| /* vi: set sw=4 ts=4: */ |
| /* |
| * 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 Public |
| * License. |
| * %End-Header% |
| */ |
| |
| #include <stdio.h> |
| #include <string.h> |
| #if HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| |
| #include "ext2_fs.h" |
| #include "ext2fs.h" |
| |
| 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 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; |
| #if BB_BIG_ENDIAN |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) |
| 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]; |
| |
| #if BB_BIG_ENDIAN |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) |
| 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; |
| |
| #if BB_BIG_ENDIAN |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE)) |
| ((blk_t *) block_buf)[nr] = ext2fs_swab32(b); |
| else |
| #endif |
| ((blk_t *) block_buf)[nr] = b; |
| |
| retval = io_channel_write_blk(fs->io, ind, 1, block_buf); |
| if (retval) |
| return retval; |
| |
| (*blocks_alloc)++; |
| } |
| |
| *ret_blk = b; |
| return 0; |
| } |
| |
| static 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; |
| 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 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; |
| 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; |
| } |
| |
| 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) |
| { |
| struct ext2_inode inode_buf; |
| blk_t addr_per_block; |
| blk_t b; |
| char *buf = NULL; |
| errcode_t retval = 0; |
| int blocks_alloc = 0, inode_dirty = 0; |
| |
| if (!(bmap_flags & BMAP_SET)) |
| *phys_blk = 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 (!block_buf) { |
| retval = ext2fs_get_mem(fs->blocksize * 2, &buf); |
| if (retval) |
| return retval; |
| block_buf = buf; |
| } |
| |
| if (block < EXT2_NDIR_BLOCKS) { |
| if (bmap_flags & BMAP_SET) { |
| b = *phys_blk; |
| #if BB_BIG_ENDIAN |
| if ((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_READ)) |
| b = ext2fs_swab32(b); |
| #endif |
| 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; |
| 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, phys_blk); |
| 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, phys_blk); |
| 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, phys_blk); |
| done: |
| ext2fs_free_mem(&buf); |
| if ((retval == 0) && (blocks_alloc || inode_dirty)) { |
| inode->i_blocks += (blocks_alloc * fs->blocksize) / 512; |
| retval = ext2fs_write_inode(fs, ino, inode); |
| } |
| return retval; |
| } |
| |
| |
| |