Re: [PATCH v4] erofs: avoid using generic_block_bmap

From: Gao Xiang
Date: Wed Dec 09 2020 - 06:41:23 EST


Hi Jianan,

On Wed, Dec 09, 2020 at 06:08:41PM +0800, Chao Yu wrote:
> On 2020/12/9 10:39, Huang Jianan wrote:
> > iblock indicates the number of i_blkbits-sized blocks rather than
> > sectors.
> >
> > In addition, considering buffer_head limits mapped size to 32-bits,
> > should avoid using generic_block_bmap.
> >
> > Fixes: 9da681e017a3 ("staging: erofs: support bmap")
> > Signed-off-by: Huang Jianan <huangjianan@xxxxxxxx>
> > Signed-off-by: Guo Weichao <guoweichao@xxxxxxxx>

Could you send out an updated version? I might get a point to freeze
dev branch since it needs some time on linux-next....

Thanks,
Gao Xiang

> > ---
> > fs/erofs/data.c | 30 ++++++++++--------------------
> > 1 file changed, 10 insertions(+), 20 deletions(-)
> >
> > diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> > index 347be146884c..d6ea0a216b57 100644
> > --- a/fs/erofs/data.c
> > +++ b/fs/erofs/data.c
> > @@ -312,36 +312,26 @@ static void erofs_raw_access_readahead(struct readahead_control *rac)
> > submit_bio(bio);
> > }
> > -static int erofs_get_block(struct inode *inode, sector_t iblock,
> > - struct buffer_head *bh, int create)
> > -{
> > - struct erofs_map_blocks map = {
> > - .m_la = iblock << 9,
> > - };
> > - int err;
> > -
> > - err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
> > - if (err)
> > - return err;
> > -
> > - if (map.m_flags & EROFS_MAP_MAPPED)
> > - bh->b_blocknr = erofs_blknr(map.m_pa);
> > -
> > - return err;
> > -}
> > -
> > static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
> > {
> > struct inode *inode = mapping->host;
> > + struct erofs_map_blocks map = {
> > + .m_la = blknr_to_addr(block),
> > + };
> > + sector_t blknr = 0;
>
> It could be removed?
>
> > if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
> > erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
> > if (block >> LOG_SECTORS_PER_BLOCK >= blks)
> > - return 0;
>
> return 0;
>
> > + goto out;
> > }
> > - return generic_block_bmap(mapping, block, erofs_get_block);
> > + if (!erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW))
> > + blknr = erofs_blknr(map.m_pa);
>
> return erofs_blknr(map.m_pa);
>
> > +
> > +out:
> > + return blknr;
>
> return 0;
>
> Anyway, LGTM.
>
> Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>
>
> Thanks,
>
> > }
> > /* for uncompressed (aligned) files and raw access for other files */
> >
>