From: "Darrick J. Wong" Subject: [PATCH 15/28] ext4: Calculate and verify block bitmap checksum Date: Sat, 08 Oct 2011 00:55:22 -0700 Message-ID: <20111008075522.20506.22239.stgit@elm3c44.beaverton.ibm.com> References: <20111008075343.20506.23155.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Martin K Petersen , Greg Freemyer , 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: <20111008075343.20506.23155.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 | 40 +++++++++++++++++++++------ fs/ext4/bitmap.c | 40 +++++++++++++++++++++++++++ fs/ext4/ext4.h | 10 +++++++ fs/ext4/ialloc.c | 4 +++ fs/ext4/mballoc.c | 78 +++++++++++++++++++++++++++++++++++++++++++++-------- 5 files changed, 151 insertions(+), 21 deletions(-) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index f8224ad..dd96a7d 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -105,6 +105,9 @@ 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_block_bitmap_csum_set(sb, block_group, gdp, bh, + EXT4_BLOCKS_PER_GROUP(sb) / + 8); return 0; } memset(bh->b_data, 0, sb->s_blocksize); @@ -175,6 +178,10 @@ 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_block_bitmap_csum_set(sb, block_group, gdp, bh, + EXT4_BLOCKS_PER_GROUP(sb) / 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 +239,10 @@ 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 +319,12 @@ 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 +343,7 @@ 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 +360,26 @@ 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_block_bitmap_csum_verify(sb, block_group, desc, bh, + EXT4_BLOCKS_PER_GROUP(sb) / 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/bitmap.c b/fs/ext4/bitmap.c index e9342f6..00ebc7a 100644 --- a/fs/ext4/bitmap.c +++ b/fs/ext4/bitmap.c @@ -81,3 +81,43 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_LOCATION) gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(crc >> 16); } + +int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + struct buffer_head *bh, int sz) +{ + __u32 hi; + __u32 provided, calculated; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 1; + + provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo); + calculated = ext4_bitmap_csum(sb, group, bh, sz); + if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) { + hi = le16_to_cpu(gdp->bg_block_bitmap_csum_hi); + provided |= (hi << 16); + } else + calculated &= 0xFFFF; + + return provided == calculated; +} + +void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + struct buffer_head *bh, int sz) +{ + __u32 crc; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return; + + crc = ext4_bitmap_csum(sb, group, bh, sz); + gdp->bg_block_bitmap_csum_lo = cpu_to_le16(crc & 0xFFFF); + if (sbi->s_desc_size >= EXT4_BG_BLOCK_BITMAP_CSUM_HI_LOCATION) + gdp->bg_block_bitmap_csum_hi = cpu_to_le16(crc >> 16); +} diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index c98bc9f..7cd3541 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1776,8 +1776,18 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, struct ext4_group_desc *gdp, struct buffer_head *bh, int sz); +void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + struct buffer_head *bh, int sz); +int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + 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 6fb00e7..77ae3df 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -981,6 +981,10 @@ 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_block_bitmap_csum_set(sb, group, gdp, + block_bitmap_bh, + EXT4_BLOCKS_PER_GROUP(sb) / + 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..3d6300a 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -753,6 +753,44 @@ void ext4_mb_generate_buddy(struct super_block *sb, spin_unlock(&EXT4_SB(sb)->s_bal_lock); } +struct ext4_csum_data { + struct super_block *cd_sb; + ext4_group_t cd_group; +}; + +static void ext4_end_buffer_read_sync(struct buffer_head *bh, int uptodate) +{ + struct ext4_group_desc *desc; + struct super_block *sb = + ((struct ext4_csum_data *)bh->b_private)->cd_sb; + ext4_group_t group = ((struct ext4_csum_data *)bh->b_private)->cd_group; + + if (!uptodate) + goto out; + + desc = ext4_get_group_desc(sb, group, NULL); + if (!desc) + goto out; + + if (buffer_verified(bh)) + goto out; + + ext4_lock_group(sb, group); + if (!ext4_valid_block_bitmap(sb, desc, group, bh) || + !ext4_block_bitmap_csum_verify(sb, group, desc, bh, + EXT4_BLOCKS_PER_GROUP(sb) / 8)) { + ext4_unlock_group(sb, group); + ext4_error(sb, "Corrupt block bitmap, group = %u", group); + goto out; + } + ext4_unlock_group(sb, group); + set_buffer_verified(bh); + +out: + bh->b_private = NULL; + end_buffer_read_sync(bh, uptodate); +} + /* The buddy information is attached the buddy cache inode * for convenience. The information regarding each group * is loaded via ext4_mb_load_buddy. The information involve @@ -785,11 +823,12 @@ static int ext4_mb_init_cache(struct page *page, char *incore) int first_block; struct super_block *sb; struct buffer_head *bhs; - struct buffer_head **bh; + struct buffer_head **bh = NULL; struct inode *inode; char *data; char *bitmap; struct ext4_group_info *grinfo; + struct ext4_csum_data *csd; mb_debug(1, "init page %lu\n", page->index); @@ -803,6 +842,11 @@ static int ext4_mb_init_cache(struct page *page, char *incore) if (groups_per_page == 0) groups_per_page = 1; + csd = kzalloc(sizeof(struct ext4_csum_data) * groups_per_page, + GFP_NOFS); + if (csd == NULL) + goto out; + /* allocate buffer_heads to read bitmaps */ if (groups_per_page > 1) { err = -ENOMEM; @@ -880,22 +924,25 @@ static int ext4_mb_init_cache(struct page *page, char *incore) * get set with buffer lock held. */ set_bitmap_uptodate(bh[i]); - bh[i]->b_end_io = end_buffer_read_sync; + csd[i].cd_sb = sb; + csd[i].cd_group = first_group + i; + bh[i]->b_private = csd + i; + bh[i]->b_end_io = ext4_end_buffer_read_sync; submit_bh(READ, bh[i]); mb_debug(1, "read bitmap for group %u\n", first_group + i); } - /* wait for I/O completion */ - for (i = 0; i < groups_per_page; i++) - if (bh[i]) - wait_on_buffer(bh[i]); - - err = -EIO; - for (i = 0; i < groups_per_page; i++) - if (bh[i] && !buffer_uptodate(bh[i])) - goto out; - + /* Wait for I/O completion and checksum verification */ err = 0; + for (i = 0; i < groups_per_page; i++) { + if (bh[i] == NULL) + continue; + wait_on_buffer(bh[i]); + if (!buffer_uptodate(bh[i]) || + !buffer_verified(bh[i])) + err = -EIO; + } + first_block = page->index * blocks_per_page; for (i = 0; i < blocks_per_page; i++) { int group; @@ -972,6 +1019,7 @@ out: if (bh != &bhs) kfree(bh); } + kfree(csd); return err; } @@ -2829,6 +2877,8 @@ 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_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh, + EXT4_BLOCKS_PER_GROUP(sb) / 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 +4688,8 @@ do_more: ret = ext4_free_blks_count(sb, gdp) + count; ext4_free_blks_set(sb, gdp, ret); + ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh, + EXT4_BLOCKS_PER_GROUP(sb) / 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 +4832,8 @@ 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_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh, + EXT4_BLOCKS_PER_GROUP(sb) / 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);