Re: [PATCH V2] f2fs: fix to adjust appropirate defragment pg_end

[Chao Yu]

On 2024/3/27 9:26, Zhiguo Niu wrote:
> On Tue, Mar 26, 2024 at 7:11 PM Chao Yu <chao@xxxxxxxxxx> wrote:
> > On 2024/3/25 13:56, Zhiguo Niu wrote:
> > > A length that exceeds the real size of the inode may be
> > > specified from user, although these out-of-range areas
> > > are not mapped, but they still need to be check in
> > > while loop, which is unnecessary.
> > >
> > > Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
> > > ---
> > > v2: check i_size within inode lock according to Chao's suggestions
> > > ---
> > > ---
> > >    fs/f2fs/file.c | 11 +++++++----
> > >    1 file changed, 7 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index 128e53d..cf63db7 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -2608,9 +2608,6 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
> > >        bool fragmented = false;
> > >        int err;
> > >
> > > -     pg_start = range->start >> PAGE_SHIFT;
> > > -     pg_end = (range->start + range->len) >> PAGE_SHIFT;
> > > -
> > >        f2fs_balance_fs(sbi, true);
> > >
> > >        inode_lock(inode);
> > > @@ -2629,10 +2626,16 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
> >
> > pg_start = range->start >> PAGE_SHIFT;
> > pg_end = min_t(pgoff_t, (range->start + range->len) >> PAGE_SHIFT,
> >                          DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));
> >
> > >        /* writeback all dirty pages in the range */
> > >        err = filemap_write_and_wait_range(inode->i_mapping, range->start,
> > > -                                             range->start + range->len - 1);
> > > +                                             min_t(loff_t, range->start + range->len - 1,
> > > +                                             i_size_read(inode) - 1));
> >
> > , pg_start << PAGE_SHIFT - 1, pg_end << PAGE_SHIFT - 1); ?
> should be  pg_start << PAGE_SHIFT , pg_end << PAGE_SHIFT - 1)??

Oh, yes. :)

Thanks,

> if range.start=0, pg_start is also 0, lstart in
> filemap_write_and_wait_range is 0,
> but pg_start << PAGE_SHIFT - 1 will get lstart=-1?
> thanks！
> > Thanks,
> >
> > >        if (err)
> > >                goto out;
> > >
> > > +     pg_start = range->start >> PAGE_SHIFT;
> > > +     pg_end = min_t(pgoff_t,
> > > +                             (range->start + range->len) >> PAGE_SHIFT,
> > > +                             DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE));
> > > +
> > >        /*
> > >         * lookup mapping info in extent cache, skip defragmenting if physical
> > >         * block addresses are continuous.