On 2020/10/20 0:32, Eric Sandeen wrote: > On 10/19/20 4:47 AM, xiakaixu1987@xxxxxxxxx wrote: >> From: Kaixu Xia <kaixuxia@xxxxxxxxxxx> >> >> We use the SECTOR_SHIFT macro to define the sector size shift, so maybe >> it is more reasonable to use it than the magic number 9. >> >> Signed-off-by: Kaixu Xia <kaixuxia@xxxxxxxxxxx> > > Hm ... SECTOR_SHIFT is a block layer #define, really, > and blkdev_issue_zeroout is a block layer interface I guess. > > We also have our own BBSHIFT in XFS which is used elsewhere, though. > > And FWIW, /many/ other fs/* manipulations still use the "- 9" today when > converting s_blocksize_bits to sectors. *shrug* this seems like something > that should change tree-wide, if it's to be changed at all. > Yeah, I think the magic number 9 is insecure, maybe a patchset is needed to change them :) Thanks, Kaixu > -Eric > >> --- >> fs/xfs/xfs_bmap_util.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c >> index f2a8a0e75e1f..9f02c1824205 100644 >> --- a/fs/xfs/xfs_bmap_util.c >> +++ b/fs/xfs/xfs_bmap_util.c >> @@ -63,8 +63,8 @@ xfs_zero_extent( >> sector_t block = XFS_BB_TO_FSBT(mp, sector); >> >> return blkdev_issue_zeroout(target->bt_bdev, >> - block << (mp->m_super->s_blocksize_bits - 9), >> - count_fsb << (mp->m_super->s_blocksize_bits - 9), >> + block << (mp->m_super->s_blocksize_bits - SECTOR_SHIFT), >> + count_fsb << (mp->m_super->s_blocksize_bits - SECTOR_SHIFT), >> GFP_NOFS, 0); >> } >> >> -- kaixuxia
