From: Jeff Layton <jlayton@redhat.com>
To: martin@omnibond.com
Cc: hubcap@omnibond.com, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 11/13] orangefs: lock inode during fsync
Date: Fri, 26 May 2017 12:58:07 -0400 [thread overview]
Message-ID: <1495817887.4299.6.camel@redhat.com> (raw)
In-Reply-To: <20170526162150.GA17804@pamir.hexium.org>
On Fri, 2017-05-26 at 12:21 -0400, martin@omnibond.com wrote:
> On Thu, May 25, 2017 at 11:58:57AM -0400, Jeff Layton wrote:
> > On Mon, 2017-05-22 at 05:58 -0400, Martin Brandenburg wrote:
> > > Signed-off-by: Martin Brandenburg <martin@omnibond.com>
> > > ---
> > > fs/orangefs/file.c | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
> > > index cd126dd..f8536a7 100644
> > > --- a/fs/orangefs/file.c
> > > +++ b/fs/orangefs/file.c
> > > @@ -652,7 +652,9 @@ static int orangefs_fsync(struct file *file,
> > > struct orangefs_kernel_op_s *new_op = NULL;
> > >
> > > /* required call */
> > > + inode_lock(file_inode(file));
> > > filemap_write_and_wait_range(file->f_mapping, start, end);
> > > + inode_unlock(file_inode(file));
> > >
> > > new_op = op_alloc(ORANGEFS_VFS_OP_FSYNC);
> > > if (!new_op)
> >
> > Why? You're just writing back the cached file data here. There's no
> > reason to lock the inode for that, AFAICS.
> >
> > --
> > Jeff Layton <jlayton@redhat.com>
>
> Because FUSE does. Now I see FUSE needs it for fuse_sync_writes.
>
> /*
> * Wait for all pending writepages on the inode to finish.
> *
> * This is currently done by blocking further writes with FUSE_NOWRITE
> * and waiting for all sent writes to complete.
> *
> * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
> * could conflict with truncation.
> */
> static void fuse_sync_writes(struct inode *inode)
>
> I think OrangeFS is okay because writepage does not return until the
> write has completed. Does that sound right?
>
I think so.
> I'm not sure about the truncate conflict. Truncates are sent to the
> server immediately. Can a pending write show past the end of the file
> show up later? I don't handle that at all.
>
IIUC, the danger there is generally that the write and truncate could
get reordered. If they're both synchronous though then I don't see how
that could happen
--
Jeff Layton <jlayton@redhat.com>
next prev parent reply other threads:[~2017-05-26 16:58 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-22 9:58 [PATCH 00/13] [RFC] orangefs page cache Martin Brandenburg
2017-05-22 9:58 ` [PATCH 01/13] orangefs: move orangefs_address_operations to file.c Martin Brandenburg
2017-05-22 9:58 ` [PATCH 02/13] orangefs: remove orangefs_readpages Martin Brandenburg
2017-05-22 9:58 ` [PATCH 03/13] orangefs: make orangefs_inode_read static Martin Brandenburg
2017-05-22 9:58 ` [PATCH 04/13] orangefs: only set a_ops for regular files Martin Brandenburg
2017-05-22 9:58 ` [PATCH 05/13] orangefs: BUG_ON if i_mode invalid Martin Brandenburg
2017-05-22 9:58 ` [PATCH 06/13] orangefs: remove mapping_nrpages macro Martin Brandenburg
2017-05-22 9:58 ` [PATCH 07/13] orangefs: set up and use backing_dev_info Martin Brandenburg
2017-05-22 9:58 ` [PATCH 08/13] orangefs: initialize new inode size to zero Martin Brandenburg
2017-05-22 9:58 ` [PATCH 09/13] orangefs: inodes linger in cache Martin Brandenburg
2017-05-22 9:58 ` [PATCH 10/13] orangefs: implement direct_IO for the read case Martin Brandenburg
2017-05-22 9:58 ` [PATCH 11/13] orangefs: lock inode during fsync Martin Brandenburg
2017-05-25 15:58 ` Jeff Layton
2017-05-26 16:21 ` martin
2017-05-26 16:58 ` Jeff Layton [this message]
2017-05-22 9:59 ` [PATCH 12/13] orangefs: call generic_file_read_iter Martin Brandenburg
2017-05-22 9:59 ` [PATCH 13/13] orangefs: implement write through the page cache Martin Brandenburg
2017-05-25 16:09 ` Jeff Layton
2017-05-26 18:09 ` martin
2017-05-26 18:48 ` Jeff Layton
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