Re: [PATCH v4] erofs: avoid using generic_block_bmap

From: Chao Yu
Date: Wed Dec 09 2020 - 05:09:29 EST


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>
---
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 */