When mounting multiple mounts from the same NFS export, attempting to override the SELinux context of each mount with a different context, results in subsequent mount commands failing. In the following example, the NFS server has a single export, /export, which has two subdirectories, web/ and database/. The following commands attempt two mounts from a single NFS export, and try to override the context for each one:

# mount server:/export/web /local/web -o\
context="system_u:object_r:httpd_sys_content_t:s0"

# mount server:/export/database /local/database -o\
context="system_u:object_r:mysqld_db_t:s0"

The second mount command fails, and the following is logged to /var/log/messages:

kernel: SELinux: mount invalid.  Same superblock, different security settings for (dev 0:15, type nfs)

To mount multiple mounts from a single NFS export, with each mount having a different context, use the -o nosharecache,context options. The following example mounts multiple mounts from a single NFS export, with a different context for each mount (allowing a single service access to each one):

# mount server:/export/web /local/web -o\
nosharecache,context="system_u:object_r:httpd_sys_content_t:s0"

# mount server:/export/database /local/database -o\
nosharecache,context="system_u:object_r:mysqld_db_t:s0"

In this example, server:/export/web is mounted locally to /local/web/, with all files being labeled with the httpd_sys_content_t type, allowing Apache HTTP Server access. server:/export/database is mounted locally to /local/database, with all files being labeled with the mysqld_db_t type, allowing MySQL access. These type changes are not written to disk.