btrfs-progs: build: add option to disable LZO support for restore

LZO as a compression format is pretty archaic these days, there are
better algorithms in all metrics for compression and decompression, and
lzo hasn't had a new release since 2017.

Add an option to disable LZO (defaulting to enabled), and respect it in
cmds/restore.c.

NOTE: disabling support for LZO will make make it impossible to restore
data from filesystems where the compression has ever been used. It's not
recommended to build without the support in general.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Makefile

@@ -335,7 +335,7 @@ endif
 btrfs_convert_cflags = -DBTRFSCONVERT_EXT2=$(BTRFSCONVERT_EXT2)
 btrfs_convert_cflags += -DBTRFSCONVERT_REISERFS=$(BTRFSCONVERT_REISERFS)
 btrfs_fragments_libs = -lgd -lpng -ljpeg -lfreetype
-cmds_restore_cflags = -DBTRFSRESTORE_ZSTD=$(BTRFSRESTORE_ZSTD)
+cmds_restore_cflags = -DBTRFSRESTORE_LZO=$(BTRFSRESTORE_LZO) -DBTRFSRESTORE_ZSTD=$(BTRFSRESTORE_ZSTD)
 
 ifeq ($(CRYPTOPROVIDER_BUILTIN),1)
 CRYPTO_OBJECTS = crypto/sha224-256.o crypto/blake2b-ref.o

Makefile.inc.in

@@ -16,6 +16,7 @@ BUILD_PROGRAMS = @BUILD_PROGRAMS@
 BUILD_SHARED_LIBRARIES = @BUILD_SHARED_LIBRARIES@
 BUILD_STATIC_LIBRARIES = @BUILD_STATIC_LIBRARIES@
 BTRFSCONVERT_EXT2 = @BTRFSCONVERT_EXT2@
+BTRFSRESTORE_LZO = @BTRFSRESTORE_LZO@
 BTRFSCONVERT_REISERFS = @BTRFSCONVERT_REISERFS@
 BTRFSRESTORE_ZSTD = @BTRFSRESTORE_ZSTD@
 PYTHON_BINDINGS = @PYTHON_BINDINGS@

cmds/restore.c

@@ -25,8 +25,10 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#if BTRFSRESTORE_LZO
 #include <lzo/lzoconf.h>
 #include <lzo/lzo1x.h>
+#endif
 #include <zlib.h>
 #if BTRFSRESTORE_ZSTD
 #include <zstd.h>
@@ -98,6 +100,10 @@ static inline size_t read_compress_length(unsigned char *buf)
 static int decompress_lzo(struct btrfs_root *root, unsigned char *inbuf,
 			char *outbuf, u64 compress_len, u64 *decompress_len)
 {
+#if !BTRFSRESTORE_LZO
+	error("btrfs-restore not compiled with lzo support");
+	return -1;
+#else
 	size_t new_len;
 	size_t in_len;
 	size_t out_len = 0;
@@ -156,6 +162,7 @@ static int decompress_lzo(struct btrfs_root *root, unsigned char *inbuf,
 	*decompress_len = out_len;
 
 	return 0;
+#endif
 }
 
 static int decompress_zstd(const char *inbuf, char *outbuf, u64 compress_len,

configure.ac

@@ -372,16 +372,26 @@ if ${PKG_CONFIG} udev --atleast-version 190; then
 fi
 AC_SUBST(UDEVDIR)
 
-dnl lzo library does not provide pkg-config, let use classic way
-AC_CHECK_LIB([lzo2], [lzo_version], [
-	LZO2_LIBS="-llzo2"
-	LZO2_CFLAGS=""
-	LZO2_LIBS_STATIC="-llzo2"],[
-	AC_MSG_ERROR([cannot find lzo2 library])
-])
-AC_SUBST([LZO2_LIBS])
-AC_SUBST([LZO2_LIBS_STATIC])
-AC_SUBST([LZO2_CFLAGS])
+AC_ARG_ENABLE([lzo],
+	AS_HELP_STRING([--disable-lzo], [build without lzo support (default: enabled)]),
+	[], [enable_lzo=yes]
+)
+
+if test "x$enable_lzo" = xyes; then
+	dnl lzo library does not provide pkg-config, use classic way
+	AC_CHECK_LIB([lzo2], [lzo_version], [
+		LZO2_LIBS="-llzo2"
+		LZO2_CFLAGS=""
+		LZO2_LIBS_STATIC="-llzo2"],[
+		AC_MSG_ERROR([cannot find lzo2 library])
+	])
+	AC_SUBST([LZO2_LIBS])
+	AC_SUBST([LZO2_LIBS_STATIC])
+	AC_SUBST([LZO2_CFLAGS])
+fi
+
+AS_IF([test "x$enable_lzo" = xyes], [BTRFSRESTORE_LZO=1], [BTRFSRESTORE_LZO=0])
+AC_SUBST(BTRFSRESTORE_LZO)
 
 dnl call PKG_INSTALLDIR from pkg.m4 to set pkgconfigdir
 m4_ifdef([PKG_INSTALLDIR], [PKG_INSTALLDIR], [AC_MSG_ERROR([please install pkgconf])])