• Christoph Hellwig's avatar
    nfsd: special case truncates some more · 783112f7
    Christoph Hellwig authored
    Both the NFS protocols and the Linux VFS use a setattr operation with a
    bitmap of attributes to set to set various file attributes including the
    file size and the uid/gid.
    
    The Linux syscalls never mix size updates with unrelated updates like
    the uid/gid, and some file systems like XFS and GFS2 rely on the fact
    that truncates don't update random other attributes, and many other file
    systems handle the case but do not update the other attributes in the
    same transaction.  NFSD on the other hand passes the attributes it gets
    on the wire more or less directly through to the VFS, leading to updates
    the file systems don't expect.  XFS at least has an assert on the
    allowed attributes, which caught an unusual NFS client setting the size
    and group at the same time.
    
    To handle this issue properly this splits the notify_change call in
    nfsd_setattr into two separate ones.
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    Cc: stable@vger.kernel.org
    Tested-by: default avatarChuck Lever <chuck.lever@oracle.com>
    Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
    783112f7
vfs.c 49.9 KB