NFS Client mounts hang when exported directory do not exist

This patch fixes a regression that was introduced by the string based mounts.

nfs_mount() statically returns -EACCES for every error returned by the remote mounted. This is incorrect because -EACCES is an non-fatal error to the mount.nfs command. This error causes mount.nfs to retry the mount even in the case when the exported directory does not exist.

This patch maps the errors returned by the remote mountd into valid errno values, exactly how it was done pre-string based mounts. By returning the correct errno enables mount.nfs to do the right thing.

Quoted 8 lines · Steve Dickson

This patch fixes a regression that was introduced by the string based mounts.

nfs_mount() statically returns -EACCES for every error returned by the remote mounted. This is incorrect because -EACCES is an non-fatal error to the mount.nfs command. This error causes mount.nfs to retry the mount even in the case when the exported directory does not exist.

Quoted 4 lines

This patch maps the errors returned by the remote mountd into valid errno values, exactly how it was done pre-string based mounts. By returning the correct errno enables mount.nfs to do the right thing.

Does this mean the EACCES can/will again become fatal in mount.nfs like it used to be?

Quoted 9 lines · Eric Paris

Quoted 8 lines · Steve Dickson

This patch fixes a regression that was introduced by the string based mounts.

nfs_mount() statically returns -EACCES for every error returned by the remote mounted. This is incorrect because -EACCES is an non-fatal error to the mount.nfs command. This error causes mount.nfs to retry the mount even in the case when the exported directory does not exist.

Quoted 7 lines

Quoted 4 lines

This patch maps the errors returned by the remote mountd into valid errno values, exactly how it was done pre-string based mounts. By returning the correct errno enables mount.nfs to do the right thing.

Does this mean the EACCES can/will again become fatal in mount.nfs like it used to be?

EACCES is still a non-fatal error as it was...

The problem is the
kernel was should have been returning ENOENT, which is a fatal error, instead of EACCES.

Quoted 3 lines · Steve Dickson

Quoted 2 lines

Does this mean the EACCES can/will again become fatal in mount.nfs like it used to be?

EACCES is still a non-fatal error as it was...

"non-fatal error as it was"? Huh? Back in the days of binary mount data it was fatal. Try this on a new and old system.

That may well have been your problem, but it doesn't change the fact the EACCES has been a fatal error in mount.nfs until just recently. Why was it changed? When is EACCES not fatal?

This patch fixes a regression that was introduced by the string based mounts.

nfs_mount() statically returns -EACCES for every error returned by the remote mounted. This is incorrect because -EACCES is an non-fatal error to the mount.nfs command. This error causes mount.nfs to retry the mount even in the case when the exported directory does not exist.

This patch maps the errors returned by the remote mountd into
valid errno values, exactly how it was done pre-string based mounts. By returning the correct errno enables mount.nfs to do the right thing.

Signed-off-by Steve Dickson <[email protected]>

---

diff -up linux/fs/nfs/mount_clnt.c.orig linux/fs/nfs/mount_clnt.c

fs/nfs/mount_clnt.c renamed from fs/nfs/mount_clnt.c.orig +33 -0

@@ -21,6 +21,49 @@
 
 static struct rpc_program	mnt_program;
 
+static struct {
+	enum nfs_stat stat;
+	int errnum;
+} mnt_errtbl[] = {
+	{ NFS_OK,		0		},
+	{ NFSERR_PERM,		EPERM		},
+	{ NFSERR_NOENT,		ENOENT		},
+	{ NFSERR_IO,		EIO		},
+	{ NFSERR_NXIO,		ENXIO		},
+	{ NFSERR_ACCES,		EACCES		},
+	{ NFSERR_EXIST,		EEXIST		},
+	{ NFSERR_NODEV,		ENODEV		},
+	{ NFSERR_NOTDIR,	ENOTDIR		},
+	{ NFSERR_ISDIR,		EISDIR		},
+#ifdef NFSERR_INVAL
+	{ NFSERR_INVAL,		EINVAL		},	/* that Sun forgot */
+#endif
+	{ NFSERR_FBIG,		EFBIG		},
+	{ NFSERR_NOSPC,		ENOSPC		},
+	{ NFSERR_ROFS,		EROFS		},
+	{ NFSERR_NAMETOOLONG,	ENAMETOOLONG	},
+	{ NFSERR_NOTEMPTY,	ENOTEMPTY	},
+	{ NFSERR_DQUOT,		EDQUOT		},
+	{ NFSERR_STALE,		ESTALE		},
+#ifdef EWFLUSH
+	{ NFSERR_WFLUSH,	EWFLUSH		},
+#endif
+	/* Throw in some NFSv3 values for even more fun (HP returns these) */
+	{ 71,			EREMOTE		},
+};
+static int mnt_errtbl_sz = sizeof(mnt_errtbl)/sizeof(mnt_errtbl[0]);
+
+static inline int mnt_err_map(int stat)

Quoted 7 lines · Steve Dickson

This patch fixes a regression that was introduced by the string based mounts.
nfs_mount() statically returns -EACCES for every error returned by the remote mounted. This is incorrect because -EACCES is an non-fatal error to the mount.nfs command. This error causes mount.nfs to retry the mount even in the case when the exported directory does not exist.

I don't doubt this is the case, but I'd like to see a few real world examples (maybe even add them as documentary comments in mount.nfs or in the kernel).