500 lines
12 KiB
C
500 lines
12 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 Library
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* General Public License, version 2.
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* %End-Header%
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*/
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#include "config.h"
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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 "ext2fsP.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 ? ext2fs_le32_to_cpu(((blk_t *)block_buf)[nr - 1]) : ind;
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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 = 0;
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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 = 0;
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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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static errcode_t extent_bmap(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode,
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ext2_extent_handle_t handle,
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char *block_buf, int bmap_flags, blk64_t block,
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int *ret_flags, int *blocks_alloc,
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blk64_t *phys_blk);
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static errcode_t implied_cluster_alloc(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode,
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ext2_extent_handle_t handle,
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blk64_t lblk, blk64_t *phys_blk)
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{
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blk64_t base_block, pblock = 0;
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int i;
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if (!ext2fs_has_feature_bigalloc(fs->super))
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return 0;
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base_block = lblk & ~EXT2FS_CLUSTER_MASK(fs);
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/*
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* Except for the logical block (lblk) that was passed in, search all
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* blocks in this logical cluster for a mapping to a physical cluster.
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* If any such map exists, calculate the physical block that maps to
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* the logical block and return that.
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*
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* The old code wouldn't even look if (block % cluster_ratio) == 0;
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* this is incorrect if we're allocating blocks in reverse order.
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*/
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for (i = 0; i < EXT2FS_CLUSTER_RATIO(fs); i++) {
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if (base_block + i == lblk)
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continue;
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extent_bmap(fs, ino, inode, handle, 0, 0,
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base_block + i, 0, 0, &pblock);
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if (pblock)
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break;
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}
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if (pblock == 0)
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return 0;
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*phys_blk = pblock - i + (lblk - base_block);
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return 0;
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}
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/* Try to map a logical block to an already-allocated physical cluster. */
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errcode_t ext2fs_map_cluster_block(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode, blk64_t lblk,
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blk64_t *pblk)
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{
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ext2_extent_handle_t handle;
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errcode_t retval;
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/* Need bigalloc and extents to be enabled */
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*pblk = 0;
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if (!ext2fs_has_feature_bigalloc(fs->super) ||
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!(inode->i_flags & EXT4_EXTENTS_FL))
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return 0;
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retval = ext2fs_extent_open2(fs, ino, inode, &handle);
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if (retval)
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goto out;
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retval = implied_cluster_alloc(fs, ino, inode, handle, lblk, pblk);
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if (retval)
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goto out2;
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out2:
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ext2fs_extent_free(handle);
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out:
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return retval;
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}
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static errcode_t extent_bmap(ext2_filsys fs, ext2_ino_t ino,
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struct ext2_inode *inode,
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ext2_extent_handle_t handle,
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char *block_buf, int bmap_flags, blk64_t block,
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int *ret_flags, int *blocks_alloc,
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blk64_t *phys_blk)
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{
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struct blk_alloc_ctx alloc_ctx;
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struct ext2fs_extent extent;
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unsigned int offset;
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errcode_t retval = 0;
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blk64_t blk64 = 0;
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int alloc = 0;
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int set_flags;
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set_flags = bmap_flags & BMAP_UNINIT ? EXT2_EXTENT_SET_BMAP_UNINIT : 0;
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if (bmap_flags & BMAP_SET) {
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retval = ext2fs_extent_set_bmap(handle, block,
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*phys_blk, set_flags);
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return retval;
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}
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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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extent.e_lblk = block;
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goto got_block;
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}
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return retval;
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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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return retval;
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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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got_block:
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if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
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implied_cluster_alloc(fs, ino, inode, handle, block, &blk64);
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if (blk64)
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goto set_extent;
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retval = extent_bmap(fs, ino, inode, handle, block_buf,
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0, block-1, 0, blocks_alloc, &blk64);
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if (retval)
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blk64 = ext2fs_find_inode_goal(fs, ino, inode, block);
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alloc_ctx.ino = ino;
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alloc_ctx.inode = inode;
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alloc_ctx.lblk = extent.e_lblk;
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alloc_ctx.flags = BLOCK_ALLOC_DATA;
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retval = ext2fs_alloc_block3(fs, blk64, block_buf, &blk64,
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&alloc_ctx);
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if (retval)
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return retval;
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blk64 &= ~EXT2FS_CLUSTER_MASK(fs);
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blk64 += EXT2FS_CLUSTER_MASK(fs) & block;
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alloc++;
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set_extent:
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retval = ext2fs_extent_set_bmap(handle, block,
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blk64, set_flags);
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if (retval) {
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ext2fs_block_alloc_stats2(fs, blk64, -1);
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return retval;
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}
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/* Update inode after setting extent */
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retval = ext2fs_read_inode(fs, ino, inode);
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if (retval)
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return retval;
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*blocks_alloc += alloc;
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*phys_blk = blk64;
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}
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return 0;
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}
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int ext2fs_file_block_offset_too_big(ext2_filsys fs,
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struct ext2_inode *inode,
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blk64_t offset)
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{
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blk64_t addr_per_block, max_map_block;
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/* Kernel seems to cut us off at 4294967294 blocks */
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if (offset >= (1ULL << 32) - 1)
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return 1;
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if (inode->i_flags & EXT4_EXTENTS_FL)
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return 0;
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addr_per_block = fs->blocksize >> 2;
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max_map_block = addr_per_block;
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max_map_block += addr_per_block * addr_per_block;
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max_map_block += addr_per_block * addr_per_block * addr_per_block;
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max_map_block += 12;
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return offset >= max_map_block;
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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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blk64_t b64;
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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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struct blk_alloc_ctx alloc_ctx = {
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.ino = ino,
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.inode = inode,
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.lblk = 0,
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.flags = BLOCK_ALLOC_DATA,
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};
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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 (ext2fs_file_block_offset_too_big(fs, inode, block))
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return EXT2_ET_FILE_TOO_BIG;
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/*
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* If an inode has inline data, that means that it doesn't have
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* any blocks and we shouldn't map any blocks for it.
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*/
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if (inode->i_flags & EXT4_INLINE_DATA_FL)
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return EXT2_ET_INLINE_DATA_NO_BLOCK;
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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 (inode->i_flags & EXT4_EXTENTS_FL) {
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retval = ext2fs_extent_open2(fs, ino, inode, &handle);
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if (retval)
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goto done;
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retval = extent_bmap(fs, ino, inode, handle, block_buf,
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bmap_flags, block, ret_flags,
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&blocks_alloc, phys_blk);
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goto done;
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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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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) :
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ext2fs_find_inode_goal(fs, ino, inode, block);
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if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
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b64 = b;
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retval = ext2fs_alloc_block3(fs, b64, block_buf, &b64,
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&alloc_ctx);
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b = b64;
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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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b64 = b;
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retval = ext2fs_alloc_block3(fs, b64, block_buf, &b64,
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&alloc_ctx);
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b = b64;
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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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b64 = b;
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retval = ext2fs_alloc_block3(fs, b64, block_buf, &b64,
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&alloc_ctx);
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b = b64;
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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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b64 = b;
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retval = ext2fs_alloc_block3(fs, b64, block_buf, &b64,
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&alloc_ctx);
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b = b64;
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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 (*phys_blk && retval == 0 && (bmap_flags & BMAP_ZERO))
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retval = ext2fs_zero_blocks2(fs, *phys_blk, 1, NULL, NULL);
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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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ext2fs_iblk_add_blocks(fs, inode, blocks_alloc);
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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 = *phys_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)
|
|
return ret;
|
|
if (ret_blk >= ((long long) 1 << 32))
|
|
return EOVERFLOW;
|
|
*phys_blk = ret_blk;
|
|
return 0;
|
|
}
|