[SMB3] Enable checking for continuous availability and persistent handle support

Validate "persistenthandles" and "nopersistenthandles" mount options against
the support the server claims in negotiate and tree connect SMB3 responses.

Signed-off-by: Steve French <steve.french@primarydata.com>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 1849e29099d01c4e2e6b235243f6a723dbd7c6fa..28bd477f6e57390bf1a26e78866b744cabfe850d 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -897,6 +897,7 @@ struct cifs_tcon {
        bool broken_posix_open; /* e.g. Samba server versions < 3.3.2, 3.2.9 */
        bool broken_sparse_sup; /* if server or share does not support sparse */
        bool need_reconnect:1; /* connection reset, tid now invalid */
+       bool use_persistent:1; /* use persistent instead of durable handles */
 #ifdef CONFIG_CIFS_SMB2
        bool print:1;           /* set if connection to printer share */
        bool bad_network_name:1; /* set if ret status STATUS_BAD_NETWORK_NAME */

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9a9a543ddf4e310d1472906e31839dd9c9040290..bb35ae735a8e4b67a7a2dd81464b144f244f7fda 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2673,6 +2673,30 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)
                cifs_dbg(FYI, "DFS disabled (%d)\n", tcon->Flags);
        }
        tcon->seal = volume_info->seal;
+       tcon->use_persistent = false;
+       /* check if SMB2 or later, CIFS does not support persistent handles */
+       if (volume_info->persistent) {
+               if (ses->server->vals->protocol_id == 0) {
+                       cifs_dbg(VFS,
+                            "SMB3 or later required for persistent handles\n");
+                       rc = -EOPNOTSUPP;
+                       goto out_fail;
+               } else if (ses->server->capabilities &
+                          SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+                       tcon->use_persistent = true;
+               else /* persistent handles requested but not supported */ {
+                       cifs_dbg(VFS,
+                               "Persistent handles not supported on share\n");
+                       rc = -EOPNOTSUPP;
+                       goto out_fail;
+               }
+       } else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
+            && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+            && (volume_info->nopersistent == false)) {
+               cifs_dbg(FYI, "enabling persistent handles\n");
+               tcon->use_persistent = true;
+       }
+
        /*
         * We can have only one retry value for a connection to a share so for
         * resources mounted more than once to the same server share the last
@@ -3521,6 +3545,12 @@ try_mount_again:
                goto mount_fail_check;
        }
 
+       if ((volume_info->persistent == true) && ((ses->server->capabilities &
+               SMB2_GLOBAL_CAP_PERSISTENT_HANDLES) == 0)) {
+               cifs_dbg(VFS, "persistent handles not supported by server\n");
+               rc = -EOPNOTSUPP;
+               goto mount_fail_check;
+       }
        /* search for existing tcon to this server share */
        tcon = cifs_get_tcon(ses, volume_info);
        if (IS_ERR(tcon)) {

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 2f169eb79b4a487b75d8e617826aa08ac946a6b1..53ccdde6ff187c16084e10dd07372d6516d25139 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1838,7 +1838,7 @@ struct smb_version_values smb21_values = {
 struct smb_version_values smb30_values = {
        .version_string = SMB30_VERSION_STRING,
        .protocol_id = SMB30_PROT_ID,
-       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU,
+       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES,
        .large_lock_type = 0,
        .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
        .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
@@ -1858,7 +1858,7 @@ struct smb_version_values smb30_values = {
 struct smb_version_values smb302_values = {
        .version_string = SMB302_VERSION_STRING,
        .protocol_id = SMB302_PROT_ID,
-       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU,
+       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES,
        .large_lock_type = 0,
        .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
        .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,
@@ -1879,7 +1879,7 @@ struct smb_version_values smb302_values = {
 struct smb_version_values smb311_values = {
        .version_string = SMB311_VERSION_STRING,
        .protocol_id = SMB311_PROT_ID,
-       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU,
+       .req_capabilities = SMB2_GLOBAL_CAP_DFS | SMB2_GLOBAL_CAP_LEASING | SMB2_GLOBAL_CAP_LARGE_MTU | SMB2_GLOBAL_CAP_PERSISTENT_HANDLES,
        .large_lock_type = 0,
        .exclusive_lock_type = SMB2_LOCKFLAG_EXCLUSIVE_LOCK,
        .shared_lock_type = SMB2_LOCKFLAG_SHARED_LOCK,