cifs: add refcounted and timestamped container for holding tcons

Eventually, we'll need to track the use of tcons on a per-sb basis, so that
we know when it's ok to tear them down. Begin this conversion by adding a
new "tcon_link" struct and accessors that get it. For now, the core data
structures are untouched -- cifs_sb still just points to a single tcon and
the pointers are just cast to deal with the accessor functions. A later
patch will flesh this out.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 48 insertions, 17 deletions

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 23ec28a4c11f..bb3ea06ca6f4 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -137,7 +137,6 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, struct file *file,
 {
 	struct cifsFileInfo *pCifsFile;
 	struct cifsInodeInfo *pCifsInode;
-	struct cifs_sb_info *cifs_sb = CIFS_SB(mnt->mnt_sb);
 
 	pCifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 	if (pCifsFile == NULL)
@@ -191,7 +190,8 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 	__u32 posix_flags = 0;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct cifs_fattr fattr;
-	struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+	struct tcon_link *tlink;
+	struct cifsTconInfo *tcon;
 
 	cFYI(1, "posix open %s", full_path);
 
@@ -226,10 +226,20 @@ int cifs_posix_open(char *full_path, struct inode **pinode,
 		posix_flags |= SMB_O_DIRECT;
 
 	mode &= ~current_umask();
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		rc = PTR_ERR(tlink);
+		goto posix_open_ret;
+	}
+
+	tcon = tlink_tcon(tlink);
 	rc = CIFSPOSIXCreate(xid, tcon, posix_flags, mode, pnetfid, presp_data,
 			     poplock, full_path, cifs_sb->local_nls,
 			     cifs_sb->mnt_cifs_flags &
 					CIFS_MOUNT_MAP_SPECIAL_CHR);
+	cifs_put_tlink(tlink);
+
 	if (rc)
 		goto posix_open_ret;
 
@@ -290,6 +300,7 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 	int desiredAccess = GENERIC_READ | GENERIC_WRITE;
 	__u16 fileHandle;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *tcon;
 	char *full_path = NULL;
 	FILE_ALL_INFO *buf = NULL;
@@ -299,13 +310,12 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 	xid = GetXid();
 
 	cifs_sb = CIFS_SB(inode->i_sb);
-	tcon = cifs_sb_tcon(cifs_sb);
-
-	full_path = build_path_from_dentry(direntry);
-	if (full_path == NULL) {
-		rc = -ENOMEM;
-		goto cifs_create_out;
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		FreeXid(xid);
+		return PTR_ERR(tlink);
 	}
+	tcon = tlink_tcon(tlink);
 
 	if (oplockEnabled)
 		oplock = REQ_OPLOCK;
@@ -315,6 +325,12 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 	else
 		oflags = FMODE_READ | SMB_O_CREAT;
 
+	full_path = build_path_from_dentry(direntry);
+	if (full_path == NULL) {
+		rc = -ENOMEM;
+		goto cifs_create_out;
+	}
+
 	if (tcon->unix_ext && (tcon->ses->capabilities & CAP_UNIX) &&
 	    (CIFS_UNIX_POSIX_PATH_OPS_CAP &
 			le64_to_cpu(tcon->fsUnixInfo.Capability))) {
@@ -481,6 +497,7 @@ cifs_create_set_dentry:
 cifs_create_out:
 	kfree(buf);
 	kfree(full_path);
+	cifs_put_tlink(tlink);
 	FreeXid(xid);
 	return rc;
 }
@@ -491,6 +508,7 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
 	int rc = -EPERM;
 	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	char *full_path = NULL;
 	struct inode *newinode = NULL;
@@ -503,10 +521,14 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
 	if (!old_valid_dev(device_number))
 		return -EINVAL;
 
-	xid = GetXid();
-
 	cifs_sb = CIFS_SB(inode->i_sb);
-	pTcon = cifs_sb_tcon(cifs_sb);
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+
+	pTcon = tlink_tcon(tlink);
+
+	xid = GetXid();
 
 	full_path = build_path_from_dentry(direntry);
 	if (full_path == NULL) {
@@ -606,6 +628,7 @@ mknod_out:
 	kfree(full_path);
 	kfree(buf);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 	return rc;
 }
 
@@ -619,6 +642,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	__u16 fileHandle = 0;
 	bool posix_open = false;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct cifsFileInfo *cfile;
 	struct inode *newInode = NULL;
@@ -633,7 +657,12 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	/* check whether path exists */
 
 	cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
-	pTcon = cifs_sb_tcon(cifs_sb);
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		FreeXid(xid);
+		return (struct dentry *)tlink;
+	}
+	pTcon = tlink_tcon(tlink);
 
 	/*
 	 * Don't allow the separator character in a path component.
@@ -644,8 +673,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 		for (i = 0; i < direntry->d_name.len; i++)
 			if (direntry->d_name.name[i] == '\\') {
 				cFYI(1, "Invalid file name");
-				FreeXid(xid);
-				return ERR_PTR(-EINVAL);
+				rc = -EINVAL;
+				goto lookup_out;
 			}
 	}
 
@@ -655,7 +684,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	 */
 	if (nd && (nd->flags & LOOKUP_EXCL)) {
 		d_instantiate(direntry, NULL);
-		return NULL;
+		rc = 0;
+		goto lookup_out;
 	}
 
 	/* can not grab the rename sem here since it would
@@ -663,8 +693,8 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 	in which we already have the sb rename sem */
 	full_path = build_path_from_dentry(direntry);
 	if (full_path == NULL) {
-		FreeXid(xid);
-		return ERR_PTR(-ENOMEM);
+		rc = -ENOMEM;
+		goto lookup_out;
 	}
 
 	if (direntry->d_inode != NULL) {
@@ -760,6 +790,7 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 
 lookup_out:
 	kfree(full_path);
+	cifs_put_tlink(tlink);
 	FreeXid(xid);
 	return ERR_PTR(rc);
 }