On Thu, 21 Feb 2013, Lukáš Czerner wrote: ..snip... > > Hi Zheng, > > thanks for the review. I know about the other issues and I'm trying > to resolve those as well. Right now I have a patch which includes > the changes ext4_calculate_overhead() you've described below and more, > but even with this I still see some problems remaining. > > Hopefully will send another patch soon. > > Thanks! > -Lukas > > > > > Subject: [PATCH] ext4: fix overhead calculation in bigalloc filesystem > > > > From: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > > > ext4_calculate_overhead() should compute the overhead and stash it in > > sbi->s_overhead. But we miss use EXT4_B2C() to calculate the number of > > clusters before first_data_block and the number of journal blocks. This > > commit use EXT4_NUM_B2C() instead of EXT4_B2C() to calculate the > > overhead. > > > > Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > Cc: "Theodore Ts'o" <tytso@xxxxxxx> > > --- > > fs/ext4/super.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > > index 3d4fb81..6165558 100644 > > --- a/fs/ext4/super.c > > +++ b/fs/ext4/super.c > > @@ -3219,7 +3219,7 @@ int ext4_calculate_overhead(struct super_block *sb) > > /* > > * All of the blocks before first_data_block are overhead > > */ > > - overhead = EXT4_B2C(sbi, le32_to_cpu(es->s_first_data_block)); > > + overhead = EXT4_NUM_B2C(sbi, le32_to_cpu(es->s_first_data_block)); ...except this. I do not think this is right because we do not skip the first cluster right ? We're still using it, but we can never use the block before es->s_first_data_block. Please correct me if I am wrong. > > > > /* > > * Add the overhead found in each block group > > @@ -3235,7 +3235,7 @@ int ext4_calculate_overhead(struct super_block *sb) > > } > > /* Add the journal blocks as well */ > > if (sbi->s_journal) > > - overhead += EXT4_B2C(sbi, sbi->s_journal->j_maxlen); > > + overhead += EXT4_NUM_B2C(sbi, sbi->s_journal->j_maxlen); This I already have in my patch I'm testing right now. And as I said there are other places where we misuse EXT4_B2C(). -Lukas > > > > sbi->s_overhead = overhead; > > smp_wmb(); > > >
