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Eliminate deadlock condition in opendir() 

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@757 7fd9a85b-ad96-42d3-883c-3090e2eb8679
This commit is contained in:
patacongo 2008-05-31 20:14:15 +00:00
parent 4035903f34
commit 0caf47378a
6 changed files with 99 additions and 85 deletions
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3
nuttx/ChangeLog
View File

@ -358,5 +358,6 @@
0.3.11 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
* Add support for recursive mutexes.
* BUGFIX: Eliminate a memory leak -- contained watchdog instance was not
* BUGFIX: Eliminate a memory leak -- contained watchdog instance was not
being deleted with a POSIX timer was deleted.
* BUGFIX: Eliminate a deadlock condition in opendir().

3
nuttx/Documentation/NuttX.html
View File

@ -1008,8 +1008,9 @@ buildroot-0.1.0 2007-03-09 &lt;spudmonkey@racsa.co.cr&gt
nuttx-0.3.11 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
* Add support for recursive mutexes.
* BUGFIX: Eliminate a memory leak -- contained watchdog instance was not
* BUGFIX: Eliminate a memory leak -- contained watchdog instance was not
being deleted with a POSIX timer was deleted.
* BUGFIX: Eliminate a deadlock condition in opendir().
pascal-0.1.3 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;

60
nuttx/fs/fs_inode.c
View File

@ -1,7 +1,7 @@
/************************************************************
/****************************************************************************
* fs_inode.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
@ -14,7 +14,7 @@
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* 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.
*
@ -31,11 +31,11 @@
* 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/types.h>
@ -48,29 +48,29 @@
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
/****************************************************************************
* Definitions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Private Variables
************************************************************/
****************************************************************************/
static sem_t tree_sem;
/************************************************************
/****************************************************************************
* Public Variables
************************************************************/
****************************************************************************/
FAR struct inode *root_inode = NULL;
/************************************************************
/****************************************************************************
* Private Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Name: _inode_compare
************************************************************/
****************************************************************************/
static int _inode_compare(const char *fname,
FAR struct inode *node)
@ -135,18 +135,18 @@ static int _inode_compare(const char *fname,
}
}
/************************************************************
/****************************************************************************
* Public Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Name: fs_initialize
*
* Description:
* This is called from the OS initialization logic to configure
* the file system.
*
************************************************************/
****************************************************************************/
void fs_initialize(void)
{
@ -166,9 +166,9 @@ void fs_initialize(void)
}
}
/************************************************************
/****************************************************************************
* Name: inode_semtake
************************************************************/
****************************************************************************/
void inode_semtake(void)
{
@ -184,16 +184,16 @@ void inode_semtake(void)
}
}
/************************************************************
/****************************************************************************
* Name: inode_semgive
************************************************************/
****************************************************************************/
void inode_semgive(void)
{
sem_post(&tree_sem);
}
/************************************************************
/****************************************************************************
* Name: inode_search
*
* Description:
@ -203,7 +203,7 @@ void inode_semgive(void)
* Assumptions:
* The caller holds the tree_sem
*
************************************************************/
****************************************************************************/
FAR struct inode *inode_search(const char **path,
FAR struct inode **peer,
@ -299,9 +299,9 @@ FAR struct inode *inode_search(const char **path,
return node;
}
/************************************************************
/****************************************************************************
* Name: inode_free
************************************************************/
****************************************************************************/
void inode_free(FAR struct inode *node)
{
@ -313,14 +313,14 @@ void inode_free(FAR struct inode *node)
}
}
/************************************************************
/****************************************************************************
* Name: inode_nextname
*
* Description:
* Given a path with node names separated by '/', return
* the next node name.
*
************************************************************/
****************************************************************************/
const char *inode_nextname(const char *name)
{

36
nuttx/fs/fs_inodeaddref.c
View File

@ -1,7 +1,7 @@
/************************************************************
/****************************************************************************
* fs_inodeaddref.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
@ -14,7 +14,7 @@
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* 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.
*
@ -31,11 +31,11 @@
* 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/types.h>
@ -43,34 +43,34 @@
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
/****************************************************************************
* Definitions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Private Variables
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Public Variables
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Private Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Public Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Name: inode_addref
*
* Description:
* Increment the reference count on an inode (as when a file
* descriptor is dup'ed.
*
************************************************************/
****************************************************************************/
void inode_addref(FAR struct inode *inode)
{

36
nuttx/fs/fs_inoderelease.c
View File

@ -1,7 +1,7 @@
/************************************************************
/****************************************************************************
* fs_inoderelease.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
@ -14,7 +14,7 @@
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* 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.
*
@ -31,11 +31,11 @@
* 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/types.h>
@ -44,34 +44,34 @@
#include <nuttx/fs.h>
#include "fs_internal.h"
/************************************************************
/****************************************************************************
* Definitions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Private Variables
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Public Variables
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Private Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Public Functions
************************************************************/
****************************************************************************/
/************************************************************
/****************************************************************************
* Name: inode_release
*
* Description:
* This is called from close() logic when it no longer refers
* to the inode.
*
************************************************************/
****************************************************************************/
void inode_release(FAR struct inode *node)
{

46
nuttx/fs/fs_opendir.c
View File

@ -38,12 +38,16 @@
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/fs.h>
#include "fs_internal.h"
/****************************************************************************
@ -152,13 +156,13 @@ FAR DIR *opendir(FAR const char *path)
if (INODE_IS_MOUNTPT(inode))
{
/* Yes, then return the inode itself as the 'root' of
* the directory. The actually directory is at relpath into the
* mounted filesystem.
*/
* the directory. The actually directory is at relpath into the
* mounted filesystem.
*/
/* The node is a file system mointpoint. Verify that the mountpoint
* supports the opendir() method
*/
* supports the opendir() method
*/
if (!inode->u.i_mops || !inode->u.i_mops->opendir)
{
@ -167,8 +171,8 @@ FAR DIR *opendir(FAR const char *path)
}
/* Take reference to the mountpoint inode (fd_root). Note that we do
* not use inode_addref() because we already hold the tree semaphore.
*/
* not use inode_addref() because we already hold the tree semaphore.
*/
inode->i_crefs++;
@ -177,8 +181,21 @@ FAR DIR *opendir(FAR const char *path)
ret = inode->u.i_mops->opendir(inode, relpath, dir);
if (ret < 0)
{
/* We now need to back off our reference to the inode. We can't
* call inode_release() to do that unless we release the tree
* semaphore. The following should be safe because: (1) after the
* reference count was incremented above it should be >1 so it should
* not decrement to zero, and (2) we hold the tree semaphore so no
* other thread should be able to change the reference count.
*/
inode->i_crefs--;
DEBUGASSERT(inode->i_crefs > 0);
/* Negate the error value so that it can be used to set errno */
ret = -ret;
goto errout_with_inode;
goto errout_with_direntry;
}
}
else
@ -200,10 +217,10 @@ FAR DIR *opendir(FAR const char *path)
}
/* It looks we have a valid psuedo-filesystem node. Take two references
* on the inode -- one for the parent (fd_root) and one for the child (fd_next).
* Note that we do not call inode_addref because we are holding
* the tree semaphore and that would result in deadlock.
*/
* on the inode -- one for the parent (fd_root) and one for the child (fd_next).
* Note that we do not call inode_addref because we are holding
* the tree semaphore and that would result in deadlock.
*/
inode->i_crefs += 2;
dir->u.psuedo.fd_next = inode; /* This is the next node to use for readdir() */
@ -219,11 +236,6 @@ FAR DIR *opendir(FAR const char *path)
/* Nasty goto's make error handling simpler */
#ifndef CONFIG_DISABLE_MOUNTPOINT
errout_with_inode:
inode_release(inode);
#endif
errout_with_direntry:
free(dir);