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>

1 files changed, 35 insertions, 39 deletions

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index 46c8c7baccba..addd1dcc2d79 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -79,6 +79,7 @@ sesInfoAlloc(void)
                 ret_buf->status = CifsNew;
                 ++ret_buf->ses_count;
                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
+                INIT_LIST_HEAD(&ret_buf->tcon_list);
                 init_MUTEX(&ret_buf->sesSem);
         }
         return ret_buf;
@@ -107,17 +108,14 @@ tconInfoAlloc(void)
         struct cifsTconInfo *ret_buf;
         ret_buf = kzalloc(sizeof(struct cifsTconInfo), GFP_KERNEL);
         if (ret_buf) {
-                write_lock(&GlobalSMBSeslock);
                 atomic_inc(&tconInfoAllocCount);
-                list_add(&ret_buf->cifsConnectionList,
-                         &GlobalTreeConnectionList);
                 ret_buf->tidStatus = CifsNew;
+                ++ret_buf->tc_count;
                 INIT_LIST_HEAD(&ret_buf->openFileList);
-                init_MUTEX(&ret_buf->tconSem);
+                INIT_LIST_HEAD(&ret_buf->tcon_list);
 #ifdef CONFIG_CIFS_STATS
                 spin_lock_init(&ret_buf->stat_lock);
 #endif
-                write_unlock(&GlobalSMBSeslock);
         }
         return ret_buf;
 }
@@ -129,10 +127,7 @@ tconInfoFree(struct cifsTconInfo *buf_to_free)
                 cFYI(1, ("Null buffer passed to tconInfoFree"));
                 return;
         }
-        write_lock(&GlobalSMBSeslock);
         atomic_dec(&tconInfoAllocCount);
-        list_del(&buf_to_free->cifsConnectionList);
-        write_unlock(&GlobalSMBSeslock);
         kfree(buf_to_free->nativeFileSystem);
         kfree(buf_to_free);
 }
@@ -493,9 +488,10 @@ bool
 is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
 {
         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
-        struct list_head *tmp;
-        struct list_head *tmp1;
+        struct list_head *tmp, *tmp1, *tmp2;
+        struct cifsSesInfo *ses;
         struct cifsTconInfo *tcon;
+        struct cifsInodeInfo *pCifsInode;
         struct cifsFileInfo *netfile;
 
         cFYI(1, ("Checking for oplock break or dnotify response"));
@@ -550,42 +546,42 @@ is_valid_oplock_break(struct smb_hdr *buf, struct TCP_Server_Info *srv)
                 return false;
 
         /* look up tcon based on tid & uid */
-        read_lock(&GlobalSMBSeslock);
-        list_for_each(tmp, &GlobalTreeConnectionList) {
-                tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
-                if ((tcon->tid == buf->Tid) && (srv == tcon->ses->server)) {
+        read_lock(&cifs_tcp_ses_lock);
+        list_for_each(tmp, &srv->smb_ses_list) {
+                ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list);
+                list_for_each(tmp1, &ses->tcon_list) {
+                        tcon = list_entry(tmp1, struct cifsTconInfo, tcon_list);
+                        if (tcon->tid != buf->Tid)
+                                continue;
+
                         cifs_stats_inc(&tcon->num_oplock_brks);
-                        list_for_each(tmp1, &tcon->openFileList) {
-                                netfile = list_entry(tmp1, struct cifsFileInfo,
+                        list_for_each(tmp2, &tcon->openFileList) {
+                                netfile = list_entry(tmp2, struct cifsFileInfo,
                                                      tlist);
-                                if (pSMB->Fid == netfile->netfid) {
-                                        struct cifsInodeInfo *pCifsInode;
-                                        read_unlock(&GlobalSMBSeslock);
-                                        cFYI(1,
-                                            ("file id match, oplock break"));
-                                        pCifsInode =
-                                                CIFS_I(netfile->pInode);
-                                        pCifsInode->clientCanCacheAll = false;
-                                        if (pSMB->OplockLevel == 0)
-                                                pCifsInode->clientCanCacheRead
-                                                        = false;
-                                        pCifsInode->oplockPending = true;
-                                        AllocOplockQEntry(netfile->pInode,
-                                                          netfile->netfid,
-                                                          tcon);
-                                        cFYI(1,
-                                            ("about to wake up oplock thread"));
-                                        if (oplockThread)
-                                            wake_up_process(oplockThread);
-                                        return true;
-                                }
+                                if (pSMB->Fid != netfile->netfid)
+                                        continue;
+
+                                read_unlock(&cifs_tcp_ses_lock);
+                                cFYI(1, ("file id match, oplock break"));
+                                pCifsInode = CIFS_I(netfile->pInode);
+                                pCifsInode->clientCanCacheAll = false;
+                                if (pSMB->OplockLevel == 0)
+                                        pCifsInode->clientCanCacheRead = false;
+                                pCifsInode->oplockPending = true;
+                                AllocOplockQEntry(netfile->pInode,
+                                                  netfile->netfid, tcon);
+                                cFYI(1, ("about to wake up oplock thread"));
+                                if (oplockThread)
+                                        wake_up_process(oplockThread);
+
+                                return true;
                         }
-                        read_unlock(&GlobalSMBSeslock);
+                        read_unlock(&cifs_tcp_ses_lock);
                         cFYI(1, ("No matching file for oplock break"));
                         return true;
                 }
         }
-        read_unlock(&GlobalSMBSeslock);
+        read_unlock(&cifs_tcp_ses_lock);
         cFYI(1, ("Can not process oplock break for non-existent connection"));
         return true;
 }