On 12/12, Chao Yu wrote:
> On 2023/12/12 6:11, Jaegeuk Kim wrote:
> > On 12/10, Chao Yu wrote:
> > > This patch adds i_size check during compress inode conversion in order
> > > to avoid .page_mkwrite races w/ conversion.
> > 
> > Which race condition do you see?
> 
> Something like:
> 
> - f2fs_setflags_common
>  - check S_ISREG && F2FS_HAS_BLOCKS
>                                       - mkwrite
>                                        - f2fs_get_block_locked
>                                         : update metadata in old inode's disk 
> layout

Don't we need to prevent setting this for mmapped file?

>  - set_compress_context
> 
> Thanks,
> 
> > 
> > > 
> > > Fixes: 4c8ff7095bef ("f2fs: support data compression")
> > > Signed-off-by: Chao Yu <c...@kernel.org>
> > > ---
> > >   fs/f2fs/f2fs.h | 8 +++++++-
> > >   fs/f2fs/file.c | 5 ++---
> > >   2 files changed, 9 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > > index 65294e3b0bef..c9b8a1953913 100644
> > > --- a/fs/f2fs/f2fs.h
> > > +++ b/fs/f2fs/f2fs.h
> > > @@ -4397,13 +4397,19 @@ static inline int set_compress_context(struct 
> > > inode *inode)
> > >   #endif
> > >   }
> > > +static inline bool inode_has_data(struct inode *inode)
> > > +{
> > > + return (S_ISREG(inode->i_mode) &&
> > > +         (F2FS_HAS_BLOCKS(inode) || i_size_read(inode)));
> > > +}
> > > +
> > >   static inline bool f2fs_disable_compressed_file(struct inode *inode)
> > >   {
> > >           struct f2fs_inode_info *fi = F2FS_I(inode);
> > >           if (!f2fs_compressed_file(inode))
> > >                   return true;
> > > - if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode))
> > > + if (inode_has_data(inode))
> > >                   return false;
> > >           fi->i_flags &= ~F2FS_COMPR_FL;
> > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > > index 1a3c29a9a6a0..8af4b29c3e1a 100644
> > > --- a/fs/f2fs/file.c
> > > +++ b/fs/f2fs/file.c
> > > @@ -1922,8 +1922,7 @@ static int f2fs_setflags_common(struct inode 
> > > *inode, u32 iflags, u32 mask)
> > >                           f2fs_down_write(&F2FS_I(inode)->i_sem);
> > >                           if (!f2fs_may_compress(inode) ||
> > > -                                 (S_ISREG(inode->i_mode) &&
> > > -                                 F2FS_HAS_BLOCKS(inode))) {
> > > +                                 inode_has_data(inode)) {
> > >                                   f2fs_up_write(&F2FS_I(inode)->i_sem);
> > >                                   return -EINVAL;
> > >                           }
> > > @@ -3996,7 +3995,7 @@ static int f2fs_ioc_set_compress_option(struct file 
> > > *filp, unsigned long arg)
> > >                   goto out;
> > >           }
> > > - if (F2FS_HAS_BLOCKS(inode)) {
> > > + if (inode_has_data(inode)) {
> > >                   ret = -EFBIG;
> > >                   goto out;
> > >           }
> > > -- 
> > > 2.40.1


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