NFSv4: Fix CLOSE races with OPEN
If the reply to a successful CLOSE call races with an OPEN to the same
file, we can end up scribbling over the stateid that represents the
new open state.
The race looks like:
Client Server
====== ======
CLOSE stateid A on file "foo"
CLOSE stateid A, return stateid C
OPEN file "foo"
OPEN "foo", return stateid B
Receive reply to OPEN
Reset open state for "foo"
Associate stateid B to "foo"
Receive CLOSE for A
Reset open state for "foo"
Replace stateid B with C
The fix is to examine the argument of the CLOSE, and check for a match
with the current stateid "other" field. If the two do not match, then
the above race occurred, and we should just ignore the CLOSE.
Reported-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2 files changed