Re: [PATCH] cifs: add shutdown support

["Aurélien Aptel" <aaptel@suse.com>]

Do we need to add code to clear the flag on remount or is it implicitely
cleared by not copying it?

Steve French <smfrench@gmail.com> writes:
>  #define CIFS_MOUNT_MODE_FROM_SID 0x10000000 /* retrieve mode from
> special ACE */
>  #define CIFS_MOUNT_RO_CACHE 0x20000000  /* assumes share will not change */
>  #define CIFS_MOUNT_RW_CACHE 0x40000000  /* assumes only client accessing */
> +#define SMB3_MOUNT_SHUTDOWN 0x80000000

While I totally understand wanting to remove the "cifs" name, those
flags are specific to the kernel & filesystem and have nothing to do
with the wire protocol so in this case I would rather use CIFS_ prefix
because SMB3_ is misleading and all the other flags are already using CIFS_.

One day we should do s/CIFS/SMBFS/i on the whole tree where CIFS refers
to kernel stuff (not protocol) and rename the module smbfs. But that's a
story for another day I guess.

>
>  struct cifs_sb_info {
>   struct rb_root tlink_tree;
> diff --git a/fs/cifs/cifs_ioctl.h b/fs/cifs/cifs_ioctl.h
> index 153d5c842a9b..a744022d2a71 100644
> --- a/fs/cifs/cifs_ioctl.h
> +++ b/fs/cifs/cifs_ioctl.h
> @@ -78,3 +78,19 @@ struct smb3_notify {
>  #define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info)
>  #define CIFS_DUMP_KEY _IOWR(CIFS_IOCTL_MAGIC, 8, struct smb3_key_debug_info)
>  #define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
> +#define SMB3_IOC_SHUTDOWN _IOR ('X', 125, __u32)

Same

> +
> +/*
> + * Flags for going down operation
> + */
> +#define SMB3_GOING_FLAGS_DEFAULT                0x0     /* going down */
> +#define SMB3_GOING_FLAGS_LOGFLUSH               0x1     /* flush log
> but not data */
> +#define SMB3_GOING_FLAGS_NOLOGFLUSH             0x2     /* don't

Same

> flush log nor data */
> +
> +static inline bool smb3_forced_shutdown(struct cifs_sb_info *sbi)

Same

> +	cifs_dbg(VFS, "shut down requested (%d)", flags); /* BB FIXME */
> +/*	trace_smb3_shutdown(sb, flags);*/

What is there to fix? It's doing like ext4 so it's fine no?

> +
> +	/*
> +	 * see:
> +	 *   https://man7.org/linux/man-pages/man2/ioctl_xfs_goingdown.2.html
> +	 * for more information and description of original intent of the flags
> +	 */
> +	switch (flags) {
> +	/*
> +	 * We could add support later for default flag which requires:
> +	 *     "Flush all dirty data and metadata to disk"
> +	 * would need to call syncfs or equivalent to flush page cache for
> +	 * the mount and then issue fsync to server (if nostrictsync not set)
> +	 */
> +	case SMB3_GOING_FLAGS_DEFAULT:
> +		cifs_dbg(VFS, "default flags\n");

Should this be removed, less verbose or more info should be printed?

Cheers,
-- 
Aurélien Aptel / SUSE Labs Samba Team
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