcn in the attribute.
|
|
*
|
|
* Locking: - The caller must have locked the runlist (for reading or writing).
|
|
* - This function does not touch the lock, nor does it modify the
|
|
* runlist.
|
|
*/
|
|
LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
|
|
{
|
|
int i;
|
|
|
|
BUG_ON(vcn < 0);
|
|
/*
|
|
* If rl is NULL, assume that we have found an unmapped runlist. The
|
|
* caller can then attempt to map it and fail appropriately if
|
|
* necessary.
|
|
*/
|
|
if (unlikely(!rl))
|
|
return LCN_RL_NOT_MAPPED;
|
|
|
|
/* Catch out of lower bounds vcn. */
|
|
if (unlikely(vcn < rl[0].vcn))
|
|
return LCN_ENOENT;
|
|
|
|
for (i = 0; likely(rl[i].length); i++) {
|
|
if (unlikely(vcn < rl[i+1].vcn)) {
|
|
if (likely(rl[i].lcn >= (LCN)0))
|
|
return rl[i].lcn + (vcn - rl[i].vcn);
|
|
return rl[i].lcn;
|
|
}
|
|
}
|
|
/*
|
|
* The terminator element is setup to the correct value, i.e. one of
|
|
* LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
|
|
*/
|
|
if (likely(rl[i].lcn < (LCN)0))
|
|
return rl[i].lcn;
|
|
/* Just in case... We could replace this with BUG() some day. */
|
|
return LCN_ENOENT;
|
|
}
|
|
|
|
#ifdef NTFS_RW
|
|
|
|
/**
|
|
* ntfs_rl_find_vcn_nolock - find a vcn in a runlist
|
|
* @rl: runlist to search
|
|
* @vcn: vcn to find
|
|
*
|
|
* Find the virtual cluster number @vcn in the runlist @rl and return the
|
|
* address of the runlist element containing the @vcn on success.
|
|
*
|
|
* Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of
|
|
* the runlist.
|
|
*
|
|
* Locking: The runlist must be locked on entry.
|
|
*/
|
|
runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl, const VCN vcn)
|
|
{
|
|
BUG_ON(vcn < 0);
|
|
if (unlikely(!rl || vcn < rl[0].vcn))
|
|
return NULL;
|
|
while (likely(rl->length)) {
|
|
if (unlikely(vcn < rl[1].vcn)) {
|
|
if (likely(rl->lcn >= LCN_HOLE))
|
|
return rl;
|
|
return NULL;
|
|
}
|
|
rl++;
|
|
}
|
|
if (likely(rl->lcn == LCN_ENOENT))
|
|
return rl;
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
|
|
* @n: number for which to get the number of bytes for
|
|
*
|
|
* Return the number of bytes required to store @n unambiguously as
|
|
* a signed number.
|
|
*
|
|
* This is used in the context of the mapping pairs array to determine how
|
|
* many bytes will be needed in the array to store a given logical cluster
|
|
* number (lcn) or a specific run length.
|
|
*
|
|
* Return the number of bytes written. This function cannot fail.
|
|
*/
|
|
static inline int ntfs_get_nr_significant_bytes(const s64 n)
|
|
{
|
|
s64 l = n;
|
|
int i;
|
|
s8 j;
|
|
|
|
i = 0;
|
|
do {
|
|
l >>= 8;
|
|
i++;
|
|
} while (l != 0 && l != -1);
|
|
j = (n >> 8 * (i - 1)) & 0xff;
|
|
/* If the sign bit is wrong, we need an extra byte. */
|
|
if ((n < 0 && j >= 0) || (n > 0 && j < 0))
|
|
i++;
|
|
return i;
|
|
}
|
|
|
|
/**
|
|
* ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
|
|
* @vol: ntfs volume (needed for the ntfs version)
|
|
* @rl: locked runlist to determine the size of the mapping pairs of
|
|
* @first_vcn: first vcn which to include in the mapping pairs array
|
|
* @last_vcn: last vcn which to include in the mapping pairs array
|
|
*
|
|
* Walk the locked runlist @rl and calculate the size in bytes of the mapping
|
|
* pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and
|
|
* finishing with vcn @last_vcn.
|
|
*
|
|
* A @last_vcn of -1 means end of runlist and in that case the size of the
|
|
* mapping pairs array corresponding to the runlist starting at vcn @first_vcn
|
|
* and finishing at the end of the runlist is determined.
|
|
*
|
|
* This for example allows us to allocate a buffer of the right size when
|
|
* building the mapping pairs array.
|
|
*
|
|
* If @rl is NULL, just return 1 (for the single terminator byte).
|
|
*
|
|
* Return the calculated size in bytes on success. On error, return -errno.
|
|
* The following error codes are defined:
|
|
* -EINVAL - Run list contains unmapped elements. Make sure to only pass
|
|
* fully mapped runlists to this function.
|
|
* -EIO - The runlist is corrupt.
|
|
*
|
|
* Locking: @rl must be locked on entry (either for reading or writing), it
|
|
* remains locked throughout, and is left locked upon return.
|
|
*/
|
|
int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
|
|
const runlist_element *rl, const VCN first_vcn,
|
|
const VCN last_vcn)
|
|
{
|
|
LCN prev_lcn;
|
|
int rls;
|
|
bool the_end = false;
|
|
|
|
BUG_ON(first_vcn < 0);
|
|
BUG_ON(last_vcn < -1);
|
|
BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
|
|
if (!rl) {
|
|
BUG_ON(first_vcn);
|
|
BUG_ON(last_vcn > 0);
|
|
return 1;
|
|
}
|
|
/* Skip to runlist element containing @first_vcn. */
|
|
while (rl->length && first_vcn >= rl[1].vcn)
|
|
rl++;
|
|
if (unlikely((!rl->length && first_vcn > rl->vcn) ||
|
|
first_vcn < rl->vcn))
|
|
return -EINVAL;
|
|
prev_lcn = 0;
|
|
/* Always need the termining zero byte. */
|
|
rls = 1;
|
|
/* Do the first partial run if present. */
|
|
if (first_vcn > rl->vcn) {
|
|
s64 delta, length = rl->length;
|
|
|
|
/* We know rl->length != 0 already. */
|
|
if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
|
|
goto err_out;
|
|
/*
|
|
* If @stop_vcn is given and finishes inside this run, cap the
|
|
* run length.
|
|
*/
|
|
if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
|
|
s64 s1 = last_vcn + 1;
|
|
if (unlikely(rl[1].vcn > s1))
|
|
length = s1 - rl->vcn;
|
|
the_end = true;
|
|
}
|
|
delta = first_vcn - rl->vcn;
|
|
/* Header byte + length. */
|
|
rls += 1 + ntfs_get_nr_significant_bytes(length - delta);
|
|
/*
|
|
* If the logical cluster number (lcn) denotes a hole and we
|
|
* are on NTFS 3.0+, we don't store it at all, i.e. we need
|
|
* zero space. On earlier NTFS versions we just store the lcn.
|
|
* Note: this assumes that on NTFS 1.2-, holes are stored with
|
|
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
|
|
*/
|
|
if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
|
|
prev_lcn = rl->lcn;
|
|
if (likely(rl->lcn >= 0))
|
|
prev_lcn += delta;
|
|
/* Change in lcn. */
|
|
rls += ntfs_get_nr_significant_bytes(prev_lcn);
|
|
}
|
|
/* Go to next runlist element. */
|
|
rl++;
|
|
}
|
|
/* Do the full runs. */
|
|
for (; rl->length && !the_end; rl++) {
|
|
s64 length = rl->length;
|
|
|
|
if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
|
|
goto err_out;
|
|
/*
|
|
* If @stop_vcn is given and finishes inside this run, cap the
|
|
* run length.
|
|
*/
|
|
if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
|
|
s64 s1 = last_vcn + 1;
|
|
if (unlikely(rl[1].vcn > s1))
|
|
length = s1 - rl->vcn;
|
|
the_end = true;
|
|
}
|
|
/* Header byte + length. */
|
|
rls += 1 + ntfs_get_nr_significant_bytes(length);
|
|
/*
|
|
* If the logical cluster number (lcn) denotes a hole and we
|
|
* are on NTFS 3.0+, we don't store it at all, i.e. we need
|
|
* zero space. On earlier NTFS versions we just store the lcn.
|
|
* Note: this assumes that on NTFS 1.2-, holes are stored with
|
|
* an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
|
|
*/
|
|
if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
|
|
/* Change in lcn. */
|
|
rls += ntfs_get_nr_significant_bytes(rl->lcn -
|
|
prev_lcn);
|
|
prev_lcn = rl->lcn;
|
|
}
|
|
}
|
|
return rls;
|
|
err_out:
|
|
if (rl->lcn == LCN_RL_NOT_MAPPED)
|
|
rls = -EINVAL;
|
|
else
|
|
rls = -EIO;
|
|
return rls;
|
|
}
|
|
|
|
/**
|
|
* ntfs_write_significant_bytes - write the significant bytes of a number
|
|
* @dst: destination buffer to write to
|
|
* @dst_max: pointer to last byte of destination buffer for bounds checking
|
|
* @n: number whose significant bytes to write
|
|
*
|
|
* Store in @dst, the minimum bytes of the number @n which are required to
|
|
* identify @n unambiguously as a signed number, taking care not to exceed
|
|
* @dest_max, the maximum position within @dst to which we are allowed to
|
|
* write.
|
|
*
|
|
* This is used when building the mapping pairs array of a runlist to compress
|
|
* a given logical cluster number (lcn) or a specific run length to the minimum
|
|
* size possible.
|
|
*
|
|
* Return the number of bytes written on success. On error, i.e. the
|
|
* destination buffer @dst is too small, return -ENOSPC.
|
|
*/
|
|
static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
|
|
const s64 n)
|
|
{
|
|
s64 l = n;
|
|
int i;
|
|
s8 j;
|
|
|
|
i = 0;
|
|
do {
|
|
if (unlikely(dst > dst_max))
|
|
goto err_out;
|
|
*dst++ = l & 0xffll;
|
|
l >>= 8;
|
|
i++;
|
|
} while (l != 0 && l != -1);
|
|
j = (n >> 8 * (i - 1)) & 0xff;
|
|
/* If the sign bit is wrong, we need an extra byte. */
|
|
if (n < 0 && j >= 0) {
|
|
if (unlikely(dst > dst_max))
|
|
goto err_out;
|
|
i++;
|
|
*dst = (s8)-1;
|
|
} else if (n > 0 && j < 0) {
|
|
if (unlikely(dst > dst_max))
|
|
goto err_out;
|
|
i++;
|
|
*dst = (s8)0;
|
|
}
|
|
return i;
|
|
err_out:
|
|
return -ENOSPC;
|
|
}
|
|
|
|
/**
|
|
* ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
|
|
* @vol: ntfs volume (needed for the ntfs version)
|
|
* @dst: destination buffer to which to write the mapping pairs array
|
|
* @dst_len: size of destination buffer @dst in bytes
|
|
* @rl: locked runlist for which to build the mapping pairs array
|
|
* @first_vcn: first vcn which to include in the mapping pairs array
|
|
* @last_vcn: last vcn which to include in the mapping pairs array
|
|
* @stop_vcn: first vcn outside destination buffer on success or -ENOSPC
|
|
*
|
|
* Create the mapping pairs array from the locked runlist @rl, starting at vcn
|
|
* @first_vcn and finishing with vcn @last_vcn and save the array in @dst.
|
|
* @dst_len is the size of @dst in bytes and it should be at least equal to the
|
|
* value obtained by calling ntfs_get_size_for_mapping_pairs().
|
|
*
|
|
* A @last_vcn of -1 means end of runlist and in that case the mapping pairs
|
|
* array corresponding to the runlist starting at vcn @first_vcn and finishing
|
|
* at the end of the runlist is created.
|
|
*
|
|
* If @rl is NULL, just write a single terminator byte to @dst.
|
|
*
|
|
* On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
|
|
* the first vcn outside the destination buffer. Note that on error, @dst has
|
|
* been filled with all the mapping pairs that will fit, thus it can be treated
|
|
* as partial success, in that a new attribute extent needs to be created or
|
|
* the next extent has to be used and the mapping pairs build has to be
|
|
* continued with @first_vcn set to *@stop_vcn.
|
|
*
|
|
* Return 0 on success and -errno on error. The following error codes are
|
|
* defined:
|
|
* -EINVAL - Run list contains unmapped elements. Make sure to only pass
|
|
* fully mapped runlists to this function.
|
|
* -EIO - The runlist is corrupt.
|
|
* -ENOSPC - The destination buffer is too small.
|
|
*
|
|
* Locking: @rl must be locked on entry (either for reading or writing), it
|
|
* remains locked throughout, and is left locked upon return.
|
|
*/
|
|
int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
|
|
const int dst_len, const runlist_element *rl,
|
|
const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn)
|
|
{
|
|
LCN prev_lcn;
|
|
s8 *dst_max, *dst_next;
|
|
int err = -ENOSPC;
|
|
bool the_end = false;
|
|
s8 len_len, lcn_len;
|
|
|
|
BUG_ON(first_vcn < 0);
|
|
BUG_ON(last_vcn < -1);
|
|
BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
|
|
BUG_ON(dst_len < 1);
|
|
if (!rl) {
|
|
BUG_ON(first_vcn);
|
|
BUG_ON(last_vcn > 0);
|
|
if (stop_vcn)
|
|
*stop_vcn = 0;
|
|
/* Terminator byte. */
|
|
*dst = 0;
|
|
return 0;
|
|
}
|
|
/* Skip to runlist element containing @first_vcn. */
|
|
while (rl->length && first_vcn >= rl[1].vcn)
|
|
rl++;
|
|
if (unlikely((!rl->length && first_vcn > rl->vcn) ||
|
|
first_vcn < rl->vcn))
|
|
return -EINVAL;
|
|
/*
|
|
* @dst_max is used for bounds checking in
|
|
* ntfs_write_significant_bytes().
|
|
*/
|
|
dst_max = dst + dst_len - 1;
|
|
prev_lcn = 0;
|
|
/* Do the first partial run if present. */
|
|
if (first_vcn > rl->vcn) {
|
|
s64 delta, length = rl->length;
|
|
|
|
/* We know rl->length != 0 already. */
|
|
if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
|
|
goto err_out;
|
|
/*
|
|
* If @stop_vcn is given and finishes inside this run, cap the
|
|
* run length.
|
|
*/
|
|
if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
|
|
s64 s1 = last_vcn + 1;
|
|
if (unlikely(rl[1].vcn > s1))
|
|
length = s1 - rl->vcn;
|
|
the_end = true;
|
|
}
|
|
delta = first_vcn - rl->vcn;
|
|
/* Write length. */
|
|
len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
|
|
length - delta);
|
|
if (unlikely(len_len < 0))
|
|
goto size_err;
|
|
/*
|
|
* If the logical cluster number (lcn) denotes a hole and we
|
|
* are on NTFS 3.0+, we don't store it at all, i.e. we need
|
|
* zero space. On earlier NTFS versions we just write the lcn
|
|
* change. FIXME: Do we need to write the lcn change or just
|
|
* the lcn in that case? Not sure as I have never seen this
|
|
* case on NT4. - We assume that we just need to write the lcn
|
|
* change until someone tells us otherwise... (AIA)
|
|
*/
|
|
if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
|
|
prev_lcn = rl->lcn;
|
|
if (likely(rl->lcn >= 0))
|
|
prev_lcn += delta;
|
|
/* Write change in lcn. */
|
|
lcn_len = ntfs_write_significant_bytes(dst + 1 +
|
|
len_len, dst_max, prev_lcn);
|
|
if (unlikely(lcn_len < 0))
|
|
goto size_err;
|
|
} else
|
|
lcn_len = 0;
|
|
dst_next = dst + len_len + lcn_len + 1;
|
|
if (unlikely(dst_next > dst_max))
|
|
goto size_err;
|
|
/* Update header byte. */
|
|
*dst = lcn_len << 4 | len_len;
|
|
/* Position at next mapping pairs array element. */
|
|
dst = dst_next;
|
|
/* Go to next runlist element. */
|
|
rl++;
|
|
}
|
|
/* Do the full runs. */
|
|
for (; rl->length && !the_end; rl++) {
|
|
s64 length = rl->length;
|
|
|
|
if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
|
|
goto err_out;
|
|
/*
|
|
* If @stop_vcn is given and finishes inside this run, cap the
|
|
* run length.
|
|
*/
|
|
if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
|
|
s64 s1 = last_vcn + 1;
|
|
if (unlikely(rl[1].vcn > s1))
|
|
length = s1 - rl->vcn;
|
|
the_end = true;
|
|
}
|
|
/* Write length. */
|
|
len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
|
|
length);
|
|
if (unlikely(len_len < 0))
|
|
goto size_err;
|
|
/*
|
|
* If the logical cluster number (lcn) denotes a hole and we
|
|
* are on NTFS 3.0+, we don't store it at all, i.e. we need
|
|
* zero space. On earlier NTFS versions we just write the lcn
|
|
* change. FIXME: Do we need to write the lcn change or just
|
|
* the lcn in that case? Not sure as I have never seen this
|
|
* case on NT4. - We assume that we just need to write the lcn
|
|
* change until someone tells us otherwise... (AIA)
|
|
*/
|
|
if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
|
|
/* Write change in lcn. */
|
|
lcn_len = ntfs_write_significant_bytes(dst + 1 +
|
|
len_len, dst_max, rl->lcn - prev_lcn);
|
|
if (unlikely(lcn_len < 0))
|
|
goto size_err;
|
|
prev_lcn = rl->lcn;
|
|
} else
|
|
lcn_len = 0;
|
|
dst_next = dst + len_len + lcn_len + 1;
|
|
if (unlikely(dst_next > dst_max))
|
|
goto size_err;
|
|
/* Update header byte. */
|
|
*dst = lcn_len << 4 | len_len;
|
|
/* Position at next mapping pairs array element. */
|
|
dst = dst_next;
|
|
}
|
|
/* Success. */
|
|
err = 0;
|
|
size_err:
|
|
/* Set stop vcn. */
|
|
if (stop_vcn)
|
|
*stop_vcn = rl->vcn;
|
|
/* Add terminator byte. */
|
|
*dst = 0;
|
|
return err;
|
|
err_out:
|
|
if (rl->lcn == LCN_RL_NOT_MAPPED)
|
|
err = -EINVAL;
|
|
else
|
|
err = -EIO;
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn
|
|
* @vol: ntfs volume (needed for error output)
|
|
* @runlist: runlist to truncate
|
|
* @new_length: the new length of the runlist in VCNs
|
|
*
|
|
* Truncate the runlist described by @runlist as well as the memory buffer
|
|
* holding the runlist elements to a length of @new_length VCNs.
|
|
*
|
|
* If @new_length lies within the runlist, the runlist elements with VCNs of
|
|
* @new_length and above are discarded. As a special case if @new_length is
|
|
* zero, the runlist is discarded and set to NULL.
|
|
*
|
|
* If @new_length lies beyond the runlist, a sparse runlist element is added to
|
|
* the end of the runlist @runlist or if the last runlist element is a sparse
|
|
* one already, this is extended.
|
|
*
|
|
* Note, no checking is done for unmapped runlist elements. It is assumed that
|
|
* the caller has mapped any elements that need to be mapped already.
|
|
*
|
|
* Return 0 on success and -errno on error.
|
|
*
|
|
* Locking: The caller must hold @runlist->lock for writing.
|
|
*/
|
|
int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist,
|
|
const s64 new_length)
|
|
{
|
|
runlist_element *rl;
|
|
int old_size;
|
|
|
|
ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length);
|
|
BUG_ON(!runlist);
|
|
BUG_ON(new_length < 0);
|
|
rl = runlist->rl;
|
|
if (!new_length) {
|
|
ntfs_debug("Freeing runlist.");
|
|
runlist->rl = NULL;
|
|
if (rl)
|
|
ntfs_free(rl);
|
|
return 0;
|
|
}
|
|
if (unlikely(!rl)) {
|
|
/*
|
|
* Create a runlist consisting of a sparse runlist element of
|
|
* length @new_length followed by a terminator runlist element.
|
|
*/
|
|
rl = ntfs_malloc_nofs(PAGE_SIZE);
|
|
if (unlikely(!rl)) {
|
|
ntfs_error(vol->sb, "Not enough memory to allocate "
|
|
"runlist element buffer.");
|
|
return -ENOMEM;
|
|
}
|
|
runlist->rl = rl;
|
|
rl[1].length = rl->vcn = 0;
|
|
rl->lcn = LCN_HOLE;
|
|
rl[1].vcn = rl->length = new_length;
|
|
rl[1].lcn = LCN_ENOENT;
|
|
return 0;
|
|
}
|
|
BUG_ON(new_length < rl->vcn);
|
|
/* Find @new_length in the runlist. */
|
|
while (likely(rl->length && new_length >= rl[1].vcn))
|
|
rl++;
|
|
/*
|
|
* If not at the end of the runlist we need to shrink it.
|
|
* If at the end of the runlist we need to expand it.
|
|
*/
|
|
if (rl->length) {
|
|
runlist_element *trl;
|
|
bool is_end;
|
|
|
|
ntfs_debug("Shrinking runlist.");
|
|
/* Determine the runlist size. */
|
|
trl = rl + 1;
|
|
while (likely(trl->length))
|
|
trl++;
|
|
old_size = trl - runlist->rl + 1;
|
|
/* Truncate the run. */
|
|
rl->length = new_length - rl->vcn;
|
|
/*
|
|
* If a run was partially truncated, make the following runlist
|
|
* element a terminator.
|
|
*/
|
|
is_end = false;
|
|
if (rl->length) {
|
|
rl++;
|
|
if (!rl->length)
|
|
is_end = true;
|
|
rl->vcn = new_length;
|
|
rl->length = 0;
|
|
}
|
|
rl->lcn = LCN_ENOENT;
|
|
/* Reallocate memory if necessary. */
|
|
if (!is_end) {
|
|
int new_size = rl - runlist->rl + 1;
|
|
rl = ntfs_rl_realloc(runlist->rl, old_size, new_size);
|
|
if (IS_ERR(rl))
|
|
ntfs_warning(vol->sb, "Failed to shrink "
|
|
"runlist buffer. This just "
|
|
"wastes a bit of memory "
|
|
"temporarily so we ignore it "
|
|
"and return success.");
|
|
else
|
|
runlist->rl = rl;
|
|
}
|
|
} else if (likely(/* !rl->length && */ new_length > rl->vcn)) {
|
|
ntfs_debug("Expanding runlist.");
|
|
/*
|
|
* If there is a previous runlist element and it is a sparse
|
|
* one, extend it. Otherwise need to add a new, sparse runlist
|
|
* element.
|
|
*/
|
|
if ((rl > runlist->rl) && ((rl - 1)->lcn == LCN_HOLE))
|
|
(rl - 1)->length = new_length - (rl - 1)->vcn;
|
|
else {
|
|
/* Determine the runlist size. */
|
|
old_size = rl - runlist->rl + 1;
|
|
/* Reallocate memory if necessary. */
|
|
rl = ntfs_rl_realloc(runlist->rl, old_size,
|
|
old_size + 1);
|
|
if (IS_ERR(rl)) {
|
|
ntfs_error(vol->sb, "Failed to expand runlist "
|
|
"buffer, aborting.");
|
|
return PTR_ERR(rl);
|
|
}
|
|
runlist->rl = rl;
|
|
/*
|
|
* Set @rl to the same runlist element in the new
|
|
* runlist as before in the old runlist.
|
|
*/
|
|
rl += old_size - 1;
|
|
/* Add a new, sparse runlist element. */
|
|
rl->lcn = LCN_HOLE;
|
|
rl->length = new_length - rl->vcn;
|
|
/* Add a new terminator runlist element. */
|
|
rl++;
|
|
rl->length = 0;
|
|
}
|
|
rl->vcn = new_length;
|
|
rl->lcn = LCN_ENOENT;
|
|
} else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ {
|
|
/* Runlist already has same size as requested. */
|
|
rl->lcn = LCN_ENOENT;
|
|
}
|
|
ntfs_debug("Done.");
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* ntfs_rl_punch_nolock - punch a hole into a runlist
|
|
* @vol: ntfs volume (needed for error output)
|
|
* @runlist: runlist to punch a hole into
|
|
* @start: starting VCN of the hole to be created
|
|
* @length: size of the hole to be created in units of clusters
|
|
*
|
|
* Punch a hole into the runlist @runlist starting at VCN @start and of size
|
|
* @length clusters.
|
|
*
|
|
* Return 0 on success and -errno on error, in which case @runlist has not been
|
|
* modified.
|
|
*
|
|
* If @start and/or @start + @length are outside the runlist return error code
|
|
* -ENOENT.
|
|
*
|
|
* If the runlist contains unmapped or error elements between @start and @start
|
|
* + @length return error code -EINVAL.
|
|
*
|
|
* Locking: The caller must hold @runlist->lock for writing.
|
|
*/
|
|
int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
|
|
const VCN start, const s64 length)
|
|
{
|
|
const VCN end = start + length;
|
|
s64 delta;
|
|
runlist_element *rl, *rl_end, *rl_real_end, *trl;
|
|
int old_size;
|
|
bool lcn_fixup = false;
|
|
|
|
ntfs_debug("Entering for start 0x%llx, length 0x%llx.",
|
|
(long long)start, (long long)length);
|
|
BUG_ON(!runlist);
|
|
BUG_ON(start < 0);
|
|
BUG_ON(length < 0);
|
|
BUG_ON(end < 0);
|
|
rl = runlist->rl;
|
|
if (unlikely(!rl)) {
|
|
if (likely(!start && !length))
|
|
return 0;
|
|
return -ENOENT;
|
|
}
|
|
/* Find @start in the runlist. */
|
|
while (likely(rl->length && start >= rl[1].vcn))
|
|
rl++;
|
|
rl_end = rl;
|
|
/* Find @end in the runlist. */
|
|
while (likely(rl_end->length && end >= rl_end[1].vcn)) {
|
|
/* Verify there are no unmapped or error elements. */
|
|
if (unlikely(rl_end->lcn < LCN_HOLE))
|
|
return -EINVAL;
|
|
rl_end++;
|
|
}
|
|
/* Check the last element. */
|
|
if (unlikely(rl_end->length && rl_end->lcn < LCN_HOLE))
|
|
return -EINVAL;
|
|
/* This covers @start being out of bounds, too. */
|
|
if (!rl_end->length && end > rl_end->vcn)
|
|
return -ENOENT;
|
|
if (!length)
|
|
return 0;
|
|
if (!rl->length)
|
|
return -ENOENT;
|
|
rl_real_end = rl_end;
|
|
/* Determine the runlist size. */
|
|
while (likely(rl_real_end->length))
|
|
rl_real_end++;
|
|
old_size = rl_real_end - runlist->rl + 1;
|
|
/* If @start is in a hole simply extend the hole. */
|
|
if (rl->lcn == LCN_HOLE) {
|
|
/*
|
|
* If both @start and @end are in the same sparse run, we are
|
|
* done.
|
|
*/
|
|
if (end <= rl[1].vcn) {
|
|
ntfs_debug("Done (requested hole is already sparse).");
|
|
return 0;
|
|
}
|
|
extend_hole:
|
|
/* Extend the hole. */
|
|
rl->length = end - rl->vcn;
|
|
/* If @end is in a hole, merge it with the current one. */
|
|
if (rl_end->lcn == LCN_HOLE) {
|
|
rl_end++;
|
|
rl->length = rl_end->vcn - rl->vcn;
|
|
}
|
|
/* We have done the hole. Now deal with the remaining tail. */
|
|
rl++;
|
|
/* Cut out all runlist elements up to @end. */
|
|
if (rl < rl_end)
|
|
memmove(rl, rl_end, (rl_real_end - rl_end + 1) *
|
|
sizeof(*rl));
|
|
/* Adjust the beginning of the tail if necessary. */
|
|
if (end > rl->vcn) {
|
|
delta = end - rl->vcn;
|
|
rl->vcn = end;
|
|
rl->length -= delta;
|
|
/* Only adjust the lcn if it is real. */
|
|
if (rl->lcn >= 0)
|
|
rl->lcn += delta;
|
|
}
|
|
shrink_allocation:
|
|
/* Reallocate memory if the allocation changed. */
|
|
if (rl < rl_end) {
|
|
rl = ntfs_rl_realloc(runlist->rl, old_size,
|
|
old_size - (rl_end - rl));
|
|
if (IS_ERR(rl))
|
|
ntfs_warning(vol->sb, "Failed to shrink "
|
|
"runlist buffer. This just "
|
|
"wastes a bit of memory "
|
|
"temporarily so we ignore it "
|
|
"and return success.");
|
|
else
|
|
runlist->rl = rl;
|
|
}
|
|
ntfs_debug("Done (extend hole).");
|
|
return 0;
|
|
}
|
|
/*
|
|
* If @start is at the beginning of a run things are easier as there is
|
|
* no need to split the first run.
|
|
*/
|
|
if (start == rl->vcn) {
|
|
/*
|
|
* @start is at the beginning of a run.
|
|
*
|
|
* If the previous run is sparse, extend its hole.
|
|
*
|
|
* If @end is not in the same run, switch the run to be sparse
|
|
* and extend the newly created hole.
|
|
*
|
|
* Thus both of these cases reduce the problem to the above
|
|
* case of "@start is in a hole".
|
|
*/
|
|
if (rl > runlist->rl && (rl - 1)->lcn == LCN_HOLE) {
|
|
rl--;
|
|
goto extend_hole;
|
|
}
|
|
if (end >= rl[1].vcn) {
|
|
rl->lcn = LCN_HOLE;
|
|
goto extend_hole;
|
|
}
|
|
/*
|
|
* The final case is when @end is in the same run as @start.
|
|
* For this need to split the run into two. One run for the
|
|
* sparse region between the beginning of the old run, i.e.
|
|
* @start, and @end and one for the remaining non-sparse
|
|
* region, i.e. between @end and the end of the old run.
|
|
*/
|
|
trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1);
|
|
if (IS_ERR(trl))
|
|
goto enomem_out;
|
|
old_size++;
|
|
if (runlist->rl != trl) {
|
|
rl = trl + (rl - runlist->rl);
|
|
rl_end = trl + (rl_end - runlist->rl);
|
|
rl_real_end = trl + (rl_real_end - runlist->rl);
|
|
runlist->rl = trl;
|
|
}
|
|
split_end:
|
|
/* Shift all the runs up by one. */
|
|
memmove(rl + 1, rl, (rl_real_end - rl + 1) * sizeof(*rl));
|
|
/* Finally, setup the two split runs. */
|
|
rl->lcn = LCN_HOLE;
|
|
rl->length = length;
|
|
rl++;
|
|
rl->vcn += length;
|
|
/* Only adjust the lcn if it is real. */
|
|
if (rl->lcn >= 0 || lcn_fixup)
|
|
rl->lcn += length;
|
|
rl->length -= length;
|
|
ntfs_debug("Done (split one).");
|
|
return 0;
|
|
}
|
|
/*
|
|
* @start is neither in a hole nor at the beginning of a run.
|
|
*
|
|
* If @end is in a hole, things are easier as simply truncating the run
|
|
* @start is in to end at @start - 1, deleting all runs after that up
|
|
* to @end, and finally extending the beginning of the run @end is in
|
|
* to be @start is all that is needed.
|
|
*/
|
|
if (rl_end->lcn == LCN_HOLE) {
|
|
/* Truncate the run containing @start. */
|
|
rl->length = start - rl->vcn;
|
|
rl++;
|
|
/* Cut out all runlist elements up to @end. */
|
|
if (rl < rl_end)
|
|
memmove(rl, rl_end, (rl_real_end - rl_end + 1) *
|
|
sizeof(*rl));
|
|
/* Extend the beginning of the run @end is in to be @start. */
|
|
rl->vcn = start;
|
|
rl->length = rl[1].vcn - start;
|
|
goto shrink_allocation;
|
|
}
|
|
/*
|
|
* If @end is not in a hole there are still two cases to distinguish.
|
|
* Either @end is or is not in the same run as @start.
|
|
*
|
|
* The second case is easier as it can be reduced to an already solved
|
|
* problem by truncating the run @start is in to end at @start - 1.
|
|
* Then, if @end is in the next run need to split the run into a sparse
|
|
* run followed by a non-sparse run (already covered above) and if @end
|
|
* is not in the next run switching it to be sparse, again reduces the
|
|
* problem to the already covered case of "@start is in a hole".
|
|
*/
|
|
if (end >= rl[1].vcn) {
|
|
/*
|
|
* If @end is not in the next run, reduce the problem to the
|
|
* case of "@start is in a hole".
|
|
*/
|
|
if (rl[1].length && end >= rl[2].vcn) {
|
|
/* Truncate the run containing @start. */
|
|
rl->length = start - rl->vcn;
|
|
rl++;
|
|
rl->vcn = start;
|
|
rl->lcn = LCN_HOLE;
|
|
goto extend_hole;
|
|
}
|
|
trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1);
|
|
if (IS_ERR(trl))
|
|
goto enomem_out;
|
|
old_size++;
|
|
if (runlist->rl != trl) {
|
|
rl = trl + (rl - runlist->rl);
|
|
rl_end = trl + (rl_end - runlist->rl);
|
|
rl_real_end = trl + (rl_real_end - runlist->rl);
|
|
runlist->rl = trl;
|
|
}
|
|
/* Truncate the run containing @start. */
|
|
rl->length = start - rl->vcn;
|
|
rl++;
|
|
/*
|
|
* @end is in the next run, reduce the problem to the case
|
|
* where "@start is at the beginning of a run and @end is in
|
|
* the same run as @start".
|
|
*/
|
|
delta = rl->vcn - start;
|
|
rl->vcn = start;
|
|
if (rl->lcn >= 0) {
|
|
rl->lcn -= delta;
|
|
/* Need this in case the lcn just became negative. */
|
|
lcn_fixup = true;
|
|
}
|
|
rl->length += delta;
|
|
goto split_end;
|
|
}
|
|
/*
|
|
* The first case from above, i.e. @end is in the same run as @start.
|
|
* We need to split the run into three. One run for the non-sparse
|
|
* region between the beginning of the old run and @start, one for the
|
|
* sparse region between @start and @end, and one for the remaining
|
|
* non-sparse region, i.e. between @end and the end of the old run.
|
|
*/
|
|
trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 2);
|
|
if (IS_ERR(trl))
|
|
goto enomem_out;
|
|
old_size += 2;
|
|
if (runlist->rl != trl) {
|
|
rl = trl + (rl - runlist->rl);
|
|
rl_end = trl + (rl_end - runlist->rl);
|
|
rl_real_end = trl + (rl_real_end - runlist->rl);
|
|
runlist->rl = trl;
|
|
}
|
|
/* Shift all the runs up by two. */
|
|
memmove(rl + 2, rl, (rl_real_end - rl + 1) * sizeof(*rl));
|
|
/* Finally, setup the three split runs. */
|
|
rl->length = start - rl->vcn;
|
|
rl++;
|
|
rl->vcn = start;
|
|
rl->lcn = LCN_HOLE;
|
|
rl->length = length;
|
|
rl++;
|
|
delta = end - rl->vcn;
|
|
rl->vcn = end;
|
|
rl->lcn += delta;
|
|
rl->length -= delta;
|
|
ntfs_debug("Done (split both).");
|
|
return 0;
|
|
enomem_out:
|
|
ntfs_error(vol->sb, "Not enough memory to extend runlist buffer.");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
#endif /* NTFS_RW */
|