[PATCH] nfsd: wake waiters blocked on file_lock before deleting it

[PATCH] nfsd: wake waiters blocked on file_lock before deleting it

[Jeff Layton]

After a blocked nfsd file_lock request is deleted, knfsd will send a
callback to the client and then free the request. Commit 16306a61d3b7
("fs/locks: always delete_block after waiting.") changed it such that
locks_delete_block is always called on a request after it is awoken,
but that patch missed fixing up blocked nfsd request handling.

Call locks_delete_block on the block to wake up any locks still blocked
on the nfsd lock request before sending the callback.

URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363
Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.")
Reported-by: Slawomir Pryczek <slawek1211@gmail.com>
Cc: Neil Brown <neilb@suse.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/nfsd/nfs4state.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 6a45fb00c5fc..1960e8fd9ad1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -298,6 +298,14 @@ remove_blocked_locks(struct nfs4_lockowner *lo)
 	}
 }
 
+static void
+nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb)
+{
+	struct nfsd4_blocked_lock	*nbl = container_of(cb,
+						struct nfsd4_blocked_lock, nbl_cb);
+	locks_delete_block(&nbl->nbl_lock);
+}
+
 static int
 nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
 {
@@ -325,6 +333,7 @@ nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
 }
 
 static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
+	.prepare	= nfsd4_cb_notify_lock_prepare,
 	.done		= nfsd4_cb_notify_lock_done,
 	.release	= nfsd4_cb_notify_lock_release,
 };
-- 
2.20.1

Re: [PATCH] nfsd: wake waiters blocked on file_lock before deleting it

[Jeff Layton]

On Sat, Apr 20, 2019 at 6:16 AM Jeff Layton <jlayton@kernel.org> wrote:
>
> After a blocked nfsd file_lock request is deleted, knfsd will send a
> callback to the client and then free the request. Commit 16306a61d3b7
> ("fs/locks: always delete_block after waiting.") changed it such that
> locks_delete_block is always called on a request after it is awoken,
> but that patch missed fixing up blocked nfsd request handling.
>
> Call locks_delete_block on the block to wake up any locks still blocked
> on the nfsd lock request before sending the callback.
>
> URL: https://bugzilla.kernel.org/show_bug.cgi?id=203363
> Fixes: 16306a61d3b7 ("fs/locks: always delete_block after waiting.")
> Reported-by: Slawomir Pryczek <slawek1211@gmail.com>
> Cc: Neil Brown <neilb@suse.com>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/nfsd/nfs4state.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 6a45fb00c5fc..1960e8fd9ad1 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -298,6 +298,14 @@ remove_blocked_locks(struct nfs4_lockowner *lo)
>         }
>  }
>
> +static void
> +nfsd4_cb_notify_lock_prepare(struct nfsd4_callback *cb)
> +{
> +       struct nfsd4_blocked_lock       *nbl = container_of(cb,
> +                                               struct nfsd4_blocked_lock, nbl_cb);
> +       locks_delete_block(&nbl->nbl_lock);
> +}
> +
>  static int
>  nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
>  {
> @@ -325,6 +333,7 @@ nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
>  }
>
>  static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
> +       .prepare        = nfsd4_cb_notify_lock_prepare,
>         .done           = nfsd4_cb_notify_lock_done,
>         .release        = nfsd4_cb_notify_lock_release,
>  };
> --
> 2.20.1
>

This should also go to stable I think. If you end up picking this up,
can you add the Cc: for stable as well?

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>