| From | Greg Kroah-Hartman <> | Subject | [ 25/46] ext4: fix long mount times on very big file systems | Date | Sun, 19 Aug 2012 20:59:01 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.5-stable review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o <tytso@mit.edu>
commit 0548bbb85337e532ca2ed697c3e9b227ff2ed4b4 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/ext4/super.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3110,6 +3110,10 @@ static int count_overhead(struct super_b 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;
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