cifs: add cifs_sb_master_tcon and convert some callers to use it

At mount time, we'll always need to create a tcon that will serve as a
template for others that are associated with the mount. This tcon is
known as the "master" tcon.

In some cases, we'll need to use that tcon regardless of who's accessing
the mount. Add an accessor function for the master tcon and go ahead and
switch the appropriate places to use it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index b9624ab..898d2a5 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -222,7 +222,7 @@
 {
 	struct super_block *sb = dentry->d_sb;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
-	struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 	int rc = -EOPNOTSUPP;
 	int xid;
 
@@ -364,7 +364,7 @@
 cifs_show_options(struct seq_file *s, struct vfsmount *m)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(m->mnt_sb);
-	struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 	struct sockaddr *srcaddr;
 	srcaddr = (struct sockaddr *)&tcon->ses->server->srcaddr;
 
@@ -455,7 +455,7 @@
 	if (cifs_sb == NULL)
 		return;
 
-	tcon = cifs_sb_tcon(cifs_sb);
+	tcon = cifs_sb_master_tcon(cifs_sb);
 
 	read_lock(&cifs_tcp_ses_lock);
 	if ((tcon->tc_count > 1) || (tcon->tidStatus == CifsExiting)) {
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index cc8300c..c265ebd 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -419,6 +419,13 @@
 	return cifs_sb->ptcon;
 }
 
+/* This function is always expected to succeed */
+static inline struct cifsTconInfo *
+cifs_sb_master_tcon(struct cifs_sb_info *cifs_sb)
+{
+	return cifs_sb->ptcon;
+}
+
 static inline char CIFS_DIR_SEP(const struct cifs_sb_info *cifs_sb)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b4bacea..f6a3091 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3025,9 +3025,9 @@
 {
 	int rc = 0;
 	char *tmp;
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 
-	if (cifs_sb_tcon(cifs_sb))
-		cifs_put_tcon(cifs_sb_tcon(cifs_sb));
+	cifs_put_tcon(tcon);
 
 	cifs_sb->ptcon = NULL;
 	tmp = cifs_sb->prepath;
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index f660a15..fe02435 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -54,18 +54,18 @@
 	int dfsplen;
 	char *full_path;
 	char dirsep;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 
 	if (direntry == NULL)
 		return NULL;  /* not much we can do if dentry is freed and
 		we need to reopen the file after it was closed implicitly
 		when the server crashed */
 
-	cifs_sb = CIFS_SB(direntry->d_sb);
 	dirsep = CIFS_DIR_SEP(cifs_sb);
 	pplen = cifs_sb->prepathlen;
-	if (cifs_sb_tcon(cifs_sb) && (cifs_sb_tcon(cifs_sb)->Flags & SMB_SHARE_IS_IN_DFS))
-		dfsplen = strnlen(cifs_sb_tcon(cifs_sb)->treeName, MAX_TREE_SIZE + 1);
+	if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
+		dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
 	else
 		dfsplen = 0;
 cifs_bp_rename_retry:
@@ -117,7 +117,7 @@
 	/* BB test paths to Windows with '/' in the midst of prepath */
 
 	if (dfsplen) {
-		strncpy(full_path, cifs_sb_tcon(cifs_sb)->treeName, dfsplen);
+		strncpy(full_path, tcon->treeName, dfsplen);
 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
 			int i;
 			for (i = 0; i < dfsplen; i++) {
diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
index ec4318b0..a2ad94e 100644
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -62,15 +62,15 @@
 {
 	struct cifsInodeInfo *cifsi = CIFS_I(inode);
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 
 	if (cifsi->fscache)
 		return;
 
-	cifsi->fscache = fscache_acquire_cookie(cifs_sb_tcon(cifs_sb)->fscache,
-				&cifs_fscache_inode_object_def,
-				cifsi);
-	cFYI(1, "CIFS: got FH cookie (0x%p/0x%p)",
-			cifs_sb_tcon(cifs_sb)->fscache, cifsi->fscache);
+	cifsi->fscache = fscache_acquire_cookie(tcon->fscache,
+				&cifs_fscache_inode_object_def, cifsi);
+	cFYI(1, "CIFS: got FH cookie (0x%p/0x%p)", tcon->fscache,
+				cifsi->fscache);
 }
 
 void cifs_fscache_release_inode_cookie(struct inode *inode)
@@ -118,7 +118,7 @@
 		fscache_relinquish_cookie(cifsi->fscache, 1);
 
 		cifsi->fscache = fscache_acquire_cookie(
-					cifs_sb_tcon(cifs_sb)->fscache,
+					cifs_sb_master_tcon(cifs_sb)->fscache,
 					&cifs_fscache_inode_object_def,
 					cifsi);
 		cFYI(1, "CIFS: new cookie 0x%p oldcookie 0x%p",
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index dce2d59..da716d9 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -52,7 +52,7 @@
 
 
 		/* check if server can support readpages */
-		if (cifs_sb_tcon(cifs_sb)->ses->server->maxBuf <
+		if (cifs_sb_master_tcon(cifs_sb)->ses->server->maxBuf <
 				PAGE_CACHE_SIZE + MAX_CIFS_HDR_SIZE)
 			inode->i_data.a_ops = &cifs_addr_ops_smallbuf;
 		else
@@ -476,6 +476,8 @@
 cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
 		       struct cifs_sb_info *cifs_sb, bool adjust_tz)
 {
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
+
 	memset(fattr, 0, sizeof(*fattr));
 	fattr->cf_cifsattrs = le32_to_cpu(info->Attributes);
 	if (info->DeletePending)
@@ -490,8 +492,8 @@
 	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 
 	if (adjust_tz) {
-		fattr->cf_ctime.tv_sec += cifs_sb_tcon(cifs_sb)->ses->server->timeAdj;
-		fattr->cf_mtime.tv_sec += cifs_sb_tcon(cifs_sb)->ses->server->timeAdj;
+		fattr->cf_ctime.tv_sec += tcon->ses->server->timeAdj;
+		fattr->cf_mtime.tv_sec += tcon->ses->server->timeAdj;
 	}
 
 	fattr->cf_eof = le64_to_cpu(info->EndOfFile);
@@ -698,6 +700,7 @@
 	int pplen = cifs_sb->prepathlen;
 	int dfsplen;
 	char *full_path = NULL;
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 
 	/* if no prefix path, simply set path to the root of share to "" */
 	if (pplen == 0) {
@@ -707,8 +710,8 @@
 		return full_path;
 	}
 
-	if (cifs_sb_tcon(cifs_sb) && (cifs_sb_tcon(cifs_sb)->Flags & SMB_SHARE_IS_IN_DFS))
-		dfsplen = strnlen(cifs_sb_tcon(cifs_sb)->treeName, MAX_TREE_SIZE + 1);
+	if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
+		dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);
 	else
 		dfsplen = 0;
 
@@ -717,7 +720,7 @@
 		return full_path;
 
 	if (dfsplen) {
-		strncpy(full_path, cifs_sb_tcon(cifs_sb)->treeName, dfsplen);
+		strncpy(full_path, tcon->treeName, dfsplen);
 		/* switch slash direction in prepath depending on whether
 		 * windows or posix style path names
 		 */
@@ -831,18 +834,18 @@
 struct inode *cifs_root_iget(struct super_block *sb, unsigned long ino)
 {
 	int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct inode *inode = NULL;
 	long rc;
 	char *full_path;
+	struct cifsTconInfo *tcon = cifs_sb_master_tcon(cifs_sb);
 
-	cifs_sb = CIFS_SB(sb);
 	full_path = cifs_build_path_to_root(cifs_sb);
 	if (full_path == NULL)
 		return ERR_PTR(-ENOMEM);
 
 	xid = GetXid();
-	if (cifs_sb_tcon(cifs_sb)->unix_ext)
+	if (tcon->unix_ext)
 		rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid);
 	else
 		rc = cifs_get_inode_info(&inode, full_path, NULL, sb,
@@ -853,10 +856,10 @@
 
 #ifdef CONFIG_CIFS_FSCACHE
 	/* populate tcon->resource_id */
-	cifs_sb_tcon(cifs_sb)->resource_id = CIFS_I(inode)->uniqueid;
+	tcon->resource_id = CIFS_I(inode)->uniqueid;
 #endif
 
-	if (rc && cifs_sb_tcon(cifs_sb)->ipc) {
+	if (rc && tcon->ipc) {
 		cFYI(1, "ipc connection - fake read inode");
 		inode->i_mode |= S_IFDIR;
 		inode->i_nlink = 2;
@@ -1661,7 +1664,7 @@
 		 "jiffies %ld", full_path, inode, inode->i_count.counter,
 		 dentry, dentry->d_time, jiffies);
 
-	if (cifs_sb_tcon(CIFS_SB(sb))->unix_ext)
+	if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
 		rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid);
 	else
 		rc = cifs_get_inode_info(&inode, full_path, NULL, sb,
@@ -2087,7 +2090,7 @@
 {
 	struct inode *inode = direntry->d_inode;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
-	struct cifsTconInfo *pTcon = cifs_sb_tcon(cifs_sb);
+	struct cifsTconInfo *pTcon = cifs_sb_master_tcon(cifs_sb);
 
 	if (pTcon->unix_ext)
 		return cifs_setattr_unix(direntry, attrs);
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index c5cbfdb..252f276 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -729,6 +729,6 @@
 			   "properly. Hardlinks will not be recognized on this "
 			   "mount. Consider mounting with the \"noserverino\" "
 			   "option to silence this message.",
-			   cifs_sb_tcon(cifs_sb)->treeName);
+			   cifs_sb_master_tcon(cifs_sb)->treeName);
 	}
 }
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 3efc242..887a7e2 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -102,7 +102,7 @@
 		return NULL;
 	}
 
-	if (cifs_sb_tcon(CIFS_SB(sb))->nocase)
+	if (cifs_sb_master_tcon(CIFS_SB(sb))->nocase)
 		dentry->d_op = &cifs_ci_dentry_ops;
 	else
 		dentry->d_op = &cifs_dentry_ops;
@@ -171,7 +171,7 @@
 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 		       struct cifs_sb_info *cifs_sb)
 {
-	int offset = cifs_sb_tcon(cifs_sb)->ses->server->timeAdj;
+	int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 
 	memset(fattr, 0, sizeof(*fattr));
 	fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,