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/****************************************************************************
* fs/fs_umount.c
*
* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/mount.h>
#include <errno.h>
#include <nuttx/fs/fs.h>
#include "fs_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: umount
*
* Description:
* umount() detaches the filesystem mounted at the path specified by
* 'target.'
*
* Return:
* Zero is returned on success; -1 is returned on an error and errno is
* set appropriately:
*
* EACCES A component of a path was not searchable or mounting a read-only
* filesystem was attempted without giving the MS_RDONLY flag.
* EBUSY The target could not be unmounted because it is busy.
* EFAULT The pointer argument points outside the user address space.
*
****************************************************************************/
int umount(const char *target)
{
FAR struct inode *mountpt_inode;
FAR struct inode *blkdrvr_inode = NULL;
int errcode = OK;
int status;
/* Verify required pointer arguments */
if (!target)
{
errcode = EFAULT;
goto errout;
}
/* Find the mountpt */
mountpt_inode = inode_find(target, NULL);
if (!mountpt_inode)
{
errcode = ENOENT;
goto errout;
}
/* Verify that the inode is a mountpoint */
if (!INODE_IS_MOUNTPT(mountpt_inode))
{
errcode = EINVAL;
goto errout_with_mountpt;
}
/* Unbind the block driver from the file system (destroying any fs
* private data.
*/
if (!mountpt_inode->u.i_mops->unbind)
{
/* The filesystem does not support the unbind operation ??? */
errcode = EINVAL;
goto errout_with_mountpt;
}
/* The unbind method returns the number of references to the
* filesystem (i.e., open files), zero if the unbind was
* performed, or a negated error code on a failure.
*/
inode_semtake(); /* Hold the semaphore through the unbind logic */
status = mountpt_inode->u.i_mops->unbind( mountpt_inode->i_private, &blkdrvr_inode);
if (status < 0)
{
/* The inode is unhappy with the blkdrvr for some reason */
errcode = -status;
goto errout_with_semaphore;
}
else if (status > 0)
{
errcode = EBUSY;
goto errout_with_semaphore;
}
/* Successfully unbound */
mountpt_inode->i_private = NULL;
/* Successfully unbound, remove the mountpoint inode from
* the inode tree. The inode will not be deleted yet because
* there is still at least reference on it (from the mount)
*/
status = inode_remove(target);
inode_semgive();
/* The return value of -EBUSY is normal (in fact, it should
* not be OK)
*/
if (status != OK && status != -EBUSY)
{
errcode = -status;
goto errout_with_mountpt;
}
/* Release the mountpoint inode and any block driver inode
* returned by the file system unbind above. This should cause
* the inode to be deleted (unless there are other references)
*/
inode_release(mountpt_inode);
/* Did the unbind method return a contained block driver */
if (blkdrvr_inode)
{
inode_release(blkdrvr_inode);
}
return OK;
/* A lot of goto's! But they make the error handling much simpler */
errout_with_semaphore:
inode_semgive();
errout_with_mountpt:
inode_release(mountpt_inode);
if (blkdrvr_inode)
{
inode_release(blkdrvr_inode);
}
errout:
set_errno(errcode);
return ERROR;
}
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