diff options
Diffstat (limited to 'nuttx/fs/nxffs/nxffs_pack.c')
| -rw-r--r-- | nuttx/fs/nxffs/nxffs_pack.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/nuttx/fs/nxffs/nxffs_pack.c b/nuttx/fs/nxffs/nxffs_pack.c index 476c5972b..b44a15736 100644 --- a/nuttx/fs/nxffs/nxffs_pack.c +++ b/nuttx/fs/nxffs/nxffs_pack.c @@ -41,7 +41,10 @@ #include <nuttx/config.h> +#include <string.h> #include <errno.h> +#include <assert.h> +#include <debug.h> #include "nxffs.h" @@ -52,6 +55,24 @@ /**************************************************************************** * Public Types ****************************************************************************/ +/* This structure supports access to one inode data stream */ + +struct nxffs_packstream_s +{ + struct nxffs_entry_s entry; /* Described the inode header */ + off_t fpos; /* Current file position */ + off_t blkoffset; /* Offset to the current data block */ + uint16_t blklen; /* Size of this block */ + uint16_t blkpos; /* Position in block corresponding to fpos */ +}; + +/* The structure supports the overall packing operation */ + +struct nxffs_pack_s +{ + struct nxffs_packstream_s src; /* Describes the src stream */ + struct nxffs_packstream_s dest; /* Describes the destination stream */ +}; /**************************************************************************** * Public Variables @@ -62,6 +83,140 @@ ****************************************************************************/ /**************************************************************************** + * Name: nxffs_startblock + * + * Description: + * Find the position in FLASH memory where we should begin packing. That + * position is the place where there is a gap between the last and the next + * valid inode. + * + * Input Parameters: + * volume - The volume to be packed. + * + * Returned Values: + * Zero on success; Otherwise, a negated errno value is returned to + * indicate the nature of the failure. + * + ****************************************************************************/ + +static int nxffs_startblock(FAR struct nxffs_volume_s *volume, + FAR struct nxffs_pack_s *pack) +{ + struct nxffs_blkentry_s blkentry; + off_t wasted; + off_t offset; + off_t nbytes; + int ret; + + memset(pack, 0, sizeof(struct nxffs_pack_s)); + + /* Find the FLASH offset to the first valid block */ + + volume->ioblock = 0; + ret = nxffs_validblock(volume, &volume->ioblock); + if (ret < 0) + { + /* No valid blocks? */ + + return nxffs_reformat(volume); + } + + volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; + offset = nxffs_iotell(volume); + + /* Loop until we find a gap of unused FLASH large enough to warrant the + * compression. + */ + + for(;;) + { + /* Get the offset to the first valid inode entry */ + + ret = nxffs_nextentry(volume, offset, &pack->src.entry); + if (ret < 0) + { + /* No valid entries -- reformat the flash */ + + return nxffs_reformat(volume); + } + + /* Is there wasted space between the offset where the we could have + * valid data and the offset to the beginning of the first valid + * inode header? NOTE: The threshold check is not accurate, there + * may or may not be intervening block headers making the separation + * seem larger than it is. + */ + + DEBUGASSERT(pack->src.entry.hoffset >= offset); + wasted = pack->src.entry.hoffset - offset; + if (wasted > CONFIG_NXFFS_PACKTHRESHOLD) + { + /* This is where we must begin packing */ + + memcpy(&pack->dest.entry, &pack->src.entry, sizeof(struct nxffs_entry_s)); + + pack->dest.entry.hoffset = offset; + pack->src.entry.name = NULL; + return OK; + } + + /* Free the allocated memory in the entry */ + + nxffs_freeentry(&pack->src.entry); + + /* Update the offset to the first byte at the end of the last data + * block. + */ + + nbytes = 0; + offset = pack->src.entry.doffset; + + while (nbytes < pack->src.entry.datlen) + { + /* Read the next data block header */ + + ret = nxffs_nextblock(volume, offset, &blkentry); + if (ret < 0) + { + fdbg("Failed to find next data block: %d\n", -ret); + return ret; + } + + /* Get the number of blocks and pointer to where the next + * data block might lie. + */ + + nbytes += blkentry.datlen; + offset = blkentry.hoffset + SIZEOF_NXFFS_DATA_HDR + blkentry.datlen; + } + + /* Make sure there is space at this location for an inode header */ + + nxffs_ioseek(volume, offset); + if (volume->iooffset + SIZEOF_NXFFS_INODE_HDR > volume->geo.blocksize) + { + /* Find the next valid block */ + + volume->ioblock++; + ret = nxffs_validblock(volume, &volume->ioblock); + if (ret < 0) + { + /* No valid blocks? Then there is nothing we can do */ + + return -ENOSPC; + } + + volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; + offset = nxffs_iotell(volume); + } + } + + /* We won't get here */ + + return -ENOSYS; +} + +/**************************************************************************** * Public Functions ****************************************************************************/ @@ -83,6 +238,29 @@ int nxffs_pack(FAR struct nxffs_volume_s *volume) { + struct nxffs_pack_s pack; + int ret; + + /* Get the offset to the first valid inode entry */ + + ret = nxffs_startblock(volume, &pack); + if (ret < 0) + { + fdbg("Failed to find a start block: %d\n", -ret); + return ret; + } + + /* A special case is where the entire FLASH needs to be reformatted. In + * this case, the source and destination offsets will both be zero. + */ + + if (pack.src.entry.hoffset == 0 && pack.dest.entry.hoffset == 0) + { + return OK; + } + + /* Otherwise, begin pack at this src/dest block combination */ + # warning "Missing logic" return -ENOSYS; } |