On Tue 07-05-13 14:33:47, Zheng Liu wrote:
> On Mon, Apr 08, 2013 at 11:32:22PM +0200, Jan Kara wrote:
> > We limit the number of blocks written in a single loop of
> > ext4_da_writepages() to 64 when inode uses indirect blocks. That is
> > unnecessary as credit estimates for mapping logically continguous run of
> > blocks is rather low even for inode with indirect blocks. So just lift
> > this limitation and properly calculate the number of necessary credits.
> >
> > This better credit estimate will also later allow us to always write at
> > least a single page in one iteration.
> >
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
>
> A minor comment below. Otherwise the patch looks good to me.
> Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
>
> > ---
> > fs/ext4/ext4.h | 3 +-
> > fs/ext4/extents.c | 16 ++++++--------
> > fs/ext4/inode.c | 58 ++++++++++++++++++++--------------------------------
> > 3 files changed, 30 insertions(+), 47 deletions(-)
> ...
> > static int ext4_da_writepages_trans_blocks(struct inode *inode)
> > {
> > - int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
> > -
> > - /*
> > - * With non-extent format the journal credit needed to
> > - * insert nrblocks contiguous block is dependent on
> > - * number of contiguous block. So we will limit
> > - * number of contiguous block to a sane value
> > - */
> > - if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) &&
> > - (max_blocks > EXT4_MAX_TRANS_DATA))
> > - max_blocks = EXT4_MAX_TRANS_DATA;
> > + int bpp = ext4_journal_blocks_per_page(inode);
> >
> > - return ext4_chunk_trans_blocks(inode, max_blocks);
> > + return ext4_meta_trans_blocks(inode,
> > + MAX_WRITEPAGES_EXTENT_LEN + bpp - 1, bpp);
>
> FWIW, MAX_WRITEPAGES_EXTENT_LEN is defined at patch 18/29. So after
> applied this patch, we will get a build error. So that would be great
> if MAX_WRITEPAGES_EXTENT_LEN can be define in this commit.
Good catch. Thanks! I've fixed that up.
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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