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cifs: during reconnect, update interface if necessary

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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: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Shyam Prasad N 2022-01-03 08:47:30 +00:00 committed by Steve French
parent aa45dadd34
commit b54034a73b
3 changed files with 88 additions and 0 deletions
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5
fs/cifs/cifsproto.h
View file

@ -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);

4
fs/cifs/connect.c
View file

@ -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;

79
fs/cifs/sess.c
View file

@ -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.