[PATCH 4/8] ntfs: parse REPARSE_TAG_WOF

Introduce parsing support for REPARSE_TAG_WOF reparse points. Rename
ntfs_make_symlink() to ntfs_parse_reparse() since it now handles both
symlinks and WOF reparse tags. Introduce NI_WofCompressed flag to
indicate files compressed via Windows System Compression (WOF), and
configure compressed block size accordingly (12 to 15 bits based on the
format).

Signed-off-by: Hyunchul Lee <[email protected]>
---
 fs/ntfs/inode.c   |  5 ++--
 fs/ntfs/inode.h   | 11 ++++++++
 fs/ntfs/reparse.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 fs/ntfs/reparse.h |  2 +-
 4 files changed, 90 insertions(+), 5 deletions(-)

diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
index 39c7fd8c1149..8d9bbc151309 100644
--- a/fs/ntfs/inode.c
+++ b/fs/ntfs/inode.c
@@ -869,7 +869,7 @@ static int ntfs_read_locked_inode(struct inode *vi)
 	if (ni->flags & FILE_ATTR_REPARSE_POINT) {
 		unsigned int mode;
 
-		mode = ntfs_make_symlink(ni);
+		mode = ntfs_parse_reparse(ni);
 		if (mode)
 			vi->i_mode |= mode;
 		else {
@@ -1214,7 +1214,8 @@ static int ntfs_read_locked_inode(struct inode *vi)
 	 * sizes of all non-resident attributes present to give us the Linux
 	 * correct size that should go into i_blocks (after division by 512).
 	 */
-	if (S_ISREG(vi->i_mode) && (NInoCompressed(ni) || NInoSparse(ni)))
+	if (S_ISREG(vi->i_mode) &&
+	    (NInoCompressed(ni) || (NInoSparse(ni) && !NInoWofCompressed(ni))))
 		vi->i_blocks = ni->itype.compressed.size >> 9;
 	else
 		vi->i_blocks = ni->allocated_size >> 9;
diff --git a/fs/ntfs/inode.h b/fs/ntfs/inode.h
index c6d065aaecd5..943a2960f029 100644
--- a/fs/ntfs/inode.h
+++ b/fs/ntfs/inode.h
@@ -189,6 +189,9 @@ enum {
 	NI_NonResident,
 	NI_IndexAllocPresent,
 	NI_Compressed,
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+	NI_WofCompressed,
+#endif
 	NI_Encrypted,
 	NI_Sparse,
 	NI_SparseDisabled,
@@ -248,6 +251,14 @@ NINO_FNS(MstProtected)
 NINO_FNS(NonResident)
 NINO_FNS(IndexAllocPresent)
 NINO_FNS(Compressed)
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+NINO_FNS(WofCompressed)
+#else
+static inline int NInoWofCompressed(struct ntfs_inode *ni)
+{
+	return 0;
+}
+#endif
 NINO_FNS(Encrypted)
 NINO_FNS(Sparse)
 NINO_FNS(SparseDisabled)
diff --git a/fs/ntfs/reparse.c b/fs/ntfs/reparse.c
index 0d3988992119..8269fab33f38 100644
--- a/fs/ntfs/reparse.c
+++ b/fs/ntfs/reparse.c
@@ -24,6 +24,27 @@ struct wsl_link_reparse_data {
 	char	link[];
 };
 
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+struct wof_reparse_data {
+	__le32 version;
+	__le32 provider;
+	__le32 provider_version;
+	__le32 compression_format;
+} __packed;
+
+#define WOF_CURRENT_VERSION			cpu_to_le32(1)
+
+#define WOF_PROVIDER_WIM			cpu_to_le32(1)
+#define WOF_PROVIDER_FILE			cpu_to_le32(2)
+
+#define WOF_PROVIDER_CURRENT_VERSION		cpu_to_le32(1)
+
+#define WOF_COMPRESSION_XPRESS4K		cpu_to_le32(0)
+#define WOF_COMPRESSION_LZX			cpu_to_le32(1)
+#define WOF_COMPRESSION_XPRESS8K		cpu_to_le32(2)
+#define WOF_COMPRESSION_XPRESS16K		cpu_to_le32(3)
+#endif
+
 static bool reparse_name_is_valid(size_t size, size_t name_off, u16 len)
 {
 	if ((name_off | len) & 1)
@@ -203,6 +224,30 @@ static bool valid_reparse_data(struct ntfs_inode *ni,
 		    !(ni->flags & FILE_ATTRIBUTE_RECALL_ON_OPEN))
 			return false;
 		break;
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+	case IO_REPARSE_TAG_WOF: {
+		const struct wof_reparse_data *wof_data =
+			(const struct wof_reparse_data *)reparse_attr->reparse_data;
+
+		if (!valid_reparse_buffer(ni, reparse_attr, size,
+					  sizeof(struct wof_reparse_data)))
+			return false;
+
+		if (le16_to_cpu(reparse_attr->reparse_data_length) <
+		    sizeof(struct wof_reparse_data) ||
+		    wof_data->version != WOF_CURRENT_VERSION ||
+		    wof_data->provider != WOF_PROVIDER_FILE ||
+		    wof_data->provider_version !=
+		    WOF_PROVIDER_CURRENT_VERSION)
+			return false;
+		if (wof_data->compression_format != WOF_COMPRESSION_XPRESS4K &&
+		    wof_data->compression_format != WOF_COMPRESSION_XPRESS8K &&
+		    wof_data->compression_format != WOF_COMPRESSION_XPRESS16K &&
+		    wof_data->compression_format != WOF_COMPRESSION_LZX)
+			return false;
+		break;
+	}
+#endif
 	default:
 		if (!valid_reparse_buffer(ni, reparse_attr, size, 0))
 			return false;
@@ -239,9 +284,9 @@ static unsigned int ntfs_reparse_tag_mode(__le32 reparse_tag)
 }
 
 /*
- * Get the target for symbolic link
+ * Parse reparse point data and initialize its in-memory representation.
  */
-unsigned int ntfs_make_symlink(struct ntfs_inode *ni)
+unsigned int ntfs_parse_reparse(struct ntfs_inode *ni)
 {
 	s64 attr_size = 0;
 	int err;
@@ -306,6 +351,34 @@ unsigned int ntfs_make_symlink(struct ntfs_inode *ni)
 			}
 			break;
 		}
+#ifdef CONFIG_NTFS_FS_WOF_COMPRESSION
+		case IO_REPARSE_TAG_WOF:
+		{
+			const struct wof_reparse_data *wof_data =
+				(const struct wof_reparse_data *)reparse_attr->reparse_data;
+
+			switch (wof_data->compression_format) {
+			case WOF_COMPRESSION_XPRESS4K:
+				ni->itype.compressed.block_size_bits = 12;
+				break;
+			case WOF_COMPRESSION_XPRESS8K:
+				ni->itype.compressed.block_size_bits = 13;
+				break;
+			case WOF_COMPRESSION_XPRESS16K:
+				ni->itype.compressed.block_size_bits = 14;
+				break;
+			case WOF_COMPRESSION_LZX:
+				ni->itype.compressed.block_size_bits = 15;
+				break;
+			}
+			ni->itype.compressed.block_size =
+				1 << ni->itype.compressed.block_size_bits;
+			NInoSetWofCompressed(ni);
+			VFS_I(ni)->i_mode &= ~0222;
+			err = 0;
+			break;
+		}
+#endif
 		default:
 			err = 0;
 		}
diff --git a/fs/ntfs/reparse.h b/fs/ntfs/reparse.h
index c11a5bb7e6a5..3bd30cb36561 100644
--- a/fs/ntfs/reparse.h
+++ b/fs/ntfs/reparse.h
@@ -9,7 +9,7 @@
 
 extern __le16 reparse_index_name[];
 
-unsigned int ntfs_make_symlink(struct ntfs_inode *ni);
+unsigned int ntfs_parse_reparse(struct ntfs_inode *ni);
 unsigned int ntfs_reparse_tag_dt_types(struct ntfs_volume *vol, unsigned long mref);
 int ntfs_translate_symlink_path(struct dentry *dentry, const char *target,
 				char **translated);

-- 
2.43.0