Messages in this thread |  | | Date | Mon, 16 Jun 2008 08:39:53 -0400 | From | Peter Staubach <> | Subject | Re: [PATCH] knfsd: nfsd: Handle ERESTARTSYS from syscalls. |
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NeilBrown wrote: > OCFS2 can return -ERESTARTSYS from write requests (and possibly > elsewhere) if there is a signal pending. > > If nfsd is shutdown (by sending a signal to each thread) while there > is still an IO load from the client, each thread could handle one last > request with a signal pending. This can result in -ERESTARTSYS > which is not understood by nfserrno() and so is reflected back to > the client as nfserr_io aka -EIO. This is wrong. > > Instead, interpret ERESTARTSYS to mean "don't send a reply". > The client will resend and - if the server is restarted - the write will > (hopefully) be successful and everyone will be happy. > >
Why not handle -ERESTARTSYS in the same fashion as -ETIMEDOUT, ie. leading to a EJUKEBOX sort of error being returned if possible?
Simply not returning is a bad thing to do for anything other than NFSv2. It is especially bad for NFSv4.
ps
> Signed-off-by: Neil Brown <neilb@suse.de> > > ### Diffstat output > ./fs/nfsd/nfsproc.c | 1 + > 1 file changed, 1 insertion(+) > > ---- > Funny how the shortest patches sometimes have the longest > descriptions. > > The symptom that I narrowed down to this was: > copy a large file via NFS to an OCFS2 filesystem, and restart > the nfs server during the copy. > The 'cp' might get an -EIO, and the file will be corrupted - > presumably holes in the middle were writes appeared to fail. > > diff .prev/fs/nfsd/nfsproc.c ./fs/nfsd/nfsproc.c > --- .prev/fs/nfsd/nfsproc.c 2008-06-13 21:31:53.000000000 +1000 > +++ ./fs/nfsd/nfsproc.c 2008-06-13 21:31:57.000000000 +1000 > @@ -614,6 +614,7 @@ nfserrno (int errno) > #endif > { nfserr_stale, -ESTALE }, > { nfserr_jukebox, -ETIMEDOUT }, > + { nfserr_dropit, -ERESTARTSYS }, > { nfserr_dropit, -EAGAIN }, > { nfserr_dropit, -ENOMEM }, > { nfserr_badname, -ESRCH }, > > ### Diffstat output > ./fs/nfsd/nfsproc.c | 1 + > 1 file changed, 1 insertion(+) > > diff .prev/fs/nfsd/nfsproc.c ./fs/nfsd/nfsproc.c > --- .prev/fs/nfsd/nfsproc.c 2008-06-13 21:31:53.000000000 +1000 > +++ ./fs/nfsd/nfsproc.c 2008-06-13 21:31:57.000000000 +1000 > @@ -614,6 +614,7 @@ nfserrno (int errno) > #endif > { nfserr_stale, -ESTALE }, > { nfserr_jukebox, -ETIMEDOUT }, > + { nfserr_dropit, -ERESTARTSYS }, > { nfserr_dropit, -EAGAIN }, > { nfserr_dropit, -ENOMEM }, > { nfserr_badname, -ESRCH }, > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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