From: "Darrick J. Wong" Subject: [PATCH 09/16] ext4: Calculate and verify block bitmap checksum Date: Wed, 31 Aug 2011 17:31:34 -0700 Message-ID: <20110901003134.31048.23806.stgit@elm3c44.beaverton.ibm.com> References: <20110901003030.31048.99467.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Amir Goldstein , linux-kernel , Andi Kleen , Mingming Cao , Joel Becker , linux-fsdevel , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: In-Reply-To: <20110901003030.31048.99467.stgit@elm3c44.beaverton.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Compute and verify the checksum of the block bitmap; this checksum is stored in the block group descriptor. Signed-off-by: Darrick J. Wong --- fs/ext4/balloc.c | 43 ++++++++++++++++++++++++++++++++++--------- fs/ext4/ext4.h | 7 ++++++- fs/ext4/ialloc.c | 5 +++++ fs/ext4/mballoc.c | 34 ++++++++++++++++++++++++++++++++++ 4 files changed, 79 insertions(+), 10 deletions(-) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index f8224ad..36d3020 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -105,6 +105,10 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, ext4_free_inodes_set(sb, gdp, 0); ext4_itable_unused_set(sb, gdp, 0); memset(bh->b_data, 0xff, sb->s_blocksize); + ext4_bitmap_csum_set(sb, block_group, + &gdp->bg_block_bitmap_csum, bh, + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / + 8); return 0; } memset(bh->b_data, 0, sb->s_blocksize); @@ -175,6 +179,11 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, */ ext4_mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data); + ext4_bitmap_csum_set(sb, block_group, + &gdp->bg_block_bitmap_csum, bh, + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 8); + gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, + gdp); } return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp); } @@ -232,10 +241,10 @@ struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, return desc; } -static int ext4_valid_block_bitmap(struct super_block *sb, - struct ext4_group_desc *desc, - unsigned int block_group, - struct buffer_head *bh) +int ext4_valid_block_bitmap(struct super_block *sb, + struct ext4_group_desc *desc, + unsigned int block_group, + struct buffer_head *bh) { ext4_grpblk_t offset; ext4_grpblk_t next_zero_bit; @@ -312,12 +321,12 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) } if (bitmap_uptodate(bh)) - return bh; + goto verify; lock_buffer(bh); if (bitmap_uptodate(bh)) { unlock_buffer(bh); - return bh; + goto verify; } ext4_lock_group(sb, block_group); if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { @@ -336,7 +345,7 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) */ set_bitmap_uptodate(bh); unlock_buffer(bh); - return bh; + goto verify; } /* * submit the buffer_head for read. We can @@ -353,11 +362,27 @@ ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) block_group, bitmap_blk); return NULL; } - ext4_valid_block_bitmap(sb, desc, block_group, bh); + +verify: + if (buffer_verified(bh)) + return bh; /* * file system mounted not to panic on error, - * continue with corrupt bitmap + * -EIO with corrupt bitmap */ + ext4_lock_group(sb, block_group); + if (!ext4_valid_block_bitmap(sb, desc, block_group, bh) || + !ext4_bitmap_csum_verify(sb, block_group, + desc->bg_block_bitmap_csum, bh, + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 8)) { + ext4_unlock_group(sb, block_group); + put_bh(bh); + ext4_error(sb, "Corrupt block bitmap - block_group = %u, " + "block_bitmap = %llu", block_group, bitmap_blk); + return NULL; + } + ext4_unlock_group(sb, block_group); + set_buffer_verified(bh); return bh; } diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 248cbd2..df149b3 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -269,7 +269,8 @@ struct ext4_group_desc __le16 bg_free_inodes_count_lo;/* Free inodes count */ __le16 bg_used_dirs_count_lo; /* Directories count */ __le16 bg_flags; /* EXT4_BG_flags (INODE_UNINIT, etc) */ - __u32 bg_reserved[2]; /* Likely block/inode bitmap checksum */ + __u32 bg_reserved[1]; /* unclaimed */ + __le32 bg_block_bitmap_csum; /* crc32c(uuid+group+bbitmap) */ __le16 bg_itable_unused_lo; /* Unused inodes count */ __le16 bg_checksum; /* crc16(sb_uuid+group+desc) */ __le32 bg_block_bitmap_hi; /* Blocks bitmap block MSB */ @@ -1731,6 +1732,10 @@ void ext4_bitmap_csum_set(struct super_block *sb, ext4_group_t group, __le32 *csum, struct buffer_head *bh, int sz); /* balloc.c */ +extern int ext4_valid_block_bitmap(struct super_block *sb, + struct ext4_group_desc *desc, + unsigned int block_group, + struct buffer_head *bh); extern unsigned int ext4_block_group(struct super_block *sb, ext4_fsblk_t blocknr); extern ext4_grpblk_t ext4_block_group_offset(struct super_block *sb, diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 53faffc..a335d19 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -984,6 +984,11 @@ got: free = ext4_free_blocks_after_init(sb, group, gdp); gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT); ext4_free_blks_set(sb, gdp, free); + ext4_bitmap_csum_set(sb, group, + &gdp->bg_block_bitmap_csum, + block_bitmap_bh, + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / + 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); } diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 17a5a57..8dc3055 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -895,6 +895,33 @@ static int ext4_mb_init_cache(struct page *page, char *incore) if (bh[i] && !buffer_uptodate(bh[i])) goto out; + for (i = 0; i < groups_per_page; i++) { + struct ext4_group_desc *desc; + + if (!bh[i] || !bh[i]->b_end_io) + continue; + desc = ext4_get_group_desc(sb, first_group + i, NULL); + if (!desc) + goto out; + + if (buffer_verified(bh[i])) + continue; + ext4_lock_group(sb, first_group + i); + if (!ext4_valid_block_bitmap(sb, desc, first_group + i, + bh[i]) || + !ext4_bitmap_csum_verify(sb, first_group + i, + desc->bg_block_bitmap_csum, bh[i], + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / + 8)) { + ext4_unlock_group(sb, first_group + i); + ext4_error(sb, "Corrupt block bitmap, group = %u", + first_group + i); + goto out; + } + ext4_unlock_group(sb, first_group + i); + set_buffer_verified(bh[i]); + } + err = 0; first_block = page->index * blocks_per_page; for (i = 0; i < blocks_per_page; i++) { @@ -2829,6 +2856,9 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac, } len = ext4_free_blks_count(sb, gdp) - ac->ac_b_ex.fe_len; ext4_free_blks_set(sb, gdp, len); + ext4_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, + &gdp->bg_block_bitmap_csum, bitmap_bh, + (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp); ext4_unlock_group(sb, ac->ac_b_ex.fe_group); @@ -4638,6 +4668,8 @@ do_more: ret = ext4_free_blks_count(sb, gdp) + count; ext4_free_blks_set(sb, gdp, ret); + ext4_bitmap_csum_set(sb, block_group, &gdp->bg_block_bitmap_csum, + bitmap_bh, (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); ext4_unlock_group(sb, block_group); percpu_counter_add(&sbi->s_freeblocks_counter, count); @@ -4780,6 +4812,8 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb, mb_free_blocks(NULL, &e4b, bit, count); blk_free_count = blocks_freed + ext4_free_blks_count(sb, desc); ext4_free_blks_set(sb, desc, blk_free_count); + ext4_bitmap_csum_set(sb, block_group, &desc->bg_block_bitmap_csum, + bitmap_bh, (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 8); desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc); ext4_unlock_group(sb, block_group); percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);