From: "Darrick J. Wong" Subject: [PATCH 08/16] ext4: Calculate and verify checksums for inode bitmaps Date: Wed, 31 Aug 2011 17:31:28 -0700 Message-ID: <20110901003127.31048.13983.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 inode bitmap; the checkum is stored in the block group descriptor. Signed-off-by: Darrick J. Wong --- fs/ext4/ext4.h | 3 ++- fs/ext4/ialloc.c | 33 ++++++++++++++++++++++++++++++--- 2 files changed, 32 insertions(+), 4 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index bc7ace1..248cbd2 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -279,7 +279,8 @@ struct ext4_group_desc __le16 bg_free_inodes_count_hi;/* Free inodes count MSB */ __le16 bg_used_dirs_count_hi; /* Directories count MSB */ __le16 bg_itable_unused_hi; /* Unused inodes count MSB */ - __u32 bg_reserved2[3]; + __le32 bg_inode_bitmap_csum; /* crc32c(uuid+group+ibitmap) */ + __u32 bg_reserved2[2]; }; /* diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 9c63f27..53faffc 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -82,12 +82,18 @@ static unsigned ext4_init_inode_bitmap(struct super_block *sb, 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_inode_bitmap_csum, bh, + (EXT4_INODES_PER_GROUP(sb) + 7) / 8); return 0; } memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8); ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8, bh->b_data); + ext4_bitmap_csum_set(sb, block_group, &gdp->bg_inode_bitmap_csum, bh, + (EXT4_INODES_PER_GROUP(sb) + 7) / 8); + gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); return EXT4_INODES_PER_GROUP(sb); } @@ -118,12 +124,12 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) return NULL; } 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); @@ -131,6 +137,7 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) ext4_init_inode_bitmap(sb, bh, block_group, desc); set_bitmap_uptodate(bh); set_buffer_uptodate(bh); + set_buffer_verified(bh); ext4_unlock_group(sb, block_group); unlock_buffer(bh); return bh; @@ -144,7 +151,7 @@ ext4_read_inode_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 @@ -161,6 +168,21 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) block_group, bitmap_blk); return NULL; } + +verify: + ext4_lock_group(sb, block_group); + if (!buffer_verified(bh) && + !ext4_bitmap_csum_verify(sb, block_group, + desc->bg_inode_bitmap_csum, bh, + (EXT4_INODES_PER_GROUP(sb) + 7) / 8)) { + ext4_unlock_group(sb, block_group); + put_bh(bh); + ext4_error(sb, "Corrupt inode bitmap - block_group = %u, " + "inode_bitmap = %llu", block_group, bitmap_blk); + return NULL; + } + ext4_unlock_group(sb, block_group); + set_buffer_verified(bh); return bh; } @@ -265,6 +287,8 @@ void ext4_free_inode(handle_t *handle, struct inode *inode) ext4_used_dirs_set(sb, gdp, count); percpu_counter_dec(&sbi->s_dirs_counter); } + ext4_bitmap_csum_set(sb, block_group, &gdp->bg_inode_bitmap_csum, + bitmap_bh, (EXT4_INODES_PER_GROUP(sb) + 7) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); ext4_unlock_group(sb, block_group); @@ -784,6 +808,9 @@ static int ext4_claim_inode(struct super_block *sb, atomic_inc(&sbi->s_flex_groups[f].used_dirs); } } + ext4_bitmap_csum_set(sb, group, &gdp->bg_inode_bitmap_csum, + inode_bitmap_bh, + (EXT4_INODES_PER_GROUP(sb) + 7) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); err_ret: ext4_unlock_group(sb, group);