Squashfs: add decompressor entries for lzma and lzo

Add knowledge of lzma/lzo compression formats to the decompressor
framework.  For now these are added as unsupported.  Without
these entries lzma/lzo compressed filesystems will be flagged as
having unknown compression which is undesirable.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>

fs/squashfs/decompressor.c

@@ -36,12 +36,22 @@
  * Squashfs, allowing multiple decompressors to be easily supported
  */
 
+static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
+	NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
+};
+
+static const struct squashfs_decompressor squashfs_lzo_unsupported_comp_ops = {
+	NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
+};
+
 static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
 	NULL, NULL, NULL, 0, "unknown", 0
 };
 
 static const struct squashfs_decompressor *decompressor[] = {
 	&squashfs_zlib_comp_ops,
+	&squashfs_lzma_unsupported_comp_ops,
+	&squashfs_lzo_unsupported_comp_ops,
 	&squashfs_unknown_comp_ops
 };
 

fs/squashfs/squashfs_fs.h

@@ -211,7 +211,9 @@ struct meta_index {
 /*
  * definitions for structures on disk
  */
-#define ZLIB_COMPRESSION	 1
+#define ZLIB_COMPRESSION	1
+#define LZMA_COMPRESSION	2
+#define LZO_COMPRESSION		3
 
 struct squashfs_super_block {
 	__le32			s_magic;