Re: [PATCH 08/14] fuse: Flush files on wb close

[Maxim V. Patlasov]

Hi Miklos,

01/30/2013 02:58 AM, Miklos Szeredi ÐÐÑÐÑ:
> On Fri, Jan 25, 2013 at 7:24 PM, Maxim V. Patlasov
> <MPatlasov@xxxxxxxxxxxxx> wrote:
> > Any write request requires a file handle to report to the userspace. Thus
> > when we close a file (and free the fuse_file with this info) we have to
> > flush all the outstanding writeback cache. Note, that simply calling the
> > filemap_write_and_wait() is not enough since fuse finishes page writeback
> > immediately and thus the -wait part of the mentioned call will be no-op.
> > Do real wait on per-inode writepages list.
> >
> > Signed-off-by: Maxim Patlasov <MPatlasov@xxxxxxxxxxxxx>
> > Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
> > ---
> >   fs/fuse/file.c |   26 +++++++++++++++++++++++++-
> >   1 files changed, 25 insertions(+), 1 deletions(-)
> >
> > diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> > index 4f8fa45..496e74c 100644
> > --- a/fs/fuse/file.c
> > +++ b/fs/fuse/file.c
> > @@ -138,6 +138,12 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
> >          }
> >   }
> >
> > +static void __fuse_file_put(struct fuse_file *ff)
> > +{
> > +       if (atomic_dec_and_test(&ff->count))
> > +               BUG();
> > +}
> > +
> >   int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
> >                   bool isdir)
> >   {
> > @@ -286,8 +292,23 @@ static int fuse_open(struct inode *inode, struct file *file)
> >          return fuse_open_common(inode, file, false);
> >   }
> >
> > +static void fuse_flush_writeback(struct inode *inode, struct file *file)
> > +{
> > +       struct fuse_conn *fc = get_fuse_conn(inode);
> > +       struct fuse_inode *fi = get_fuse_inode(inode);
> > +
> > +       filemap_write_and_wait(file->f_mapping);
> > +       wait_event(fi->page_waitq, list_empty_careful(&fi->writepages));
> > +       spin_unlock_wait(&fc->lock);
> > +}
> > +
> >   static int fuse_release(struct inode *inode, struct file *file)
> >   {
> > +       struct fuse_conn *fc = get_fuse_conn(inode);
> > +
> > +       if (fc->writeback_cache)
> > +               fuse_flush_writeback(inode, file);
> > +
> >          fuse_release_common(file, FUSE_RELEASE);
> >
> >          /* return value is ignored by VFS */
> > @@ -1343,7 +1364,8 @@ static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
> >
> >          for (i = 0; i < req->num_pages; i++)
> >                  __free_page(req->pages[i]);
> > -       fuse_file_put(req->ff, false);
> > +       if (!fc->writeback_cache)
> > +               fuse_file_put(req->ff, false);
> >   }
> >
> >   static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
> > @@ -1360,6 +1382,8 @@ static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
> >          }
> >          bdi_writeout_inc(bdi);
> >          wake_up(&fi->page_waitq);
> > +       if (fc->writeback_cache)
> > +               __fuse_file_put(req->ff);
> >   }
> I don't see how this belongs in this patch.  And I suspect this can be
> done unconditionally (for the non-writeback-cache case as well), but
> please move it into a separate patch.

OK, I'll do.

Thanks,
Maxim

> Thanks,
> Miklos

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