On Sat, Jun 25, 2016 at 7:19 PM, Trond Myklebust
<trond.myklebust@xxxxxxxxxxxxxxx> wrote:
> Olga Kornievskaia reports that the following test fails to trigger
> an OPEN_DOWNGRADE on the wire, and only triggers the final CLOSE.
>
> fd0 = open(foo, RDRW) -- should be open on the wire for "both"
> fd1 = open(foo, RDONLY) -- should be open on the wire for "read"
> close(fd0) -- should trigger an open_downgrade
> read(fd1)
> close(fd1)
>
> The issue is that we're missing a check for whether or not the current
> state transitioned from an O_RDWR state as opposed to having transitioned
> from a combination of O_RDONLY and O_WRONLY.
>
> Reported-by: Olga Kornievskaia <aglo@xxxxxxxxx>
> Fixes: cd9288ffaea4 ("NFSv4: Fix another bug in the close/open_downgrade code")
> Cc: stable@xxxxxxxxxxxxxxx # 2.6.33+
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/nfs4proc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 406dd3eb68e2..ff416d0e24bc 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -2882,12 +2882,11 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
> call_close |= is_wronly;
> else if (is_wronly)
> calldata->arg.fmode |= FMODE_WRITE;
> + if (calldata->arg.fmode != (FMODE_READ|FMODE_WRITE))
> + call_close |= is_rdwr;
> } else if (is_rdwr)
> calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;
>
> - if (calldata->arg.fmode == 0)
> - call_close |= is_rdwr;
> -
> if (!nfs4_valid_open_stateid(state))
> call_close = 0;
> spin_unlock(&state->owner->so_lock);
> --
> 2.7.4
>
Thanks Trond. With this patch, in my test I see OPEN_DOWNGRADE sent.
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