[PATCH 26/31] libext2fs: openfs() musn't allow bigalloc without EXT2_FLAGS_64BITS

Darrick J. Wong
2013-10-01T01:29:38Z

Currently, only the 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().

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
lib/ext2fs/openfs.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 3c0bf14..f486a35 100644
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -272,6 +272,18 @@ errcode_t ext2fs_open3(const char *name, const char *io_options,
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)) {