1 files changed, 170 insertions, 174 deletions

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 372c7fcdc068..cfca17384115 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -525,6 +525,7 @@ static int ntfs_read_locked_inode(struct inode *vi)
 	ntfs_volume *vol = NTFS_SB(vi->i_sb);
 	ntfs_inode *ni;
 	MFT_RECORD *m;
+	ATTR_RECORD *a;
 	STANDARD_INFORMATION *si;
 	ntfs_attr_search_ctx *ctx;
 	int err = 0;
@@ -633,9 +634,10 @@ static int ntfs_read_locked_inode(struct inode *vi)
 		}
 		goto unm_err_out;
 	}
+	a = ctx->attr;
 	/* Get the standard information attribute value. */
-	si = (STANDARD_INFORMATION*)((char*)ctx->attr +
-			le16_to_cpu(ctx->attr->data.resident.value_offset));
+	si = (STANDARD_INFORMATION*)((u8*)a +
+			le16_to_cpu(a->data.resident.value_offset));
 
 	/* Transfer information from the standard information into vi. */
 	/*
@@ -674,15 +676,16 @@ static int ntfs_read_locked_inode(struct inode *vi)
 			goto skip_attr_list_load;
 		ntfs_debug("Attribute list found in inode 0x%lx.", vi->i_ino);
 		NInoSetAttrList(ni);
-		if (ctx->attr->flags & ATTR_IS_ENCRYPTED ||
-				ctx->attr->flags & ATTR_COMPRESSION_MASK ||
-				ctx->attr->flags & ATTR_IS_SPARSE) {
+		a = ctx->attr;
+		if (a->flags & ATTR_IS_ENCRYPTED ||
+				a->flags & ATTR_COMPRESSION_MASK ||
+				a->flags & ATTR_IS_SPARSE) {
 			ntfs_error(vi->i_sb, "Attribute list attribute is "
 					"compressed/encrypted/sparse.");
 			goto unm_err_out;
 		}
 		/* Now allocate memory for the attribute list. */
-		ni->attr_list_size = (u32)ntfs_attr_size(ctx->attr);
+		ni->attr_list_size = (u32)ntfs_attr_size(a);
 		ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
 		if (!ni->attr_list) {
 			ntfs_error(vi->i_sb, "Not enough memory to allocate "
@@ -690,9 +693,9 @@ static int ntfs_read_locked_inode(struct inode *vi)
 			err = -ENOMEM;
 			goto unm_err_out;
 		}
-		if (ctx->attr->non_resident) {
+		if (a->non_resident) {
 			NInoSetAttrListNonResident(ni);
-			if (ctx->attr->data.non_resident.lowest_vcn) {
+			if (a->data.non_resident.lowest_vcn) {
 				ntfs_error(vi->i_sb, "Attribute list has non "
 						"zero lowest_vcn.");
 				goto unm_err_out;
@@ -702,7 +705,7 @@ static int ntfs_read_locked_inode(struct inode *vi)
 			 * exclusive access to the inode at this time.
 			 */
 			ni->attr_list_rl.rl = ntfs_mapping_pairs_decompress(vol,
-					ctx->attr, NULL);
+					a, NULL);
 			if (IS_ERR(ni->attr_list_rl.rl)) {
 				err = PTR_ERR(ni->attr_list_rl.rl);
 				ni->attr_list_rl.rl = NULL;
@@ -713,27 +716,26 @@ static int ntfs_read_locked_inode(struct inode *vi)
 			/* Now load the attribute list. */
 			if ((err = load_attribute_list(vol, &ni->attr_list_rl,
 					ni->attr_list, ni->attr_list_size,
-					sle64_to_cpu(ctx->attr->data.
-					non_resident.initialized_size)))) {
+					sle64_to_cpu(a->data.non_resident.
+					initialized_size)))) {
 				ntfs_error(vi->i_sb, "Failed to load "
 						"attribute list attribute.");
 				goto unm_err_out;
 			}
-		} else /* if (!ctx.attr->non_resident) */ {
-			if ((u8*)ctx->attr + le16_to_cpu(
-					ctx->attr->data.resident.value_offset) +
-					le32_to_cpu(
-					ctx->attr->data.resident.value_length) >
+		} else /* if (!a->non_resident) */ {
+			if ((u8*)a + le16_to_cpu(a->data.resident.value_offset)
+					+ le32_to_cpu(
+					a->data.resident.value_length) >
 					(u8*)ctx->mrec + vol->mft_record_size) {
 				ntfs_error(vi->i_sb, "Corrupt attribute list "
 						"in inode.");
 				goto unm_err_out;
 			}
 			/* Now copy the attribute list. */
-			memcpy(ni->attr_list, (u8*)ctx->attr + le16_to_cpu(
-					ctx->attr->data.resident.value_offset),
+			memcpy(ni->attr_list, (u8*)a + le16_to_cpu(
+					a->data.resident.value_offset),
 					le32_to_cpu(
-					ctx->attr->data.resident.value_length));
+					a->data.resident.value_length));
 		}
 	}
 skip_attr_list_load:
@@ -746,7 +748,7 @@ skip_attr_list_load:
 		struct inode *bvi;
 		ntfs_inode *bni;
 		INDEX_ROOT *ir;
-		char *ir_end, *index_end;
+		u8 *ir_end, *index_end;
 
 		/* It is a directory, find index root attribute. */
 		ntfs_attr_reinit_search_ctx(ctx);
@@ -762,17 +764,16 @@ skip_attr_list_load:
 			}
 			goto unm_err_out;
 		}
+		a = ctx->attr;
 		/* Set up the state. */
-		if (unlikely(ctx->attr->non_resident)) {
+		if (unlikely(a->non_resident)) {
 			ntfs_error(vol->sb, "$INDEX_ROOT attribute is not "
 					"resident.");
 			goto unm_err_out;
 		}
 		/* Ensure the attribute name is placed before the value. */
-		if (unlikely(ctx->attr->name_length &&
-				(le16_to_cpu(ctx->attr->name_offset) >=
-				le16_to_cpu(ctx->attr->data.resident.
-				value_offset)))) {
+		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+				le16_to_cpu(a->data.resident.value_offset)))) {
 			ntfs_error(vol->sb, "$INDEX_ROOT attribute name is "
 					"placed after the attribute value.");
 			goto unm_err_out;
@@ -783,28 +784,27 @@ skip_attr_list_load:
 		 * encrypted. However index root cannot be both compressed and
 		 * encrypted.
 		 */
-		if (ctx->attr->flags & ATTR_COMPRESSION_MASK)
+		if (a->flags & ATTR_COMPRESSION_MASK)
 			NInoSetCompressed(ni);
-		if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
-			if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+		if (a->flags & ATTR_IS_ENCRYPTED) {
+			if (a->flags & ATTR_COMPRESSION_MASK) {
 				ntfs_error(vi->i_sb, "Found encrypted and "
 						"compressed attribute.");
 				goto unm_err_out;
 			}
 			NInoSetEncrypted(ni);
 		}
-		if (ctx->attr->flags & ATTR_IS_SPARSE)
+		if (a->flags & ATTR_IS_SPARSE)
 			NInoSetSparse(ni);
-		ir = (INDEX_ROOT*)((char*)ctx->attr + le16_to_cpu(
-				ctx->attr->data.resident.value_offset));
-		ir_end = (char*)ir + le32_to_cpu(
-				ctx->attr->data.resident.value_length);
-		if (ir_end > (char*)ctx->mrec + vol->mft_record_size) {
+		ir = (INDEX_ROOT*)((u8*)a +
+				le16_to_cpu(a->data.resident.value_offset));
+		ir_end = (u8*)ir + le32_to_cpu(a->data.resident.value_length);
+		if (ir_end > (u8*)ctx->mrec + vol->mft_record_size) {
 			ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is "
 					"corrupt.");
 			goto unm_err_out;
 		}
-		index_end = (char*)&ir->index +
+		index_end = (u8*)&ir->index +
 				le32_to_cpu(ir->index.index_length);
 		if (index_end > ir_end) {
 			ntfs_error(vi->i_sb, "Directory index is corrupt.");
@@ -891,7 +891,8 @@ skip_attr_list_load:
 						"attribute.");
 			goto unm_err_out;
 		}
-		if (!ctx->attr->non_resident) {
+		a = ctx->attr;
+		if (!a->non_resident) {
 			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
 					"is resident.");
 			goto unm_err_out;
@@ -900,42 +901,40 @@ skip_attr_list_load:
 		 * Ensure the attribute name is placed before the mapping pairs
 		 * array.
 		 */
-		if (unlikely(ctx->attr->name_length &&
-				(le16_to_cpu(ctx->attr->name_offset) >=
-				le16_to_cpu(ctx->attr->data.non_resident.
-				mapping_pairs_offset)))) {
+		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+				le16_to_cpu(
+				a->data.non_resident.mapping_pairs_offset)))) {
 			ntfs_error(vol->sb, "$INDEX_ALLOCATION attribute name "
 					"is placed after the mapping pairs "
 					"array.");
 			goto unm_err_out;
 		}
-		if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
+		if (a->flags & ATTR_IS_ENCRYPTED) {
 			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
 					"is encrypted.");
 			goto unm_err_out;
 		}
-		if (ctx->attr->flags & ATTR_IS_SPARSE) {
+		if (a->flags & ATTR_IS_SPARSE) {
 			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
 					"is sparse.");
 			goto unm_err_out;
 		}
-		if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+		if (a->flags & ATTR_COMPRESSION_MASK) {
 			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
 					"is compressed.");
 			goto unm_err_out;
 		}
-		if (ctx->attr->data.non_resident.lowest_vcn) {
+		if (a->data.non_resident.lowest_vcn) {
 			ntfs_error(vi->i_sb, "First extent of "
 					"$INDEX_ALLOCATION attribute has non "
 					"zero lowest_vcn.");
 			goto unm_err_out;
 		}
-		vi->i_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.data_size);
+		vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
 		ni->initialized_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.initialized_size);
+				a->data.non_resident.initialized_size);
 		ni->allocated_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.allocated_size);
+				a->data.non_resident.allocated_size);
 		/*
 		 * We are done with the mft record, so we release it. Otherwise
 		 * we would deadlock in ntfs_attr_iget().
@@ -1013,10 +1012,11 @@ skip_large_dir_stuff:
 			ntfs_error(vi->i_sb, "$DATA attribute is missing.");
 			goto unm_err_out;
 		}
+		a = ctx->attr;
 		/* Setup the state. */
-		if (ctx->attr->non_resident) {
+		if (a->non_resident) {
 			NInoSetNonResident(ni);
-			if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+			if (a->flags & ATTR_COMPRESSION_MASK) {
 				NInoSetCompressed(ni);
 				if (vol->cluster_size > 4096) {
 					ntfs_error(vi->i_sb, "Found "
@@ -1026,7 +1026,7 @@ skip_large_dir_stuff:
 						vol->cluster_size);
 					goto unm_err_out;
 				}
-				if ((ctx->attr->flags & ATTR_COMPRESSION_MASK)
+				if ((a->flags & ATTR_COMPRESSION_MASK)
 						!= ATTR_IS_COMPRESSED) {
 					ntfs_error(vi->i_sb, "Found "
 						"unknown compression method or "
@@ -1034,37 +1034,37 @@ skip_large_dir_stuff:
 					goto unm_err_out;
 				}
 				ni->itype.compressed.block_clusters = 1U <<
-						ctx->attr->data.non_resident.
+						a->data.non_resident.
 						compression_unit;
-				if (ctx->attr->data.non_resident.
-						compression_unit != 4) {
+				if (a->data.non_resident.compression_unit !=
+						4) {
 					ntfs_error(vi->i_sb, "Found "
 						"nonstandard compression unit "
 						"(%u instead of 4).  Cannot "
 						"handle this.",
-						ctx->attr->data.non_resident.
+						a->data.non_resident.
 						compression_unit);
 					err = -EOPNOTSUPP;
 					goto unm_err_out;
 				}
 				ni->itype.compressed.block_size = 1U << (
-						ctx->attr->data.non_resident.
+						a->data.non_resident.
 						compression_unit +
 						vol->cluster_size_bits);
 				ni->itype.compressed.block_size_bits = ffs(
 					ni->itype.compressed.block_size) - 1;
 			}
-			if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
-				if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+			if (a->flags & ATTR_IS_ENCRYPTED) {
+				if (a->flags & ATTR_COMPRESSION_MASK) {
 					ntfs_error(vi->i_sb, "Found encrypted "
 							"and compressed data.");
 					goto unm_err_out;
 				}
 				NInoSetEncrypted(ni);
 			}
-			if (ctx->attr->flags & ATTR_IS_SPARSE)
+			if (a->flags & ATTR_IS_SPARSE)
 				NInoSetSparse(ni);
-			if (ctx->attr->data.non_resident.lowest_vcn) {
+			if (a->data.non_resident.lowest_vcn) {
 				ntfs_error(vi->i_sb, "First extent of $DATA "
 						"attribute has non zero "
 						"lowest_vcn.");
@@ -1072,28 +1072,28 @@ skip_large_dir_stuff:
 			}
 			/* Setup all the sizes. */
 			vi->i_size = sle64_to_cpu(
-					ctx->attr->data.non_resident.data_size);
+					a->data.non_resident.data_size);
 			ni->initialized_size = sle64_to_cpu(
-					ctx->attr->data.non_resident.
-					initialized_size);
+					a->data.non_resident.initialized_size);
 			ni->allocated_size = sle64_to_cpu(
-					ctx->attr->data.non_resident.
-					allocated_size);
-			if (NInoCompressed(ni)) {
+					a->data.non_resident.allocated_size);
+			if (NInoCompressed(ni))
 				ni->itype.compressed.size = sle64_to_cpu(
-						ctx->attr->data.non_resident.
+						a->data.non_resident.
 						compressed_size);
-			}
 		} else { /* Resident attribute. */
-			/*
-			 * Make all sizes equal for simplicity in read code
-			 * paths. FIXME: Need to keep this in mind when
-			 * converting to non-resident attribute in write code
-			 * path. (Probably only affects truncate().)
-			 */
-			vi->i_size = ni->initialized_size = ni->allocated_size =
-					le32_to_cpu(
-					ctx->attr->data.resident.value_length);
+			/* Setup all the sizes. */
+			vi->i_size = ni->initialized_size = le32_to_cpu(
+					a->data.resident.value_length);
+			ni->allocated_size = le32_to_cpu(a->length) -
+					le16_to_cpu(
+					a->data.resident.value_offset);
+			if (vi->i_size > ni->allocated_size) {
+				ntfs_error(vi->i_sb, "Resident data attribute "
+						"is corrupt (size exceeds "
+						"allocation).");
+				goto unm_err_out;
+			}
 		}
 no_data_attr_special_case:
 		/* We are done with the mft record, so we release it. */
@@ -1169,6 +1169,7 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 	ntfs_volume *vol = NTFS_SB(vi->i_sb);
 	ntfs_inode *ni, *base_ni;
 	MFT_RECORD *m;
+	ATTR_RECORD *a;
 	ntfs_attr_search_ctx *ctx;
 	int err = 0;
 
@@ -1203,24 +1204,21 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 		err = -ENOMEM;
 		goto unm_err_out;
 	}
-
 	/* Find the attribute. */
 	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
 			CASE_SENSITIVE, 0, NULL, 0, ctx);
 	if (unlikely(err))
 		goto unm_err_out;
-
-	if (!ctx->attr->non_resident) {
+	a = ctx->attr;
+	if (!a->non_resident) {
 		/* Ensure the attribute name is placed before the value. */
-		if (unlikely(ctx->attr->name_length &&
-				(le16_to_cpu(ctx->attr->name_offset) >=
-				le16_to_cpu(ctx->attr->data.resident.
-				value_offset)))) {
+		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+				le16_to_cpu(a->data.resident.value_offset)))) {
 			ntfs_error(vol->sb, "Attribute name is placed after "
 					"the attribute value.");
 			goto unm_err_out;
 		}
-		if (NInoMstProtected(ni) || ctx->attr->flags) {
+		if (NInoMstProtected(ni) || a->flags) {
 			ntfs_error(vi->i_sb, "Found mst protected attribute "
 					"or attribute with non-zero flags but "
 					"the attribute is resident.  Please "
@@ -1228,27 +1226,30 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 					"linux-ntfs-dev@lists.sourceforge.net");
 			goto unm_err_out;
 		}
-		/*
-		 * Resident attribute. Make all sizes equal for simplicity in
-		 * read code paths.
-		 */
-		vi->i_size = ni->initialized_size = ni->allocated_size =
-			le32_to_cpu(ctx->attr->data.resident.value_length);
+		/* Resident attribute.  Setup all the sizes. */
+		vi->i_size = ni->initialized_size = le32_to_cpu(
+				a->data.resident.value_length);
+		ni->allocated_size = le32_to_cpu(a->length) -
+				le16_to_cpu(a->data.resident.value_offset);
+		if (vi->i_size > ni->allocated_size) {
+			ntfs_error(vi->i_sb, "Resident data attribute is "
+					"corrupt (size exceeds allocation).");
+			goto unm_err_out;
+		}
 	} else {
 		NInoSetNonResident(ni);
 		/*
 		 * Ensure the attribute name is placed before the mapping pairs
 		 * array.
 		 */
-		if (unlikely(ctx->attr->name_length &&
-				(le16_to_cpu(ctx->attr->name_offset) >=
-				le16_to_cpu(ctx->attr->data.non_resident.
-				mapping_pairs_offset)))) {
+		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+				le16_to_cpu(
+				a->data.non_resident.mapping_pairs_offset)))) {
 			ntfs_error(vol->sb, "Attribute name is placed after "
 					"the mapping pairs array.");
 			goto unm_err_out;
 		}
-		if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+		if (a->flags & ATTR_COMPRESSION_MASK) {
 			if (NInoMstProtected(ni)) {
 				ntfs_error(vi->i_sb, "Found mst protected "
 						"attribute but the attribute "
@@ -1277,36 +1278,33 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 						vol->cluster_size);
 				goto unm_err_out;
 			}
-			if ((ctx->attr->flags & ATTR_COMPRESSION_MASK)
-					!= ATTR_IS_COMPRESSED) {
+			if ((a->flags & ATTR_COMPRESSION_MASK) !=
+					ATTR_IS_COMPRESSED) {
 				ntfs_error(vi->i_sb, "Found unknown "
 						"compression method.");
 				goto unm_err_out;
 			}
 			ni->itype.compressed.block_clusters = 1U <<
-					ctx->attr->data.non_resident.
-					compression_unit;
-			if (ctx->attr->data.non_resident.compression_unit !=
-					4) {
+					a->data.non_resident.compression_unit;
+			if (a->data.non_resident.compression_unit != 4) {
 				ntfs_error(vi->i_sb, "Found nonstandard "
 						"compression unit (%u instead "
 						"of 4).  Cannot handle this.",
-						ctx->attr->data.non_resident.
+						a->data.non_resident.
 						compression_unit);
 				err = -EOPNOTSUPP;
 				goto unm_err_out;
 			}
 			ni->itype.compressed.block_size = 1U << (
-					ctx->attr->data.non_resident.
-					compression_unit +
+					a->data.non_resident.compression_unit +
 					vol->cluster_size_bits);
 			ni->itype.compressed.block_size_bits = ffs(
-				ni->itype.compressed.block_size) - 1;
+					ni->itype.compressed.block_size) - 1;
 		}
-		if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
-			if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
-				ntfs_error(vi->i_sb, "Found encrypted "
-						"and compressed data.");
+		if (a->flags & ATTR_IS_ENCRYPTED) {
+			if (a->flags & ATTR_COMPRESSION_MASK) {
+				ntfs_error(vi->i_sb, "Found encrypted and "
+						"compressed data.");
 				goto unm_err_out;
 			}
 			if (NInoMstProtected(ni)) {
@@ -1320,7 +1318,7 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 			}
 			NInoSetEncrypted(ni);
 		}
-		if (ctx->attr->flags & ATTR_IS_SPARSE) {
+		if (a->flags & ATTR_IS_SPARSE) {
 			if (NInoMstProtected(ni)) {
 				ntfs_error(vi->i_sb, "Found mst protected "
 						"attribute but the attribute "
@@ -1332,23 +1330,20 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 			}
 			NInoSetSparse(ni);
 		}
-		if (ctx->attr->data.non_resident.lowest_vcn) {
+		if (a->data.non_resident.lowest_vcn) {
 			ntfs_error(vi->i_sb, "First extent of attribute has "
 					"non-zero lowest_vcn.");
 			goto unm_err_out;
 		}
 		/* Setup all the sizes. */
-		vi->i_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.data_size);
+		vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
 		ni->initialized_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.initialized_size);
+				a->data.non_resident.initialized_size);
 		ni->allocated_size = sle64_to_cpu(
-				ctx->attr->data.non_resident.allocated_size);
-		if (NInoCompressed(ni)) {
+				a->data.non_resident.allocated_size);
+		if (NInoCompressed(ni))
 			ni->itype.compressed.size = sle64_to_cpu(
-					ctx->attr->data.non_resident.
-					compressed_size);
-		}
+					a->data.non_resident.compressed_size);
 	}
 
 	/* Setup the operations for this attribute inode. */
@@ -1437,6 +1432,7 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
 	ntfs_inode *ni, *base_ni, *bni;
 	struct inode *bvi;
 	MFT_RECORD *m;
+	ATTR_RECORD *a;
 	ntfs_attr_search_ctx *ctx;
 	INDEX_ROOT *ir;
 	u8 *ir_end, *index_end;
@@ -1478,30 +1474,28 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
 					"missing.");
 		goto unm_err_out;
 	}
+	a = ctx->attr;
 	/* Set up the state. */
-	if (unlikely(ctx->attr->non_resident)) {
+	if (unlikely(a->non_resident)) {
 		ntfs_error(vol->sb, "$INDEX_ROOT attribute is not resident.");
 		goto unm_err_out;
 	}
 	/* Ensure the attribute name is placed before the value. */
-	if (unlikely(ctx->attr->name_length &&
-			(le16_to_cpu(ctx->attr->name_offset) >=
-			le16_to_cpu(ctx->attr->data.resident.
-			value_offset)))) {
+	if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+			le16_to_cpu(a->data.resident.value_offset)))) {
 		ntfs_error(vol->sb, "$INDEX_ROOT attribute name is placed "
 				"after the attribute value.");
 		goto unm_err_out;
 	}
 	/* Compressed/encrypted/sparse index root is not allowed. */
-	if (ctx->attr->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_ENCRYPTED |
+	if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_ENCRYPTED |
 			ATTR_IS_SPARSE)) {
 		ntfs_error(vi->i_sb, "Found compressed/encrypted/sparse index "
 				"root attribute.");
 		goto unm_err_out;
 	}
-	ir = (INDEX_ROOT*)((u8*)ctx->attr +
-			le16_to_cpu(ctx->attr->data.resident.value_offset));
-	ir_end = (u8*)ir + le32_to_cpu(ctx->attr->data.resident.value_length);
+	ir = (INDEX_ROOT*)((u8*)a + le16_to_cpu(a->data.resident.value_offset));
+	ir_end = (u8*)ir + le32_to_cpu(a->data.resident.value_length);
 	if (ir_end > (u8*)ctx->mrec + vol->mft_record_size) {
 		ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is corrupt.");
 		goto unm_err_out;
@@ -1574,7 +1568,7 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
 					"$INDEX_ALLOCATION attribute.");
 		goto unm_err_out;
 	}
-	if (!ctx->attr->non_resident) {
+	if (!a->non_resident) {
 		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
 				"resident.");
 		goto unm_err_out;
@@ -1582,37 +1576,36 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
 	/*
 	 * Ensure the attribute name is placed before the mapping pairs array.
 	 */
-	if (unlikely(ctx->attr->name_length && (le16_to_cpu(
-			ctx->attr->name_offset) >= le16_to_cpu(
-			ctx->attr->data.non_resident.mapping_pairs_offset)))) {
+	if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
+			le16_to_cpu(
+			a->data.non_resident.mapping_pairs_offset)))) {
 		ntfs_error(vol->sb, "$INDEX_ALLOCATION attribute name is "
 				"placed after the mapping pairs array.");
 		goto unm_err_out;
 	}
-	if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
+	if (a->flags & ATTR_IS_ENCRYPTED) {
 		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
 				"encrypted.");
 		goto unm_err_out;
 	}
-	if (ctx->attr->flags & ATTR_IS_SPARSE) {
+	if (a->flags & ATTR_IS_SPARSE) {
 		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is sparse.");
 		goto unm_err_out;
 	}
-	if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
+	if (a->flags & ATTR_COMPRESSION_MASK) {
 		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
 				"compressed.");
 		goto unm_err_out;
 	}
-	if (ctx->attr->data.non_resident.lowest_vcn) {
+	if (a->data.non_resident.lowest_vcn) {
 		ntfs_error(vi->i_sb, "First extent of $INDEX_ALLOCATION "
 				"attribute has non zero lowest_vcn.");
 		goto unm_err_out;
 	}
-	vi->i_size = sle64_to_cpu(ctx->attr->data.non_resident.data_size);
+	vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
 	ni->initialized_size = sle64_to_cpu(
-			ctx->attr->data.non_resident.initialized_size);
-	ni->allocated_size = sle64_to_cpu(
-			ctx->attr->data.non_resident.allocated_size);
+			a->data.non_resident.initialized_size);
+	ni->allocated_size = sle64_to_cpu(a->data.non_resident.allocated_size);
 	/*
 	 * We are done with the mft record, so we release it.  Otherwise
 	 * we would deadlock in ntfs_attr_iget().
@@ -1716,7 +1709,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 	struct buffer_head *bh;
 	ntfs_inode *ni;
 	MFT_RECORD *m = NULL;
-	ATTR_RECORD *attr;
+	ATTR_RECORD *a;
 	ntfs_attr_search_ctx *ctx;
 	unsigned int i, nr_blocks;
 	int err;
@@ -1813,9 +1806,10 @@ int ntfs_read_inode_mount(struct inode *vi)
 
 		ntfs_debug("Attribute list attribute found in $MFT.");
 		NInoSetAttrList(ni);
-		if (ctx->attr->flags & ATTR_IS_ENCRYPTED ||
-				ctx->attr->flags & ATTR_COMPRESSION_MASK ||
-				ctx->attr->flags & ATTR_IS_SPARSE) {
+		a = ctx->attr;
+		if (a->flags & ATTR_IS_ENCRYPTED ||
+				a->flags & ATTR_COMPRESSION_MASK ||
+				a->flags & ATTR_IS_SPARSE) {
 			ntfs_error(sb, "Attribute list attribute is "
 					"compressed/encrypted/sparse. Not "
 					"allowed. $MFT is corrupt. You should "
@@ -1823,16 +1817,16 @@ int ntfs_read_inode_mount(struct inode *vi)
 			goto put_err_out;
 		}
 		/* Now allocate memory for the attribute list. */
-		ni->attr_list_size = (u32)ntfs_attr_size(ctx->attr);
+		ni->attr_list_size = (u32)ntfs_attr_size(a);
 		ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
 		if (!ni->attr_list) {
 			ntfs_error(sb, "Not enough memory to allocate buffer "
 					"for attribute list.");
 			goto put_err_out;
 		}
-		if (ctx->attr->non_resident) {
+		if (a->non_resident) {
 			NInoSetAttrListNonResident(ni);
-			if (ctx->attr->data.non_resident.lowest_vcn) {
+			if (a->data.non_resident.lowest_vcn) {
 				ntfs_error(sb, "Attribute list has non zero "
 						"lowest_vcn. $MFT is corrupt. "
 						"You should run chkdsk.");
@@ -1840,7 +1834,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 			}
 			/* Setup the runlist. */
 			ni->attr_list_rl.rl = ntfs_mapping_pairs_decompress(vol,
-					ctx->attr, NULL);
+					a, NULL);
 			if (IS_ERR(ni->attr_list_rl.rl)) {
 				err = PTR_ERR(ni->attr_list_rl.rl);
 				ni->attr_list_rl.rl = NULL;
@@ -1852,7 +1846,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 			/* Now load the attribute list. */
 			if ((err = load_attribute_list(vol, &ni->attr_list_rl,
 					ni->attr_list, ni->attr_list_size,
-					sle64_to_cpu(ctx->attr->data.
+					sle64_to_cpu(a->data.
 					non_resident.initialized_size)))) {
 				ntfs_error(sb, "Failed to load attribute list "
 						"attribute with error code %i.",
@@ -1860,20 +1854,20 @@ int ntfs_read_inode_mount(struct inode *vi)
 				goto put_err_out;
 			}
 		} else /* if (!ctx.attr->non_resident) */ {
-			if ((u8*)ctx->attr + le16_to_cpu(
-					ctx->attr->data.resident.value_offset) +
+			if ((u8*)a + le16_to_cpu(
+					a->data.resident.value_offset) +
 					le32_to_cpu(
-					ctx->attr->data.resident.value_length) >
+					a->data.resident.value_length) >
 					(u8*)ctx->mrec + vol->mft_record_size) {
 				ntfs_error(sb, "Corrupt attribute list "
 						"attribute.");
 				goto put_err_out;
 			}
 			/* Now copy the attribute list. */
-			memcpy(ni->attr_list, (u8*)ctx->attr + le16_to_cpu(
-					ctx->attr->data.resident.value_offset),
+			memcpy(ni->attr_list, (u8*)a + le16_to_cpu(
+					a->data.resident.value_offset),
 					le32_to_cpu(
-					ctx->attr->data.resident.value_length));
+					a->data.resident.value_length));
 		}
 		/* The attribute list is now setup in memory. */
 		/*
@@ -1939,25 +1933,25 @@ int ntfs_read_inode_mount(struct inode *vi)
 	ntfs_attr_reinit_search_ctx(ctx);
 
 	/* Now load all attribute extents. */
-	attr = NULL;
+	a = NULL;
 	next_vcn = last_vcn = highest_vcn = 0;
 	while (!(err = ntfs_attr_lookup(AT_DATA, NULL, 0, 0, next_vcn, NULL, 0,
 			ctx))) {
 		runlist_element *nrl;
 
 		/* Cache the current attribute. */
-		attr = ctx->attr;
+		a = ctx->attr;
 		/* $MFT must be non-resident. */
-		if (!attr->non_resident) {
+		if (!a->non_resident) {
 			ntfs_error(sb, "$MFT must be non-resident but a "
 					"resident extent was found. $MFT is "
 					"corrupt. Run chkdsk.");
 			goto put_err_out;
 		}
 		/* $MFT must be uncompressed and unencrypted. */
-		if (attr->flags & ATTR_COMPRESSION_MASK ||
-				attr->flags & ATTR_IS_ENCRYPTED ||
-				attr->flags & ATTR_IS_SPARSE) {
+		if (a->flags & ATTR_COMPRESSION_MASK ||
+				a->flags & ATTR_IS_ENCRYPTED ||
+				a->flags & ATTR_IS_SPARSE) {
 			ntfs_error(sb, "$MFT must be uncompressed, "
 					"non-sparse, and unencrypted but a "
 					"compressed/sparse/encrypted extent "
@@ -1971,7 +1965,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 		 * as we have exclusive access to the inode at this time and we
 		 * are a mount in progress task, too.
 		 */
-		nrl = ntfs_mapping_pairs_decompress(vol, attr, ni->runlist.rl);
+		nrl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl);
 		if (IS_ERR(nrl)) {
 			ntfs_error(sb, "ntfs_mapping_pairs_decompress() "
 					"failed with error code %ld.  $MFT is "
@@ -1982,7 +1976,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 
 		/* Are we in the first extent? */
 		if (!next_vcn) {
-			if (attr->data.non_resident.lowest_vcn) {
+			if (a->data.non_resident.lowest_vcn) {
 				ntfs_error(sb, "First extent of $DATA "
 						"attribute has non zero "
 						"lowest_vcn. $MFT is corrupt. "
@@ -1991,15 +1985,15 @@ int ntfs_read_inode_mount(struct inode *vi)
 			}
 			/* Get the last vcn in the $DATA attribute. */
 			last_vcn = sle64_to_cpu(
-					attr->data.non_resident.allocated_size)
+					a->data.non_resident.allocated_size)
 					>> vol->cluster_size_bits;
 			/* Fill in the inode size. */
 			vi->i_size = sle64_to_cpu(
-					attr->data.non_resident.data_size);
-			ni->initialized_size = sle64_to_cpu(attr->data.
-					non_resident.initialized_size);
+					a->data.non_resident.data_size);
+			ni->initialized_size = sle64_to_cpu(
+					a->data.non_resident.initialized_size);
 			ni->allocated_size = sle64_to_cpu(
-					attr->data.non_resident.allocated_size);
+					a->data.non_resident.allocated_size);
 			/*
 			 * Verify the number of mft records does not exceed
 			 * 2^32 - 1.
@@ -2056,7 +2050,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 		}
 
 		/* Get the lowest vcn for the next extent. */
-		highest_vcn = sle64_to_cpu(attr->data.non_resident.highest_vcn);
+		highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
 		next_vcn = highest_vcn + 1;
 
 		/* Only one extent or error, which we catch below. */
@@ -2065,7 +2059,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 
 		/* Avoid endless loops due to corruption. */
 		if (next_vcn < sle64_to_cpu(
-				attr->data.non_resident.lowest_vcn)) {
+				a->data.non_resident.lowest_vcn)) {
 			ntfs_error(sb, "$MFT has corrupt attribute list "
 					"attribute. Run chkdsk.");
 			goto put_err_out;
@@ -2076,7 +2070,7 @@ int ntfs_read_inode_mount(struct inode *vi)
 				"$MFT is corrupt. Run chkdsk.");
 		goto put_err_out;
 	}
-	if (!attr) {
+	if (!a) {
 		ntfs_error(sb, "$MFT/$DATA attribute not found. $MFT is "
 				"corrupt. Run chkdsk.");
 		goto put_err_out;
@@ -2318,6 +2312,7 @@ int ntfs_truncate(struct inode *vi)
 	ntfs_volume *vol = ni->vol;
 	ntfs_attr_search_ctx *ctx;
 	MFT_RECORD *m;
+	ATTR_RECORD *a;
 	const char *te = "  Leaving file length out of sync with i_size.";
 	int err;
 
@@ -2354,14 +2349,15 @@ int ntfs_truncate(struct inode *vi)
 					vi->i_ino, err);
 		goto err_out;
 	}
+	a = ctx->attr;
 	/* If the size has not changed there is nothing to do. */
-	if (ntfs_attr_size(ctx->attr) == i_size_read(vi))
+	if (ntfs_attr_size(a) == i_size_read(vi))
 		goto done;
 	// TODO: Implement the truncate...
 	ntfs_error(vi->i_sb, "Inode size has changed but this is not "
 			"implemented yet.  Resetting inode size to old value. "
 			" This is most likely a bug in the ntfs driver!");
-	i_size_write(vi, ntfs_attr_size(ctx->attr)); 
+	i_size_write(vi, ntfs_attr_size(a)); 
 done:
 	ntfs_attr_put_search_ctx(ctx);
 	unmap_mft_record(ni);