On 2012-08-16, at 12:53, Theodore Ts'o <tytso@xxxxxxx> wrote: > On Thu, Aug 16, 2012 at 10:42:19AM -0400, Theodore Ts'o wrote: >> On Thu, Aug 16, 2012 at 10:16:48AM -0400, Calvin Walton wrote: >>> On Thu, 2012-08-16 at 03:09 -0600, Andreas Dilger wrote: >>> Is there any fix for this issue queued up for an upcoming stable >>> release? It still reverts cleanly on 3.5.2. >> >> There isn't a fix queued up yet, but there will be one soon.... > > This patch should solve the problem (as an alternative to reverting > 8aeb00ff85a). Why not save the newly calculated value for s_oberhead_blocks to disk after the first time it is calculated? The only time it would need to be changed again is after a resize operation, which could be done by calling count_overhead() at the end again. Cheers, Andreas > From dc43c7a8a6c266c31aa4f0408000c4d1b9f3c787 Mon Sep 17 00:00:00 2001 > From: Theodore Ts'o <tytso@xxxxxxx> > 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" <tytso@xxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > fs/ext4/super.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 603023b..055c65b 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -3129,6 +3129,10 @@ 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, i) + > + 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; > -- > 1.7.12.rc0.22.gcdd159b > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
