csum.c revision 4729455f0a68f2fa0a83ec8460d1d4bccba9dcfa
1ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos/* 2ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * csum.c --- checksumming of ext3 structures 3ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * 4ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * Copyright (C) 2006 Cluster File Systems, Inc. 5ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * 6ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * %Begin-Header% 7ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * This file may be redistributed under the terms of the GNU Public 8ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * License. 9ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * %End-Header% 10ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos */ 11ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 12ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#include "ext2_fs.h" 13ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#include "ext2fs.h" 14ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#include "crc16.h" 15ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#include <assert.h> 16ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 17ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#ifndef offsetof 18ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER) 19ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#endif 20ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 21ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#ifdef DEBUG 22ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#define STATIC 23ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#else 24ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#define STATIC static 25ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#endif 26ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 27ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. SantosSTATIC __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group) 28ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos{ 29ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos __u16 crc = 0; 30ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos struct ext2_group_desc *desc; 31ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 32ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos desc = &fs->group_desc[group]; 33ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 34ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) { 35ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos int offset = offsetof(struct ext2_group_desc, bg_checksum); 36ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 37ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#ifdef WORDS_BIGENDIAN 38ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos struct ext2_group_desc swabdesc = *desc; 39ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 40ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos /* Have to swab back to little-endian to do the checksum */ 41ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos ext2fs_swap_group_desc(&swabdesc); 42ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos desc = &swabdesc; 43ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 44ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos group = ext2fs_swab32(group); 45ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos#endif 46ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos crc = crc16(~0, fs->super->s_uuid, sizeof(fs->super->s_uuid)); 47ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos crc = crc16(crc, &group, sizeof(group)); 48ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos crc = crc16(crc, desc, offset); 49ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos offset += sizeof(desc->bg_checksum); /* skip checksum */ 50ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos assert(offset == sizeof(*desc)); 51ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos /* for checksum of struct ext4_group_desc do the rest...*/ 52ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos if (offset < fs->super->s_desc_size) { 53ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos crc = crc16(crc, (char *)desc + offset, 54ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos fs->super->s_desc_size - offset); 55ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos } 56ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos } 57ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 58ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos return crc; 59ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos} 60ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 61ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santosint ext2fs_group_desc_csum_verify(ext2_filsys fs, dgrp_t group) 62ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos{ 634729455f0a68f2fa0a83ec8460d1d4bccba9dcfaTheodore Ts'o if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 644729455f0a68f2fa0a83ec8460d1d4bccba9dcfaTheodore Ts'o EXT4_FEATURE_RO_COMPAT_GDT_CSUM) && 654729455f0a68f2fa0a83ec8460d1d4bccba9dcfaTheodore Ts'o (fs->group_desc[group].bg_checksum != 664729455f0a68f2fa0a83ec8460d1d4bccba9dcfaTheodore Ts'o ext2fs_group_desc_csum(fs, group))) 67ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos return 0; 68ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 69ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos return 1; 70ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos} 71ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 72ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santosvoid ext2fs_group_desc_csum_set(ext2_filsys fs, dgrp_t group) 73ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos{ 745711ed297b1a3d94086256b5b3b891d4f77b21caTheodore Ts'o if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 755711ed297b1a3d94086256b5b3b891d4f77b21caTheodore Ts'o EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) 765711ed297b1a3d94086256b5b3b891d4f77b21caTheodore Ts'o fs->group_desc[group].bg_checksum = 775711ed297b1a3d94086256b5b3b891d4f77b21caTheodore Ts'o ext2fs_group_desc_csum(fs, group); 78ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos} 79ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 80ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santosstatic __u32 find_last_inode_ingrp(ext2fs_inode_bitmap bitmap, 81ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos __u32 inodes_per_grp, dgrp_t grp_no) 82ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos{ 83ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos ext2_ino_t i, start_ino, end_ino; 84ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 85ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos start_ino = grp_no * inodes_per_grp + 1; 86ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos end_ino = start_ino + inodes_per_grp - 1; 87ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 88ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos for (i = end_ino; i >= start_ino; i--) { 89ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos if (ext2fs_fast_test_inode_bitmap(bitmap, i)) 90ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos return i - start_ino + 1; 91ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos } 92ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos return inodes_per_grp; 93ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos} 94ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 95ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos/* update the bitmap flags, set the itable high watermark, and calculate 96ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos * checksums for the group descriptors */ 97f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilgererrcode_t ext2fs_set_gdt_csum(ext2_filsys fs) 98ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos{ 99ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos struct ext2_super_block *sb = fs->super; 100ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos struct ext2_group_desc *bg = fs->group_desc; 1018895f43a60269464f654e9d87c28768875cd703aTheodore Ts'o int dirty = 0; 102ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos dgrp_t i; 103ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 104f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilger if (!fs->inode_map) 105f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilger return EXT2_ET_NO_INODE_BITMAP; 106f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilger 10716b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 10816b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) 109f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilger return 0; 110ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 111ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos for (i = 0; i < fs->group_desc_count; i++, bg++) { 112ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos int old_csum = bg->bg_checksum; 11380fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger int old_unused = bg->bg_itable_unused; 11480fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger int old_flags = bg->bg_flags; 115ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 11616b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o if (bg->bg_free_inodes_count == sb->s_inodes_per_group) { 11716b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o bg->bg_flags |= EXT2_BG_INODE_UNINIT; 11816b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o bg->bg_itable_unused = sb->s_inodes_per_group; 11916b851cdae98244e117fe91d93b267fcad1102b3Theodore Ts'o } else { 120ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos bg->bg_flags &= ~EXT2_BG_INODE_UNINIT; 121ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos bg->bg_itable_unused = sb->s_inodes_per_group - 122ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos find_last_inode_ingrp(fs->inode_map, 123ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos sb->s_inodes_per_group,i); 124ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos } 125ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos 126ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos ext2fs_group_desc_csum_set(fs, i); 12780fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger if (old_flags != bg->bg_flags) 12880fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger dirty = 1; 12980fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger if (old_unused != bg->bg_itable_unused) 13080fc4e698a308de22ace6179f45e0bb67befa74bAndreas Dilger dirty = 1; 131ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos if (old_csum != bg->bg_checksum) 132ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos dirty = 1; 133ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos } 134ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos if (dirty) 135ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos ext2fs_mark_super_dirty(fs); 136f628acea2671dda839fc086f1017718e41e34ecaAndreas Dilger return 0; 137ca2634a46ab9da85a3a015a7772770d9dbe5848eJose R. Santos} 138