From: Meetakshi Setiya <meetakshisetiyaoss@gmail.com>
To: rajasimandalos@gmail.com
Cc: sfrench@samba.org, linux-cifs@vger.kernel.org, pc@manguebit.org,
ronniesahlberg@gmail.com, sprasad@microsoft.com, tom@talpey.com,
metze@samba.org, bharathsm@microsoft.com,
samba-technical@lists.samba.org, linux-kernel@vger.kernel.org,
Rajasi Mandal <rajasimandal@microsoft.com>
Subject: Re: [PATCH 7/9] smb: client: block cache=ro and cache=singleclient on remount
Date: Mon, 13 Apr 2026 06:40:48 -0700 [thread overview]
Message-ID: <CAFTVevVLJg59YjUPu8HBA4+emN_eUVJe8H9UCUCswY1ui6cnVw@mail.gmail.com> (raw)
In-Reply-To: <20260409095926.905020-7-rajasimandalos@gmail.com>
Hey Rajasi,
I guess this is not handling remounts where cache=singleclient/ro is
not specified i.e. preserving previous behaviour.
To reproduce, mount with cache=ro and remount without providing cache=ro.
sudo mount -t cifs //server/winshare /mnt/mainshare -o
remount,username=demouser
mount error(22): Invalid argument
On Thu, Apr 9, 2026 at 3:07 AM <rajasimandalos@gmail.com> wrote:
>
> From: Rajasi Mandal <rajasimandal@microsoft.com>
>
> cache=ro and cache=singleclient are mount-time environment declarations
> where the admin promises that the share is read-only or exclusively
> accessed. The client bypasses server-based coherency (oplocks/leases)
> and caches aggressively based on this promise.
>
> These modes were intentionally excluded from smb3_update_mnt_flags()
> when it was introduced in commit 2d39f50c2b15 ("cifs: move update of
> flags into a separate function") — only cache=strict, cache=none and
> cache=loose were made reconfigurable. However, remount currently
> silently accepts cache=ro and cache=singleclient without actually
> applying them, which is confusing.
>
> Add explicit checks in smb3_verify_reconfigure_ctx() to reject
> attempts to change these options during remount with a clear error
> message.
>
> Signed-off-by: Rajasi Mandal <rajasimandal@microsoft.com>
> ---
> fs/smb/client/fs_context.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
> index ce4842e778c4..2be72733ef2e 100644
> --- a/fs/smb/client/fs_context.c
> +++ b/fs/smb/client/fs_context.c
> @@ -1180,6 +1180,14 @@ static int smb3_verify_reconfigure_ctx(struct fs_context *fc,
> cifs_errorf(fc, "can not change rdma during remount\n");
> return -EINVAL;
> }
> + if (new_ctx->cache_ro != old_ctx->cache_ro) {
> + cifs_errorf(fc, "can not change cache=ro during remount\n");
> + return -EINVAL;
> + }
> + if (new_ctx->cache_rw != old_ctx->cache_rw) {
> + cifs_errorf(fc, "can not change cache=singleclient during remount\n");
> + return -EINVAL;
> + }
>
> return 0;
> }
> --
> 2.43.0
>
>
next prev parent reply other threads:[~2026-04-13 13:40 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-09 9:59 [PATCH 1/9] smb: client: block non-reconfigurable option changes on remount rajasimandalos
2026-04-09 9:59 ` [PATCH 2/9] smb: client: allow both 'lease' and 'nolease' mount options rajasimandalos
2026-04-13 13:30 ` Meetakshi Setiya
2026-04-09 9:59 ` [PATCH 3/9] smb: client: sync tcon-level options on remount rajasimandalos
2026-04-17 14:29 ` Meetakshi Setiya
2026-04-09 9:59 ` [PATCH 4/9] smb: client: sync retrans " rajasimandalos
2026-04-09 9:59 ` [PATCH 5/9] smb: client: sync echo_interval " rajasimandalos
2026-04-22 4:42 ` [PATCH v2] " rajasimandalos
2026-04-09 9:59 ` [PATCH 6/9] smb: client: allow nolease option to be reconfigured " rajasimandalos
2026-04-22 5:06 ` [PATCH v2] " rajasimandalos
2026-04-22 8:36 ` Bharath SM
2026-04-22 15:29 ` Steve French
2026-04-09 9:59 ` [PATCH 7/9] smb: client: block cache=ro and cache=singleclient " rajasimandalos
2026-04-13 13:40 ` Meetakshi Setiya [this message]
2026-04-22 4:34 ` RAJASI MANDAL
2026-04-09 9:59 ` [PATCH 8/9] smb: client: fix domainauto remount by syncing domainname from session rajasimandalos
2026-04-09 9:59 ` [PATCH 9/9] smb: client: apply rasize on remount rajasimandalos
2026-04-13 13:29 ` Meetakshi Setiya
2026-04-13 7:32 ` [PATCH v2 1/9] smb: client: block non-reconfigurable option changes " Rajasi Mandal
2026-04-17 14:05 ` Meetakshi Setiya
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