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Commit 0548bbb8 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

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: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent 7a4c5de2

fs/ext4/super.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -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);

	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);

	int			s, j, count = 0;

	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) +

	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +

		(grp * EXT4_BLOCKS_PER_GROUP(sb));

		(grp * EXT4_BLOCKS_PER_GROUP(sb));

	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;

	last_block = first_block + EXT4_BLOCKS_PER_GROUP(sb) - 1;