| /* vi: set sw=4 ts=4: */ |
| /* |
| * rw_bitmaps.c --- routines to read and write the inode and block bitmaps. |
| * |
| * Copyright (C) 1993, 1994, 1994, 1996 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 <fcntl.h> |
| #include <time.h> |
| #ifdef HAVE_SYS_STAT_H |
| #include <sys/stat.h> |
| #endif |
| #ifdef HAVE_SYS_TYPES_H |
| #include <sys/types.h> |
| #endif |
| |
| #include "ext2_fs.h" |
| #include "ext2fs.h" |
| #include "e2image.h" |
| |
| #if defined(__powerpc__) && BB_BIG_ENDIAN |
| /* |
| * On the PowerPC, the big-endian variant of the ext2 filesystem |
| * has its bitmaps stored as 32-bit words with bit 0 as the LSB |
| * of each word. Thus a bitmap with only bit 0 set would be, as |
| * a string of bytes, 00 00 00 01 00 ... |
| * To cope with this, we byte-reverse each word of a bitmap if |
| * we have a big-endian filesystem, that is, if we are *not* |
| * byte-swapping other word-sized numbers. |
| */ |
| #define EXT2_BIG_ENDIAN_BITMAPS |
| #endif |
| |
| #ifdef EXT2_BIG_ENDIAN_BITMAPS |
| static void ext2fs_swap_bitmap(ext2_filsys fs, char *bitmap, int nbytes) |
| { |
| __u32 *p = (__u32 *) bitmap; |
| int n; |
| |
| for (n = nbytes / sizeof(__u32); n > 0; --n, ++p) |
| *p = ext2fs_swab32(*p); |
| } |
| #endif |
| |
| errcode_t ext2fs_write_inode_bitmap(ext2_filsys fs) |
| { |
| dgrp_t i; |
| size_t nbytes; |
| errcode_t retval; |
| char * inode_bitmap = fs->inode_map->bitmap; |
| char * bitmap_block = NULL; |
| blk_t blk; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (!(fs->flags & EXT2_FLAG_RW)) |
| return EXT2_ET_RO_FILSYS; |
| if (!inode_bitmap) |
| return 0; |
| nbytes = (size_t) ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8); |
| |
| retval = ext2fs_get_mem(fs->blocksize, &bitmap_block); |
| if (retval) |
| return retval; |
| memset(bitmap_block, 0xff, fs->blocksize); |
| for (i = 0; i < fs->group_desc_count; i++) { |
| memcpy(bitmap_block, inode_bitmap, nbytes); |
| blk = fs->group_desc[i].bg_inode_bitmap; |
| if (blk) { |
| #ifdef EXT2_BIG_ENDIAN_BITMAPS |
| if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))) |
| ext2fs_swap_bitmap(fs, bitmap_block, nbytes); |
| #endif |
| retval = io_channel_write_blk(fs->io, blk, 1, |
| bitmap_block); |
| if (retval) |
| return EXT2_ET_INODE_BITMAP_WRITE; |
| } |
| inode_bitmap += nbytes; |
| } |
| fs->flags &= ~EXT2_FLAG_IB_DIRTY; |
| ext2fs_free_mem(&bitmap_block); |
| return 0; |
| } |
| |
| errcode_t ext2fs_write_block_bitmap (ext2_filsys fs) |
| { |
| dgrp_t i; |
| unsigned int j; |
| int nbytes; |
| unsigned int nbits; |
| errcode_t retval; |
| char * block_bitmap = fs->block_map->bitmap; |
| char * bitmap_block = NULL; |
| blk_t blk; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (!(fs->flags & EXT2_FLAG_RW)) |
| return EXT2_ET_RO_FILSYS; |
| if (!block_bitmap) |
| return 0; |
| nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8; |
| retval = ext2fs_get_mem(fs->blocksize, &bitmap_block); |
| if (retval) |
| return retval; |
| memset(bitmap_block, 0xff, fs->blocksize); |
| for (i = 0; i < fs->group_desc_count; i++) { |
| memcpy(bitmap_block, block_bitmap, nbytes); |
| if (i == fs->group_desc_count - 1) { |
| /* Force bitmap padding for the last group */ |
| nbits = ((fs->super->s_blocks_count |
| - fs->super->s_first_data_block) |
| % EXT2_BLOCKS_PER_GROUP(fs->super)); |
| if (nbits) |
| for (j = nbits; j < fs->blocksize * 8; j++) |
| ext2fs_set_bit(j, bitmap_block); |
| } |
| blk = fs->group_desc[i].bg_block_bitmap; |
| if (blk) { |
| #ifdef EXT2_BIG_ENDIAN_BITMAPS |
| if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))) |
| ext2fs_swap_bitmap(fs, bitmap_block, nbytes); |
| #endif |
| retval = io_channel_write_blk(fs->io, blk, 1, |
| bitmap_block); |
| if (retval) |
| return EXT2_ET_BLOCK_BITMAP_WRITE; |
| } |
| block_bitmap += nbytes; |
| } |
| fs->flags &= ~EXT2_FLAG_BB_DIRTY; |
| ext2fs_free_mem(&bitmap_block); |
| return 0; |
| } |
| |
| static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) |
| { |
| dgrp_t i; |
| char *block_bitmap = NULL, *inode_bitmap = NULL; |
| char *buf; |
| errcode_t retval; |
| int block_nbytes = (int) EXT2_BLOCKS_PER_GROUP(fs->super) / 8; |
| int inode_nbytes = (int) EXT2_INODES_PER_GROUP(fs->super) / 8; |
| blk_t blk; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| fs->write_bitmaps = ext2fs_write_bitmaps; |
| |
| retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); |
| if (retval) |
| return retval; |
| if (do_block) { |
| ext2fs_free_block_bitmap(fs->block_map); |
| sprintf(buf, "block bitmap for %s", fs->device_name); |
| retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); |
| if (retval) |
| goto cleanup; |
| block_bitmap = fs->block_map->bitmap; |
| } |
| if (do_inode) { |
| ext2fs_free_inode_bitmap(fs->inode_map); |
| sprintf(buf, "inode bitmap for %s", fs->device_name); |
| retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); |
| if (retval) |
| goto cleanup; |
| inode_bitmap = fs->inode_map->bitmap; |
| } |
| ext2fs_free_mem(&buf); |
| |
| if (fs->flags & EXT2_FLAG_IMAGE_FILE) { |
| if (inode_bitmap) { |
| blk = (fs->image_header->offset_inodemap / |
| fs->blocksize); |
| retval = io_channel_read_blk(fs->image_io, blk, |
| -(inode_nbytes * fs->group_desc_count), |
| inode_bitmap); |
| if (retval) |
| goto cleanup; |
| } |
| if (block_bitmap) { |
| blk = (fs->image_header->offset_blockmap / |
| fs->blocksize); |
| retval = io_channel_read_blk(fs->image_io, blk, |
| -(block_nbytes * fs->group_desc_count), |
| block_bitmap); |
| if (retval) |
| goto cleanup; |
| } |
| return 0; |
| } |
| |
| for (i = 0; i < fs->group_desc_count; i++) { |
| if (block_bitmap) { |
| blk = fs->group_desc[i].bg_block_bitmap; |
| if (blk) { |
| retval = io_channel_read_blk(fs->io, blk, |
| -block_nbytes, block_bitmap); |
| if (retval) { |
| retval = EXT2_ET_BLOCK_BITMAP_READ; |
| goto cleanup; |
| } |
| #ifdef EXT2_BIG_ENDIAN_BITMAPS |
| if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))) |
| ext2fs_swap_bitmap(fs, block_bitmap, block_nbytes); |
| #endif |
| } else |
| memset(block_bitmap, 0, block_nbytes); |
| block_bitmap += block_nbytes; |
| } |
| if (inode_bitmap) { |
| blk = fs->group_desc[i].bg_inode_bitmap; |
| if (blk) { |
| retval = io_channel_read_blk(fs->io, blk, |
| -inode_nbytes, inode_bitmap); |
| if (retval) { |
| retval = EXT2_ET_INODE_BITMAP_READ; |
| goto cleanup; |
| } |
| #ifdef EXT2_BIG_ENDIAN_BITMAPS |
| if (!((fs->flags & EXT2_FLAG_SWAP_BYTES) || |
| (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))) |
| ext2fs_swap_bitmap(fs, inode_bitmap, inode_nbytes); |
| #endif |
| } else |
| memset(inode_bitmap, 0, inode_nbytes); |
| inode_bitmap += inode_nbytes; |
| } |
| } |
| return 0; |
| |
| cleanup: |
| if (do_block) { |
| ext2fs_free_mem(&fs->block_map); |
| } |
| if (do_inode) { |
| ext2fs_free_mem(&fs->inode_map); |
| } |
| ext2fs_free_mem(&buf); |
| return retval; |
| } |
| |
| errcode_t ext2fs_read_inode_bitmap (ext2_filsys fs) |
| { |
| return read_bitmaps(fs, 1, 0); |
| } |
| |
| errcode_t ext2fs_read_block_bitmap(ext2_filsys fs) |
| { |
| return read_bitmaps(fs, 0, 1); |
| } |
| |
| errcode_t ext2fs_read_bitmaps(ext2_filsys fs) |
| { |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (fs->inode_map && fs->block_map) |
| return 0; |
| |
| return read_bitmaps(fs, !fs->inode_map, !fs->block_map); |
| } |
| |
| errcode_t ext2fs_write_bitmaps(ext2_filsys fs) |
| { |
| errcode_t retval; |
| |
| EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| |
| if (fs->block_map && ext2fs_test_bb_dirty(fs)) { |
| retval = ext2fs_write_block_bitmap(fs); |
| if (retval) |
| return retval; |
| } |
| if (fs->inode_map && ext2fs_test_ib_dirty(fs)) { |
| retval = ext2fs_write_inode_bitmap(fs); |
| if (retval) |
| return retval; |
| } |
| return 0; |
| } |
