+
+int generic_delete_lease(struct file *filp, struct file_lock **flp)
+{
+ struct file_lock *fl, **before;
+ struct dentry *dentry = filp->f_path.dentry;
+ struct inode *inode = dentry->d_inode;
+
+ for (before = &inode->i_flock;
+ ((fl = *before) != NULL) && IS_LEASE(fl);
+ before = &fl->fl_next) {
+ if (fl->fl_file != filp)
+ continue;
+ return (*flp)->fl_lmops->lm_change(before, F_UNLCK);
+ }
+ return -EAGAIN;
+}
+
+/**
+ * generic_setlease - sets a lease on an open file
+ * @filp: file pointer
+ * @arg: type of lease to obtain
+ * @flp: input - file_lock to use, output - file_lock inserted
+ *
+ * The (input) flp->fl_lmops->lm_break function is required
+ * by break_lease().
+ *
+ * Called with file_lock_lock held.
+ */
+int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
+{
+ struct dentry *dentry = filp->f_path.dentry;
+ struct inode *inode = dentry->d_inode;
+ int error;
+
+ if ((!uid_eq(current_fsuid(), inode->i_uid)) && !capable(CAP_LEASE))
+ return -EACCES;
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+ error = security_file_lock(filp, arg);
+ if (error)
+ return error;
+
+ time_out_leases(inode);
+
+ BUG_ON(!(*flp)->fl_lmops->lm_break);
+
+ switch (arg) {
+ case F_UNLCK:
+ return generic_delete_lease(filp, flp);
+ case F_RDLCK:
+ case F_WRLCK:
+ return generic_add_lease(filp, arg, flp);
+ default:
+ return -EINVAL;
+ }
+}