On Mon, Mar 31, 2014 at 06:12:39PM +0400, Dmitry Monakhov wrote:
> On Mon, 31 Mar 2014 11:11:33 +0200, Lukas Czerner <lczerner@xxxxxxxxxx> wrote:
> > In commit 1f0e51771281 "ext4: Introduce FALLOC_FL_ZERO_RANGE flag
> > for fallocate" we've introduced wrong flag handling. Fix it.
> >
> > Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> > ---
> > fs/ext4/extents.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> > index 243a02e..491208c 100644
> > --- a/fs/ext4/extents.c
> > +++ b/fs/ext4/extents.c
> > @@ -3644,13 +3644,13 @@ static int ext4_split_convert_extents(handle_t *handle,
> > ee_len = ext4_ext_get_actual_len(ex);
> >
> > /* Convert to unwritten */
> > - if (flags | EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
> > + if (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
> :). But how did you found this?
> I think that this type of bugs should be caught by some semantics
> analyzer? I've done simple test and sparse(1) owerlooked this,
> Also I cant find specific rule for Coccinelle ( if (var | CONST)).
This one was found with a Smatch warning:
fs/ext4/extents.c:3647 ext4_split_convert_extents() warn: suspicious bitop condition
>
> > split_flag |= EXT4_EXT_DATA_VALID1;
> > /* Convert to initialized */
> > - } else if (flags | EXT4_GET_BLOCKS_CONVERT) {
> > + } else if (flags & EXT4_GET_BLOCKS_CONVERT) {
> > split_flag |= ee_block + ee_len <= eof_block ?
> > EXT4_EXT_MAY_ZEROOUT : 0;
> > - split_flag |= (EXT4_EXT_MARK_UNINIT2 & EXT4_EXT_DATA_VALID2);
> > + split_flag |= (EXT4_EXT_MARK_UNINIT2 | EXT4_EXT_DATA_VALID2);
I would like to push the Smatch warning for this one as well, but there
are too many places where these kinds of AND operations are valid.
regards,
dan carpenter
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