/*
* bmap.c --- logical to physical block mapping
*
* Copyright (C) 1997 Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Library
* General Public License, version 2.
* %End-Header%
*/
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#include "ext2_fs.h"
#include "ext2fsP.h"
#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
#define _BMAP_INLINE_ __inline__
#else
#define _BMAP_INLINE_
#endif
extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode,
char *block_buf, int bmap_flags,
blk_t block, blk_t *phys_blk);
#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
blk_t ind, char *block_buf,
int *blocks_alloc,
blk_t nr, blk_t *ret_blk)
{
errcode_t retval;
blk_t b;
if (!ind) {
if (flags & BMAP_SET)
return EXT2_ET_SET_BMAP_NO_IND;
*ret_blk = 0;
return 0;
}
retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
if (retval)
return retval;
if (flags & BMAP_SET) {
b = *ret_blk;
#ifdef WORDS_BIGENDIAN
b = ext2fs_swab32(b);
#endif
((blk_t *) block_buf)[nr] = b;
return io_channel_write_blk(fs->io, ind, 1, block_buf);
}
b = ((blk_t *) block_buf)[nr];
#ifdef WORDS_BIGENDIAN
b = ext2fs_swab32(b);
#endif
if (!b && (flags & BMAP_ALLOC)) {
b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
retval = ext2fs_alloc_block(fs, b,
block_buf + fs->blocksize, &b);
if (retval)
return retval;
#ifdef WORDS_BIGENDIAN
((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
#else
((blk_t *) block_buf)[nr] = b;
#endif
retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
if (retval)
return retval;
(*blocks_alloc)++;
}
*ret_blk = b;
return 0;
}
static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
blk_t dind, char *block_buf,
int *blocks_alloc,
blk_t nr, blk_t *ret_blk)
{
blk_t b = 0;
errcode_t retval;
blk_t addr_per_block;
addr_per_block = (blk_t) fs->blocksize >> 2;
retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf,
blocks_alloc, nr / addr_per_block, &b);
if (retval)
return retval;
retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
nr % addr_per_block, ret_blk);
return retval;
}
static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
blk_t tind, char *block_buf,
int *blocks_alloc,
blk_t nr, blk_t *ret_blk)
{
blk_t b = 0;
errcode_t retval;
blk_t addr_per_block;
addr_per_block = (blk_t) fs->blocksize >> 2;
retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf,
blocks_alloc, nr / addr_per_block, &b);
if (retval)
return retval;
retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
nr % addr_per_block, ret_blk);
return retval;
}
static errcode_t extent_bmap(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode,
ext2_extent_handle_t handle,
char *block_buf, int bmap_flags, blk64_t block,
int *ret_flags, int *blocks_alloc,
blk64_t *phys_blk);
static errcode_t implied_cluster_alloc(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode,
ext2_extent_handle_t handle,
blk64_t lblk, blk64_t *phys_blk)
{
blk64_t base_block, pblock = 0;
int i;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
EXT4_FEATURE_RO_COMPAT_BIGALLOC))
return 0;
base_block = lblk & ~EXT2FS_CLUSTER_MASK(fs);
/*
* Except for the logical block (lblk) that was passed in, search all
* blocks in this logical cluster for a mapping to a physical cluster.
* If any such map exists, calculate the physical block that maps to
* the logical block and return that.
*
* The old code wouldn't even look if (block % cluster_ratio) == 0;
* this is incorrect if we're allocating blocks in reverse order.
*/
for (i = 0; i < EXT2FS_CLUSTER_RATIO(fs); i++) {
if (base_block + i == lblk)
continue;
extent_bmap(fs, ino, inode, handle, 0, 0,
base_block + i, 0, 0, &pblock);
if (pblock)
break;
}
if (pblock == 0)
return 0;
*phys_blk = pblock - i + (lblk - base_block);
return 0;
}
/* Try to map a logical block to an already-allocated physical cluster. */
errcode_t ext2fs_map_cluster_block(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode, blk64_t lblk,
blk64_t *pblk)
{
ext2_extent_handle_t handle;
errcode_t retval;
/* Need bigalloc and extents to be enabled */
*pblk = 0;
if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
EXT4_FEATURE_RO_COMPAT_BIGALLOC) ||
!(inode->i_flags & EXT4_EXTENTS_FL))
return 0;
retval = ext2fs_extent_open2(fs, ino, inode, &handle);
if (retval)
goto out;
retval = implied_cluster_alloc(fs, ino, inode, handle, lblk, pblk);
if (retval)
goto out2;
out2:
ext2fs_extent_free(handle);
out:
return retval;
}
static errcode_t extent_bmap(ext2_filsys fs, ext2_ino_t ino,
struct ext2_inode *inode,
ext2_extent_handle_t handle,
char *block_buf, int bmap_flags, blk64_t block,
int *ret_flags, int *blocks_alloc,
blk64_t *phys_blk)
{
struct ext2fs_extent extent;
unsigned int offset;
errcode_t retval = 0;
blk64_t blk64 = 0;
int alloc = 0;
if (bmap_flags & BMAP_SET) {
retval = ext2fs_extent_set_bmap(handle, block,
*phys_blk, 0);
return retval;
}
retval = ext2fs_extent_goto(handle, block);
if (retval) {
/* If the extent is not found, return phys_blk = 0 */
if (retval == EXT2_ET_EXTENT_NOT_FOUND)
goto got_block;
return retval;
}
retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
if (retval)
return retval;
offset = block - extent.e_lblk;
if (block >= extent.e_lblk && (offset <= extent.e_len)) {
*phys_blk = extent.e_pblk + offset;
if (ret_flags && extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
*ret_flags |= BMAP_RET_UNINIT;
}
got_block:
if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
implied_cluster_alloc(fs, ino, inode, handle, block, &blk64);
if (blk64)
goto set_extent;
retval = extent_bmap(fs, ino, inode, handle, block_buf,
0, block-1, 0, blocks_alloc, &blk64);
if (retval)
blk64 = 0;
retval = ext2fs_alloc_block2(fs, blk64, block_buf,
&blk64);
if (retval)
return retval;
blk64 &= ~EXT2FS_CLUSTER_MASK(fs);
blk64 += EXT2FS_CLUSTER_MASK(fs) & block;
alloc++;
set_extent:
retval = ext2fs_extent_set_bmap(handle, block,
blk64, 0);
if (retval)
return retval;
/* Update inode after setting extent */
retval = ext2fs_read_inode(fs, ino, inode);
if (retval)
return retval;
*blocks_alloc += alloc;
*phys_blk = blk64;
}
return 0;
}
int ext2fs_file_block_offset_too_big(ext2_filsys fs,
struct ext2_inode *inode,
blk64_t offset)
{
blk64_t addr_per_block, max_map_block;
/* Kernel seems to cut us off at 4294967294 blocks */
if (offset >= (1ULL << 32) - 1)
return 1;
if (inode->i_flags & EXT4_EXTENTS_FL)
return 0;
addr_per_block = fs->blocksize >> 2;
max_map_block = addr_per_block;
max_map_block += addr_per_block * addr_per_block;
max_map_block += addr_per_block * addr_per_block * addr_per_block;
max_map_block += 12;
return offset >= max_map_block;
}
errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
char *block_buf, int bmap_flags, blk64_t block,
int *ret_flags, blk64_t *phys_blk)
{
struct ext2_inode inode_buf;
ext2_extent_handle_t handle = 0;
blk_t addr_per_block;
blk_t b, blk32;
char *buf = 0;
errcode_t retval = 0;
int blocks_alloc = 0, inode_dirty = 0;
if (!(bmap_flags & BMAP_SET))
*phys_blk = 0;
if (ret_flags)
*ret_flags = 0;
/* Read inode structure if necessary */
if (!inode) {
retval = ext2fs_read_inode(fs, ino, &inode_buf);
if (retval)
return retval;
inode = &inode_buf;
}
addr_per_block = (blk_t) fs->blocksize >> 2;
if (ext2fs_file_block_offset_too_big(fs, inode, block))
return EXT2_ET_FILE_TOO_BIG;
if (!block_buf) {
retval = ext2fs_get_array(2, fs->blocksize, &buf);
if (retval)
return retval;
block_buf = buf;
}
if (inode->i_flags & EXT4_EXTENTS_FL) {
retval = ext2fs_extent_open2(fs, ino, inode, &handle);
if (retval)
goto done;
retval = extent_bmap(fs, ino, inode, handle, block_buf,
bmap_flags, block, ret_flags,
&blocks_alloc, phys_blk);
goto done;
}
if (block < EXT2_NDIR_BLOCKS) {
if (bmap_flags & BMAP_SET) {
b = *phys_blk;
inode_bmap(inode, block) = b;
inode_dirty++;
goto done;
}
*phys_blk = inode_bmap(inode, block);
b = block ? inode_bmap(inode, block-1) : 0;
if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
retval = ext2fs_alloc_block(fs, b, block_buf, &b);
if (retval)
goto done;
inode_bmap(inode, block) = b;
blocks_alloc++;
*phys_blk = b;
}
goto done;
}
/* Indirect block */
block -= EXT2_NDIR_BLOCKS;
blk32 = *phys_blk;
if (block < addr_per_block) {
b = inode_bmap(inode, EXT2_IND_BLOCK);
if (!b) {
if (!(bmap_flags & BMAP_ALLOC)) {
if (bmap_flags & BMAP_SET)
retval = EXT2_ET_SET_BMAP_NO_IND;
goto done;
}
b = inode_bmap(inode, EXT2_IND_BLOCK-1);
retval = ext2fs_alloc_block(fs, b, block_buf, &b);
if (retval)
goto done;
inode_bmap(inode, EXT2_IND_BLOCK) = b;
blocks_alloc++;
}
retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
&blocks_alloc, block, &blk32);
if (retval == 0)
*phys_blk = blk32;
goto done;
}
/* Doubly indirect block */
block -= addr_per_block;
if (block < addr_per_block * addr_per_block) {
b = inode_bmap(inode, EXT2_DIND_BLOCK);
if (!b) {
if (!(bmap_flags & BMAP_ALLOC)) {
if (bmap_flags & BMAP_SET)
retval = EXT2_ET_SET_BMAP_NO_IND;
goto done;
}
b = inode_bmap(inode, EXT2_IND_BLOCK);
retval = ext2fs_alloc_block(fs, b, block_buf, &b);
if (retval)
goto done;
inode_bmap(inode, EXT2_DIND_BLOCK) = b;
blocks_alloc++;
}
retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
&blocks_alloc, block, &blk32);
if (retval == 0)
*phys_blk = blk32;
goto done;
}
/* Triply indirect block */
block -= addr_per_block * addr_per_block;
b = inode_bmap(inode, EXT2_TIND_BLOCK);
if (!b) {
if (!(bmap_flags & BMAP_ALLOC)) {
if (bmap_flags & BMAP_SET)
retval = EXT2_ET_SET_BMAP_NO_IND;
goto done;
}
b = inode_bmap(inode, EXT2_DIND_BLOCK);
retval = ext2fs_alloc_block(fs, b, block_buf, &b);
if (retval)
goto done;
inode_bmap(inode, EXT2_TIND_BLOCK) = b;
blocks_alloc++;
}
retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
&blocks_alloc, block, &blk32);
if (retval == 0)
*phys_blk = blk32;
done:
if (buf)
ext2fs_free_mem(&buf);
if (handle)
ext2fs_extent_free(handle);
if ((retval == 0) && (blocks_alloc || inode_dirty)) {
ext2fs_iblk_add_blocks(fs, inode, blocks_alloc);
retval = ext2fs_write_inode(fs, ino, inode);
}
return retval;
}
errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
char *block_buf, int bmap_flags, blk_t block,
blk_t *phys_blk)
{
errcode_t ret;
blk64_t ret_blk = *phys_blk;
ret = ext2fs_bmap2(fs, ino, inode, block_buf, bmap_flags, block,
0, &ret_blk);
if (ret)
return ret;
if (ret_blk >= ((long long) 1 << 32))
return EOVERFLOW;
*phys_blk = ret_blk;
return 0;
}