NFS: Restore missing hunk in NFS mount option parser

NFS: Restore missing hunk in NFS mount option parser

Automounter maps can contain mount options valid for other NFS
implementations but not for Linux.  The Linux automounter uses the
mount command's "-s" command line option ("s" for "sloppy") so that
mount requests containing such options are not rejected.

Commit e9150548f1544b72c7d9f33efb868b4fe99b4cb0 attempted to address a
known regression with text-based NFS mount option parsing.  Unrecognized
mount options would cause mount requests to fail, even if the "-s"
option was used on the mount command line.

Unfortunately, this commit was not complete as submitted.  It adds a
new mount option, "sloppy".  But it is missing a hunk, so it now allows
NFS mounts with unrecognized mount options, even if the "sloppy" option
is not present.  This could be a problem if a required critical mount
option such as "sync" is misspelled, for example, and is considered a
regression from 2.6.26.

This patch restores the missing hunk.  Now, the default behavior of
text-based NFS mount options is as before: any unrecognized mount option
will cause the mount to fail.

Please include this in 2.6.27-rc.

Thanks to Neil Brown for reporting this.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>