/**************************************************************************** * fs/nxffs/nxffs_write.c * * Copyright (C) 2011 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include "nxffs.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* When we allocate FLASH for a new inode data block, we will require that * space is available to hold this minimum number of data bytes in addition * to the size of the data block headeer. */ #define NXFFS_MINDATA 16 /**************************************************************************** * Public Types ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Public Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: nxffs_hdrpos * * Description: * Find a valid location for the data block header. A valid location will * have these properties: * * 1. It will lie in the free flash region. * 2. It will have enough contiguous memory to hold the entire header * PLUS some meaningful amount of data (NXFFS_MINDATA). * 3. The memory at this location will be fully erased. * * This function will only perform the checks of 1) and 2). * * Input Parameters: * volume - Describes the NXFFS volume * wrfile - Contains the current guess for the header position. On * successful return, this field will hold the selected header * position. * size - The minimum size of the current write. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. Of special interest * the return error of -ENOSPC which means that the FLASH volume is * full and should be repacked. * * On successful return the following are also valid: * * wrfile->doffset - Flash offset to candidate header position * volume->ioblock - Read/write block number of the block containing the * header position * volume->iooffset - The offset in the block to the candidate header * position. * volume->froffset - Updated offset to the first free FLASH block. * ****************************************************************************/ static inline int nxffs_hdrpos(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile, size_t size) { int ret; /* Reserve memory for the object */ ret = nxffs_wrreserve(volume, SIZEOF_NXFFS_DATA_HDR + size); if (ret == OK) { /* Save the offset to the FLASH region reserved for the inode header */ wrfile->doffset = nxffs_iotell(volume); } return OK; } /**************************************************************************** * Name: nxffs_hdrerased * * Description: * Find a valid location for the data block header. A valid location will * have these properties: * * 1. It will lie in the free flash region. * 2. It will have enough contiguous memory to hold the entire header * PLUS some meaningful amount of data (NXFFS_MINDATA). * 3. The memory at this location will be fully erased. * * This function will only perform the check 3). On entry it assumes: * * volume->ioblock - Read/write block number of the block containing the * header position * volume->iooffset - The offset in the block to the candidate header * position. * * Input Parameters: * volume - Describes the NXFFS volume * wrfile - Contains the current guess for the header position. On * successful return, this field will hold the selected header * position. * size - The minimum size of the current write. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. Of special interest * the return error of -ENOSPC which means that the FLASH volume is * full and should be repacked. * * On successful return the following are also valid: * * wrfile->doffset - Flash offset to candidate header position * volume->ioblock - Read/write block number of the block containing the * header position * volume->iooffset - The offset in the block to the candidate header * position. * volume->froffset - Updated offset to the first free FLASH block. * ****************************************************************************/ static inline int nxffs_hdrerased(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile, size_t size) { int ret; /* Find a valid location to save the inode header */ ret = nxffs_wrverify(volume, SIZEOF_NXFFS_DATA_HDR + size); if (ret == OK) { /* This is where we will put the header */ wrfile->doffset = nxffs_iotell(volume); } return ret; } /**************************************************************************** * Name: nxffs_wralloc * * Description: * Allocate FLASH memory for the data block. * * Input Parameters: * volume - Describes the NXFFS volume * wrfile - Describes the open file to be written. * size - Size of the current write operation. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. * ****************************************************************************/ static inline int nxffs_wralloc(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile, size_t size) { bool packed; int ret; /* Allocate FLASH memory for the data block. * * Loop until the data block header is configured or until a failure * occurs. Note that nothing is written to FLASH. The data block header * is not written until either (1) the file is closed, or (2) the data * region is fully populated. */ packed = false; for (;;) { size_t mindata = MIN(NXFFS_MINDATA, size); /* File a valid location to position the data block. Start with * the first byte in the free FLASH region. */ ret = nxffs_hdrpos(volume, wrfile, mindata); if (ret == OK) { /* Find a region of memory in the block that is fully erased */ ret = nxffs_hdrerased(volume, wrfile, mindata); if (ret == OK) { /* Valid memory for the data block was found. Return success. */ return OK; } } /* If no valid memory is found searching to the end of the volume, * then -ENOSPC will be returned. Other errors are not handled. */ if (ret != -ENOSPC || packed) { fdbg("Failed to find inode header memory: %d\n", -ret); return -ENOSPC; } /* -ENOSPC is a special case.. It means that the volume is full. * Try to pack the volume in order to free up some space. */ ret = nxffs_pack(volume); if (ret < 0) { fdbg("Failed to pack the volume: %d\n", -ret); return ret; } /* After packing the volume, froffset will be updated to point to the * new free flash region. Try again. */ packed = true; } /* Can't get here */ return OK; } /**************************************************************************** * Name: nxffs_reverify * * Description: * Verify that the partial flash data block in the volume cache is valid. * On entry, this function assumes: * * volume->ioblock - Read/write block number of the block containing the * data block. * volume->iooffset - The offset in the block to the data block. * * Input Parameters: * volume - Describes the NXFFS volume * wrfile - Describes the open file to be written. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. * ****************************************************************************/ static inline int nxffs_reverify(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile) { uint32_t crc; off_t offset; if (wrfile->datlen > 0) { /* Get the offset to the start of the data */ offset = volume->iooffset + SIZEOF_NXFFS_DATA_HDR; DEBUGASSERT(offset + wrfile->datlen < volume->geo.blocksize); /* Calculate the CRC of the partial data block */ crc = crc32(&volume->cache[offset], wrfile->datlen); /* It must match the previoulsy calculated CRC value */ if (crc != wrfile->crc) { fdbg("CRC failure\n"); return -EIO; } } return OK; } /**************************************************************************** * Name: nxffs_wrappend * * Description: * Append FLASH data to the data block. * * Input Parameters: * volume - Describes the NXFFS volume * wrfile - Describes the open file to be written. * buffer - Address of buffer of data to be written. * buflen - The number of bytes remaimining to be written * * Returned Value: * The number of bytes written is returned on success. Otherwise, a * negated errno value is returned indicating the nature of the failure. * ****************************************************************************/ static inline ssize_t nxffs_wrappend(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile, FAR const char *buffer, size_t buflen) { ssize_t maxsize; size_t nbytestowrite; ssize_t nbytesleft; off_t offset; int ret; /* Get the offset to the start of unwritten data */ offset = volume->iooffset + wrfile->datlen + SIZEOF_NXFFS_DATA_HDR; /* Determine that maximum amount of data that can be written to this * block. */ maxsize = volume->geo.blocksize - offset; DEBUGASSERT(maxsize > 0); /* But don't try to write over any unerased bytes */ maxsize = nxffs_erased(&volume->cache[offset], maxsize); /* Write as many bytes as we can into the data buffer */ nbytestowrite = MIN(maxsize, buflen); nbytesleft = maxsize - nbytestowrite; if (nbytestowrite > 0) { /* Copy the data into the volume write cache */ memcpy(&volume->cache[offset], buffer, nbytestowrite); /* Increment the number of bytes written to the data block */ wrfile->datlen += nbytestowrite; /* Re-calculate the CRC */ offset = volume->iooffset + SIZEOF_NXFFS_DATA_HDR; wrfile->crc = crc32(&volume->cache[offset], wrfile->datlen); /* And write the partial write block to FLASH -- unless the data * block is full. In that case, the block will be written below. */ if (nbytesleft > 0) { ret = nxffs_wrcache(volume); if (ret < 0) { fdbg("nxffs_wrcache failed: %d\n", -ret); return ret; } } } /* Check if the data block is now full */ if (nbytesleft <= 0) { /* The data block is full, write the block to FLASH */ ret = nxffs_wrblkhdr(volume, wrfile); if (ret < 0) { fdbg("nxffs_wrblkdhr failed: %d\n", -ret); return ret; } } /* Return the number of bytes written to FLASH this time */ return nbytestowrite; } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: nxffs_write * * Description: * This is an implementation of the NuttX standard file system write * method. * ****************************************************************************/ ssize_t nxffs_write(FAR struct file *filep, FAR const char *buffer, size_t buflen) { FAR struct nxffs_volume_s *volume; FAR struct nxffs_wrfile_s *wrfile; ssize_t remaining; ssize_t nwritten; ssize_t total; int ret; fvdbg("Write %d bytes to offset %d\n", buflen, filep->f_pos); /* Sanity checks */ DEBUGASSERT(filep->f_priv != NULL && filep->f_inode != NULL); /* Recover the open file state from the struct file instance */ wrfile = (FAR struct nxffs_wrfile_s *)filep->f_priv; /* Recover the volume state from the open file */ volume = (FAR struct nxffs_volume_s *)filep->f_inode->i_private; DEBUGASSERT(volume != NULL); /* Get exclusive access to the volume. Note that the volume exclsem * protects the open file list. */ ret = sem_wait(&volume->exclsem); if (ret != OK) { ret = -errno; fdbg("sem_wait failed: %d\n", ret); goto errout; } /* Check if the file was opened with write access */ if ((wrfile->ofile.mode & O_WROK) == 0) { fdbg("File not open for write access\n"); ret = -EACCES; goto errout_with_semaphore; } /* Loop until we successfully appended all of the data to the file (or an * error occurs) */ for (total = 0; total < buflen; ) { remaining = buflen- total; /* Have we already allocated the data block? */ if (wrfile->doffset == 0) { /* No, allocate the data block now */ wrfile->datlen = 0; ret = nxffs_wralloc(volume, wrfile, remaining); if (ret < 0) { fdbg("Failed to allocate a data block: %d\n", -ret); goto errout_with_semaphore; } } /* Seek to the FLASH block containing the data block */ nxffs_ioseek(volume, wrfile->doffset); /* Verify that the FLASH data that was previously written is still intact */ ret = nxffs_reverify(volume, wrfile); if (ret < 0) { fdbg("Failed to verify FLASH data block: %d\n", -ret); goto errout_with_semaphore; } /* Append the data to the end of the data block and write the updated * block to flash. */ nwritten = nxffs_wrappend(volume, wrfile, &buffer[total], remaining); if (nwritten < 0) { fdbg("Failed to append to FLASH to a data block: %d\n", -ret); goto errout_with_semaphore; } /* Decrement the number of bytes remaining to be written */ total += nwritten; } /* Success.. return the number of bytes written */ ret = total; filep->f_pos = wrfile->datlen; errout_with_semaphore: sem_post(&volume->exclsem); errout: return ret; } /**************************************************************************** * Name: nxffs_wrreserve * * Description: * Find a valid location for a file system object of 'size'. A valid * location will have these properties: * * 1. It will lie in the free flash region. * 2. It will have enough contiguous memory to hold the entire object * 3. The memory at this location will be fully erased. * * This function will only perform the checks of 1) and 2). The * end-of-filesystem offset, froffset, is update past this memory which, * in effect, reserves the memory. * * Input Parameters: * volume - Describes the NXFFS volume * size - The size of the object to be reserved. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. Of special interest * the return error of -ENOSPC which means that the FLASH volume is * full and should be repacked. * * On successful return the following are also valid: * * volume->ioblock - Read/write block number of the block containing the * candidate oject position * volume->iooffset - The offset in the block to the candidate object * position. * volume->froffset - Updated offset to the first free FLASH block after * the reserved memory. * ****************************************************************************/ int nxffs_wrreserve(FAR struct nxffs_volume_s *volume, size_t size) { int ret; /* Seek to the beginning of the free FLASH region */ nxffs_ioseek(volume, volume->froffset); /* Check for a seek past the end of the volume */ if (volume->ioblock >= volume->nblocks) { /* Return -ENOSPC to indicate that the volume is full */ return -ENOSPC; } /* Skip over block headers */ if (volume->iooffset < SIZEOF_NXFFS_BLOCK_HDR) { volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; } /* Make sure that there is space there to hold the entire object */ if (volume->iooffset + size > volume->geo.blocksize) { /* We will need to skip to the next block. But first, check if we are * already at the final block. */ if (volume->ioblock + 1 >= volume->geo.neraseblocks) { /* Return -ENOSPC to indicate that the volume is full */ fdbg("No space in last block\n"); return -ENOSPC; } /* This is not the last block in the volume, so just seek to the * beginning of the next, valid block. */ volume->ioblock++; ret = nxffs_validblock(volume, &volume->ioblock); if (ret < 0) { fdbg("No more valid blocks\n"); return ret; } volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; } /* Update the pointer to the first next free FLASH memory -- reserving this * block of memory. */ volume->froffset = nxffs_iotell(volume) + size; return OK; } /**************************************************************************** * Name: nxffs_wrverify * * Description: * Find a valid location for the object. A valid location will have * these properties: * * 1. It will lie in the free flash region. * 2. It will have enough contiguous memory to hold the entire header * (excluding the file name which may lie in the next block). * 3. The memory at this location will be fully erased. * * This function will only perform the check 3). On entry it assumes the * following settings (left by nxffs_wrreserve()): * * volume->ioblock - Read/write block number of the block containing the * candidate oject position * volume->iooffset - The offset in the block to the candidate object * position. * * Input Parameters: * volume - Describes the NXFFS volume * size - The size of the object to be verifed. * * Returned Value: * Zero is returned on success. Otherwise, a negated errno value is * returned indicating the nature of the failure. Of special interest * the return error of -ENOSPC which means that the FLASH volume is * full and should be repacked. * * On successful return the following are also valid: * * volume->ioblock - Read/write block number of the block containing the * verified object position * volume->iooffset - The offset in the block to the verified object * position. * volume->froffset - Updated offset to the first free FLASH block. * ****************************************************************************/ int nxffs_wrverify(FAR struct nxffs_volume_s *volume, size_t size) { uint16_t iooffset; int nerased; int ret; int i; /* Search to the very last block in the volume if we have to */ while (volume->ioblock < volume->nblocks) { /* Make sure that the block is in memory */ ret = nxffs_rdcache(volume, volume->ioblock, 1); if (ret < 0) { fdbg("nxffsx_rdcache failed: %d\n", -ret); return ret; } /* Search to the very end of this block if we have to */ iooffset = volume->iooffset; nerased = 0; for (i = volume->iooffset; i <= volume->geo.blocksize - size; i++) { /* Is this byte erased? */ if (volume->cache[i] == CONFIG_NXFFS_ERASEDSTATE) { /* Yes.. increment the count of contiguous, erased bytes */ nerased++; /* Is the whole header memory erased? */ if (nerased >= size) { /* Yes.. this this is where we will put the object */ off_t offset = volume->ioblock * volume->geo.blocksize + iooffset; /* Update the free flash offset and return success */ volume->froffset = offset + size; return OK; } } /* This byte is not erased! (It should be unless the block is bad) */ else { nerased = 0; iooffset = volume->iooffset + 1; } } /* If we get here, then we have looked at every byte in the the block * and did not find any sequence of erased bytes long enough to hold * the object. Skip to the next, valid block. */ volume->ioblock++; ret = nxffs_validblock(volume, &volume->ioblock); if (ret < 0) { fdbg("No more valid blocks\n"); return ret; } volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; volume->froffset = volume->ioblock * volume->geo.blocksize + SIZEOF_NXFFS_BLOCK_HDR; } /* Return -ENOSPC if there is no erased memory left in the volume for * the object. */ fdbg("Not enough memory left to hold the file header\n"); return -ENOSPC; } /**************************************************************************** * Name: nxffs_wrblkhdr * * Description: * Write the block header information. This is done (1) whenever the end- * block is encountered and (2) also when the file is closed in order to * flush the final block of data to FLASH. * * Input Parameters: * volume - Describes the state of the NXFFS volume * wrfile - Describes the state of the open file * * Returned Value: * Zero is returned on success; Otherwise, a negated errno value is * returned to indicate the nature of the failure. * ****************************************************************************/ int nxffs_wrblkhdr(FAR struct nxffs_volume_s *volume, FAR struct nxffs_wrfile_s *wrfile) { FAR struct nxffs_data_s *dathdr; int ret; /* Write the dat block header to memory */ nxffs_ioseek(volume, wrfile->doffset); dathdr = (FAR struct nxffs_data_s *)&volume->cache[volume->iooffset]; memcpy(dathdr->magic, g_datamagic, NXFFS_MAGICSIZE); nxffs_wrle32(dathdr->crc, 0); nxffs_wrle16(dathdr->datlen, wrfile->datlen); /* Update the entire data block CRC (including the header) */ wrfile->crc = crc32(&volume->cache[volume->iooffset], wrfile->datlen + SIZEOF_NXFFS_DATA_HDR); nxffs_wrle32(dathdr->crc, wrfile->crc); /* And write the data block to FLASH */ ret = nxffs_wrcache(volume); if (ret < 0) { fdbg("nxffs_wrcache failed: %d\n", -ret); goto errout; } /* After the block has been successfully written to flash, update the inode * statistics and reset the write state. * * volume: * froffset - The offset the next free FLASH region. Set to just after * the inode data block that we just wrote. This is where we will * begin the search for the next inode header or data block. */ volume->froffset = (wrfile->doffset + wrfile->datlen + SIZEOF_NXFFS_DATA_HDR); /* wrfile->file.entry: * datlen: Total file length accumulated so far. When the file is * closed, this will hold the file length. * doffset: Offset to the first data block. Only the offset to the * first data block is saved. */ wrfile->ofile.entry.datlen += wrfile->datlen; if (wrfile->ofile.entry.doffset == 0) { wrfile->ofile.entry.doffset = wrfile->doffset; } /* Return success */ ret = OK; errout: wrfile->crc = 0; wrfile->doffset = 0; wrfile->datlen = 0; return ret; }