/**
* runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
*
- * Copyright (c) 2001-2004 Anton Altaparmakov
- * Copyright (c) 2002 Richard Russon
+ * Copyright (c) 2001-2005 Anton Altaparmakov
+ * Copyright (c) 2002-2005 Richard Russon
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
int size)
{
if (likely((dst != src) && (size > 0)))
- memmove(base + dst, base + src, size * sizeof (*base));
+ memmove(base + dst, base + src, size * sizeof(*base));
}
/**
*
* 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 and entire page of memory.
+ * memory, this function returns an entire page of memory.
*
* It is up to the caller to serialize access to the runlist @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
BUG_ON(!dst);
BUG_ON(!src);
- if ((dst->lcn < 0) || (src->lcn < 0)) /* Are we merging holes? */
- return FALSE;
- if ((dst->lcn + dst->length) != src->lcn) /* Are the runs contiguous? */
+ /* 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 ((dst->vcn + dst->length) != src->vcn) /* Are the runs misaligned? */
- return FALSE;
-
- return TRUE;
+ /* 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;
}
/**
static inline runlist_element *ntfs_rl_append(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc)
{
- BOOL right;
- int magic;
+ BOOL right = 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. */
- right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
+ 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 (right)
__ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
- magic = loc + ssize;
+ /* First run after the @src runs that have been inserted. */
+ marker = loc + ssize + 1;
/* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, magic + 1, loc + 1 + right, dsize - loc - 1 - right);
+ ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right));
ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
/* Adjust the size of the preceding hole. */
dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
/* We may have changed the length of the file, so fix the end marker */
- if (dst[magic + 1].lcn == LCN_ENOENT)
- dst[magic + 1].vcn = dst[magic].vcn + dst[magic].length;
+ if (dst[marker].lcn == LCN_ENOENT)
+ dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
return dst;
}
static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc)
{
- BOOL left = FALSE;
- BOOL disc = FALSE; /* Discontinuity */
- BOOL hole = FALSE; /* Following a hole */
- int magic;
+ BOOL left = FALSE; /* Left end of @src needs merging. */
+ BOOL disc = FALSE; /* Discontinuity between @dst and @src. */
+ int marker; /* End of the inserted runs. */
BUG_ON(!dst);
BUG_ON(!src);
- /* disc => Discontinuity between the end of @dst and the start of @src.
- * This means we might need to insert a hole.
- * hole => @dst ends with a hole or an unmapped region which we can
- * extend to match the discontinuity. */
+ /*
+ * disc => Discontinuity between the end of @dst and the start of @src.
+ * This means we might need to insert a "not mapped" run.
+ */
if (loc == 0)
disc = (src[0].vcn > 0);
else {
merged_length += src->length;
disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
- if (disc)
- hole = (dst[loc - 1].lcn == LCN_HOLE);
}
-
- /* Space required: @dst size + @src size, less one if we merged, plus
- * one if there was a discontinuity, less one for a trailing hole. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc - hole);
+ /*
+ * Space required: @dst size + @src size, less one if we merged, plus
+ * one if there was a discontinuity.
+ */
+ dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
if (IS_ERR(dst))
return dst;
/*
* We are guaranteed to succeed from here so can start modifying the
* original runlist.
*/
-
if (left)
__ntfs_rl_merge(dst + loc - 1, src);
-
- magic = loc + ssize - left + disc - hole;
+ /*
+ * First run after the @src runs that have been inserted.
+ * Nominally, @marker equals @loc + @ssize, i.e. location + number of
+ * runs in @src. However, if @left, then the first run in @src has
+ * been merged with one in @dst. And if @disc, then @dst and @src do
+ * not meet and we need an extra run to fill the gap.
+ */
+ marker = loc + ssize - left + disc;
/* Move the tail of @dst out of the way, then copy in @src. */
- ntfs_rl_mm(dst, magic, loc, dsize - loc);
- ntfs_rl_mc(dst, loc + disc - hole, src, left, ssize - left);
+ ntfs_rl_mm(dst, marker, loc, dsize - loc);
+ ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
- /* Adjust the VCN of the last run ... */
- if (dst[magic].lcn <= LCN_HOLE)
- dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
+ /* Adjust the VCN of the first run after the insertion... */
+ dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
/* ... and the length. */
- if (dst[magic].lcn == LCN_HOLE || dst[magic].lcn == LCN_RL_NOT_MAPPED)
- dst[magic].length = dst[magic + 1].vcn - dst[magic].vcn;
+ if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
+ dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;
- /* Writing beyond the end of the file and there's a discontinuity. */
+ /* Writing beyond the end of the file and there is a discontinuity. */
if (disc) {
- if (hole)
- dst[loc - 1].length = dst[loc].vcn - dst[loc - 1].vcn;
- else {
- if (loc > 0) {
- dst[loc].vcn = dst[loc - 1].vcn +
- dst[loc - 1].length;
- dst[loc].length = dst[loc + 1].vcn -
- dst[loc].vcn;
- } else {
- dst[loc].vcn = 0;
- dst[loc].length = dst[loc + 1].vcn;
- }
- dst[loc].lcn = LCN_RL_NOT_MAPPED;
+ 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;
}
-
- magic += hole;
-
- if (dst[magic].lcn == LCN_ENOENT)
- dst[magic].vcn = dst[magic - 1].vcn +
- dst[magic - 1].length;
+ dst[loc].lcn = LCN_RL_NOT_MAPPED;
}
return dst;
}
static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
int dsize, runlist_element *src, int ssize, int loc)
{
- BOOL left = FALSE;
- BOOL right;
- int magic;
+ 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, merge the left and right ends, if necessary. */
- right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
+ /* 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'll need less if the left, right, or both
- * ends were merged. */
- dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);
- if (IS_ERR(dst))
- return dst;
+ /*
+ * 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);
-
- /* FIXME: What does this mean? (AIA) */
- magic = loc + ssize - left;
+ /*
+ * 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, magic, loc + right + 1, dsize - loc - right - 1);
+ ntfs_rl_mm(dst, marker, tail, dsize - tail);
ntfs_rl_mc(dst, loc, src, left, ssize - left);
- /* We may have changed the length of the file, so fix the end marker */
- if (dst[magic].lcn == LCN_ENOENT)
- dst[magic].vcn = dst[magic - 1].vcn + dst[magic - 1].length;
+ /* We may have changed the length of the file, so fix the end marker. */
+ if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)
+ dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
return dst;
}
/* 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;
((drl[dins].vcn + drl[dins].length) <= /* End of hole */
(srl[send - 1].vcn + srl[send - 1].length)));
- /* Or we'll lose an end marker */
- if (start && finish && (drl[dins].length == 0))
+ /* 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 (drl[ds].lcn != LCN_RL_NOT_MAPPED) {
/* Add an unmapped runlist element. */
if (!slots) {
- /* FIXME/TODO: We need to have the
- * extra memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 2);
- if (!drl)
- goto critical_error;
+ drl = ntfs_rl_realloc_nofail(drl, ds,
+ ds + 2);
slots = 2;
}
ds++;
drl[ds].length = marker_vcn - drl[ds].vcn;
/* Finally add the ENOENT terminator. */
ds++;
- if (!slots) {
- /* FIXME/TODO: We need to have the extra
- * memory already! (AIA) */
- drl = ntfs_rl_realloc(drl, ds, ds + 1);
- if (!drl)
- goto critical_error;
- }
+ 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;
ntfs_debug("Merged runlist:");
ntfs_debug_dump_runlist(drl);
return drl;
-
-critical_error:
- /* Critical error! We cannot afford to fail here. */
- ntfs_error(NULL, "Critical error! Not enough memory.");
- panic("NTFS: Cannot continue.");
}
/**
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. */
if (!attr->data.non_resident.lowest_vcn) {
VCN max_cluster;
- max_cluster = (sle64_to_cpu(
+ max_cluster = ((sle64_to_cpu(
attr->data.non_resident.allocated_size) +
vol->cluster_size - 1) >>
- vol->cluster_size_bits;
+ vol->cluster_size_bits) - 1;
/*
- * 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.
+ * A highest_vcn of zero means this is a single extent
+ * attribute so simply terminate the runlist with LCN_ENOENT).
*/
- 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;
+ 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. */
*
* It is up to the caller to serialize access to the runlist @rl.
*
- * Since lcns must be >= 0, we use negative return values with special meaning:
+ * Since lcns must be >= 0, we use negative return codes with special meaning:
*
- * Return value Meaning / Description
+ * Return code Meaning / Description
* ==================================================
- * -1 = LCN_HOLE Hole / not allocated on disk.
- * -2 = LCN_RL_NOT_MAPPED This is part of the runlist which has not been
- * inserted into the runlist yet.
- * -3 = LCN_ENOENT There is no such vcn in the attribute.
+ * 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.
+ * - 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)
{
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
* 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
- * @start_vcn: vcn at which to start 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
*
* Walk the locked runlist @rl and calculate the size in bytes of the mapping
- * pairs array corresponding to the runlist @rl, starting at vcn @start_vcn.
+ * 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.
*
* 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 start_vcn)
+ const runlist_element *rl, const VCN first_vcn,
+ const VCN last_vcn)
{
LCN prev_lcn;
int rls;
+ BOOL the_end = FALSE;
- BUG_ON(start_vcn < 0);
+ BUG_ON(first_vcn < 0);
+ BUG_ON(last_vcn < -1);
+ BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
if (!rl) {
- BUG_ON(start_vcn);
+ BUG_ON(first_vcn);
+ BUG_ON(last_vcn > 0);
return 1;
}
- /* Skip to runlist element containing @start_vcn. */
- while (rl->length && start_vcn >= rl[1].vcn)
+ /* Skip to runlist element containing @first_vcn. */
+ while (rl->length && first_vcn >= rl[1].vcn)
rl++;
- if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
+ 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 (start_vcn > rl->vcn) {
- s64 delta;
+ if (first_vcn > rl->vcn) {
+ s64 delta, length = rl->length;
/* We know rl->length != 0 already. */
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
- delta = start_vcn - rl->vcn;
+ /*
+ * 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(rl->length - delta);
+ 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
* 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 (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
prev_lcn = rl->lcn;
- if (rl->lcn >= 0)
+ if (likely(rl->lcn >= 0))
prev_lcn += delta;
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(prev_lcn);
rl++;
}
/* Do the full runs. */
- for (; rl->length; rl++) {
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ 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(rl->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
* 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 (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
/* Change in lcn. */
rls += ntfs_get_nr_significant_bytes(rl->lcn -
prev_lcn);
i = 0;
do {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
*dst++ = l & 0xffll;
l >>= 8;
j = (n >> 8 * (i - 1)) & 0xff;
/* If the sign bit is wrong, we need an extra byte. */
if (n < 0 && j >= 0) {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
i++;
*dst = (s8)-1;
} else if (n > 0 && j < 0) {
- if (dst > dst_max)
+ if (unlikely(dst > dst_max))
goto err_out;
i++;
*dst = (s8)0;
* @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
- * @start_vcn: vcn at which to start 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
- * @start_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().
+ * @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.
*
* 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 @start_vcn set to *@stop_vcn.
+ * continued with @first_vcn set to *@stop_vcn.
*
* Return 0 on success and -errno on error. The following error codes are
* defined:
*/
int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
const int dst_len, const runlist_element *rl,
- const VCN start_vcn, VCN *const stop_vcn)
+ 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(start_vcn < 0);
+ 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(start_vcn);
+ 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 @start_vcn. */
- while (rl->length && start_vcn >= rl[1].vcn)
+ /* Skip to runlist element containing @first_vcn. */
+ while (rl->length && first_vcn >= rl[1].vcn)
rl++;
- if ((!rl->length && start_vcn > rl->vcn) || start_vcn < rl->vcn)
+ if (unlikely((!rl->length && first_vcn > rl->vcn) ||
+ first_vcn < rl->vcn))
return -EINVAL;
/*
* @dst_max is used for bounds checking in
dst_max = dst + dst_len - 1;
prev_lcn = 0;
/* Do the first partial run if present. */
- if (start_vcn > rl->vcn) {
- s64 delta;
+ if (first_vcn > rl->vcn) {
+ s64 delta, length = rl->length;
/* We know rl->length != 0 already. */
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
goto err_out;
- delta = start_vcn - rl->vcn;
+ /*
+ * 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,
- rl->length - delta);
- if (len_len < 0)
+ length - delta);
+ if (unlikely(len_len < 0))
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
prev_lcn = rl->lcn;
- if (rl->lcn >= 0)
+ 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 (lcn_len < 0)
+ if (unlikely(lcn_len < 0))
goto size_err;
} else
lcn_len = 0;
dst_next = dst + len_len + lcn_len + 1;
- if (dst_next > dst_max)
+ if (unlikely(dst_next > dst_max))
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;
rl++;
}
/* Do the full runs. */
- for (; rl->length; rl++) {
- if (rl->length < 0 || rl->lcn < LCN_HOLE)
+ 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,
- rl->length);
- if (len_len < 0)
+ length);
+ if (unlikely(len_len < 0))
goto size_err;
/*
* If the logical cluster number (lcn) denotes a hole and we
* case on NT4. - We assume that we just need to write the lcn
* change until someone tells us otherwise... (AIA)
*/
- if (rl->lcn >= 0 || vol->major_ver < 3) {
+ 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 (lcn_len < 0)
+ 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 (dst_next > dst_max)
+ if (unlikely(dst_next > dst_max))
goto size_err;
/* Update header byte. */
*dst = lcn_len << 4 | len_len;
/**
* 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
*
* 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.
+ * @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.
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
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) {
+ s64 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 */
git://git.onelab.eu / linux-2.6.git / blobdiff