cifs: add witness mount option and data structs

Add 'witness' mount option to register for witness notifications.

Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 5d32561ae2ed6edfb036930440f9cbddd38e2770..f810b25dfeb8ae1e8834b1146456867a8a7810cd 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -638,6 +638,11 @@ cifs_show_options(struct seq_file *s, struct dentry *root)
                seq_printf(s, ",multichannel,max_channels=%zu",
                           tcon->ses->chan_max);
 
+#ifdef CONFIG_CIFS_SWN_UPCALL
+       if (tcon->use_witness)
+               seq_puts(s, ",witness");
+#endif
+
        return 0;
 }
 

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b46809260e79a97110f423a26becf40c798e6d98..78438102f0918d2729655de102c6af85eef7aacd 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1086,6 +1086,9 @@ struct cifs_tcon {
        int remap:2;
        struct list_head ulist; /* cache update list */
 #endif
+#ifdef CONFIG_CIFS_SWN_UPCALL
+       bool use_witness:1; /* use witness protocol */
+#endif
 };
 
 /*

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ec80b6c3e20f896f7f0cc6984d335aa726ec0f6f..ead1c086b88d547ed7267a2e8e1df49f239d9709 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1944,6 +1944,8 @@ cifs_put_tcon(struct cifs_tcon *tcon)
                return;
        }
 
+       /* TODO witness unregister */
+
        list_del_init(&tcon->tcon_list);
        spin_unlock(&cifs_tcp_ses_lock);
 
@@ -2104,6 +2106,26 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb3_fs_context *ctx)
                }
                tcon->use_resilient = true;
        }
+#ifdef CONFIG_CIFS_SWN_UPCALL
+       tcon->use_witness = false;
+       if (ctx->witness) {
+               if (ses->server->vals->protocol_id >= SMB30_PROT_ID) {
+                       if (tcon->capabilities & SMB2_SHARE_CAP_CLUSTER) {
+                               /* TODO witness register */
+                               tcon->use_witness = true;
+                       } else {
+                               /* TODO: try to extend for non-cluster uses (eg multichannel) */
+                               cifs_dbg(VFS, "witness requested on mount but no CLUSTER capability on share\n");
+                               rc = -EOPNOTSUPP;
+                               goto out_fail;
+                       }
+               } else {
+                       cifs_dbg(VFS, "SMB3 or later required for witness option\n");
+                       rc = -EOPNOTSUPP;
+                       goto out_fail;
+               }
+       }
+#endif
 
        /* If the user really knows what they are doing they can override */
        if (tcon->share_flags & SMB2_SHAREFLAG_NO_CACHING) {
@@ -3856,6 +3878,9 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
        ctx->sectype = master_tcon->ses->sectype;
        ctx->sign = master_tcon->ses->sign;
        ctx->seal = master_tcon->seal;
+#ifdef CONFIG_CIFS_SWN_UPCALL
+       ctx->witness = master_tcon->use_witness;
+#endif
 
        rc = cifs_set_vol_auth(ctx, master_tcon->ses);
        if (rc) {

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index 9120d148c5f1d279eef6394f5932c3b766a7a530..fe5cc60f43930e13da5a1161312f13df62142b8d 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -119,6 +119,7 @@ const struct fs_parameter_spec smb3_fs_parameters[] = {
        fsparam_flag("modesid", Opt_modesid),
        fsparam_flag("rootfs", Opt_rootfs),
        fsparam_flag("compress", Opt_compress),
+       fsparam_flag("witness", Opt_witness),
 
        /* Mount options which take numeric value */
        fsparam_u32("backupuid", Opt_backupuid),
@@ -1004,6 +1005,13 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
                if (cifs_parse_cache_flavor(param->string, ctx) != 0)
                        goto cifs_parse_mount_err;
                break;
+       case Opt_witness:
+#ifndef CONFIG_CIFS_SWN_UPCALL
+               cifs_dbg(VFS, "Witness support needs CONFIG_CIFS_SWN_UPCALL config option\n");
+                       goto cifs_parse_mount_err;
+#endif
+               ctx->witness = true;
+               break;
        case Opt_rootfs:
 #ifdef CONFIG_CIFS_ROOT
                ctx->rootfs = true;

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index d4a905a808830de5ce86afe2b756cf1a59a38117..aaec8a819d34c6208c6d68a991eb1ea65d567123 100644 (file)
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -102,6 +102,7 @@ enum cifs_param {
        Opt_rootfs,
        Opt_multichannel,
        Opt_compress,
+       Opt_witness,
 
        /* Mount options which take numeric value */
        Opt_backupuid,
@@ -241,6 +242,7 @@ struct smb3_fs_context {
        unsigned int max_channels;
        __u16 compression; /* compression algorithm 0xFFFF default 0=disabled */
        bool rootfs:1; /* if it's a SMB root file system */
+       bool witness:1; /* use witness protocol */
 
        char *mount_options;
 };