ext4: fix long mount times on very big file systems
Commit 8aeb00ff85a: "ext4: fix overhead calculation used by
ext4_statfs()" introduced a O(n**2) calculation which makes very large
file systems take forever to mount. Fix this with an optimization for
non-bigalloc file systems. (For bigalloc file systems the overhead
needs to be set in the the superblock.)
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 56bcaec..5984989 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3120,6 +3120,10 @@
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
int s, j, count = 0;
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_BIGALLOC))
+ return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
+ sbi->s_itb_per_group + 2);
+
first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +
(grp * EXT4_BLOCKS_PER_GROUP(sb));
last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;