tree 17b28bd50fd22ae65f90e9bd09cc5b14415a0049
parent e0b93eddfe17dcb7d644eb5d6ad02a86fc41a977
author Jeff Layton <jlayton@primarydata.com> 1408717124 -0400
committer Jeff Layton <jlayton@primarydata.com> 1412705172 -0400

locks: close potential race in lease_get_mtime

lease_get_mtime is called without the i_lock held, so there's no
guarantee about the stability of the list. Between the time when we
assign "flock" and then dereference it to check whether it's a lease
and for write, the lease could be freed.

Ensure that that doesn't occur by taking the i_lock before trying
to check the lease.

Cc: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>