Manual merge with Linus

1 files changed, 353 insertions, 21 deletions

diff --git a/fs/ntfs/runlist.c b/fs/ntfs/runlist.c
index 758855b0414..f5b2ac92908 100644
--- a/fs/ntfs/runlist.c
+++ b/fs/ntfs/runlist.c
@@ -35,7 +35,7 @@ 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));
+		memmove(base + dst, base + src, size * sizeof(*base));
 }
 
 /**
@@ -95,6 +95,51 @@ static inline runlist_element *ntfs_rl_realloc(runlist_element *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
@@ -497,6 +542,7 @@ runlist_element *ntfs_runlists_merge(runlist_element *drl,
 			/* 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;
@@ -566,8 +612,8 @@ runlist_element *ntfs_runlists_merge(runlist_element *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;
@@ -621,11 +667,8 @@ runlist_element *ntfs_runlists_merge(runlist_element *drl,
 			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++;
@@ -640,13 +683,8 @@ runlist_element *ntfs_runlists_merge(runlist_element *drl,
 			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;
@@ -659,11 +697,6 @@ finished:
 	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.");
 }
 
 /**
@@ -727,6 +760,9 @@ runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
 		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. */
@@ -1419,6 +1455,7 @@ err_out:
 
 /**
  * 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
  *
@@ -1426,12 +1463,16 @@ err_out:
  * 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.
@@ -1446,6 +1487,13 @@ int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist,
 	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
@@ -1553,4 +1601,288 @@ int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist,
 	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 */