From 0548bbb85337e532ca2ed697c3e9b227ff2ed4b4 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 16 Aug 2012 11:59:04 -0400 Subject: [PATCH] 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" Cc: stable@vger.kernel.org --- fs/ext4/super.c | 4 ++++ 1 file changed, 4 insertions(+) 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 @@ static int count_overhead(struct super_block *sb, ext4_group_t grp, 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; -- 2.7.4