From: NeilBrown Subject: [PATCH] knfsd: nfsd: Handle ERESTARTSYS from syscalls. Date: Fri, 13 Jun 2008 21:42:15 +1000 Message-ID: <1080613114215.27095@suse.de> References: <20080613213759.26929.patches@notabene> Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org To: "J. Bruce Fields" Return-path: Received: from ns1.suse.de ([195.135.220.2]:33229 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754047AbYFMLmy (ORCPT ); Fri, 13 Jun 2008 07:42:54 -0400 Sender: linux-nfs-owner@vger.kernel.org List-ID: 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. Signed-off-by: Neil Brown ### 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 },