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px4-firmware/nuttx/fs/nxffs/nxffs_initialize.c

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/****************************************************************************
* fs/nxffs/nxffs_initialize.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/kmalloc.h>
#include <nuttx/mtd.h>
#include <nuttx/fs.h>
#include <nuttx/ioctl.h>
#include "nxffs.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/* See fs_mount.c -- this structure is explicitly externed there.
* We use the old-fashioned kind of initializers so that this will compile
* with any compiler.
*/
const struct mountpt_operations nxffs_operations =
{
nxffs_open, /* open */
nxffs_close, /* close */
nxffs_read, /* read */
nxffs_write, /* write */
NULL, /* seek -- Use f_pos in struct file */
nxffs_ioctl, /* ioctl */
NULL, /* sync -- No buffered data */
nxffs_opendir, /* opendir */
NULL, /* closedir */
nxffs_readdir, /* readdir */
nxffs_rewinddir, /* rewinddir */
nxffs_bind, /* bind */
nxffs_unbind, /* unbind */
nxffs_statfs, /* statfs */
nxffs_unlink, /* unlink */
NULL, /* mkdir -- no directories */
NULL, /* rmdir -- no directories */
NULL, /* rename -- cannot rename in place if name is longer */
nxffs_stat /* stat */
};
/****************************************************************************
* Public Variables
****************************************************************************/
/* The magic number that appears that the beginning of each NXFFS (logical)
* block
*/
const uint8_t g_blockmagic[NXFFS_MAGICSIZE] = { 'B', 'l', 'c', 'k' };
/* The magic number that appears that the beginning of each NXFFS inode */
const uint8_t g_inodemagic[NXFFS_MAGICSIZE] = { 'I', 'n', 'o', 'd' };
/* The magic number that appears that the beginning of each NXFFS inode
* data block.
*/
const uint8_t g_datamagic[NXFFS_MAGICSIZE] = { 'D', 'a', 't', 'a' };
/* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
* allocated NXFFS volume instance.
*/
#ifdef CONFIG_NXFSS_PREALLOCATED
struct nxffs_volume_s g_volume;
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxffs_initialize
*
* Description:
* Initialize to provide NXFFS on an MTD interface
*
* Input Parameters:
* mtd - The MTD device that supports the FLASH interface.
*
* Returned Value:
* Zero is returned on success. Otherwise, a negated errno value is
* returned to indicate the nature of the failure.
*
****************************************************************************/
int nxffs_initialize(FAR struct mtd_dev_s *mtd)
{
FAR struct nxffs_volume_s *volume;
struct nxffs_blkstats_s stats;
off_t threshold;
int ret;
/* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
* allocated NXFFS volume instance.
*/
#ifdef CONFIG_NXFSS_PREALLOCATED
volume = &g_volume;
memset(volume, 0, sizeof(struct nxffs_volume_s));
#else
/* Allocate a NXFFS volume structure */
volume = (FAR struct nxffs_volume_s *)kzalloc(sizeof(struct nxffs_volume_s));
if (!volume)
{
ret = -ENOMEM;
goto errout;
}
#endif
/* Initialize the NXFFS volume structure */
volume->mtd = mtd;
volume->cblock = (off_t)-1;
sem_init(&volume->exclsem, 0, 1);
sem_init(&volume->wrsem, 0, 1);
/* Get the volume geometry. (casting to uintptr_t first eliminates
* complaints on some architectures where the sizeof long is different
* from the size of a pointer).
*/
ret = MTD_IOCTL(mtd, MTDIOC_GEOMETRY, (unsigned long)((uintptr_t)&volume->geo));
if (ret < 0)
{
fdbg("MTD ioctl(MTDIOC_GEOMETRY) failed: %d\n", -ret);
goto errout_with_volume;
}
/* Allocate one I/O block buffer to general files system access */
volume->cache = (FAR uint8_t *)kmalloc(volume->geo.blocksize);
if (!volume->cache)
{
fdbg("Failed to allocate an erase block buffer\n");
ret = -ENOMEM;
goto errout_with_volume;
}
/* Pre-allocate one, full, in-memory erase block. This is needed for filesystem
* packing (but is useful in other places as well). This buffer is not needed
* often, but is best to have pre-allocated and in-place.
*/
volume->pack = (FAR uint8_t *)kmalloc(volume->geo.erasesize);
if (!volume->pack)
{
fdbg("Failed to allocate an I/O block buffer\n");
ret = -ENOMEM;
goto errout_with_cache;
}
/* Get the number of R/W blocks per erase block and the total number o
* R/W blocks
*/
volume->blkper = volume->geo.erasesize / volume->geo.blocksize;
volume->nblocks = volume->geo.neraseblocks * volume->blkper;
DEBUGASSERT((off_t)volume->blkper * volume->geo.blocksize == volume->geo.erasesize);
/* Check if there is a valid NXFFS file system on the flash */
ret = nxffs_blockstats(volume, &stats);
if (ret < 0)
{
fdbg("Failed to collect block statistics: %d\n", -ret);
goto errout_with_buffer;
}
/* If the proportion of good blocks is low or the proportion of unformatted
* blocks is high, then reformat the FLASH.
*/
threshold = stats.nblocks / 5;
if (stats.ngood < threshold || stats.nunformat > threshold)
{
/* Reformat the volume */
ret = nxffs_reformat(volume);
if (ret < 0)
{
fdbg("Failed to reformat the volume: %d\n", -ret);
goto errout_with_buffer;
}
/* Get statistics on the re-formatted volume */
#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_FS)
ret = nxffs_blockstats(volume, &stats);
if (ret < 0)
{
fdbg("Failed to collect block statistics: %d\n", -ret);
goto errout_with_buffer;
}
#endif
}
/* Get the file system limits */
ret = nxffs_limits(volume);
if (ret == OK)
{
return OK;
}
fdbg("Failed to calculate file system limits: %d\n", -ret);
errout_with_buffer:
kfree(volume->pack);
errout_with_cache:
kfree(volume->cache);
errout_with_volume:
#ifndef CONFIG_NXFSS_PREALLOCATED
kfree(volume);
#endif
return ret;
}
/****************************************************************************
* Name: nxffs_limits
*
* Description:
* Recalculate file system limits: (1) the FLASH offset to the first,
* valid inode, and (2) the FLASH offset to the first, unused byte after
* the last inode (invalid or not).
*
* The first, lower limit must be recalculated: (1) initially, (2)
* whenever the first inode is deleted, or (3) whenever inode is moved
* as part of the file system packing operation.
*
* The second, upper limit must be (1) incremented whenever new file
* data is written, or (2) recalculated as part of the file system packing
* operation.
*
* Input Parameters:
* volume - Identifies the NXFFS volume
*
* Returned Value:
* Zero on success. Otherwise, a negated error is returned indicating the
* nature of the failure.
*
****************************************************************************/
int nxffs_limits(FAR struct nxffs_volume_s *volume)
{
FAR struct nxffs_entry_s entry;
off_t block;
off_t offset;
bool noinodes = false;
int nerased;
int ret;
/* Get the offset to the first valid block on the FLASH */
block = 0;
ret = nxffs_validblock(volume, &block);
if (ret < 0)
{
fdbg("Failed to find a valid block: %d\n", -ret);
return ret;
}
/* Then find the first valid inode in or beyond the first valid block */
offset = block * volume->geo.blocksize;
ret = nxffs_nextentry(volume, offset, &entry);
if (ret < 0)
{
/* The value -ENOENT is special. This simply means that the FLASH
* was searched to the end and no valid inode was found... the file
* system is empty (or, in more perverse cases, all inodes are
* deleted or corrupted).
*/
if (ret != -ENOENT)
{
fdbg("nxffs_nextentry failed: %d\n", -ret);
return ret;
}
/* Set a flag the just indicates that no inodes were found. Later,
* we will set the location of the first inode to be the same as
* the location of the free FLASH region.
*/
fvdbg("No inodes found\n");
noinodes = true;
}
else
{
/* Save the offset to the first inode */
volume->inoffset = entry.hoffset;
fvdbg("First inode at offset %d\n", volume->inoffset);
/* Discard this entry and set the next offset. */
offset = nxffs_inodeend(volume, &entry);
nxffs_freeentry(&entry);
}
/* Now, search for the last valid entry */
if (!noinodes)
{
while ((ret = nxffs_nextentry(volume, offset, &entry)) == OK)
{
/* Discard the entry and guess the next offset. */
offset = nxffs_inodeend(volume, &entry);
nxffs_freeentry(&entry);
}
fvdbg("Last inode before offset %d\n", offset);
}
/* No inodes were found after this offset. Now search for a block of
* erased flash.
*/
nxffs_ioseek(volume, offset);
nerased = 0;
for (;;)
{
int ch = nxffs_getc(volume, 1);
if (ch < 0)
{
/* Failed to read the next byte... this could mean that the FLASH
* is full?
*/
if (volume->ioblock + 1 >= volume->nblocks &&
volume->iooffset + 1 >= volume->geo.blocksize)
{
/* Yes.. the FLASH is full. Force the offsets to the end of FLASH */
volume->froffset = volume->nblocks * volume->geo.blocksize;
fvdbg("Assume no free FLASH, froffset: %d\n", volume->froffset);
if (noinodes)
{
volume->inoffset = volume->froffset;
fvdbg("No inodes, inoffset: %d\n", volume->inoffset);
}
return OK;
}
// No? Then it is some other failure that we do not know how to handle
fdbg("nxffs_getc failed: %d\n", -ch);
return ch;
}
/* Check for another erased byte */
else if (ch == CONFIG_NXFFS_ERASEDSTATE)
{
/* If we have encountered NXFFS_NERASED number of consecutive
* erased bytes, then presume we have reached the end of valid
* data.
*/
if (++nerased >= NXFFS_NERASED)
{
/* Okay.. we have a long stretch of erased FLASH in a valid
* FLASH block. Let's say that this is the beginning of
* the free FLASH region.
*/
volume->froffset = offset;
fvdbg("Free FLASH region begins at offset: %d\n", volume->froffset);
if (noinodes)
{
volume->inoffset = offset;
fvdbg("First inode at offset %d\n", volume->inoffset);
}
return OK;
}
}
else
{
offset += nerased + 1;
nerased = 0;
}
}
/* Won't get here */
return OK;
}
/****************************************************************************
* Name: nxffs_bind
*
* Description:
* This function implements a portion of the mount operation. Normmally,
* the bind() method allocates and initializes the mountpoint private data
* then binds the blockdriver inode to the filesystem private data. The
* final binding of the private data (containing the blockdriver) to the
* mountpoint is performed by mount().
*
* For the NXFFS, this sequence is quite different for the following
* reasons:
*
* 1. A block driver is not used. Instead, an MTD instance was provided
* to nxfs_initialize prior to mounting. So, in this sense, the NXFFS
* file system is already bound.
*
* 2. Since the volume was already bound to the MTD driver, all allocations
* and initializations have already been performed. Essentially, all
* mount operations have been bypassed and now we just need to provide
* the pre-allocated volume instance.
*
* 3. The tricky thing is that there is no mechanism to associate multiple
* NXFFS volumes to the multiple volumes bound to different MTD drivers.
* Hence, the limitation of a single NXFFS volume.
*
****************************************************************************/
int nxffs_bind(FAR struct inode *blkdriver, FAR const void *data,
FAR void **handle)
{
#ifndef CONFIG_NXFSS_PREALLOCATED
# error "No design to support dynamic allocation of volumes"
#else
/* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
* allocated NXFFS volume instance.
*/
DEBUGASSERT(g_volume.cache);
*handle = &g_volume;
#endif
return OK;
}
/****************************************************************************
* Name: nxffs_unbind
*
* Description: This implements the filesystem portion of the umount
* operation.
*
****************************************************************************/
int nxffs_unbind(FAR void *handle, FAR struct inode **blkdriver)
{
#ifndef CONFIG_NXFSS_PREALLOCATED
# error "No design to support dynamic allocation of volumes"
#else
return g_volume.ofiles ? -EBUSY : OK;
#endif
}
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