From:   Rick Macklem <rmacklem@uoguelph.ca>
To:     Armin Zentai <armin@zentai.name>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "J. Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@kernel.org>
Subject: Re: [PATCH] Add EMFILE to nfsd errors
Thread-Topic: [PATCH] Add EMFILE to nfsd errors
Thread-Index: AQHU5NEBqrcKtYWwGUW+HjBTriQlx6Yf/UYU
Date:   Wed, 27 Mar 2019 21:25:01 +0000
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I don't believe that EMFILE is specified as an NFS error in the RFCs?

rick

________________________________________
From: linux-nfs-owner@vger.kernel.org <linux-nfs-owner@vger.kernel.org> on behalf of Armin Zentai <armin@zentai.name>
Sent: Wednesday, March 27, 2019 3:03:43 PM
To: linux-nfs@vger.kernel.org; J. Bruce Fields; Jeff Layton
Subject: [PATCH] Add EMFILE to nfsd errors

This patch adds the EMFILE to nfsd errors for better error output.

I've encountered a hard-to-debug situation, when I used a fuse under an NFS export, because of a 'too many open files' error.

Before the patch nfsd warns with this message:
'nfsd4_process_open2 failed to open newly-created file! status=5'  (5: EIO)

After the patch:
'nfsd4_process_open2 failed to open newly-created file! status=24' (24: EMFILE)

Also the client returns with EREMOTEIO instead of EIO, which indicates a server error from the NFS client side.

Signed-off-by: Armin ZENTAI <armin@zentai.name>
---
 fs/nfsd/nfsd.h           | 1 +
 fs/nfsd/nfsproc.c        | 1 +
 include/uapi/linux/nfs.h | 1 +
 3 files changed, 3 insertions(+)

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 066899929863..19a269d75fb5 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -217,6 +217,7 @@ void                nfsd_lockd_shutdown(void);
 #define        nfserr_cb_path_down     cpu_to_be32(NFSERR_CB_PATH_DOWN)
 #define        nfserr_locked           cpu_to_be32(NFSERR_LOCKED)
 #define        nfserr_wrongsec         cpu_to_be32(NFSERR_WRONGSEC)
+#define nfserr_emfile                  cpu_to_be32(NFSERR_EMFILE)
 #define nfserr_badiomode               cpu_to_be32(NFS4ERR_BADIOMODE)
 #define nfserr_badlayout               cpu_to_be32(NFS4ERR_BADLAYOUT)
 #define nfserr_bad_session_digest      cpu_to_be32(NFS4ERR_BAD_SESSION_DIGEST)
diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 0d20fd161225..ff9e883c7829 100644
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -810,6 +810,7 @@ nfserrno (int errno)
                { nfserr_serverfault, -ENFILE },
                { nfserr_io, -EUCLEAN },
                { nfserr_perm, -ENOKEY },
+               { nfserr_emfile, -EMFILE },
        };
        int     i;

diff --git a/include/uapi/linux/nfs.h b/include/uapi/linux/nfs.h
index 946cb62d64b0..dcb0ea33f2db 100644
--- a/include/uapi/linux/nfs.h
+++ b/include/uapi/linux/nfs.h
@@ -57,6 +57,7 @@
        NFSERR_NOTDIR = 20,             /* v2 v3 v4 */
        NFSERR_ISDIR = 21,              /* v2 v3 v4 */
        NFSERR_INVAL = 22,              /* v2 v3 v4 */
+       NFSERR_EMFILE = 24,             /* v2 v3 v4 */
        NFSERR_FBIG = 27,               /* v2 v3 v4 */
        NFSERR_NOSPC = 28,              /* v2 v3 v4 */
        NFSERR_ROFS = 30,               /* v2 v3 v4 */
--
2.11.0