On Mon, 2023-08-14 at 17:11 -0400, Alexander Aring wrote:
> This patch uses the FL_SLEEP flag in struct file_lock to check if it's a
> blocking request in case if the request coming from nfs lockd process
> indicated by lm_grant() is set.
>
> IF FL_SLEEP is set a asynchronous blocking request is being made and
> it's waiting for lm_grant() callback being called to signal the lock was
> granted. If it's not set a synchronous non-blocking request is being made.
>
> Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
> ---
> fs/dlm/plock.c | 38 ++++++++++++++++++++++----------------
> 1 file changed, 22 insertions(+), 16 deletions(-)
>
> diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
> index 0094fa4004cc..524771002a2f 100644
> --- a/fs/dlm/plock.c
> +++ b/fs/dlm/plock.c
> @@ -140,7 +140,6 @@ int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
> op->info.optype = DLM_PLOCK_OP_LOCK;
> op->info.pid = fl->fl_pid;
> op->info.ex = (fl->fl_type == F_WRLCK);
> - op->info.wait = IS_SETLKW(cmd);
> op->info.fsid = ls->ls_global_id;
> op->info.number = number;
> op->info.start = fl->fl_start;
> @@ -148,24 +147,31 @@ int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
> op->info.owner = (__u64)(long)fl->fl_owner;
> /* async handling */
> if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
> - op_data = kzalloc(sizeof(*op_data), GFP_NOFS);
> - if (!op_data) {
> - dlm_release_plock_op(op);
> - rv = -ENOMEM;
> - goto out;
> - }
> + if (fl->fl_flags & FL_SLEEP) {
> + op_data = kzalloc(sizeof(*op_data), GFP_NOFS);
> + if (!op_data) {
> + dlm_release_plock_op(op);
> + rv = -ENOMEM;
> + goto out;
> + }
>
> - op_data->callback = fl->fl_lmops->lm_grant;
> - locks_init_lock(&op_data->flc);
> - locks_copy_lock(&op_data->flc, fl);
> - op_data->fl = fl;
> - op_data->file = file;
> + op->info.wait = 1;
> + op_data->callback = fl->fl_lmops->lm_grant;
> + locks_init_lock(&op_data->flc);
> + locks_copy_lock(&op_data->flc, fl);
> + op_data->fl = fl;
> + op_data->file = file;
>
> - op->data = op_data;
> + op->data = op_data;
>
> - send_op(op);
> - rv = FILE_LOCK_DEFERRED;
> - goto out;
> + send_op(op);
> + rv = FILE_LOCK_DEFERRED;
> + goto out;
A question...we're returning FILE_LOCK_DEFERRED after the DLM request is
sent. If it ends up being blocked, what happens? Does it do a lm_grant
downcall with -EAGAIN or something as the result?
> + } else {
> + op->info.wait = 0;
> + }
> + } else {
> + op->info.wait = IS_SETLKW(cmd);
> }
>
> send_op(op);
Looks reasonable overall.
Now that I look, we have quite a number of places in the kernel that
seem to check for F_SETLKW, when what they really want is to check
FL_SLEEP.
--
Jeff Layton <jlayton@xxxxxxxxxx>
