From: "Darrick J. Wong" Subject: [PATCH 13/47] libext2fs: Create the block bitmap checksum Date: Sat, 08 Oct 2011 00:34:38 -0700 Message-ID: <20111008073438.17888.63128.stgit@elm3c44.beaverton.ibm.com> References: <20111008073315.17888.22132.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 , Andi Kleen , Mingming Cao , Joel Becker , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: Received: from e2.ny.us.ibm.com ([32.97.182.142]:42340 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751287Ab1JHHh2 (ORCPT ); Sat, 8 Oct 2011 03:37:28 -0400 Received: from /spool/local by us.ibm.com with XMail ESMTP for from ; Sat, 8 Oct 2011 03:37:27 -0400 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p987YfVB168432 for ; Sat, 8 Oct 2011 03:34:41 -0400 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p987YdCL005357 for ; Sat, 8 Oct 2011 01:34:41 -0600 In-Reply-To: <20111008073315.17888.22132.stgit@elm3c44.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Provide a field in the block group descriptor to store block bitmap checksum, and some helper functions to calculate and verify it. Signed-off-by: Darrick J. Wong --- lib/ext2fs/blknum.c | 15 +++++++++++++++ lib/ext2fs/csum.c | 39 +++++++++++++++++++++++++++++++++++++++ lib/ext2fs/ext2_fs.h | 3 +++ lib/ext2fs/ext2fs.h | 6 ++++++ lib/ext2fs/rw_bitmaps.c | 16 ++++++++++++++++ 5 files changed, 79 insertions(+), 0 deletions(-) diff --git a/lib/ext2fs/blknum.c b/lib/ext2fs/blknum.c index 30987fc..64f9b94 100644 --- a/lib/ext2fs/blknum.c +++ b/lib/ext2fs/blknum.c @@ -203,6 +203,21 @@ static struct ext4_group_desc *ext4fs_group_desc(ext2_filsys fs, } /* + * Return the block bitmap checksum of a group + */ +__u32 ext2fs_block_bitmap_checksum(ext2_filsys fs, dgrp_t group) +{ + struct ext4_group_desc *gdp; + __u32 csum; + + gdp = ext4fs_group_desc(fs, fs->group_desc, group); + csum = gdp->bg_block_bitmap_csum_lo; + if (fs->super->s_desc_size < EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) + csum |= ((__u32)gdp->bg_block_bitmap_csum_hi << 16); + return csum; +} + +/* * Return the block bitmap block of a group */ blk64_t ext2fs_block_bitmap_loc(ext2_filsys fs, dgrp_t group) diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c index 91b1892..524d0e5 100644 --- a/lib/ext2fs/csum.c +++ b/lib/ext2fs/csum.c @@ -83,6 +83,45 @@ errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group, return 0; } +int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group, + char *bitmap, int size) +{ + struct ext4_group_desc *gdp = (struct ext4_group_desc *) + ext2fs_group_desc(fs, fs->group_desc, group); + __u32 provided, calculated; + + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 1; + provided = gdp->bg_block_bitmap_csum_lo; + calculated = ext2fs_bitmap_csum(fs, group, bitmap, size); + if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) + provided |= ((__u32)gdp->bg_block_bitmap_csum_hi << 16); + else + calculated &= 0xFFFF; + + return provided == calculated; +} + +errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group, + char *bitmap, int size) +{ + __u32 crc; + struct ext4_group_desc *gdp = (struct ext4_group_desc *) + ext2fs_group_desc(fs, fs->group_desc, group); + + if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 0; + + crc = ext2fs_bitmap_csum(fs, group, bitmap, size); + gdp->bg_block_bitmap_csum_lo = crc & 0xFFFF; + if (fs->super->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) + gdp->bg_block_bitmap_csum_hi = crc >> 16; + + return 0; +} + static errcode_t ext2fs_inode_csum(ext2_filsys fs, ext2_ino_t inum, struct ext2_inode_large *inode, __u32 *crc) diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h index e7f8bb4..cdfc4a8 100644 --- a/lib/ext2fs/ext2_fs.h +++ b/lib/ext2fs/ext2_fs.h @@ -194,6 +194,9 @@ struct ext4_group_desc #define EXT4_BG_INODE_BITMAP_CSUM_HI_LOCATION \ (offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \ sizeof(__u16)) +#define EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION \ + (offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \ + sizeof(__u16)) #define EXT2_BG_INODE_UNINIT 0x0001 /* Inode table/bitmap not initialized */ #define EXT2_BG_BLOCK_UNINIT 0x0002 /* Block bitmap not initialized */ diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index d71181b..3b514a7 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -789,6 +789,7 @@ extern errcode_t ext2fs_get_block_bitmap_range2(ext2fs_block_bitmap bmap, /* blknum.c */ extern __u32 ext2fs_inode_bitmap_checksum(ext2_filsys fs, dgrp_t group); +extern __u32 ext2fs_block_bitmap_checksum(ext2_filsys fs, dgrp_t group); extern dgrp_t ext2fs_group_of_blk2(ext2_filsys fs, blk64_t); extern blk64_t ext2fs_group_first_block2(ext2_filsys fs, dgrp_t group); extern blk64_t ext2fs_group_last_block2(ext2_filsys fs, dgrp_t group); @@ -816,6 +817,7 @@ extern void ext2fs_free_blocks_count_add(struct ext2_super_block *super, extern struct ext2_group_desc *ext2fs_group_desc(ext2_filsys fs, struct opaque_ext2_group_desc *gdp, dgrp_t group); +extern blk64_t ext2fs_block_bitmap_csum(ext2_filsys fs, dgrp_t group); extern blk64_t ext2fs_block_bitmap_loc(ext2_filsys fs, dgrp_t group); extern void ext2fs_block_bitmap_loc_set(ext2_filsys fs, dgrp_t group, blk64_t blk); @@ -927,6 +929,10 @@ extern __u32 ext2fs_crc32c_be(__u32 crc, unsigned char const *p, size_t len); extern __u32 ext2fs_crc32c_le(__u32 crc, unsigned char const *p, size_t len); /* csum.c */ +extern errcode_t ext2fs_block_bitmap_csum_set(ext2_filsys fs, dgrp_t group, + char *bitmap, int size); +extern int ext2fs_block_bitmap_csum_verify(ext2_filsys fs, dgrp_t group, + char *bitmap, int size); extern errcode_t ext2fs_inode_bitmap_csum_set(ext2_filsys fs, dgrp_t group, char *bitmap, int size); extern int ext2fs_inode_bitmap_csum_verify(ext2_filsys fs, dgrp_t group, diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c index a325fdb..df755cc 100644 --- a/lib/ext2fs/rw_bitmaps.c +++ b/lib/ext2fs/rw_bitmaps.c @@ -92,6 +92,13 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block) for (j = nbits; j < fs->blocksize * 8; j++) ext2fs_set_bit(j, block_buf); } + + retval = ext2fs_block_bitmap_csum_set(fs, i, block_buf, + block_nbytes); + if (retval) + return retval; + ext2fs_group_desc_csum_set(fs, i); + blk = ext2fs_block_bitmap_loc(fs, i); if (blk) { retval = io_channel_write_blk64(fs->io, blk, 1, @@ -273,6 +280,15 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block) retval = EXT2_ET_BLOCK_BITMAP_READ; goto cleanup; } + /* verify block bitmap checksum */ + gdp = (struct ext4_group_desc *) + ext2fs_group_desc(fs, fs->group_desc, + i); + if (!(fs->flags & + EXT2_FLAG_IGNORE_CSUM_ERRORS) && + !ext2fs_block_bitmap_csum_verify(fs, i, + block_bitmap, block_nbytes)) + return EXT2_ET_BLOCK_BITMAP_READ; } else memset(block_bitmap, 0, block_nbytes); cnt = block_nbytes << 3;