diff options
Diffstat (limited to 'fs/befs/datastream.c')
| -rw-r--r-- | fs/befs/datastream.c | 253 |
1 files changed, 125 insertions, 128 deletions
diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c index af1bc19b7c85..b4c7ba013c0d 100644 --- a/fs/befs/datastream.c +++ b/fs/befs/datastream.c @@ -22,22 +22,22 @@ const befs_inode_addr BAD_IADDR = { 0, 0, 0 }; static int befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data, - befs_blocknr_t blockno, befs_block_run * run); + befs_blocknr_t blockno, befs_block_run *run); static int befs_find_brun_indirect(struct super_block *sb, const befs_data_stream *data, befs_blocknr_t blockno, - befs_block_run * run); + befs_block_run *run); static int befs_find_brun_dblindirect(struct super_block *sb, const befs_data_stream *data, befs_blocknr_t blockno, - befs_block_run * run); + befs_block_run *run); /** * befs_read_datastream - get buffer_head containing data, starting from pos. * @sb: Filesystem superblock - * @ds: datastrem to find data with + * @ds: datastream to find data with * @pos: start of data * @off: offset of data in buffer_head->b_data * @@ -46,7 +46,7 @@ static int befs_find_brun_dblindirect(struct super_block *sb, */ struct buffer_head * befs_read_datastream(struct super_block *sb, const befs_data_stream *ds, - befs_off_t pos, uint * off) + befs_off_t pos, uint *off) { struct buffer_head *bh; befs_block_run run; @@ -75,7 +75,13 @@ befs_read_datastream(struct super_block *sb, const befs_data_stream *ds, return bh; } -/* +/** + * befs_fblock2brun - give back block run for fblock + * @sb: the superblock + * @data: datastream to read from + * @fblock: the blocknumber with the file position to find + * @run: The found run is passed back through this pointer + * * Takes a file position and gives back a brun who's starting block * is block number fblock of the file. * @@ -88,7 +94,7 @@ befs_read_datastream(struct super_block *sb, const befs_data_stream *ds, */ int befs_fblock2brun(struct super_block *sb, const befs_data_stream *data, - befs_blocknr_t fblock, befs_block_run * run) + befs_blocknr_t fblock, befs_block_run *run) { int err; befs_off_t pos = fblock << BEFS_SB(sb)->block_shift; @@ -115,7 +121,7 @@ befs_fblock2brun(struct super_block *sb, const befs_data_stream *data, /** * befs_read_lsmylink - read long symlink from datastream. * @sb: Filesystem superblock - * @ds: Datastrem to read from + * @ds: Datastream to read from * @buff: Buffer in which to place long symlink data * @len: Length of the long symlink in bytes * @@ -128,6 +134,7 @@ befs_read_lsymlink(struct super_block *sb, const befs_data_stream *ds, befs_off_t bytes_read = 0; /* bytes readed */ u16 plen; struct buffer_head *bh; + befs_debug(sb, "---> %s length: %llu", __func__, len); while (bytes_read < len) { @@ -183,13 +190,13 @@ befs_count_blocks(struct super_block *sb, const befs_data_stream *ds) metablocks += ds->indirect.len; /* - Double indir block, plus all the indirect blocks it mapps - In the double-indirect range, all block runs of data are - BEFS_DBLINDIR_BRUN_LEN blocks long. Therefore, we know - how many data block runs are in the double-indirect region, - and from that we know how many indirect blocks it takes to - map them. We assume that the indirect blocks are also - BEFS_DBLINDIR_BRUN_LEN blocks long. + * Double indir block, plus all the indirect blocks it maps. + * In the double-indirect range, all block runs of data are + * BEFS_DBLINDIR_BRUN_LEN blocks long. Therefore, we know + * how many data block runs are in the double-indirect region, + * and from that we know how many indirect blocks it takes to + * map them. We assume that the indirect blocks are also + * BEFS_DBLINDIR_BRUN_LEN blocks long. */ if (ds->size > ds->max_indirect_range && ds->max_indirect_range != 0) { uint dbl_bytes; @@ -212,58 +219,50 @@ befs_count_blocks(struct super_block *sb, const befs_data_stream *ds) return blocks; } -/* - Finds the block run that starts at file block number blockno - in the file represented by the datastream data, if that - blockno is in the direct region of the datastream. - - sb: the superblock - data: the datastream - blockno: the blocknumber to find - run: The found run is passed back through this pointer - - Return value is BEFS_OK if the blockrun is found, BEFS_ERR - otherwise. - - Algorithm: - Linear search. Checks each element of array[] to see if it - contains the blockno-th filesystem block. This is necessary - because the block runs map variable amounts of data. Simply - keeps a count of the number of blocks searched so far (sum), - incrementing this by the length of each block run as we come - across it. Adds sum to *count before returning (this is so - you can search multiple arrays that are logicaly one array, - as in the indirect region code). - - When/if blockno is found, if blockno is inside of a block - run as stored on disk, we offset the start and length members - of the block run, so that blockno is the start and len is - still valid (the run ends in the same place). - - 2001-11-15 Will Dyson -*/ +/** + * befs_find_brun_direct - find a direct block run in the datastream + * @sb: the superblock + * @data: the datastream + * @blockno: the blocknumber to find + * @run: The found run is passed back through this pointer + * + * Finds the block run that starts at file block number blockno + * in the file represented by the datastream data, if that + * blockno is in the direct region of the datastream. + * + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR + * otherwise. + * + * Algorithm: + * Linear search. Checks each element of array[] to see if it + * contains the blockno-th filesystem block. This is necessary + * because the block runs map variable amounts of data. Simply + * keeps a count of the number of blocks searched so far (sum), + * incrementing this by the length of each block run as we come + * across it. Adds sum to *count before returning (this is so + * you can search multiple arrays that are logicaly one array, + * as in the indirect region code). + * + * When/if blockno is found, if blockno is inside of a block + * run as stored on disk, we offset the start and length members + * of the block run, so that blockno is the start and len is + * still valid (the run ends in the same place). + */ static int befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data, - befs_blocknr_t blockno, befs_block_run * run) + befs_blocknr_t blockno, befs_block_run *run) { int i; const befs_block_run *array = data->direct; befs_blocknr_t sum; - befs_blocknr_t max_block = - data->max_direct_range >> BEFS_SB(sb)->block_shift; befs_debug(sb, "---> %s, find %lu", __func__, (unsigned long)blockno); - if (blockno > max_block) { - befs_error(sb, "%s passed block outside of direct region", - __func__); - return BEFS_ERR; - } - for (i = 0, sum = 0; i < BEFS_NUM_DIRECT_BLOCKS; sum += array[i].len, i++) { if (blockno >= sum && blockno < sum + (array[i].len)) { int offset = blockno - sum; + run->allocation_group = array[i].allocation_group; run->start = array[i].start + offset; run->len = array[i].len - offset; @@ -275,38 +274,39 @@ befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data, } } + befs_error(sb, "%s failed to find file block %lu", __func__, + (unsigned long)blockno); befs_debug(sb, "---> %s ERROR", __func__); return BEFS_ERR; } -/* - Finds the block run that starts at file block number blockno - in the file represented by the datastream data, if that - blockno is in the indirect region of the datastream. - - sb: the superblock - data: the datastream - blockno: the blocknumber to find - run: The found run is passed back through this pointer - - Return value is BEFS_OK if the blockrun is found, BEFS_ERR - otherwise. - - Algorithm: - For each block in the indirect run of the datastream, read - it in and search through it for search_blk. - - XXX: - Really should check to make sure blockno is inside indirect - region. - - 2001-11-15 Will Dyson -*/ +/** + * befs_find_brun_indirect - find a block run in the datastream + * @sb: the superblock + * @data: the datastream + * @blockno: the blocknumber to find + * @run: The found run is passed back through this pointer + * + * Finds the block run that starts at file block number blockno + * in the file represented by the datastream data, if that + * blockno is in the indirect region of the datastream. + * + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR + * otherwise. + * + * Algorithm: + * For each block in the indirect run of the datastream, read + * it in and search through it for search_blk. + * + * XXX: + * Really should check to make sure blockno is inside indirect + * region. + */ static int befs_find_brun_indirect(struct super_block *sb, const befs_data_stream *data, befs_blocknr_t blockno, - befs_block_run * run) + befs_block_run *run) { int i, j; befs_blocknr_t sum = 0; @@ -326,11 +326,12 @@ befs_find_brun_indirect(struct super_block *sb, /* Examine blocks of the indirect run one at a time */ for (i = 0; i < indirect.len; i++) { - indirblock = befs_bread(sb, indirblockno + i); + indirblock = sb_bread(sb, indirblockno + i); if (indirblock == NULL) { - befs_debug(sb, "---> %s failed to read " + befs_error(sb, "---> %s failed to read " "disk block %lu from the indirect brun", __func__, (unsigned long)indirblockno + i); + befs_debug(sb, "<--- %s ERROR", __func__); return BEFS_ERR; } @@ -370,52 +371,51 @@ befs_find_brun_indirect(struct super_block *sb, return BEFS_ERR; } -/* - Finds the block run that starts at file block number blockno - in the file represented by the datastream data, if that - blockno is in the double-indirect region of the datastream. - - sb: the superblock - data: the datastream - blockno: the blocknumber to find - run: The found run is passed back through this pointer - - Return value is BEFS_OK if the blockrun is found, BEFS_ERR - otherwise. - - Algorithm: - The block runs in the double-indirect region are different. - They are always allocated 4 fs blocks at a time, so each - block run maps a constant amount of file data. This means - that we can directly calculate how many block runs into the - double-indirect region we need to go to get to the one that - maps a particular filesystem block. - - We do this in two stages. First we calculate which of the - inode addresses in the double-indirect block will point us - to the indirect block that contains the mapping for the data, - then we calculate which of the inode addresses in that - indirect block maps the data block we are after. - - Oh, and once we've done that, we actually read in the blocks - that contain the inode addresses we calculated above. Even - though the double-indirect run may be several blocks long, - we can calculate which of those blocks will contain the index - we are after and only read that one. We then follow it to - the indirect block and perform a similar process to find - the actual block run that maps the data block we are interested - in. - - Then we offset the run as in befs_find_brun_array() and we are - done. - - 2001-11-15 Will Dyson -*/ +/** + * befs_find_brun_dblindirect - find a block run in the datastream + * @sb: the superblock + * @data: the datastream + * @blockno: the blocknumber to find + * @run: The found run is passed back through this pointer + * + * Finds the block run that starts at file block number blockno + * in the file represented by the datastream data, if that + * blockno is in the double-indirect region of the datastream. + * + * Return value is BEFS_OK if the blockrun is found, BEFS_ERR + * otherwise. + * + * Algorithm: + * The block runs in the double-indirect region are different. + * They are always allocated 4 fs blocks at a time, so each + * block run maps a constant amount of file data. This means + * that we can directly calculate how many block runs into the + * double-indirect region we need to go to get to the one that + * maps a particular filesystem block. + * + * We do this in two stages. First we calculate which of the + * inode addresses in the double-indirect block will point us + * to the indirect block that contains the mapping for the data, + * then we calculate which of the inode addresses in that + * indirect block maps the data block we are after. + * + * Oh, and once we've done that, we actually read in the blocks + * that contain the inode addresses we calculated above. Even + * though the double-indirect run may be several blocks long, + * we can calculate which of those blocks will contain the index + * we are after and only read that one. We then follow it to + * the indirect block and perform a similar process to find + * the actual block run that maps the data block we are interested + * in. + * + * Then we offset the run as in befs_find_brun_array() and we are + * done. + */ static int befs_find_brun_dblindirect(struct super_block *sb, const befs_data_stream *data, befs_blocknr_t blockno, - befs_block_run * run) + befs_block_run *run) { int dblindir_indx; int indir_indx; @@ -430,10 +430,9 @@ befs_find_brun_dblindirect(struct super_block *sb, struct buffer_head *indir_block; befs_block_run indir_run; befs_disk_inode_addr *iaddr_array; - struct befs_sb_info *befs_sb = BEFS_SB(sb); befs_blocknr_t indir_start_blk = - data->max_indirect_range >> befs_sb->block_shift; + data->max_indirect_range >> BEFS_SB(sb)->block_shift; off_t dbl_indir_off = blockno - indir_start_blk; @@ -471,7 +470,7 @@ befs_find_brun_dblindirect(struct super_block *sb, } dbl_indir_block = - befs_bread(sb, iaddr2blockno(sb, &data->double_indirect) + + sb_bread(sb, iaddr2blockno(sb, &data->double_indirect) + dbl_which_block); if (dbl_indir_block == NULL) { befs_error(sb, "%s couldn't read the " @@ -479,7 +478,6 @@ befs_find_brun_dblindirect(struct super_block *sb, (unsigned long) iaddr2blockno(sb, &data->double_indirect) + dbl_which_block); - brelse(dbl_indir_block); return BEFS_ERR; } @@ -499,12 +497,11 @@ befs_find_brun_dblindirect(struct super_block *sb, } indir_block = - befs_bread(sb, iaddr2blockno(sb, &indir_run) + which_block); + sb_bread(sb, iaddr2blockno(sb, &indir_run) + which_block); if (indir_block == NULL) { befs_error(sb, "%s couldn't read the indirect block " "at blockno %lu", __func__, (unsigned long) iaddr2blockno(sb, &indir_run) + which_block); - brelse(indir_block); return BEFS_ERR; } |