Re: [PATCH] f2fs: avoid stale FI_COMPRESS_RELEASED on release failure

[Wenjie Qi]

  Yes, that is intentional.

  If ret < 0 but released_blocks > 0, the ioctl has already released some
  compressed reserved blocks and updated the inode/block accounting
  partially. At that point the inode is no longer in the original
  pre-release state, so keeping FI_COMPRESS_RELEASED is deliberate.

  The case this patch is trying to fix is only ret < 0 &&
  released_blocks == 0, where no release-side state change happened but
  the old code still left FI_COMPRESS_RELEASED set.

On Mon, Aug 3, 2026 at 4:31 PM Chao Yu <chao@xxxxxxxxxx> wrote:
>
> On 7/24/26 21:50, Wenjie Qi wrote:
> > F2FS_IOC_RELEASE_COMPRESS_BLOCKS sets FI_COMPRESS_RELEASED before walking
> > data nodes. If release_compress_blocks() fails before freeing any reserved
> > block, the inode keeps the flag while i_compr_blocks is still non-zero.
> >
> > Then F2FS_IOC_RESERVE_COMPRESS_BLOCKS returns success with zero reserved
> > blocks, and regular writes keep failing with -EPERM.
> >
> > Set the flag only after the ioctl succeeds, or after it has actually
> > released some blocks. This preserves the existing partial-release error
> > handling and leaves a failed zero-release attempt unchanged.
> >
> > Fixes: ef8d563f184e ("f2fs: introduce F2FS_IOC_RELEASE_COMPRESS_BLOCKS")
> > Cc: stable@xxxxxxxxxx
> > Signed-off-by: Wenjie Qi <qiwenjie@xxxxxxxxxx>
> > ---
> > QEMU fault-injection test with FAULT_BLKADDR_VALIDITY:
> > - before: release failed with -EFSCORRUPTED, reserve returned 0 blocks,
> >    and pwrite kept failing with -EPERM after remount.
> > - after: release still failed, reserve returned -EINVAL, and pwrite succeeded.
> > - normal release/reserve still released and reserved 192 blocks.
> >
> >   fs/f2fs/file.c | 10 ++++++----
> >   1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index c54897a25981..dca1722f92b3 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -3916,10 +3916,6 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
> >               goto out;
> >       }
> >
> > -     set_inode_flag(inode, FI_COMPRESS_RELEASED);
> > -     inode_set_ctime_current(inode);
> > -     f2fs_mark_inode_dirty_sync(inode, true);
> > -
> >       f2fs_down_write(&fi->i_gc_rwsem[WRITE]);
> >       filemap_invalidate_lock(inode->i_mapping);
> >
> > @@ -3963,6 +3959,12 @@ static int f2fs_release_compress_blocks(struct file *filp, unsigned long arg)
> >
> >       filemap_invalidate_unlock(inode->i_mapping);
> >       f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
> > +
> > +     if (ret >= 0 || released_blocks) {
>
> We will set FI_COMPRESS_RELEASED if ret < 0 and released_blocks > 0?
>
> Thanks,
>
> > +             set_inode_flag(inode, FI_COMPRESS_RELEASED);
> > +             inode_set_ctime_current(inode);
> > +             f2fs_mark_inode_dirty_sync(inode, true);
> > +     }
> >   out:
> >       if (released_blocks)
> >               f2fs_update_time(sbi, REQ_TIME);
>