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/****************************************************************************
* fs/nxffs/nxffs_block.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* References: Linux/Documentation/filesystems/romfs.txt
*
* 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 <string.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/mtd.h>
#include "nxffs.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Types
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxffs_verifyblock
*
* Description:
* Assure the the provided (logical) block number is in the block cache
* and that it has a valid block header (i.e., proper magic and
* marked good)
*
* Input Parameters:
* volume - Describes the NXFFS volume
* block - The (logical) block number to load and verify.
*
* Returned Values:
* Zero is returned on success. Otherwise, a negated errno value is
* returned indicating the nature of the failure. -ENOENT is returned
* if the block is a bad block.
*
****************************************************************************/
int nxffs_verifyblock(FAR struct nxffs_volume_s *volume, off_t block)
{
FAR struct nxffs_block_s *blkhdr;
int ret;
/* Make sure the the block is in the cache */
ret = nxffs_rdcache(volume, block);
if (ret < 0)
{
/* Perhaps we are at the end of the media */
fvdbg("Failed to read data into cache: %d\n", ret);
return ret;
}
/* Check if the block has a magic number (meaning that it is not
* erased) and that it is valid (meaning that it is not marked
* for deletion)
*/
blkhdr = (FAR struct nxffs_block_s *)volume->cache;
if (memcmp(blkhdr->magic, g_blockmagic, NXFFS_MAGICSIZE) == 0)
{
/* This does appear to be a block */
if (blkhdr->state == BLOCK_STATE_GOOD)
{
/* The block is valid */
return OK;
}
else if (blkhdr->state == BLOCK_STATE_BAD)
{
/* -ENOENT is a special indication that this is a properly marked
* bad block
*/
return -ENOENT;
}
}
/* Whatever is here where a block header should be is invalid */
return -EINVAL;
}
/****************************************************************************
* Name: nxffs_validblock
*
* Description:
* Find the next valid (logical) block in the volume.
*
* Input Parameters:
* volume - Describes the NXFFS volume
* block - On entry, this provides the starting block number. If the
* function is succesfful, then this memory location will hold the
* block number of the next valid block on return.
*
* Returned Value:
* Zero on success otherwise a negated errno value indicating the nature
* of the failure.
*
****************************************************************************/
int nxffs_validblock(struct nxffs_volume_s *volume, off_t *block)
{
off_t i;
int ret;
DEBUGASSERT(volume && block);
/* Loop for each possible block or until a valid block is found */
for (i = *block; i < volume->nblocks; i++)
{
/* Loop until we find a valid block */
ret = nxffs_verifyblock(volume, i);
if (ret == OK)
{
/* We found it, return the block number */
*block = i;
return OK;
}
}
/* ENOSPC is special return value that means that there is no further,
* valid blocks left in the volume.
*/
fdbg("No valid block found\n");
return -ENOSPC;
}
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