tree 7fbfe0ffc4f5a5b3f9ccf56de8fe887c7394027c
parent 140e049c64ce848392adbf4678983ecc76888dde
author Trond Myklebust <trond.myklebust@primarydata.com> 1424984944 -0500
committer Trond Myklebust <trond.myklebust@primarydata.com> 1425270185 -0500

NFS: Add attribute update barriers to nfs_setattr_update_inode()

Ensure that other operations which raced with our setattr RPC call
cannot revert the file attribute changes that were made on the server.
To do so, we artificially bump the attribute generation counter on
the inode so that all calls to nfs_fattr_init() that precede ours
will be dropped.

The motivation for the patch came from Chuck Lever's reports of readaheads
racing with truncate operations and causing the file size to be reverted.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>