/*
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
*/
static int
befs_find_brun_dblindirect(struct super_block *sb,
befs_data_stream * data, befs_blocknr_t blockno,
befs_block_run * run)
{
int dblindir_indx;
int indir_indx;
int offset;
int dbl_which_block;
int which_block;
int dbl_block_indx;
int block_indx;
off_t dblindir_leftover;
befs_blocknr_t blockno_at_run_start;
struct buffer_head *dbl_indir_block;
struct buffer_head *indir_block;
befs_block_run indir_run;
befs_disk_inode_addr *iaddr_array = NULL;
befs_sb_info *befs_sb = BEFS_SB(sb);
befs_blocknr_t indir_start_blk =
data->max_indirect_range >> befs_sb->block_shift;
off_t dbl_indir_off = blockno - indir_start_blk;
/* number of data blocks mapped by each of the iaddrs in
* the indirect block pointed to by the double indirect block
*/
size_t iblklen = BEFS_DBLINDIR_BRUN_LEN;
/* number of data blocks mapped by each of the iaddrs in
* the double indirect block
*/
size_t diblklen = iblklen * befs_iaddrs_per_block(sb)
* BEFS_DBLINDIR_BRUN_LEN;
befs_debug(sb, "---> befs_find_brun_dblindirect() find %lu", blockno);
/* First, discover which of the double_indir->indir blocks
* contains pos. Then figure out how much of pos that
* accounted for. Then discover which of the iaddrs in
* the indirect block contains pos.
*/
dblindir_indx = dbl_indir_off / diblklen;
dblindir_leftover = dbl_indir_off % diblklen;
indir_indx = dblindir_leftover / diblklen;
/* Read double indirect block */
dbl_which_block = dblindir_indx / befs_iaddrs_per_block(sb);
if (dbl_which_block > data->double_indirect.len) {
befs_error(sb, "The double-indirect index calculated by "
"befs_read_brun_dblindirect(), %d, is outside the range "
"of the double-indirect block", dblindir_indx);
return BEFS_ERR;
}
dbl_indir_block =
befs_bread(sb, iaddr2blockno(sb, &data->double_indirect) +
dbl_which_block);
if (dbl_indir_block == NULL) {
befs_error(sb, "befs_read_brun_dblindirect() couldn't read the "
"double-indirect block at blockno %lu",
iaddr2blockno(sb,
&data->double_indirect) +
dbl_which_block);
brelse(dbl_indir_block);
return BEFS_ERR;
}
dbl_block_indx =
dblindir_indx - (dbl_which_block * befs_iaddrs_per_block(sb));
iaddr_array = (befs_disk_inode_addr *) dbl_indir_block->b_data;
indir_run = fsrun_to_cpu(sb, iaddr_array[dbl_block_indx]);
brelse(dbl_indir_block);
iaddr_array = NULL;
/* Read indirect block */
which_block = indir_indx / befs_iaddrs_per_block(sb);
if (which_block > indir_run.len) {
befs_error(sb, "The indirect index calculated by "
"befs_read_brun_dblindirect(), %d, is outside the range "
"of the indirect block", indir_indx);
return BEFS_ERR;
}
indir_block =
befs_bread(sb, iaddr2blockno(sb, &indir_run) + which_block);
if (indir_block == NULL) {
befs_error(sb, "befs_read_brun_dblindirect() couldn't read the "
"indirect block at blockno %lu",
iaddr2blockno(sb, &indir_run) + which_block);
brelse(indir_block);
return BEFS_ERR;
}
block_indx = indir_indx - (which_block * befs_iaddrs_per_block(sb));
iaddr_array = (befs_disk_inode_addr *) indir_block->b_data;
*run = fsrun_to_cpu(sb, iaddr_array[block_indx]);
brelse(indir_block);
iaddr_array = NULL;
blockno_at_run_start = indir_start_blk;
blockno_at_run_start += diblklen * dblindir_indx;
blockno_at_run_start += iblklen * indir_indx;
offset = blockno - blockno_at_run_start;
run->start += offset;
run->len -= offset;
befs_debug(sb, "Found file block %lu in double_indirect[%d][%d],"
" double_indirect_leftover = %lu",
blockno, dblindir_indx, indir_indx, dblindir_leftover);
return BEFS_OK;
}
static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
{
struct buffer_head *bh = NULL;
befs_inode *raw_inode = NULL;
befs_sb_info *befs_sb = BEFS_SB(sb);
befs_inode_info *befs_ino = NULL;
struct inode *inode;
long ret = -EIO;
befs_debug(sb, "---> befs_read_inode() " "inode = %lu", ino);
inode = iget_locked(sb, ino);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
befs_ino = BEFS_I(inode);
/* convert from vfs's inode number to befs's inode number */
befs_ino->i_inode_num = blockno2iaddr(sb, inode->i_ino);
befs_debug(sb, " real inode number [%u, %hu, %hu]",
befs_ino->i_inode_num.allocation_group,
befs_ino->i_inode_num.start, befs_ino->i_inode_num.len);
bh = befs_bread(sb, inode->i_ino);
if (!bh) {
befs_error(sb, "unable to read inode block - "
"inode = %lu", inode->i_ino);
goto unacquire_none;
}
raw_inode = (befs_inode *) bh->b_data;
befs_dump_inode(sb, raw_inode);
if (befs_check_inode(sb, raw_inode, inode->i_ino) != BEFS_OK) {
befs_error(sb, "Bad inode: %lu", inode->i_ino);
goto unacquire_bh;
}
inode->i_mode = (umode_t) fs32_to_cpu(sb, raw_inode->mode);
/*
* set uid and gid. But since current BeOS is single user OS, so
* you can change by "uid" or "gid" options.
*/
inode->i_uid = befs_sb->mount_opts.use_uid ?
befs_sb->mount_opts.uid :
make_kuid(&init_user_ns, fs32_to_cpu(sb, raw_inode->uid));
inode->i_gid = befs_sb->mount_opts.use_gid ?
befs_sb->mount_opts.gid :
make_kgid(&init_user_ns, fs32_to_cpu(sb, raw_inode->gid));
set_nlink(inode, 1);
/*
* BEFS's time is 64 bits, but current VFS is 32 bits...
* BEFS don't have access time. Nor inode change time. VFS
* doesn't have creation time.
* Also, the lower 16 bits of the last_modified_time and
* create_time are just a counter to help ensure uniqueness
* for indexing purposes. (PFD, page 54)
*/
inode->i_mtime.tv_sec =
fs64_to_cpu(sb, raw_inode->last_modified_time) >> 16;
inode->i_mtime.tv_nsec = 0; /* lower 16 bits are not a time */
inode->i_ctime = inode->i_mtime;
inode->i_atime = inode->i_mtime;
befs_ino->i_inode_num = fsrun_to_cpu(sb, raw_inode->inode_num);
befs_ino->i_parent = fsrun_to_cpu(sb, raw_inode->parent);
befs_ino->i_attribute = fsrun_to_cpu(sb, raw_inode->attributes);
befs_ino->i_flags = fs32_to_cpu(sb, raw_inode->flags);
if (S_ISLNK(inode->i_mode) && !(befs_ino->i_flags & BEFS_LONG_SYMLINK)){
inode->i_size = 0;
inode->i_blocks = befs_sb->block_size / VFS_BLOCK_SIZE;
strncpy(befs_ino->i_data.symlink, raw_inode->data.symlink,
BEFS_SYMLINK_LEN - 1);
befs_ino->i_data.symlink[BEFS_SYMLINK_LEN - 1] = '\0';
} else {
int num_blks;
befs_ino->i_data.ds =
fsds_to_cpu(sb, &raw_inode->data.datastream);
num_blks = befs_count_blocks(sb, &befs_ino->i_data.ds);
inode->i_blocks =
num_blks * (befs_sb->block_size / VFS_BLOCK_SIZE);
inode->i_size = befs_ino->i_data.ds.size;
}
inode->i_mapping->a_ops = &befs_aops;
if (S_ISREG(inode->i_mode)) {
inode->i_fop = &generic_ro_fops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = &befs_dir_inode_operations;
inode->i_fop = &befs_dir_operations;
} else if (S_ISLNK(inode->i_mode)) {
if (befs_ino->i_flags & BEFS_LONG_SYMLINK)
inode->i_op = &befs_symlink_inode_operations;
else
inode->i_op = &befs_fast_symlink_inode_operations;
} else {
befs_error(sb, "Inode %lu is not a regular file, "
"directory or symlink. THAT IS WRONG! BeFS has no "
"on disk special files", inode->i_ino);
goto unacquire_bh;
}
brelse(bh);
befs_debug(sb, "<--- befs_read_inode()");
unlock_new_inode(inode);
return inode;
unacquire_bh:
brelse(bh);
unacquire_none:
iget_failed(inode);
befs_debug(sb, "<--- befs_read_inode() - Bad inode");
return ERR_PTR(ret);
}
/*
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
*/
static int
befs_find_brun_indirect(struct super_block *sb,
befs_data_stream * data, befs_blocknr_t blockno,
befs_block_run * run)
{
int i, j;
befs_blocknr_t sum = 0;
befs_blocknr_t indir_start_blk;
befs_blocknr_t search_blk;
struct buffer_head *indirblock;
befs_disk_block_run *array;
befs_block_run indirect = data->indirect;
befs_blocknr_t indirblockno = iaddr2blockno(sb, &indirect);
int arraylen = befs_iaddrs_per_block(sb);
befs_debug(sb, "---> befs_find_brun_indirect(), find %lu", blockno);
indir_start_blk = data->max_direct_range >> BEFS_SB(sb)->block_shift;
search_blk = blockno - indir_start_blk;
/* Examine blocks of the indirect run one at a time */
for (i = 0; i < indirect.len; i++) {
indirblock = befs_bread(sb, indirblockno + i);
if (indirblock == NULL) {
befs_debug(sb,
"---> befs_find_brun_indirect() failed to "
"read disk block %lu from the indirect brun",
indirblockno + i);
return BEFS_ERR;
}
array = (befs_disk_block_run *) indirblock->b_data;
for (j = 0; j < arraylen; ++j) {
int len = fs16_to_cpu(sb, array[j].len);
if (search_blk >= sum && search_blk < sum + len) {
int offset = search_blk - sum;
run->allocation_group =
fs32_to_cpu(sb, array[j].allocation_group);
run->start =
fs16_to_cpu(sb, array[j].start) + offset;
run->len =
fs16_to_cpu(sb, array[j].len) - offset;
brelse(indirblock);
befs_debug(sb,
"<--- befs_find_brun_indirect() found "
"file block %lu at indirect[%d]",
blockno, j + (i * arraylen));
return BEFS_OK;
}
sum += len;
}
brelse(indirblock);
}
/* Only fallthrough is an error */
befs_error(sb, "BeFS: befs_find_brun_indirect() failed to find "
"file block %lu", blockno);
befs_debug(sb, "<--- befs_find_brun_indirect() ERROR");
return BEFS_ERR;
}
