03.12.2010 20:35, Chuck Lever ÐÐÑÐÑ:
On Dec 3, 2010, at 12:11 PM, Stanislav Kinsbursky wrote:
Default value for mount server port is set to NFS_UNSPEC_PORT (-1) and will not
be changed during parsing mount options for mound data version 6. This default
value will be showed for mountport in /proc/mounts always since current default
check is for zero value. This small mistake leads to big problem, because
during umount.nfs execution from old user-space utils (at least nfs-utils
1.0.9) this value will be used as the server port to connect to. This request
will be rejected (since port is 65535) and thus nfs mount point can't be
unmounted.
Note: this is only possible if /etc/mtab is a link to /proc/mounts. Not all systems have this configuration.
I found it on CentOs 5.5 with RHEL6 kernel.
Actually, the current patch has a specific flaw: if mount port is not passed by nfs utils using mount options version 6, then it will be set to 0 and showed in /proc/mounts as "mountport=0".
Another fix solution is to call "nfs_set_port(sap, &args->nfs_server.port, 0);" when parsing mount options version 6 (like in done in default casein nfs_validate_mount_data) instead of changing
nfs_show_mountd_options().
Kernel version affected: 2.6.37-rc4
Signed-off-by: Stanislav Kinsbursky<skinsbursky@xxxxxxxxxxxxx>
---
fs/nfs/super.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 6d6e21d..fd4cac8 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -681,7 +681,8 @@ static void nfs_show_mountd_options(struct seq_file *m, struct nfs_server *nfss,
if (nfss->mountd_version || showdefaults)
seq_printf(m, ",mountvers=%u", nfss->mountd_version);
- if (nfss->mountd_port || showdefaults)
+ if (nfss->mountd_port != (unsigned short)NFS_UNSPEC_PORT ||
+ showdefaults)
seq_printf(m, ",mountport=%u", nfss->mountd_port);
nfs_show_mountd_netid(m, nfss, showdefaults);
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--
Best regards,
Stanislav Kinsbursky
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