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linux-next/fs/befs/datastream.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

527 lines
16 KiB
C

/*
* linux/fs/befs/datastream.c
*
* Copyright (C) 2001 Will Dyson <will_dyson@pobox.com>
*
* Based on portions of file.c by Makoto Kato <m_kato@ga2.so-net.ne.jp>
*
* Many thanks to Dominic Giampaolo, author of "Practical File System
* Design with the Be File System", for such a helpful book.
*
*/
#include <linux/kernel.h>
#include <linux/buffer_head.h>
#include <linux/string.h>
#include "befs.h"
#include "datastream.h"
#include "io.h"
const befs_inode_addr BAD_IADDR = { 0, 0, 0 };
static int befs_find_brun_direct(struct super_block *sb,
befs_data_stream * data,
befs_blocknr_t blockno, befs_block_run * run);
static int befs_find_brun_indirect(struct super_block *sb,
befs_data_stream * data,
befs_blocknr_t blockno,
befs_block_run * run);
static int befs_find_brun_dblindirect(struct super_block *sb,
befs_data_stream * data,
befs_blocknr_t blockno,
befs_block_run * run);
/**
* befs_read_datastream - get buffer_head containing data, starting from pos.
* @sb: Filesystem superblock
* @ds: datastrem to find data with
* @pos: start of data
* @off: offset of data in buffer_head->b_data
*
* Returns pointer to buffer_head containing data starting with offset @off,
* if you don't need to know offset just set @off = NULL.
*/
struct buffer_head *
befs_read_datastream(struct super_block *sb, befs_data_stream * ds,
befs_off_t pos, uint * off)
{
struct buffer_head *bh = NULL;
befs_block_run run;
befs_blocknr_t block; /* block coresponding to pos */
befs_debug(sb, "---> befs_read_datastream() %Lu", pos);
block = pos >> BEFS_SB(sb)->block_shift;
if (off)
*off = pos - (block << BEFS_SB(sb)->block_shift);
if (befs_fblock2brun(sb, ds, block, &run) != BEFS_OK) {
befs_error(sb, "BeFS: Error finding disk addr of block %lu",
block);
befs_debug(sb, "<--- befs_read_datastream() ERROR");
return NULL;
}
bh = befs_bread_iaddr(sb, run);
if (!bh) {
befs_error(sb, "BeFS: Error reading block %lu from datastream",
block);
return NULL;
}
befs_debug(sb, "<--- befs_read_datastream() read data, starting at %Lu",
pos);
return bh;
}
/*
* Takes a file position and gives back a brun who's starting block
* is block number fblock of the file.
*
* Returns BEFS_OK or BEFS_ERR.
*
* Calls specialized functions for each of the three possible
* datastream regions.
*
* 2001-11-15 Will Dyson
*/
int
befs_fblock2brun(struct super_block *sb, befs_data_stream * data,
befs_blocknr_t fblock, befs_block_run * run)
{
int err;
befs_off_t pos = fblock << BEFS_SB(sb)->block_shift;
if (pos < data->max_direct_range) {
err = befs_find_brun_direct(sb, data, fblock, run);
} else if (pos < data->max_indirect_range) {
err = befs_find_brun_indirect(sb, data, fblock, run);
} else if (pos < data->max_double_indirect_range) {
err = befs_find_brun_dblindirect(sb, data, fblock, run);
} else {
befs_error(sb,
"befs_fblock2brun() was asked to find block %lu, "
"which is not mapped by the datastream\n", fblock);
err = BEFS_ERR;
}
return err;
}
/**
* befs_read_lsmylink - read long symlink from datastream.
* @sb: Filesystem superblock
* @ds: Datastrem to read from
* @buf: Buffer in which to place long symlink data
* @len: Length of the long symlink in bytes
*
* Returns the number of bytes read
*/
size_t
befs_read_lsymlink(struct super_block * sb, befs_data_stream * ds, void *buff,
befs_off_t len)
{
befs_off_t bytes_read = 0; /* bytes readed */
u16 plen;
struct buffer_head *bh = NULL;
befs_debug(sb, "---> befs_read_lsymlink() length: %Lu", len);
while (bytes_read < len) {
bh = befs_read_datastream(sb, ds, bytes_read, NULL);
if (!bh) {
befs_error(sb, "BeFS: Error reading datastream block "
"starting from %Lu", bytes_read);
befs_debug(sb, "<--- befs_read_lsymlink() ERROR");
return bytes_read;
}
plen = ((bytes_read + BEFS_SB(sb)->block_size) < len) ?
BEFS_SB(sb)->block_size : len - bytes_read;
memcpy(buff + bytes_read, bh->b_data, plen);
brelse(bh);
bytes_read += plen;
}
befs_debug(sb, "<--- befs_read_lsymlink() read %u bytes", bytes_read);
return bytes_read;
}
/**
* befs_count_blocks - blocks used by a file
* @sb: Filesystem superblock
* @ds: Datastream of the file
*
* Counts the number of fs blocks that the file represented by
* inode occupies on the filesystem, counting both regular file
* data and filesystem metadata (and eventually attribute data
* when we support attributes)
*/
befs_blocknr_t
befs_count_blocks(struct super_block * sb, befs_data_stream * ds)
{
befs_blocknr_t blocks;
befs_blocknr_t datablocks; /* File data blocks */
befs_blocknr_t metablocks; /* FS metadata blocks */
befs_sb_info *befs_sb = BEFS_SB(sb);
befs_debug(sb, "---> befs_count_blocks()");
datablocks = ds->size >> befs_sb->block_shift;
if (ds->size & (befs_sb->block_size - 1))
datablocks += 1;
metablocks = 1; /* Start with 1 block for inode */
/* Size of indirect block */
if (ds->size > ds->max_direct_range)
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.
*/
if (ds->size > ds->max_indirect_range && ds->max_indirect_range != 0) {
uint dbl_bytes;
uint dbl_bruns;
uint indirblocks;
dbl_bytes =
ds->max_double_indirect_range - ds->max_indirect_range;
dbl_bruns =
dbl_bytes / (befs_sb->block_size * BEFS_DBLINDIR_BRUN_LEN);
indirblocks = dbl_bruns / befs_iaddrs_per_block(sb);
metablocks += ds->double_indirect.len;
metablocks += indirblocks;
}
blocks = datablocks + metablocks;
befs_debug(sb, "<--- befs_count_blocks() %u blocks", blocks);
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
*/
static int
befs_find_brun_direct(struct super_block *sb, befs_data_stream * data,
befs_blocknr_t blockno, befs_block_run * run)
{
int i;
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, "---> befs_find_brun_direct(), find %lu", blockno);
if (blockno > max_block) {
befs_error(sb, "befs_find_brun_direct() passed block outside of"
"direct region");
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;
befs_debug(sb, "---> befs_find_brun_direct(), "
"found %lu at direct[%d]", blockno, i);
return BEFS_OK;
}
}
befs_debug(sb, "---> befs_find_brun_direct() ERROR");
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
*/
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;
}
/*
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;
}