On Fri, Jan 29, 2010 at 06:53:54PM -0500, Dr. J. Bruce Fields wrote:
> On Fri, Jan 29, 2010 at 04:44:25PM -0500, Trond Myklebust wrote:
> > nfsd: Use vfs_fsync_range() in nfsd_commit
> >
> > From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> >
> > The NFS COMMIT operation allows the client to specify the exact byte range
> > that it wishes to sync to disk in order to optimise server performance.
> >
> > Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> > Reviewed-by: Christoph Hellwig <hch@xxxxxx>
>
> Applied, thanks!
Do you have any performance results, by the way?
--b.
>
> --b.
>
> > ---
> >
> > fs/nfsd/vfs.c | 30 ++++++++++++++++++++----------
> > 1 files changed, 20 insertions(+), 10 deletions(-)
> >
> >
> > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > index 79d216f..ed024d3 100644
> > --- a/fs/nfsd/vfs.c
> > +++ b/fs/nfsd/vfs.c
> > @@ -1141,8 +1141,9 @@ out:
> > #ifdef CONFIG_NFSD_V3
> > /*
> > * Commit all pending writes to stable storage.
> > - * Strictly speaking, we could sync just the indicated file region here,
> > - * but there's currently no way we can ask the VFS to do so.
> > + *
> > + * Note: we only guarantee that data that lies within the range specified
> > + * by the 'offset' and 'count' parameters will be synced.
> > *
> > * Unfortunately we cannot lock the file to make sure we return full WCC
> > * data to the client, as locking happens lower down in the filesystem.
> > @@ -1152,23 +1153,32 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
> > loff_t offset, unsigned long count)
> > {
> > struct file *file;
> > - __be32 err;
> > + loff_t end = LLONG_MAX;
> > + __be32 err = nfserr_inval;
> >
> > - if ((u64)count > ~(u64)offset)
> > - return nfserr_inval;
> > + if (offset < 0)
> > + goto out;
> > + if (count != 0) {
> > + end = offset + (loff_t)count - 1;
> > + if (end < offset)
> > + goto out;
> > + }
> >
> > err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
> > if (err)
> > - return err;
> > + goto out;
> > if (EX_ISSYNC(fhp->fh_export)) {
> > - if (file->f_op && file->f_op->fsync) {
> > - err = nfserrno(vfs_fsync(file, file->f_path.dentry, 0));
> > - } else {
> > + int err2 = vfs_fsync_range(file, file->f_path.dentry,
> > + offset, end, 0);
> > +
> > + if (err2 != -EINVAL)
> > + err = nfserrno(err2);
> > + else
> > err = nfserr_notsupp;
> > - }
> > }
> >
> > nfsd_close(file);
> > +out:
> > return err;
> > }
> > #endif /* CONFIG_NFSD_V3 */
> >
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