Re: [PATCH v2] f2fs: support zero sized file truncate for device aliasing files

From: Daeho Jeong
Date: Mon Mar 24 2025 - 12:56:50 EST


On Mon, Mar 24, 2025 at 9:28 AM Jaegeuk Kim <jaegeuk@xxxxxxxxxx> wrote:
>
> Do we still need this patch?

Yes, in many circumstances, we cannot remove the aliasing file because
of SELinux.

>
> On 03/21, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@xxxxxxxxxx>
> >
> > support a file truncation to zero size for device aliasing files.
> >
> > Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
> > ---
> > v2: make the extent length zero
> > ---
> > fs/f2fs/file.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> > index f92a9fba9991..69952f208086 100644
> > --- a/fs/f2fs/file.c
> > +++ b/fs/f2fs/file.c
> > @@ -775,6 +775,11 @@ int f2fs_do_truncate_blocks(struct inode *inode, u64 from, bool lock)
> > f2fs_update_time(sbi, REQ_TIME);
> >
> > f2fs_put_page(ipage, 1);
> > +
> > + write_lock(&et->lock);
> > + et->largest.len = 0;
> > + write_unlock(&et->lock);
> > +
> > goto out;
> > }
> >
> > @@ -1036,7 +1041,7 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> >
> > if ((attr->ia_valid & ATTR_SIZE)) {
> > if (!f2fs_is_compress_backend_ready(inode) ||
> > - IS_DEVICE_ALIASING(inode))
> > + (IS_DEVICE_ALIASING(inode) && attr->ia_size))
> > return -EOPNOTSUPP;
> > if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED) &&
> > !IS_ALIGNED(attr->ia_size,
> > --
> > 2.49.0.395.g12beb8f557-goog
> >