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>

8 files changed, 42 insertions, 32 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index b9624abb7261..898d2a5cfad2 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -222,7 +222,7 @@ cifs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
         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 @@ static int
 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 @@ static void cifs_umount_begin(struct super_block *sb)
         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 cc8300c741b6..c265ebdcd177 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -419,6 +419,13 @@ cifs_sb_tcon(struct cifs_sb_info *cifs_sb)
         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 b4bacea54626..f6a3091c2874 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3025,9 +3025,9 @@ cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
 {
         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 f660a15eb14f..fe02435acb3c 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -54,18 +54,18 @@ build_path_from_dentry(struct dentry *direntry)
         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 @@ cifs_bp_rename_retry:
         /* 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 ec4318b019cc..a2ad94efcfe6 100644
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -62,15 +62,15 @@ static void cifs_fscache_enable_inode_cookie(struct inode *inode)
 {
         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 @@ void cifs_fscache_reset_inode_cookie(struct inode *inode)
                 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 dce2d598927e..da716d96dae6 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -52,7 +52,7 @@ static void cifs_set_ops(struct inode *inode, const bool is_dfs_referral)
 
 
                 /* 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 @@ static void
 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 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
         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 @@ char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb)
         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 @@ char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb)
                 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 @@ char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb)
                 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 @@ retry_iget5_locked:
 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 @@ struct inode *cifs_root_iget(struct super_block *sb, unsigned long ino)
 
 #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 @@ int cifs_revalidate_dentry(struct dentry *dentry)
                  "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 @@ cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 {
         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 c5cbfdb2a58b..252f2768db84 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -729,6 +729,6 @@ cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
                            "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 3efc2424964f..887a7e230376 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -102,7 +102,7 @@ cifs_readdir_lookup(struct dentry *parent, struct qstr *name,
                 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 @@ static void
 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,