libext2fs: openfs() musn't allow bigalloc without EXT2_FLAGS_64BITS
Currently, only the new 64-bit bitmap implementation supports the
block<->cluster conversions that bigalloc requires. Therefore, if we
have a bigalloc filesystem, require EXT2_FLAGS_64BITS be passed in to
ext2fs_open(). This does not mean that bigalloc file systems have to
be 64-bits; just that the userspace utilities have to be able to use
the new 64-bit capable library functions.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 113b80e..9fe1645 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -253,6 +253,18 @@
retval = EXT2_ET_CORRUPT_SUPERBLOCK;
goto cleanup;
}
+
+ /*
+ * bigalloc requires cluster-aware bitfield operations, which at the
+ * moment means we need EXT2_FLAG_64BITS.
+ */
+ if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
+ !(flags & EXT2_FLAG_64BITS)) {
+ retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
+ goto cleanup;
+ }
+
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
(fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {