knfsd: nfsd: Handle ERESTARTSYS from syscalls.
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 "try again later" by returning
nfserr_jukebox. The client will resend and - if the server is
restarted - the write will (hopefully) be successful and everyone will
be happy.
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 where writes appeared to fail.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 6cfc96a..b5a20c4 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -614,6 +614,7 @@
#endif
{ nfserr_stale, -ESTALE },
{ nfserr_jukebox, -ETIMEDOUT },
+ { nfserr_jukebox, -ERESTARTSYS },
{ nfserr_dropit, -EAGAIN },
{ nfserr_dropit, -ENOMEM },
{ nfserr_badname, -ESRCH },