Re: [PATCH 09/14] cifs: add a back pointer to cifs_sb from tcon

Steve French
2023-11-01T03:30:35Z

merged into cifs-2.6.git for-next pending more testing

added cc:stable

On Mon, Oct 30, 2023 at 6:00 AM <nspmangalore@gmail.com> wrote:
>
> From: Shyam Prasad N <sprasad@microsoft.com>
>
> Today, we have no way to access the cifs_sb when we
> just have pointers to struct tcon. This is very
> limiting as many functions deal with cifs_sb, and
> these calls do not directly originate from VFS.
>
> This change introduces a new cifs_sb field in cifs_tcon
> that points to the cifs_sb for the tcon. The assumption
> here is that a tcon will always map to this cifs_sb and
> will never change.
>
> Also, refcounting should not be necessary, since cifs_sb
> will never be freed before tcon.
>
> Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
> ---
> fs/smb/client/cifsglob.h | 1 +
> fs/smb/client/connect.c | 2 ++
> 2 files changed, 3 insertions(+)
>
> diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
> index 81e7a45f413d..cdbc2cd207dc 100644
> --- a/fs/smb/client/cifsglob.h
> +++ b/fs/smb/client/cifsglob.h
> @@ -1134,6 +1134,7 @@ struct cifs_tcon {
> int tc_count;
> struct list_head rlist; /* reconnect list */
> spinlock_t tc_lock; /* protect anything here that is not protected */
> + struct cifs_sb_info *cifs_sb; /* back pointer to cifs super block */
> atomic_t num_local_opens; /* num of all opens including disconnected */
> atomic_t num_remote_opens; /* num of all network opens on server */
> struct list_head openFileList;
> diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
> index 8393977e21ee..184075da5c6e 100644
> --- a/fs/smb/client/connect.c
> +++ b/fs/smb/client/connect.c
> @@ -3355,6 +3355,7 @@ int cifs_mount_get_tcon(struct cifs_mount_ctx *mnt_ctx)
> tcon = NULL;
> goto out;
> }
> + tcon->cifs_sb = cifs_sb;
>
> /* if new SMB3.11 POSIX extensions are supported do not remap / and \ */
> if (tcon->posix_extensions)
> @@ -3986,6 +3987,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
> cifs_put_smb_ses(ses);
> goto out;
> }
> + tcon->cifs_sb = cifs_sb;
>
> #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
> if (cap_unix(ses))
> --
> 2.34.1
>

--
Thanks,

Steve