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Commit 28eb24ff authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

cifs: Always resolve hostname before reconnecting 



In case a hostname resolves to a different IP address (e.g. long
running mounts), make sure to resolve it every time prior to calling
generic_ip_connect() in reconnect.

Suggested-by: default avatarSteve French <stfrench@microsoft.com>
Signed-off-by: default avatarPaulo Alcantara <palcantara@suse.de>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 08744015

fs/cifs/connect.c

+52 −32
Original line number Diff line number Diff line
@@ -325,6 +325,53 @@ static int cifs_setup_volume_info(struct smb_vol *volume_info, char *mount_data, 
					const char *devname, bool is_smb3);

static char *extract_hostname(const char *unc);



/*

 * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may

 * get their ip addresses changed at some point.

 *

 * This should be called with server->srv_mutex held.

 */

#ifdef CONFIG_CIFS_DFS_UPCALL

static int reconn_set_ipaddr(struct TCP_Server_Info *server)

{

	int rc;

	int len;

	char *unc, *ipaddr = NULL;



	if (!server->hostname)

		return -EINVAL;



	len = strlen(server->hostname) + 3;



	unc = kmalloc(len, GFP_KERNEL);

	if (!unc) {

		cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);

		return -ENOMEM;

	}

	snprintf(unc, len, "\\\\%s", server->hostname);



	rc = dns_resolve_server_name_to_ip(unc, &ipaddr);

	kfree(unc);



	if (rc < 0) {

		cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n",

			 __func__, server->hostname, rc);

		return rc;

	}



	rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,

				  strlen(ipaddr));

	kfree(ipaddr);



	return !rc ? -1 : 0;

}

#else

static inline int reconn_set_ipaddr(struct TCP_Server_Info *server)

{

	return 0;

}

#endif



#ifdef CONFIG_CIFS_DFS_UPCALL

struct super_cb_data {

	struct TCP_Server_Info *server;
@@ -366,10 +413,6 @@ static void reconn_inval_dfs_target(struct TCP_Server_Info *server, 
				    struct dfs_cache_tgt_iterator **tgt_it)

{

	const char *name;

	int rc;

	char *ipaddr = NULL;

	char *unc;

	int len;



	if (!cifs_sb || !cifs_sb->origin_fullpath || !tgt_list ||

	    !server->nr_targets)
@@ -393,34 +436,6 @@ static void reconn_inval_dfs_target(struct TCP_Server_Info *server, 
	if (!server->hostname) {

		cifs_dbg(FYI, "%s: failed to extract hostname from target: %d\n",

			 __func__, -ENOMEM);

		return;

	}



	len = strlen(server->hostname) + 3;



	unc = kmalloc(len, GFP_KERNEL);

	if (!unc) {

		cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);

		return;

	}

	snprintf(unc, len, "\\\\%s", server->hostname);



	rc = dns_resolve_server_name_to_ip(unc, &ipaddr);

	kfree(unc);



	if (rc < 0) {

		cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",

			 __func__, server->hostname, rc);

		return;

	}



	rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,

				  strlen(ipaddr));

	kfree(ipaddr);



	if (!rc) {

		cifs_dbg(FYI, "%s: failed to get ipaddr out of hostname\n",

			 __func__);

	}

}
@@ -567,6 +582,11 @@ cifs_reconnect(struct TCP_Server_Info *server) 
			reconn_inval_dfs_target(server, cifs_sb, &tgt_list,

						&tgt_it);

#endif

			rc = reconn_set_ipaddr(server);

			if (rc) {

				cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n",

					 __func__, rc);

			}

			mutex_unlock(&server->srv_mutex);

			msleep(3000);

		} else {