Re: [PATCH v2] smb: client: allow nolease option to be reconfigured on remount

Bharath SM
2026-04-22T08:36:52Z

On Tue, Apr 21, 2026 at 10:06 PM <rajasimandalos@gmail.com> wrote:
>
> From: Rajasi Mandal <rajasimandal@microsoft.com>
>
> tcon->no_lease controls whether the client requests leases from the
> server. Changing nolease via remount is silently accepted but has
> no effect because the value is never propagated to the live tcon.
>
> Add no_lease to smb3_sync_tcon_opts() so the flag is propagated to
> every tcon on remount.
>
> When switching to nolease, close all deferred file handles via
> cifs_close_all_deferred_files_sb() outside the tlink_tree_lock,
> since closing deferred handles can sleep. Deferred handles retain
> active leases from before the switch; without closing them, those
> files continue using lease-based caching despite nolease being set.
>
> Both transitions are safe:
> - lease -> nolease: deferred handles are closed, future opens
> get OPLOCK_LEVEL_NONE.
> - nolease -> lease: future opens request leases normally.
>
> Signed-off-by: Rajasi Mandal <rajasimandal@microsoft.com>
> ---
> fs/smb/client/fs_context.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
> index 45173f287f00..fb59b45c7f66 100644
> --- a/fs/smb/client/fs_context.c
> +++ b/fs/smb/client/fs_context.c
> @@ -1317,6 +1317,7 @@ static void smb3_sync_tcon_opts(struct cifs_sb_info *cifs_sb,
>
> spin_lock(&tcon->tc_lock);
> tcon->retry = ctx->retry;
> + tcon->no_lease = ctx->no_lease;
> /*
> * Note: this updates the limit for new cached dir opens
> * but does not resize or evict existing cached dirents.
> @@ -1325,6 +1326,14 @@ static void smb3_sync_tcon_opts(struct cifs_sb_info *cifs_sb,
> spin_unlock(&tcon->tc_lock);
> }
> spin_unlock(&cifs_sb->tlink_tree_lock);
> +
> + /*
> + * When switching to nolease, close all deferred file handles.
> + * cifs_close_all_deferred_files_sb() handles its own locking
> + * and must be called outside tlink_tree_lock since it can sleep.
> + */
> + if (ctx->no_lease)
> + cifs_close_all_deferred_files_sb(cifs_sb);
> }
Similar to deferred files, I think we probably need to invalidate the
cached directory
entries when we remount with 'nolease' considering 'nolease' is a
superset mount option
and should affect all types of leases.

One additional case to consider: if an application already has a file
open with an RWH
lease acquired before the remount, that handle may continue to hold
its lease and benefit
from caching until the server sends a lease break or the application
closes the handle.
Is that correct.?
I think nolease remount only affects new opens; it cannot
retroactively revoke leases on
existing active file handles. It may be worth documenting and/or
comment this behavior,
so it's clear that lease->nolease takes effect gradually as old
handles are closed rather than
instantaneously across all files & handles.

Other than these comments, change looks good to me.