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>

fs/cifs/cifs_dfs_ref.c

@@ -306,6 +306,7 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
 	int xid, i;
 	int rc = 0;
 	struct vfsmount *mnt = ERR_PTR(-ENOENT);
+	struct tcon_link *tlink;
 
 	cFYI(1, "in %s", __func__);
 	BUG_ON(IS_ROOT(dentry));
@@ -315,14 +316,6 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
 	dput(nd->path.dentry);
 	nd->path.dentry = dget(dentry);
 
-	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
-	ses = cifs_sb_tcon(cifs_sb)->ses;
-
-	if (!ses) {
-		rc = -EINVAL;
-		goto out_err;
-	}
-
 	/*
 	 * The MSDFS spec states that paths in DFS referral requests and
 	 * responses must be prefixed by a single '\' character instead of
@@ -335,10 +328,20 @@ cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
 		goto out_err;
 	}
 
-	rc = get_dfs_path(xid, ses , full_path + 1, cifs_sb->local_nls,
+	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		rc = PTR_ERR(tlink);
+		goto out_err;
+	}
+	ses = tlink_tcon(tlink)->ses;
+
+	rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
 		&num_referrals, &referrals,
 		cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 
+	cifs_put_tlink(tlink);
+
 	for (i = 0; i < num_referrals; i++) {
 		int len;
 		dump_referral(referrals+i);

fs/cifs/cifsacl.c

@@ -557,11 +557,16 @@ static struct cifs_ntsd *get_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb,
 {
 	struct cifs_ntsd *pntsd = NULL;
 	int xid, rc;
+	struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
+
+	if (IS_ERR(tlink))
+		return NULL;
 
 	xid = GetXid();
-	rc = CIFSSMBGetCIFSACL(xid, cifs_sb_tcon(cifs_sb), fid, &pntsd, pacllen);
+	rc = CIFSSMBGetCIFSACL(xid, tlink_tcon(tlink), fid, &pntsd, pacllen);
 	FreeXid(xid);
 
+	cifs_put_tlink(tlink);
 
 	cFYI(1, "GetCIFSACL rc = %d ACL len %d", rc, *pacllen);
 	return pntsd;
@@ -574,10 +579,16 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
 	int oplock = 0;
 	int xid, rc;
 	__u16 fid;
+	struct cifsTconInfo *tcon;
+	struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
+
+	if (IS_ERR(tlink))
+		return NULL;
 
+	tcon = tlink_tcon(tlink);
 	xid = GetXid();
 
-	rc = CIFSSMBOpen(xid, cifs_sb_tcon(cifs_sb), path, FILE_OPEN, READ_CONTROL, 0,
+	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL, 0,
 			 &fid, &oplock, NULL, cifs_sb->local_nls,
 			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 	if (rc) {
@@ -585,11 +596,12 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
 		goto out;
 	}
 
-	rc = CIFSSMBGetCIFSACL(xid, cifs_sb_tcon(cifs_sb), fid, &pntsd, pacllen);
+	rc = CIFSSMBGetCIFSACL(xid, tcon, fid, &pntsd, pacllen);
 	cFYI(1, "GetCIFSACL rc = %d ACL len %d", rc, *pacllen);
 
-	CIFSSMBClose(xid, cifs_sb_tcon(cifs_sb), fid);
+	CIFSSMBClose(xid, tcon, fid);
  out:
+	cifs_put_tlink(tlink);
 	FreeXid(xid);
 	return pntsd;
 }
@@ -616,10 +628,15 @@ static int set_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb, __u16 fid,
 		struct cifs_ntsd *pnntsd, u32 acllen)
 {
 	int xid, rc;
+	struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
+
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
 
 	xid = GetXid();
-	rc = CIFSSMBSetCIFSACL(xid, cifs_sb_tcon(cifs_sb), fid, pnntsd, acllen);
+	rc = CIFSSMBSetCIFSACL(xid, tlink_tcon(tlink), fid, pnntsd, acllen);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 
 	cFYI(DBG2, "SetCIFSACL rc = %d", rc);
 	return rc;
@@ -631,10 +648,16 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
 	int oplock = 0;
 	int xid, rc;
 	__u16 fid;
+	struct cifsTconInfo *tcon;
+	struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
 
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+
+	tcon = tlink_tcon(tlink);
 	xid = GetXid();
 
-	rc = CIFSSMBOpen(xid, cifs_sb_tcon(cifs_sb), path, FILE_OPEN, WRITE_DAC, 0,
+	rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, WRITE_DAC, 0,
 			 &fid, &oplock, NULL, cifs_sb->local_nls,
 			 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
 	if (rc) {
@@ -642,12 +665,13 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
 		goto out;
 	}
 
-	rc = CIFSSMBSetCIFSACL(xid, cifs_sb_tcon(cifs_sb), fid, pnntsd, acllen);
+	rc = CIFSSMBSetCIFSACL(xid, tcon, fid, pnntsd, acllen);
 	cFYI(DBG2, "SetCIFSACL rc = %d", rc);
 
-	CIFSSMBClose(xid, cifs_sb_tcon(cifs_sb), fid);
- out:
+	CIFSSMBClose(xid, tcon, fid);
+out:
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 	return rc;
 }
 

fs/cifs/cifsglob.h

@@ -310,6 +310,44 @@ struct cifsTconInfo {
 	/* BB add field for back pointer to sb struct(s)? */
 };
 
+/*
+ * This is a refcounted and timestamped container for a tcon pointer. The
+ * container holds a tcon reference. It is considered safe to free one of
+ * these when the tl_count goes to 0. The tl_time is the time of the last
+ * "get" on the container.
+ */
+struct tcon_link {
+	spinlock_t		tl_lock;
+	u32			tl_count;
+	u64			tl_time;
+	struct cifsTconInfo	*tl_tcon;
+};
+
+static inline struct tcon_link *
+cifs_sb_tlink(struct cifs_sb_info *cifs_sb)
+{
+	return (struct tcon_link *)cifs_sb->ptcon;
+}
+
+static inline struct cifsTconInfo *
+tlink_tcon(struct tcon_link *tlink)
+{
+	return (struct cifsTconInfo *)tlink;
+}
+
+static inline void
+cifs_put_tlink(struct tcon_link *tlink)
+{
+	return;
+}
+
+/* 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;
+}
+
 /*
  * This info hangs off the cifsFileInfo structure, pointed to by llist.
  * This is used to track byte stream locks on the file
@@ -413,19 +451,6 @@ CIFS_SB(struct super_block *sb)
 	return sb->s_fs_info;
 }
 
-static inline struct cifsTconInfo *
-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)

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(struct inode *inode, struct dentry *direntry, int mode,
 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 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
 	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);
 }

fs/cifs/file.c

@@ -224,6 +224,7 @@ int cifs_open(struct inode *inode, struct file *file)
 	__u32 oplock;
 	struct cifs_sb_info *cifs_sb;
 	struct cifsTconInfo *tcon;
+	struct tcon_link *tlink;
 	struct cifsFileInfo *pCifsFile = NULL;
 	struct cifsInodeInfo *pCifsInode;
 	char *full_path = NULL;
@@ -235,7 +236,12 @@ int cifs_open(struct inode *inode, struct file *file)
 	xid = GetXid();
 
 	cifs_sb = CIFS_SB(inode->i_sb);
-	tcon = cifs_sb_tcon(cifs_sb);
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		FreeXid(xid);
+		return PTR_ERR(tlink);
+	}
+	tcon = tlink_tcon(tlink);
 
 	pCifsInode = CIFS_I(file->f_path.dentry->d_inode);
 
@@ -402,6 +408,7 @@ int cifs_open(struct inode *inode, struct file *file)
 	kfree(buf);
 	kfree(full_path);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 	return rc;
 }
 

fs/cifs/link.c

@@ -249,7 +249,8 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 	int rc;
 	int oplock = 0;
 	__u16 netfid = 0;
-	struct cifsTconInfo *pTcon = cifs_sb_tcon(cifs_sb);
+	struct tcon_link *tlink;
+	struct cifsTconInfo *pTcon;
 	u8 *buf;
 	char *pbuf;
 	unsigned int bytes_read = 0;
@@ -261,23 +262,30 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 		/* it's not a symlink */
 		return 0;
 
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+	pTcon = tlink_tcon(tlink);
+
 	rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
 			 CREATE_NOT_DIR, &netfid, &oplock, &file_info,
 			 cifs_sb->local_nls,
 			 cifs_sb->mnt_cifs_flags &
 				CIFS_MOUNT_MAP_SPECIAL_CHR);
 	if (rc != 0)
-		return rc;
+		goto out;
 
 	if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
 		CIFSSMBClose(xid, pTcon, netfid);
 		/* it's not a symlink */
-		return 0;
+		goto out;
 	}
 
 	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+	if (!buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
 	pbuf = buf;
 
 	rc = CIFSSMBRead(xid, pTcon, netfid,
@@ -287,23 +295,28 @@ CIFSCheckMFSymlink(struct cifs_fattr *fattr,
 	CIFSSMBClose(xid, pTcon, netfid);
 	if (rc != 0) {
 		kfree(buf);
-		return rc;
+		goto out;
 	}
 
 	rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
 	kfree(buf);
-	if (rc == -EINVAL)
+	if (rc == -EINVAL) {
 		/* it's not a symlink */
-		return 0;
+		rc = 0;
+		goto out;
+	}
+
 	if (rc != 0)
-		return rc;
+		goto out;
 
 	/* it is a symlink */
 	fattr->cf_eof = link_len;
 	fattr->cf_mode &= ~S_IFMT;
 	fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
 	fattr->cf_dtype = DT_LNK;
-	return 0;
+out:
+	cifs_put_tlink(tlink);
+	return rc;
 }
 
 int
@@ -314,17 +327,17 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	int xid;
 	char *fromName = NULL;
 	char *toName = NULL;
-	struct cifs_sb_info *cifs_sb_target;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct cifsInodeInfo *cifsInode;
 
-	xid = GetXid();
-
-	cifs_sb_target = CIFS_SB(inode->i_sb);
-	pTcon = cifs_sb_tcon(cifs_sb_target);
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+	pTcon = tlink_tcon(tlink);
 
-/* No need to check for cross device links since server will do that
-   BB note DFS case in future though (when we may have to check) */
+	xid = GetXid();
 
 	fromName = build_path_from_dentry(old_file);
 	toName = build_path_from_dentry(direntry);
@@ -336,13 +349,13 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 /*	if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
 	if (pTcon->unix_ext)
 		rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
-					    cifs_sb_target->local_nls,
-					    cifs_sb_target->mnt_cifs_flags &
+					    cifs_sb->local_nls,
+					    cifs_sb->mnt_cifs_flags &
 						CIFS_MOUNT_MAP_SPECIAL_CHR);
 	else {
 		rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
-					cifs_sb_target->local_nls,
-					cifs_sb_target->mnt_cifs_flags &
+					cifs_sb->local_nls,
+					cifs_sb->mnt_cifs_flags &
 						CIFS_MOUNT_MAP_SPECIAL_CHR);
 		if ((rc == -EIO) || (rc == -EINVAL))
 			rc = -EOPNOTSUPP;
@@ -378,6 +391,7 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	kfree(fromName);
 	kfree(toName);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 	return rc;
 }
 
@@ -390,10 +404,19 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	char *full_path = NULL;
 	char *target_path = NULL;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
-	struct cifsTconInfo *tcon = cifs_sb_tcon(cifs_sb);
+	struct tcon_link *tlink = NULL;
+	struct cifsTconInfo *tcon;
 
 	xid = GetXid();
 
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		rc = PTR_ERR(tlink);
+		tlink = NULL;
+		goto out;
+	}
+	tcon = tlink_tcon(tlink);
+
 	/*
 	 * For now, we just handle symlinks with unix extensions enabled.
 	 * Eventually we should handle NTFS reparse points, and MacOS
@@ -442,6 +465,8 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	}
 
 	FreeXid(xid);
+	if (tlink)
+		cifs_put_tlink(tlink);
 	nd_set_link(nd, target_path);
 	return NULL;
 }
@@ -451,22 +476,25 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 {
 	int rc = -EOPNOTSUPP;
 	int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	char *full_path = NULL;
 	struct inode *newinode = NULL;
 
 	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)) {
+		rc = PTR_ERR(tlink);
+		goto symlink_exit;
+	}
+	pTcon = tlink_tcon(tlink);
 
 	full_path = build_path_from_dentry(direntry);
-
 	if (full_path == NULL) {
 		rc = -ENOMEM;
-		FreeXid(xid);
-		return rc;
+		goto symlink_exit;
 	}
 
 	cFYI(1, "Full path: %s", full_path);
@@ -504,8 +532,9 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 			d_instantiate(direntry, newinode);
 		}
 	}
-
+symlink_exit:
 	kfree(full_path);
+	cifs_put_tlink(tlink);
 	FreeXid(xid);
 	return rc;
 }

fs/cifs/readdir.c

@@ -223,33 +223,35 @@ int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 static int initiate_cifs_search(const int xid, struct file *file)
 {
 	int rc = 0;
-	char *full_path;
+	char *full_path = NULL;
 	struct cifsFileInfo *cifsFile;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 
-	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-	if (cifs_sb == NULL)
-		return -EINVAL;
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+	pTcon = tlink_tcon(tlink);
 
 	if (file->private_data == NULL)
 		file->private_data =
 			kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
+	if (file->private_data == NULL) {
+		rc = -ENOMEM;
+		goto error_exit;
+	}
 
-	if (file->private_data == NULL)
-		return -ENOMEM;
 	cifsFile = file->private_data;
 	cifsFile->invalidHandle = true;
 	cifsFile->srch_inf.endOfSearch = false;
-	cifsFile->tcon = cifs_sb_tcon(cifs_sb);
-	pTcon = cifsFile->tcon;
-	if (pTcon == NULL)
-		return -EINVAL;
+	cifsFile->tcon = pTcon;
 
 	full_path = build_path_from_dentry(file->f_path.dentry);
-
-	if (full_path == NULL)
-		return -ENOMEM;
+	if (full_path == NULL) {
+		rc = -ENOMEM;
+		goto error_exit;
+	}
 
 	cFYI(1, "Full path: %s start at: %lld", full_path, file->f_pos);
 
@@ -282,7 +284,9 @@ static int initiate_cifs_search(const int xid, struct file *file)
 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 		goto ffirst_retry;
 	}
+error_exit:
 	kfree(full_path);
+	cifs_put_tlink(tlink);
 	return rc;
 }
 

fs/cifs/xattr.c

@@ -47,9 +47,10 @@ int cifs_removexattr(struct dentry *direntry, const char *ea_name)
 #ifdef CONFIG_CIFS_XATTR
 	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct super_block *sb;
-	char *full_path;
+	char *full_path = NULL;
 
 	if (direntry == NULL)
 		return -EIO;
@@ -58,16 +59,19 @@ int cifs_removexattr(struct dentry *direntry, const char *ea_name)
 	sb = direntry->d_inode->i_sb;
 	if (sb == NULL)
 		return -EIO;
-	xid = GetXid();
 
 	cifs_sb = CIFS_SB(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) {
 		rc = -ENOMEM;
-		FreeXid(xid);
-		return rc;
+		goto remove_ea_exit;
 	}
 	if (ea_name == NULL) {
 		cFYI(1, "Null xattr names not supported");
@@ -91,6 +95,7 @@ int cifs_removexattr(struct dentry *direntry, const char *ea_name)
 remove_ea_exit:
 	kfree(full_path);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 #endif
 	return rc;
 }
@@ -102,6 +107,7 @@ int cifs_setxattr(struct dentry *direntry, const char *ea_name,
 #ifdef CONFIG_CIFS_XATTR
 	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct super_block *sb;
 	char *full_path;
@@ -113,16 +119,19 @@ int cifs_setxattr(struct dentry *direntry, const char *ea_name,
 	sb = direntry->d_inode->i_sb;
 	if (sb == NULL)
 		return -EIO;
-	xid = GetXid();
 
 	cifs_sb = CIFS_SB(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) {
 		rc = -ENOMEM;
-		FreeXid(xid);
-		return rc;
+		goto set_ea_exit;
 	}
 	/* return dos attributes as pseudo xattr */
 	/* return alt name if available as pseudo attr */
@@ -132,9 +141,8 @@ int cifs_setxattr(struct dentry *direntry, const char *ea_name,
 		returns as xattrs */
 	if (value_size > MAX_EA_VALUE_SIZE) {
 		cFYI(1, "size of EA value too large");
-		kfree(full_path);
-		FreeXid(xid);
-		return -EOPNOTSUPP;
+		rc = -EOPNOTSUPP;
+		goto set_ea_exit;
 	}
 
 	if (ea_name == NULL) {
@@ -198,6 +206,7 @@ int cifs_setxattr(struct dentry *direntry, const char *ea_name,
 set_ea_exit:
 	kfree(full_path);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 #endif
 	return rc;
 }
@@ -209,6 +218,7 @@ ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
 #ifdef CONFIG_CIFS_XATTR
 	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct super_block *sb;
 	char *full_path;
@@ -221,16 +231,18 @@ ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
 	if (sb == NULL)
 		return -EIO;
 
-	xid = GetXid();
-
 	cifs_sb = CIFS_SB(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) {
 		rc = -ENOMEM;
-		FreeXid(xid);
-		return rc;
+		goto get_ea_exit;
 	}
 	/* return dos attributes as pseudo xattr */
 	/* return alt name if available as pseudo attr */
@@ -323,6 +335,7 @@ ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
 get_ea_exit:
 	kfree(full_path);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 #endif
 	return rc;
 }
@@ -333,6 +346,7 @@ ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 #ifdef CONFIG_CIFS_XATTR
 	int xid;
 	struct cifs_sb_info *cifs_sb;
+	struct tcon_link *tlink;
 	struct cifsTconInfo *pTcon;
 	struct super_block *sb;
 	char *full_path;
@@ -346,18 +360,20 @@ ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 		return -EIO;
 
 	cifs_sb = CIFS_SB(sb);
-	pTcon = cifs_sb_tcon(cifs_sb);
-
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 		return -EOPNOTSUPP;
 
+	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) {
 		rc = -ENOMEM;
-		FreeXid(xid);
-		return rc;
+		goto list_ea_exit;
 	}
 	/* return dos attributes as pseudo xattr */
 	/* return alt name if available as pseudo attr */
@@ -370,8 +386,10 @@ ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 				cifs_sb->mnt_cifs_flags &
 					CIFS_MOUNT_MAP_SPECIAL_CHR);
 
+list_ea_exit:
 	kfree(full_path);
 	FreeXid(xid);
+	cifs_put_tlink(tlink);
 #endif
 	return rc;
 }