Description of problem:

When an NFS server has many exports to netgroups a client may fail to mount a share with NFS4 (the mount command will hang indefinitely).

When I run rpc.mountd with '-d all' and use the reproducer below I get the following output:

rpc.mountd: v4root_create: path '/'
rpc.mountd: v4root_create: path '/export'
rpc.mountd: v4root_create: path '/'
rpc.mountd: v4root_create: path '/export'
rpc.mountd: v4root_create: path '/export/test2'
...
rpc.mountd: v4root_create: path '/export'
rpc.mountd: v4root_create: path '/export/test2'
rpc.mountd: v4root_create: path '/'
rpc.mountd: v4root_create: path '/export'
rpc.mountd: auth_unix_ip: client (nil) 'DEFAULT'
rpc.mountd: nfsd_fh: inbuf '129.132.10.7 1 \x00000000'
rpc.mountd: nfsd_fh: found 0x213d5f0 path /
rpc.mountd: nfsd_export: inbuf '129.132.10.7 /export'

Additionally here is the content of the various pipes when the above mount fails:

# cat /proc/net/rpc/nfsd.fh/content
#domain fsidtype fsid [path]
129.132.10.7 1 0x00000000 /
# cat /proc/net/rpc/nfsd.export/channel 
129.132.10.7 /export
129.132.10.7 /export
# cat /proc/net/rpc/nfsd.export/content 
#path domain(flags)
# /export	129.132.10.7()
/	129.132.10.7(ro,root_squash,sync,no_wdelay,no_subtree_check,v4root,fsid=0,uuid=2e8bd014:febf431f:a2127b34:4f1fcb95)
# cat /proc/net/rpc/nfsd.export/flush 
1335255591

Version-Release number of selected component (if applicable):

nfs-utils-1.2.3-15.el6.x86_64
kernel-2.6.32-220.13.1.el6.x86_64

This happens both with the stock nfs-utils package as well with a modified package that incorporates the patches from BZ 797209 and BZ 812364.


How reproducible:

Always.


Steps to Reproduce:

Requires an up-to-date RHEL 6.2 server and client.

1. Create /export/test1 and /export/test2 on the server

2. Create /etc/exports with the following content:

/export/test1 *(rw,async,no_root_squash,no_subtree_check,fsid=99999)

3. Optionally configure 1000 netgroups named 1 to 1000 and populate them with some host triplets. This is not needed to reproduce the bug though.

4. Restart the nfs service or boot the system.

5. Add 1000 exports to netgroups by running

for i in `seq 1 1000`; do mkdir -p /export/test2/$i ; exportfs -o
rw,async,no_root_squash,no_subtree_check,fsid=19898$i @$i:/export/test2/$i ;
done

6. On the client try to mount /export/test1 from the server with NFS4. This will not succeed.


Additional info:

The problem is probably related to the one of BZ 797209 and BZ 812364 which are for NFS3.