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Commit 8b217fe7 authored by Steve French's avatar Steve French
Browse files

SMB3: parsing for new snapshot timestamp mount parm 



New mount option "snapshot=<time>" to allow mounting an earlier
version of the remote volume (if such a snapshot exists on
the server).

Note that eventually specifying a snapshot time of 1 will allow
the user to mount the oldest snapshot. A subsequent patch
add the processing for that and another for actually specifying
the "time warp" create context on SMB2/SMB3 open.

Check to make sure SMB2 negotiated, and ensure that
we use a different tcon if mount same share twice
but with different snaphshot times

Signed-off-by: default avatarSteve French <smfrench@gmail.com>
Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
parent 43c4f67c

fs/cifs/cifsglob.h

+2 −0
Original line number Diff line number Diff line
@@ -525,6 +525,7 @@ struct smb_vol { 
	struct sockaddr_storage srcaddr; /* allow binding to a local IP */

	struct nls_table *local_nls;

	unsigned int echo_interval; /* echo interval in secs */

	__u64 snapshot_time; /* needed for timewarp tokens */

	unsigned int max_credits; /* smb3 max_credits 10 < credits < 60000 */

};
@@ -932,6 +933,7 @@ struct cifs_tcon { 
	__u32 maximal_access;

	__u32 vol_serial_number;

	__le64 vol_create_time;

	__u64 snapshot_time; /* for timewarp tokens - timestamp of snapshot */

	__u32 ss_flags;		/* sector size flags */

	__u32 perf_sector_size; /* best sector size for perf */

	__u32 max_chunks;

fs/cifs/connect.c

+35 −3
Original line number Diff line number Diff line
@@ -95,6 +95,7 @@ enum { 
	Opt_dirmode, Opt_port,

	Opt_rsize, Opt_wsize, Opt_actimeo,

	Opt_echo_interval, Opt_max_credits,

	Opt_snapshot,



	/* Mount options which take string value */

	Opt_user, Opt_pass, Opt_ip,
@@ -191,6 +192,7 @@ static const match_table_t cifs_mount_option_tokens = { 
	{ Opt_actimeo, "actimeo=%s" },

	{ Opt_echo_interval, "echo_interval=%s" },

	{ Opt_max_credits, "max_credits=%s" },

	{ Opt_snapshot, "snapshot=%s" },



	{ Opt_blank_user, "user=" },

	{ Opt_blank_user, "username=" },
@@ -1601,6 +1603,14 @@ cifs_parse_mount_options(const char *mountdata, const char *devname, 
			}

			vol->echo_interval = option;

			break;

		case Opt_snapshot:

			if (get_option_ul(args, &option)) {

				cifs_dbg(VFS, "%s: Invalid snapshot time\n",

					 __func__);

				goto cifs_parse_mount_err;

			}

			vol->snapshot_time = option;

			break;

		case Opt_max_credits:

			if (get_option_ul(args, &option) || (option < 20) ||

			    (option > 60000)) {
@@ -2586,7 +2596,7 @@ static int match_tcon(struct cifs_tcon *tcon, const char *unc) 
}



static struct cifs_tcon *

cifs_find_tcon(struct cifs_ses *ses, const char *unc)

cifs_find_tcon(struct cifs_ses *ses, struct smb_vol *volume_info)

{

	struct list_head *tmp;

	struct cifs_tcon *tcon;
@@ -2594,8 +2604,14 @@ cifs_find_tcon(struct cifs_ses *ses, const char *unc) 
	spin_lock(&cifs_tcp_ses_lock);

	list_for_each(tmp, &ses->tcon_list) {

		tcon = list_entry(tmp, struct cifs_tcon, tcon_list);

		if (!match_tcon(tcon, unc))

		if (!match_tcon(tcon, volume_info->UNC))

			continue;



#ifdef CONFIG_CIFS_SMB2

		if (tcon->snapshot_time != volume_info->snapshot_time)

			continue;

#endif /* CONFIG_CIFS_SMB2 */



		++tcon->tc_count;

		spin_unlock(&cifs_tcp_ses_lock);

		return tcon;
@@ -2636,7 +2652,7 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) 
	int rc, xid;

	struct cifs_tcon *tcon;



	tcon = cifs_find_tcon(ses, volume_info->UNC);

	tcon = cifs_find_tcon(ses, volume_info);

	if (tcon) {

		cifs_dbg(FYI, "Found match on UNC path\n");

		/* existing tcon already has a reference */
@@ -2657,6 +2673,22 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) 
		goto out_fail;

	}



	if (volume_info->snapshot_time) {

#ifdef CONFIG_CIFS_SMB2

		if (ses->server->vals->protocol_id == 0) {

			cifs_dbg(VFS,

			     "Use SMB2 or later for snapshot mount option\n");

			rc = -EOPNOTSUPP;

			goto out_fail;

		} else

			tcon->snapshot_time = volume_info->snapshot_time;

#else

		cifs_dbg(VFS, "Snapshot mount option requires SMB2 support\n");

		rc = -EOPNOTSUPP;

		goto out_fail;

#endif /* CONFIG_CIFS_SMB2 */

	}



	tcon->ses = ses;

	if (volume_info->password) {

		tcon->password = kstrdup(volume_info->password, GFP_KERNEL);