btrfs-progs: convert: add compatibility layer for e2fsprogs < 1.42

The new convert framework copies code from current dumpe2fs, which uses
BIGALLOC feature introduced in e2fsprogs v1.42.

While there are a lot of enterprise distributions which are still using
v1.41 e2fsprogs, this will cause compile error for them.

This patch introduces backward compatibility for new convert framework,
by manually introduce macros for ext2 BIGALLOC feature.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/btrfs-convert.c b/btrfs-convert.c
index 9f90651081c4cc19917582ca32e5d21f2bdd79d3..e9e6d0b32795e5f32948a1dc818506cb01f92bfa 100644 (file)
--- a/btrfs-convert.c
+++ b/btrfs-convert.c
@@ -44,6 +44,18 @@
 #define INO_OFFSET (BTRFS_FIRST_FREE_OBJECTID - EXT2_ROOT_INO)
 #define CONV_IMAGE_SUBVOL_OBJECTID BTRFS_FIRST_FREE_OBJECTID
 
+/*
+ * Compatibility code for e2fsprogs 1.41 which doesn't support RO compat flag
+ * BIGALLOC.
+ * Unlike normal RO compat flag, BIGALLOC affects how e2fsprogs check used
+ * space, and btrfs-convert heavily relies on it.
+ */
+#ifdef HAVE_OLD_E2FSPROGS
+#define EXT2FS_CLUSTER_RATIO(fs)       (1)
+#define EXT2_CLUSTERS_PER_GROUP(s)     (EXT2_BLOCKS_PER_GROUP(s))
+#define EXT2FS_B2C(fs, blk)            (blk)
+#endif
+
 struct task_ctx {
        uint32_t max_copy_inodes;
        uint32_t cur_copy_inodes;
@@ -183,9 +195,23 @@ static int ext2_open_fs(struct btrfs_convert_context *cctx, const char *name)
        errcode_t ret;
        ext2_filsys ext2_fs;
        ext2_ino_t ino;
+       u32 ro_feature;
+
        ret = ext2fs_open(name, 0, 0, 0, unix_io_manager, &ext2_fs);
        if (ret) {
                fprintf(stderr, "ext2fs_open: %s\n", error_message(ret));
+               return -1;
+       }
+       /*
+        * We need to know exactly the used space, some RO compat flags like
+        * BIGALLOC will affect how used space is present.
+        * So we need manuall check any unsupported RO compat flags
+        */
+       ro_feature = ext2_fs->super->s_feature_ro_compat;
+       if (ro_feature & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
+               error(
+"unsupported RO features detected: %x, abort convert to avoid possible corruption",
+                     ro_feature & ~EXT2_LIB_FEATURE_COMPAT_SUPP);
                goto fail;
        }
        ret = ext2fs_read_inode_bitmap(ext2_fs);
@@ -227,6 +253,7 @@ static int ext2_open_fs(struct btrfs_convert_context *cctx, const char *name)
        cctx->free_inodes_count = ext2_fs->super->s_free_inodes_count;
        return 0;
 fail:
+       ext2fs_close(ext2_fs);
        return -1;
 }
 

diff --git a/configure.ac b/configure.ac
index 6b68c090c52ddf2251d850e08791321df86c405f..c79472cc2c9328d9a11fd2a67efbaceab31f0a42 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -105,7 +105,11 @@ AS_IF([test "x$enable_convert" = xyes], [DISABLE_BTRFSCONVERT=0], [DISABLE_BTRFS
 AC_SUBST([DISABLE_BTRFSCONVERT])
 
 if test "x$enable_convert" = xyes; then
-       PKG_CHECK_MODULES(EXT2FS, [ext2fs >= 1.41])
+       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(COM_ERR, [com_err])
 fi