btrfs-progs: build on SLE11

From: Jeff Mahoney <[email protected]>

This patch set allows btrfs-progs to build without further patching on a stock SLE11 SP4 install. The major issues were:
- new dependencies on e2fsprogs 1.42
- use of -std=gnu90, which gcc 4.3.4 doesn't support
- use of m4_chomp, introduced in autoconf 2.64.

This patch set is also posted as a GitHub pull request:
https://github.com/kdave/btrfs-progs/pull/125

-Jeff

---

Jeff Mahoney (3):
btrfs-progs: convert: fix support for e2fsprogs < 1.42
btrfs-progs: build: detect whether -std=gnu90 is supported
btrfs-progs: build: use m4_flatten instead of m4_chomp

 Makefile                    |  1 -
 Makefile.inc.in             |  1 +
 configure.ac                | 10 +++---
 convert/source-ext2.h       | 12 +++++++-
 m4/ax_check_compile_flag.m4 | 74 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 90 insertions(+), 8 deletions(-)
 create mode 100644 m4/ax_check_compile_flag.m4

2.12.3

From: Jeff Mahoney <[email protected]>

Commit 324d4c1857a (btrfs-progs: convert: Add larger device support) introduced new dependencies on the 64-bit API provided by e2fsprogs. That API was introduced in v1.42 (along with bigalloc).

This patch maps the following to their equivalents in e2fsprogs < 1.42.
- ext2fs_get_block_bitmap_range2
- ext2fs_inode_data_blocks2
- ext2fs_read_ext_attr2

Since we need to detect and define EXT2_FLAG_64BITS for compatibilty anyway, it makes sense to use that to detect the older e2fsprogs instead of defining a new flag ourselves.

---
 configure.ac          |  6 +-----
 convert/source-ext2.h | 12 +++++++++++-
 2 files changed, 12 insertions(+), 6 deletions(-)

index af13a959..2dea1c64 100644
@@ -140,11 +140,7 @@ BTRFSCONVERT_EXT2=0
 BTRFSCONVERT_REISERFS=0
 if test "x$enable_convert" = xyes; then
 	if test "x$with_convert" = "xauto" || echo "$with_convert" | grep -q "ext2"; then
-		PKG_CHECK_MODULES(EXT2FS, [ext2fs >= 1.42],,
-			[PKG_CHECK_MODULES(EXT2FS, [ext2fs],
-				[AC_DEFINE([HAVE_OLD_E2FSPROGS], [1],
-					  [E2fsprogs does not support BIGALLOC])]
-				)])
+		PKG_CHECK_MODULES(EXT2FS, [ext2fs])
 		PKG_CHECK_MODULES(COM_ERR, [com_err])
 		convertfs="${convertfs:+$convertfs,}ext2"
 		BTRFSCONVERT_EXT2=1

index 80833b21..c3214125 100644
@@ -33,8 +33,18 @@
  * BIGALLOC.
  * Unlike normal RO compat flag, BIGALLOC affects how e2fsprogs check used
  * space, and btrfs-convert heavily relies on it.
+ *
+ * e2fsprogs 1.42 also introduced the 64-bit API.  Any file system
+ * that requires it will have EXT4_FEATURE_INCOMPAT_64BIT set and
+ * will fail to open with earlier releases.  We can map it to the
+ * older API without risk of corruption.
  */
-#ifdef HAVE_OLD_E2FSPROGS
+#ifndef EXT2_FLAG_64BITS
+#define EXT2_FLAG_64BITS		(0)
+#define ext2fs_get_block_bitmap_range2 ext2fs_get_block_bitmap_range
+#define ext2fs_inode_data_blocks2 ext2fs_inode_data_blocks
+#define ext2fs_read_ext_attr2 ext2fs_read_ext_attr
+#define ext2fs_blocks_count(s)		((s)->s_blocks_count)
 #define EXT2FS_CLUSTER_RATIO(fs)	(1)
 #define EXT2_CLUSTERS_PER_GROUP(s)	(EXT2_BLOCKS_PER_GROUP(s))
 #define EXT2FS_B2C(fs, blk)		(blk)

2.12.3

From: Jeff Mahoney <[email protected]>

Older versions of gcc don't support -std=gnu90 so btrfs-progs won't build at all on older distros. We can detect whether the compiler supports -std=gnu90 and fall back to -std=gnu89 if it doesn't.

---
 Makefile                    |  1 -
 Makefile.inc.in             |  1 +
 configure.ac                |  2 ++
 m4/ax_check_compile_flag.m4 | 74 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 m4/ax_check_compile_flag.m4

index 5ba76d2e..c0eb3d68 100644
@@ -63,7 +63,6 @@ ABSTOPDIR = $(shell pwd)
 TOPDIR := .
 
 # Common build flags
-CSTD = -std=gnu90
 CFLAGS = $(SUBST_CFLAGS) \
 	 $(CSTD) \
 	 -include config.h \

index 52410f69..fc3dec69 100644
@@ -4,6 +4,7 @@
 export
 
 CC = @CC@
+CSTD = @CSTD@
 LN_S = @LN_S@
 AR = @AR@
 RM = @RM@

index 2dea1c64..17880206 100644
@@ -30,6 +30,8 @@ AC_CANONICAL_HOST
 AC_C_CONST
 AC_C_VOLATILE
 AC_C_BIGENDIAN
+AX_CHECK_COMPILE_FLAG([-std=gnu90],[CSTD=-std=gnu90],[CSTD=-std=gnu89])
+AC_SUBST([CSTD])
 
 AC_SYS_LARGEFILE
 

2.12.3

From: Jeff Mahoney <[email protected]>

Commit 2e1932e6a38 (btrfs-progs: build: simplify version tracking) started m4_chomp to strip the newlines from the version file. m4_chomp was introduced in autoconf 2.64 but SLE11 ships with autoconf 2.63. For purposes of just stripping the newline, m4_flatten is sufficient.

---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 17880206..a0cebf15 100644
@@ -1,5 +1,5 @@
 AC_INIT([btrfs-progs],
-	m4_chomp(m4_include([VERSION])),
+	m4_flatten(m4_include([VERSION])),
 	[[email protected]],,
 	[http://btrfs.wiki.kernel.org])
 

2.12.3

Scratch that. The previous patch also requires autoconf 2.64.

-Jeff

Jeff Mahoney
SUSE Labs

I wanted to avoid shell tricks, but this should work everywhere:

m4_esyscmd([echo -n $(cat VERSION)])

m4_flatten should work everywhere. It's the AX_CHECK_COMPILE_FLAGS that depends on autoconf 2.64.

I can fix the dependency, but it ends up looking like:

m4_version_prereq([2.64], [

    AX_CHECK_COMPILE_FLAG([-std=gnu90],[CSTD=-std=gnu90],[CSTD=-std=gnu89])
  ], [
    AX_GCC_VERSION([4], [5], [0], [CSTD=-std=gnu90],[CSTD=-std=gnu89])

])
AC_SUBST([CSTD])

AX_GCC_VERSION is deprecated, but works with earlier autoconf versions. I'm not thrilled about it, but keying off the autoconf version and using the newer way for newer versions means it'll be easier to drop it later when we drop support for earlier autoconf.

Alternatively, I can just put this patch in the OBS project.

-Jeff

Jeff Mahoney
SUSE Labs