ext4: fix block bitmap initialization under sparse_super2
The ext4_bg_has_super() function doesn't know about the new rules for
where backup superblocks go on a sparse_super2 filesystem. Therefore,
block bitmap initialization doesn't know that it shouldn't reserve
space for backups in groups that are never going to contain backups.
The result of this is e2fsck complaining about the block bitmap being
incorrect (fortunately not in a way that results in cross-linked
files), so fix the whole thing.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 5c56785..a4950e9 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -708,16 +708,6 @@
}
}
-static int ext4_group_sparse(ext4_group_t group)
-{
- if (group <= 1)
- return 1;
- if (!(group & 1))
- return 0;
- return (test_root(group, 7) || test_root(group, 5) ||
- test_root(group, 3));
-}
-
/**
* ext4_bg_has_super - number of blocks used by the superblock in group
* @sb: superblock for filesystem
@@ -728,11 +718,26 @@
*/
int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
{
- if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
- EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
- !ext4_group_sparse(group))
+ struct ext4_super_block *es = EXT4_SB(sb)->s_es;
+
+ if (group == 0)
+ return 1;
+ if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_SPARSE_SUPER2)) {
+ if (group == le32_to_cpu(es->s_backup_bgs[0]) ||
+ group == le32_to_cpu(es->s_backup_bgs[1]))
+ return 1;
return 0;
- return 1;
+ }
+ if ((group <= 1) || !EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
+ return 1;
+ if (!(group & 1))
+ return 0;
+ if (test_root(group, 3) || (test_root(group, 5)) ||
+ test_root(group, 7))
+ return 1;
+
+ return 0;
}
static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,