/* 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 = 0; 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; }