NTFS: Add support for sparse files which have a compression unit of 0.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

1 files changed, 12 insertions, 7 deletions

diff --git a/fs/ntfs/layout.h b/fs/ntfs/layout.h
index bb408d4dcbb0..f4283e120709 100644
--- a/fs/ntfs/layout.h
+++ b/fs/ntfs/layout.h
@@ -769,7 +769,7 @@ typedef struct {
                                 compressed.  (This effectively limits the
                                 compression unit size to be a power of two
                                 clusters.)  WinNT4 only uses a value of 4.
-                                Sparse files also have this set to 4. */
+                                Sparse files have this set to 0 on XPSP2. */
 /* 35*/                 u8 reserved[5];         /* Align to 8-byte boundary. */
 /* The sizes below are only used when lowest_vcn is zero, as otherwise it would
    be difficult to keep them up-to-date.*/
@@ -1076,16 +1076,21 @@ typedef struct {
 /* 20*/ sle64 last_access_time;         /* Time this mft record was last
                                            accessed. */
 /* 28*/ sle64 allocated_size;           /* Byte size of on-disk allocated space
-                                           for the data attribute.  So for
-                                           normal $DATA, this is the
+                                           for the unnamed data attribute.  So
+                                           for normal $DATA, this is the
                                            allocated_size from the unnamed
                                            $DATA attribute and for compressed
                                            and/or sparse $DATA, this is the
                                            compressed_size from the unnamed
-                                           $DATA attribute.  NOTE: This is a
-                                           multiple of the cluster size. */
-/* 30*/ sle64 data_size;                /* Byte size of actual data in data
-                                           attribute. */
+                                           $DATA attribute.  For a directory or
+                                           other inode without an unnamed $DATA
+                                           attribute, this is always 0.  NOTE:
+                                           This is a multiple of the cluster
+                                           size. */
+/* 30*/ sle64 data_size;                /* Byte size of actual data in unnamed
+                                           data attribute.  For a directory or
+                                           other inode without an unnamed $DATA
+                                           attribute, this is always 0. */
 /* 38*/ FILE_ATTR_FLAGS file_attributes;        /* Flags describing the file. */
 /* 3c*/ union {
         /* 3c*/ struct {