nfsd4: fix open downgrade, again
commit 3d02fa29dec920c597dd7b7db608a4bc71f088ce upstream.
Yet another open-management regression:
- nfs4_file_downgrade() doesn't remove the BOTH access bit on
downgrade, so the server's idea of the stateid's access gets
out of sync with the client's. If we want to keep an O_RDWR
open in this case, we should do that in the file_put_access
logic rather than here.
- We forgot to convert v4 access to an open mode here.
This logic has proven too hard to get right. In the future we may
consider:
- reexamining the lock/openowner relationship (locks probably
don't really need to take their own references here).
- adding open upgrade/downgrade support to the vfs.
- removing the atomic operations. They're redundant as long as
this is all under some other lock.
Also, maybe some kind of additional static checking would help catch
O_/NFS4_SHARE_ACCESS confusion.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
1 file changed