mirror of https://github.com/vitalif/e2fsprogs
322 lines
7.4 KiB
C
322 lines
7.4 KiB
C
/*
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* bmap.c --- logical to physical block mapping
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*
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* Copyright (C) 1997 Theodore Ts'o.
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*
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* %Begin-Header%
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* This file may be redistributed under the terms of the GNU Public
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* License.
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* %End-Header%
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*/
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#include <stdio.h>
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#include <string.h>
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#if HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <errno.h>
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#include "ext2_fs.h"
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#include "ext2fs.h"
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#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
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#define _BMAP_INLINE_ __inline__
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#else
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#define _BMAP_INLINE_
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#endif
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extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode,
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char *block_buf, int bmap_flags,
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blk_t block, blk_t *phys_blk);
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#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
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static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
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blk_t ind, char *block_buf,
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int *blocks_alloc,
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blk_t nr, blk_t *ret_blk)
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{
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errcode_t retval;
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blk_t b;
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if (!ind) {
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if (flags & BMAP_SET)
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return EXT2_ET_SET_BMAP_NO_IND;
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*ret_blk = 0;
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return 0;
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}
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retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
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if (retval)
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return retval;
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if (flags & BMAP_SET) {
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b = *ret_blk;
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#ifdef WORDS_BIGENDIAN
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b = ext2fs_swab32(b);
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#endif
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((blk_t *) block_buf)[nr] = b;
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return io_channel_write_blk(fs->io, ind, 1, block_buf);
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}
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b = ((blk_t *) block_buf)[nr];
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#ifdef WORDS_BIGENDIAN
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b = ext2fs_swab32(b);
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#endif
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if (!b && (flags & BMAP_ALLOC)) {
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b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
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retval = ext2fs_alloc_block(fs, b,
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block_buf + fs->blocksize, &b);
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if (retval)
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return retval;
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#ifdef WORDS_BIGENDIAN
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((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
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#else
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((blk_t *) block_buf)[nr] = b;
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#endif
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retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
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if (retval)
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return retval;
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(*blocks_alloc)++;
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}
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*ret_blk = b;
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return 0;
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}
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static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
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blk_t dind, char *block_buf,
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int *blocks_alloc,
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blk_t nr, blk_t *ret_blk)
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{
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blk_t b;
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errcode_t retval;
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blk_t addr_per_block;
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addr_per_block = (blk_t) fs->blocksize >> 2;
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retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf,
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blocks_alloc, nr / addr_per_block, &b);
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if (retval)
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return retval;
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retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
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nr % addr_per_block, ret_blk);
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return retval;
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}
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static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
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blk_t tind, char *block_buf,
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int *blocks_alloc,
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blk_t nr, blk_t *ret_blk)
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{
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blk_t b;
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errcode_t retval;
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blk_t addr_per_block;
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addr_per_block = (blk_t) fs->blocksize >> 2;
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retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf,
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blocks_alloc, nr / addr_per_block, &b);
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if (retval)
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return retval;
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retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
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nr % addr_per_block, ret_blk);
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return retval;
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}
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errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
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char *block_buf, int bmap_flags, blk64_t block,
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int *ret_flags, blk64_t *phys_blk)
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{
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struct ext2_inode inode_buf;
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ext2_extent_handle_t handle = 0;
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blk_t addr_per_block;
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blk_t b, blk32;
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char *buf = 0;
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errcode_t retval = 0;
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int blocks_alloc = 0, inode_dirty = 0;
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if (!(bmap_flags & BMAP_SET))
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*phys_blk = 0;
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if (ret_flags)
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*ret_flags = 0;
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/* Read inode structure if necessary */
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if (!inode) {
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retval = ext2fs_read_inode(fs, ino, &inode_buf);
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if (retval)
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return retval;
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inode = &inode_buf;
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}
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addr_per_block = (blk_t) fs->blocksize >> 2;
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if (inode->i_flags & EXT4_EXTENTS_FL) {
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struct ext2fs_extent extent;
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unsigned int offset;
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if (bmap_flags & BMAP_SET) {
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retval = EXT2_ET_EXTENT_NOT_SUPPORTED;
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goto done;
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}
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retval = ext2fs_extent_open(fs, ino, &handle);
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if (retval)
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goto done;
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retval = ext2fs_extent_goto(handle, block);
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if (retval) {
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/* If the extent is not found, return phys_blk = 0 */
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if (retval == EXT2_ET_EXTENT_NOT_FOUND)
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retval = 0;
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goto done;
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}
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retval = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
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if (retval)
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goto done;
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offset = block - extent.e_lblk;
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if (block >= extent.e_lblk && (offset <= extent.e_len)) {
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*phys_blk = extent.e_pblk + offset;
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if (ret_flags && extent.e_flags & EXT2_EXTENT_FLAGS_UNINIT)
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*ret_flags |= BMAP_RET_UNINIT;
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}
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retval = 0;
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goto done;
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}
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if (!block_buf) {
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retval = ext2fs_get_array(2, fs->blocksize, &buf);
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if (retval)
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return retval;
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block_buf = buf;
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}
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if (block < EXT2_NDIR_BLOCKS) {
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if (bmap_flags & BMAP_SET) {
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b = *phys_blk;
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#ifdef WORDS_BIGENDIAN
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b = ext2fs_swab32(b);
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#endif
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inode_bmap(inode, block) = b;
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inode_dirty++;
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goto done;
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}
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*phys_blk = inode_bmap(inode, block);
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b = block ? inode_bmap(inode, block-1) : 0;
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if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
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retval = ext2fs_alloc_block(fs, b, block_buf, &b);
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if (retval)
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goto done;
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inode_bmap(inode, block) = b;
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blocks_alloc++;
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*phys_blk = b;
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}
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goto done;
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}
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/* Indirect block */
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block -= EXT2_NDIR_BLOCKS;
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blk32 = *phys_blk;
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if (block < addr_per_block) {
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b = inode_bmap(inode, EXT2_IND_BLOCK);
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if (!b) {
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if (!(bmap_flags & BMAP_ALLOC)) {
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if (bmap_flags & BMAP_SET)
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retval = EXT2_ET_SET_BMAP_NO_IND;
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goto done;
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}
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b = inode_bmap(inode, EXT2_IND_BLOCK-1);
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retval = ext2fs_alloc_block(fs, b, block_buf, &b);
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if (retval)
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goto done;
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inode_bmap(inode, EXT2_IND_BLOCK) = b;
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blocks_alloc++;
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}
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retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
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&blocks_alloc, block, &blk32);
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if (retval == 0)
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*phys_blk = blk32;
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goto done;
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}
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/* Doubly indirect block */
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block -= addr_per_block;
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if (block < addr_per_block * addr_per_block) {
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b = inode_bmap(inode, EXT2_DIND_BLOCK);
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if (!b) {
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if (!(bmap_flags & BMAP_ALLOC)) {
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if (bmap_flags & BMAP_SET)
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retval = EXT2_ET_SET_BMAP_NO_IND;
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goto done;
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}
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b = inode_bmap(inode, EXT2_IND_BLOCK);
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retval = ext2fs_alloc_block(fs, b, block_buf, &b);
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if (retval)
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goto done;
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inode_bmap(inode, EXT2_DIND_BLOCK) = b;
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blocks_alloc++;
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}
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retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
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&blocks_alloc, block, &blk32);
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if (retval == 0)
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*phys_blk = blk32;
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goto done;
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}
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/* Triply indirect block */
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block -= addr_per_block * addr_per_block;
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b = inode_bmap(inode, EXT2_TIND_BLOCK);
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if (!b) {
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if (!(bmap_flags & BMAP_ALLOC)) {
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if (bmap_flags & BMAP_SET)
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retval = EXT2_ET_SET_BMAP_NO_IND;
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goto done;
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}
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b = inode_bmap(inode, EXT2_DIND_BLOCK);
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retval = ext2fs_alloc_block(fs, b, block_buf, &b);
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if (retval)
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goto done;
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inode_bmap(inode, EXT2_TIND_BLOCK) = b;
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blocks_alloc++;
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}
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retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
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&blocks_alloc, block, &blk32);
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if (retval == 0)
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*phys_blk = blk32;
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done:
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if (buf)
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ext2fs_free_mem(&buf);
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if (handle)
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ext2fs_extent_free(handle);
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if ((retval == 0) && (blocks_alloc || inode_dirty)) {
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inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
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retval = ext2fs_write_inode(fs, ino, inode);
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}
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return retval;
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}
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errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
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char *block_buf, int bmap_flags, blk_t block,
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blk_t *phys_blk)
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{
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errcode_t ret;
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blk64_t ret_blk;
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ret = ext2fs_bmap2(fs, ino, inode, block_buf, bmap_flags, block,
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0, &ret_blk);
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if (ret)
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return ret;
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if (ret_blk >= ((long long) 1 << 32))
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return EOVERFLOW;
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*phys_blk = ret_blk;
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return 0;
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}
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