NTFS: Minor bug fix in attribute list attribute handling that fixes the

I/O errors on "ls" of certain fragmented files found by at least two
people running Windows XP.

Documentation/filesystems/ntfs.txt

@@ -272,6 +272,10 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.1.5:
+	- Minor bug fix in attribute list attribute handling that fixes the
+	  I/O errors on "ls" of certain fragmented files found by at least two
+	  people running Windows XP.
 2.1.4:
 	- Minor update allowing compilation with all gcc versions (well, the
 	  ones the kernel can be compiled with anyway).

fs/ntfs/ChangeLog

@@ -20,6 +20,14 @@ ToDo:
 	  sufficient for synchronisation here. We then just need to make sure
 	  ntfs_readpage/writepage/truncate interoperate properly with us.
 
+2.1.5 - Fix minor bug in attribute list attribute handling.
+
+	- Fix bug in attribute list handling.  Actually it is not as much a bug
+	  as too much protection in that we were not allowing attribute lists
+	  which waste space on disk while Windows XP clearly allows it and in
+	  fact creates such attribute lists so our driver was failing.
+	- Update NTFS documentation ready for 2.6 kernel release.
+
 2.1.4 - Reduce compiler requirements.
 
 	- Remove all uses of unnamed structs and unions in the driver to make

fs/ntfs/Makefile

@@ -5,7 +5,7 @@ obj-$(CONFIG_NTFS_FS) += ntfs.o
 ntfs-objs := aops.o attrib.o compress.o debug.o dir.o file.o inode.o mft.o \
 	     mst.o namei.o super.o sysctl.o time.o unistr.o upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.4\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.5\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG

fs/ntfs/attrib.c

@@ -1215,7 +1215,7 @@ BOOL find_attr(const ATTR_TYPES type, const uchar_t *name, const u32 name_len,
  * load_attribute_list - load an attribute list into memory
  * @vol:		ntfs volume from which to read
  * @run_list:		run list of the attribute list
- * @al:			destination buffer
+ * @al_start:		destination buffer
  * @size:		size of the destination buffer in bytes
  * @initialized_size:	initialized size of the attribute list
  *
@@ -1227,10 +1227,11 @@ BOOL find_attr(const ATTR_TYPES type, const uchar_t *name, const u32 name_len,
  *
  * Return 0 on success or -errno on error.
  */
-int load_attribute_list(ntfs_volume *vol, run_list *run_list, u8 *al,
+int load_attribute_list(ntfs_volume *vol, run_list *run_list, u8 *al_start,
 		const s64 size, const s64 initialized_size)
 {
 	LCN lcn;
+	u8 *al = al_start;
 	u8 *al_end = al + initialized_size;
 	run_list_element *rl;
 	struct buffer_head *bh;
@@ -1284,31 +1285,27 @@ int load_attribute_list(ntfs_volume *vol, run_list *run_list, u8 *al,
 	}
 	if (initialized_size < size) {
 initialize:
-		memset(al + initialized_size, 0, size - initialized_size);
+		memset(al_start + initialized_size, 0, size - initialized_size);
 	}
 done:
 	up_read(&run_list->lock);
 	return err;
 do_final:
 	if (al < al_end) {
-		/* Partial block. */
-		memcpy(al, bh->b_data, al_end - al);
-		brelse(bh);
 		/*
-		 * Skip sanity checking if initialized_size < size as it is
-		 * too much trouble.
+		 * Partial block.
+		 *
+		 * Note: The attribute list can be smaller than its allocation
+		 * by multiple clusters.  This has been encountered by at least
+		 * two people running Windows XP, thus we cannot do any
+		 * truncation sanity checking here. (AIA)
 		 */
+		memcpy(al, bh->b_data, al_end - al);
+		brelse(bh);
 		if (initialized_size < size)
 			goto initialize;
-		/* If the final lcn is partial all is fine. */
-		if (((s64)(block - (lcn << vol->cluster_size_bits >>
-				block_size_bits)) << block_size_bits >>
-				vol->cluster_size_bits) == rl->length - 1) {
-			if (!rl[1].length || (rl[1].lcn == LCN_RL_NOT_MAPPED
-					&& !rl[2].length))
 		goto done;
 	}
-	} else
 	brelse(bh);
 	/* Real overflow! */
 	ntfs_error(sb, "Attribute list buffer overflow. Read attribute list "

fs/ntfs/attrib.h

@@ -87,7 +87,7 @@ BOOL lookup_attr(const ATTR_TYPES type, const uchar_t *name, const u32 name_len,
 		const IGNORE_CASE_BOOL ic, const VCN lowest_vcn, const u8 *val,
 		const u32 val_len, attr_search_context *ctx);
 
-extern int load_attribute_list(ntfs_volume *vol, run_list *rl, u8 *al,
+extern int load_attribute_list(ntfs_volume *vol, run_list *rl, u8 *al_start,
 		const s64 size, const s64 initialized_size);
 
 static inline s64 attribute_value_length(const ATTR_RECORD *a)