On Fri, Oct 09, 2015 at 04:04:38PM -0400, J. Bruce Fields wrote: > On Fri, Oct 09, 2015 at 01:54:22PM -0400, Trond Myklebust wrote: > > On Fri, Oct 9, 2015 at 1:45 PM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote: > > > > > > On Fri, Oct 09, 2015 at 07:04:00PM +0200, Christoph Hellwig wrote: > > > > On Fri, Oct 09, 2015 at 11:28:03AM -0400, J. Bruce Fields wrote: > > > > > OK, planning to apply for 4.3 just on the assumption that you know what > > > > > you're doing, but: I don't get it--it looks like the worst that can > > > > > happen here is we just reuturn LAYOUTUNAVAILABLE to LAYOUTGET. > > > > > Shouldn't the client then just fall back on normal NFS IO? Why the > > > > > hang? > > > > > > > > I've just retested with Trond's latest tree and can't reproduce the > > > > hang anymore. It used to fence the client due to a lack of response, > > > > but that might have been a different client bug that has now been fixed. > > > > > > OK, makes sense. > > > > > > This still looks like a harmless enough change, but is it still stable > > > and 4.3 material? > > > > > > If it affected a released client then it's probably worth it even if > > > it's really a client bug. If it's just something you saw once against > > > an -rc1, I'd rather leave it for 4.4. > > > > It's not a client bug. > > > > The server is supposed to comply with the requirements in table 13 of > > https://tools.ietf.org/html/rfc5661#section-18.43.3 > > Note that it should also be returning NFS4ERR_BADLAYOUT (or > > NFS4ERR_LAYOUTTRYLATER if loga_minlength == 0) instead of > > layoutunavailable if the loga_minlength request cannot be met. > > I had some ideas that layouts were something a server could decline just > on random whim. Rereading that section.... OK, looks like I was > confused, TRYLATER is the closest we come to random whim. So, updated the changelog as follows, let me know if I've got anything wrong. --b. commit 8c3ad9cb7343 Author: Christoph Hellwig <hch@xxxxxx> Date: Fri Oct 9 15:03:26 2015 +0200 nfsd/blocklayout: accept any minlength Recent Linux clients have started to send GETLAYOUT requests with minlength less than blocksize. Servers aren't really allowed to impose this kind of restriction on layouts; see RFC 5661 section 18.43.3 for details. This has been observed to cause indefinite hangs on fsx runs on some clients. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx> diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c index cdefaa331a07..c29d9421bd5e 100644 --- a/fs/nfsd/blocklayout.c +++ b/fs/nfsd/blocklayout.c @@ -56,14 +56,6 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp, u32 device_generation = 0; int error; - /* - * We do not attempt to support I/O smaller than the fs block size, - * or not aligned to it. - */ - if (args->lg_minlength < block_size) { - dprintk("pnfsd: I/O too small\n"); - goto out_layoutunavailable; - } if (seg->offset & (block_size - 1)) { dprintk("pnfsd: I/O misaligned\n"); goto out_layoutunavailable; -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
