Commit b54034a7 authored by Shyam Prasad N's avatar Shyam Prasad N Committed by Steve French
Browse files

cifs: during reconnect, update interface if necessary 



Going forward, the plan is to periodically query the server
for it's interfaces (when multichannel is enabled).

This change allows checking for inactive interfaces during
reconnect, and reconnect to a new interface if necessary.

Signed-off-by: default avatarShyam Prasad N <sprasad@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent aa45dadd

fs/cifs/cifsproto.h

+5 −0
Original line number Diff line number Diff line
@@ -636,6 +636,11 @@ cifs_chan_clear_need_reconnect(struct cifs_ses *ses, 
bool

cifs_chan_needs_reconnect(struct cifs_ses *ses,

			  struct TCP_Server_Info *server);

bool

cifs_chan_is_iface_active(struct cifs_ses *ses,

			  struct TCP_Server_Info *server);

int

cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server);



void extract_unc_hostname(const char *unc, const char **h, size_t *len);

int copy_path_name(char *dst, const char *src);

fs/cifs/connect.c

+4 −0
Original line number Diff line number Diff line
@@ -232,6 +232,10 @@ cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server, 


	spin_lock(&cifs_tcp_ses_lock);

	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {

		/* check if iface is still active */

		if (!cifs_chan_is_iface_active(ses, server))

			cifs_chan_update_iface(ses, server);



		spin_lock(&ses->chan_lock);

		if (!mark_smb_session && cifs_chan_needs_reconnect(ses, server))

			goto next_session;

fs/cifs/sess.c

+79 −0
Original line number Diff line number Diff line
@@ -146,6 +146,16 @@ cifs_chan_needs_reconnect(struct cifs_ses *ses, 
	return CIFS_CHAN_NEEDS_RECONNECT(ses, chan_index);

}



bool

cifs_chan_is_iface_active(struct cifs_ses *ses,

			  struct TCP_Server_Info *server)

{

	unsigned int chan_index = cifs_ses_get_chan_index(ses, server);



	return ses->chans[chan_index].iface &&

		ses->chans[chan_index].iface->is_active;

}



/* returns number of channels added */

int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses)

{
@@ -244,6 +254,75 @@ int cifs_try_adding_channels(struct cifs_sb_info *cifs_sb, struct cifs_ses *ses) 
	return new_chan_count - old_chan_count;

}



/*

 * update the iface for the channel if necessary.

 * will return 0 when iface is updated. 1 otherwise

 * Must be called with chan_lock held.

 */

int

cifs_chan_update_iface(struct cifs_ses *ses, struct TCP_Server_Info *server)

{

	unsigned int chan_index = cifs_ses_get_chan_index(ses, server);

	struct cifs_server_iface *iface = NULL;

	struct cifs_server_iface *old_iface = NULL;

	int rc = 0;



	/* primary channel. This can never go away */

	if (!chan_index)

		return 0;



	if (ses->chans[chan_index].iface) {

		old_iface = ses->chans[chan_index].iface;

		if (old_iface->is_active)

			return 1;

	}



	spin_lock(&ses->iface_lock);



	/* then look for a new one */

	list_for_each_entry(iface, &ses->iface_list, iface_head) {

		if (!iface->is_active ||

		    (is_ses_using_iface(ses, iface) &&

		     !iface->rss_capable)) {

			continue;

		}

		kref_get(&iface->refcount);

	}



	if (!list_entry_is_head(iface, &ses->iface_list, iface_head)) {

		rc = 1;

		iface = NULL;

		cifs_dbg(FYI, "unable to find a suitable iface\n");

	}



	ses->chans[chan_index].iface = iface;



	/* now drop the ref to the current iface */

	if (old_iface && iface) {

		kref_put(&old_iface->refcount, release_iface);

		cifs_dbg(FYI, "replacing iface: %pIS with %pIS\n",

			 &old_iface->sockaddr,

			 &iface->sockaddr);

	} else if (old_iface) {

		kref_put(&old_iface->refcount, release_iface);

		cifs_dbg(FYI, "releasing ref to iface: %pIS\n",

			 &old_iface->sockaddr);

	} else {

		WARN_ON(!iface);

		cifs_dbg(FYI, "adding new iface: %pIS\n", &iface->sockaddr);

	}



	spin_unlock(&ses->iface_lock);



	/* No iface is found. if secondary chan, drop connection */

	if (!iface && CIFS_SERVER_IS_CHAN(server)) {

		cifs_put_tcp_session(server, false);

		ses->chans[chan_index].server = NULL;

	}



	return rc;

}



/*

 * If server is a channel of ses, return the corresponding enclosing

 * cifs_chan otherwise return NULL.