Re: [f2fs-dev] [PATCH v3 3/6] f2fs: compress: fix to check unreleased compressed cluster

[Chao Yu]

On 2024/1/11 9:18, Daeho Jeong wrote:
> On Thu, Dec 28, 2023 at 6:33 AM Chao Yu <chao@xxxxxxxxxx> wrote:
> > From: Sheng Yong <shengyong@xxxxxxxx>
> >
> > Compressed cluster may not be released due to we can fail in
> > release_compress_blocks(), fix to handle reserved compressed
> > cluster correctly in reserve_compress_blocks().
> >
> > Fixes: 4c8ff7095bef ("f2fs: support data compression")
> > Signed-off-by: Sheng Yong <shengyong@xxxxxxxx>
> > Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
> > ---
> >   fs/f2fs/file.c | 12 ++++++++++++
> >   1 file changed, 12 insertions(+)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index 026d05a7edd8..782ae3be48f6 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -3624,6 +3624,15 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
> >                                  goto next;
> >                          }
> >
> > +                       /*
> > +                        * compressed cluster was not released due to
> > +                        * it fails in release_compress_blocks().
> > +                        */
> > +                       if (blkaddr == NEW_ADDR) {
> > +                               compr_blocks++;
> > +                               continue;
> > +                       }
> > +
> >                          if (__is_valid_data_blkaddr(blkaddr)) {
> >                                  compr_blocks++;
> >                                  continue;
>
> How about merging two conditions like "blkaddr == NEW_ADDR ||
> __is_valid_data_blkaddr(blkaddr)"?

Oh, sure.

> > @@ -3633,6 +3642,9 @@ static int reserve_compress_blocks(struct dnode_of_data *dn, pgoff_t count)
> >                  }
> >
> >                  reserved = cluster_size - compr_blocks;
> > +               if (!reserved)
> > +                       goto next;
> > +
>
> How can the reserved variable be zero?

I guess it can happen if a cluster was not released during
release_compress_blocks(), then all blocks in the cluster should
has been reserved, so, in this round of reserving, it needs to skip
reserve blocks, right?

Thanks,

> >                  ret = inc_valid_block_count(sbi, dn->inode, &reserved);
> >                  if (ret)
> >                          return ret;
> > --
> > 2.40.1
> >
> >
> >
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