On Mon, Jul 04, 2022 at 09:13:44AM +0800, Xiubo Li wrote:
> On 7/1/22 6:38 PM, Jeff Layton wrote:
> > I don't know here... I think it might be better to just expect that when
> > this function returns an error that the folio has already been unlocked.
> > Doing it this way will mean that you will lock and unlock the folio a
> > second time for no reason.
> >
> > Maybe something like this instead?
> >
> > diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
> > index 42f892c5712e..8ae7b0f4c909 100644
> > --- a/fs/netfs/buffered_read.c
> > +++ b/fs/netfs/buffered_read.c
> > @@ -353,7 +353,7 @@ int netfs_write_begin(struct netfs_inode *ctx,
> > trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin);
> > if (ret == -EAGAIN)
> > goto retry;
> > - goto error;
> > + goto error_unlocked;
> > }
> > }
> > @@ -418,6 +418,7 @@ int netfs_write_begin(struct netfs_inode *ctx,
> > error:
> > folio_unlock(folio);
> > folio_put(folio);
> > +error_unlocked:
> > _leave(" = %d", ret);
> > return ret;
> > }
>
> Then the "afs" won't work correctly:
>
> 377 static int afs_check_write_begin(struct file *file, loff_t pos, unsigned
> len,
> 378 struct folio *folio, void **_fsdata)
> 379 {
> 380 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
> 381
> 382 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
> 383 }
>
> The "afs" does nothing with the folio lock.
It's OK to fix AFS too.
