mkdir can now be used to create empty directories in the pseudo-filesystem.

ChangeLog

@@ -6610,7 +6610,8 @@
 	* fs/fs_opendir.c, fs_readdir.c, et al: Modified so that errors
 	  will not be reported if you attempt to list a empty pseudo-directory
 	  (2014-2-19).
-	* fs/fs_rmdir.c: rmdir can be used to removed empty directories in
+	* fs/fs_rmdir.c: rmdir can now be used to remove empty directories in
 	  the pseudo-filesystem such as might be left after umounting a
 	  file system (2014-2-19).
-
+	* fs/fs_mkdir.c: mkdir can now be used to create empty directories in
+	  the pseudo-filesystem (2014-2-19).

fs/Makefile

@@ -62,13 +62,15 @@ else
 # Common file/socket descriptor support
 
 CSRCS += fs_close.c fs_closedir.c fs_dup.c fs_dup2.c fs_fcntl.c
-CSRCS += fs_filedup.c fs_filedup2.c fs_ioctl.c fs_lseek.c fs_open.c
-CSRCS += fs_opendir.c fs_poll.c fs_read.c fs_readdir.c fs_rewinddir.c
-CSRCS += fs_rmdir.c fs_seekdir.c fs_stat.c fs_statfs.c fs_select.c
-CSRCS += fs_write.c
+CSRCS += fs_filedup.c fs_filedup2.c fs_ioctl.c fs_lseek.c fs_mkdir.c
+CSRCS += fs_open.c fs_opendir.c fs_poll.c fs_read.c fs_readdir.c
+CSRCS += fs_rewinddir.c fs_rmdir.c fs_seekdir.c fs_stat.c fs_statfs.c
+CSRCS += fs_select.c fs_write.c
+
 CSRCS += fs_files.c fs_foreachinode.c fs_inode.c fs_inodeaddref.c
 CSRCS += fs_inodefind.c fs_inoderelease.c fs_inoderemove.c
 CSRCS += fs_inodereserve.c
+
 CSRCS += fs_registerdriver.c fs_unregisterdriver.c
 CSRCS += fs_registerblockdriver.c fs_unregisterblockdriver.c
 CSRCS += fs_findblockdriver.c fs_openblockdriver.c fs_closeblockdriver.c
@@ -102,7 +104,7 @@ endif
 
 ifneq ($(CONFIG_DISABLE_MOUNTPOINT),y)
 
-CSRCS += fs_fsync.c fs_mkdir.c fs_mount.c fs_rename.c fs_umount.c
+CSRCS += fs_fsync.c fs_mount.c fs_rename.c fs_umount.c
 CSRCS += fs_unlink.c
 CSRCS += fs_foreachmountpoint.c
 

fs/fs_mkdir.c

 /****************************************************************************
  * fs/fs_mkdir.c
  *
- *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007, 2008, 2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -76,55 +76,85 @@ int mkdir(const char *pathname, mode_t mode)
 {
   FAR struct inode *inode;
   const char       *relpath = NULL;
+  int               errcode;
   int               ret;
 
-  /* Get an inode for this file */
+  /* Find the inode that includes this path */
 
   inode = inode_find(pathname, &relpath);
-  if (!inode)
+  if (inode)
     {
-      /* There is no mountpoint that includes in this path */
+      /* An inode was found that includes this path and possibly refers to a
+       * mountpoint.
+       */
 
-      ret = ENOENT;
-      goto errout;
-    }
+#ifndef CONFIG_DISABLE_MOUNTPOINT
+      /* Check if the inode is a valid mountpoint. */
 
-  /* Verify that the inode is a valid mountpoint. */
+      if (!INODE_IS_MOUNTPT(inode) || !inode->u.i_mops)
+        {
+          /* The inode is not a mountpoint */
 
-  if (!INODE_IS_MOUNTPT(inode) || !inode->u.i_mops)
-    {
-      ret = ENXIO;
-      goto errout_with_inode;
+          errcode = ENXIO;
+          goto errout_with_inode;
+        }
+
+      /* Perform the mkdir operation using the relative path
+       * at the mountpoint.
+       */
+
+      if (inode->u.i_mops->mkdir)
+        {
+          ret = inode->u.i_mops->mkdir(inode, relpath, mode);
+          if (ret < 0)
+            {
+              errcode = -ret;
+              goto errout_with_inode;
+            }
+        }
+      else
+        { 
+          errcode = ENOSYS;
+          goto errout_with_inode;
+        }
+
+      /* Release our reference on the inode */
+
+      inode_release(inode);
+#else
+      /* But mountpoints are not supported in this configuration */
+
+      errocode = EEXIST;
+      goto errout_with_inode;     
+#endif
     }
 
-  /* Perform the mkdir operation using the relative path
-   * at the mountpoint.
+  /* No inode exists that contains this path.  Create a new inode in the
+   * pseudo-filesystem at this location.
    */
 
-  if (inode->u.i_mops->mkdir)
+  else
     {
-      ret = inode->u.i_mops->mkdir(inode, relpath, mode);
+      /* Create an inode in the pseudo-filesystem at this path */
+
+      inode_semtake();
+      ret = inode_reserve(pathname, &inode);
+      inode_semgive();
+
       if (ret < 0)
         {
-          ret = -ret;
-          goto errout_with_inode;
+          errcode = -ret;
+          goto errout;
         }
     }
-  else
-    { 
-      ret = ENOSYS;
-      goto errout_with_inode;
-    }
 
   /* Directory successfully created */
 
-  inode_release(inode);
   return OK;
 
  errout_with_inode:
   inode_release(inode);
  errout:
-  set_errno(ret);
+  set_errno(errcode);
   return ERROR;
 }
-