cifs: reinstate sharing of tree connections
Use a similar approach to the SMB session sharing. Add a list of tcons
attached to each SMB session. Move the refcount to non-atomic. Protect
all of the above with the cifs_tcp_ses_lock. Add functions to
properly find and put references to the tcons.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a3dc0d7..2f2be8f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -124,7 +124,7 @@
cifs_reconnect(struct TCP_Server_Info *server)
{
int rc = 0;
- struct list_head *tmp;
+ struct list_head *tmp, *tmp2;
struct cifsSesInfo *ses;
struct cifsTconInfo *tcon;
struct mid_q_entry *mid_entry;
@@ -149,13 +149,12 @@
ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list);
ses->need_reconnect = true;
ses->ipc_tid = 0;
+ list_for_each(tmp2, &ses->tcon_list) {
+ tcon = list_entry(tmp2, struct cifsTconInfo, tcon_list);
+ tcon->need_reconnect = true;
+ }
}
read_unlock(&cifs_tcp_ses_lock);
- list_for_each(tmp, &GlobalTreeConnectionList) {
- tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
- if ((tcon->ses) && (tcon->ses->server == server))
- tcon->need_reconnect = true;
- }
/* do not want to be sending data on a socket we are freeing */
down(&server->tcpSem);
if (server->ssocket) {
@@ -1462,6 +1461,52 @@
cifs_put_tcp_session(server);
}
+static struct cifsTconInfo *
+cifs_find_tcon(struct cifsSesInfo *ses, const char *unc)
+{
+ struct list_head *tmp;
+ struct cifsTconInfo *tcon;
+
+ write_lock(&cifs_tcp_ses_lock);
+ list_for_each(tmp, &ses->tcon_list) {
+ tcon = list_entry(tmp, struct cifsTconInfo, tcon_list);
+ if (tcon->tidStatus == CifsExiting)
+ continue;
+ if (strncmp(tcon->treeName, unc, MAX_TREE_SIZE))
+ continue;
+
+ ++tcon->tc_count;
+ write_unlock(&cifs_tcp_ses_lock);
+ return tcon;
+ }
+ write_unlock(&cifs_tcp_ses_lock);
+ return NULL;
+}
+
+static void
+cifs_put_tcon(struct cifsTconInfo *tcon)
+{
+ int xid;
+ struct cifsSesInfo *ses = tcon->ses;
+
+ write_lock(&cifs_tcp_ses_lock);
+ if (--tcon->tc_count > 0) {
+ write_unlock(&cifs_tcp_ses_lock);
+ return;
+ }
+
+ list_del_init(&tcon->tcon_list);
+ write_unlock(&cifs_tcp_ses_lock);
+
+ xid = GetXid();
+ CIFSSMBTDis(xid, tcon);
+ _FreeXid(xid);
+
+ DeleteTconOplockQEntries(tcon);
+ tconInfoFree(tcon);
+ cifs_put_smb_ses(ses);
+}
+
int
get_dfs_path(int xid, struct cifsSesInfo *pSesInfo, const char *old_path,
const struct nls_table *nls_codepage, unsigned int *pnum_referrals,
@@ -2220,11 +2265,11 @@
if (!rc) {
setup_cifs_sb(&volume_info, cifs_sb);
+ tcon = cifs_find_tcon(pSesInfo, volume_info.UNC);
if (tcon) {
cFYI(1, ("Found match on UNC path"));
- if (tcon->seal != volume_info.seal)
- cERROR(1, ("transport encryption setting "
- "conflicts with existing tid"));
+ /* existing tcon already has a reference */
+ cifs_put_smb_ses(pSesInfo);
} else {
tcon = tconInfoAlloc();
if (tcon == NULL) {
@@ -2257,6 +2302,10 @@
if (rc)
goto mount_fail_check;
tcon->seal = volume_info.seal;
+ tcon->ses = pSesInfo;
+ write_lock(&cifs_tcp_ses_lock);
+ list_add(&tcon->tcon_list, &pSesInfo->tcon_list);
+ write_unlock(&cifs_tcp_ses_lock);
}
/* we can have only one retry value for a connection
@@ -2283,18 +2332,14 @@
/* If find_unc succeeded then rc == 0 so we can not end */
/* up accidently freeing someone elses tcon struct */
if (tcon)
- tconInfoFree(tcon);
-
- /* should also end up putting our tcp session ref if needed */
- if (pSesInfo)
+ cifs_put_tcon(tcon);
+ else if (pSesInfo)
cifs_put_smb_ses(pSesInfo);
else
cifs_put_tcp_session(srvTcp);
goto out;
}
- atomic_inc(&tcon->useCount);
cifs_sb->tcon = tcon;
- tcon->ses = pSesInfo;
/* do not care if following two calls succeed - informational */
if (!tcon->ipc) {
@@ -3565,23 +3610,10 @@
cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
{
int rc = 0;
- int xid;
- struct cifsSesInfo *ses = NULL;
char *tmp;
- xid = GetXid();
-
- if (cifs_sb->tcon) {
- ses = cifs_sb->tcon->ses; /* save ptr to ses before delete tcon!*/
- rc = CIFSSMBTDis(xid, cifs_sb->tcon);
- if (rc == -EBUSY) {
- FreeXid(xid);
- return 0;
- }
- DeleteTconOplockQEntries(cifs_sb->tcon);
- tconInfoFree(cifs_sb->tcon);
- cifs_put_smb_ses(ses);
- }
+ if (cifs_sb->tcon)
+ cifs_put_tcon(cifs_sb->tcon);
cifs_sb->tcon = NULL;
tmp = cifs_sb->prepath;
@@ -3589,7 +3621,6 @@
cifs_sb->prepath = NULL;
kfree(tmp);
- FreeXid(xid);
return rc;
}