[PATCH 5.10 389/717] erofs: avoid using generic_block_bmap

Greg Kroah-Hartman
2020-12-28T14:17:42Z

From: Huang Jianan <huangjianan@oppo.com>

[ Upstream commit d8b3df8b1048405e73558b88cba2adf29490d468 ]

Surprisingly, `block' in sector_t indicates the number of
i_blkbits-sized blocks rather than sectors for bmap.

In addition, considering buffer_head limits mapped size to 32-bits,
should avoid using generic_block_bmap.

Link: https://lore.kernel.org/r/20201209115740.18802-1-huangjianan@oppo.com
Fixes: 9da681e017a3 ("staging: erofs: support bmap")
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Guo Weichao <guoweichao@oppo.com>
[ Gao Xiang: slightly update the commit message description. ]
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/erofs/data.c | 26 +++++++-------------------
1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 347be146884c3..ea4f693bee224 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -312,27 +312,12 @@ 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),
+ };

if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
@@ -341,7 +326,10 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
return 0;
}

- return generic_block_bmap(mapping, block, erofs_get_block);
+ if (!erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW))
+ return erofs_blknr(map.m_pa);
+
+ return 0;
}

/* for uncompressed (aligned) files and raw access for other files */
--
2.27.0