From 41a246d1ff75a95d2be3191ca6e6db139dc0f430 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sun, 29 Apr 2012 18:33:10 -0400 Subject: [PATCH 1/1] ext4: calculate and verify checksums for inode bitmaps Compute and verify the checksum of the inode bitmap; the checkum is stored in the block group descriptor. Signed-off-by: Darrick J. Wong Signed-off-by: "Theodore Ts'o" --- fs/ext4/bitmap.c | 39 +++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4.h | 20 ++++++++++++++++++++ fs/ext4/ialloc.c | 34 +++++++++++++++++++++++++++++----- fs/ext4/resize.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 135 insertions(+), 5 deletions(-) diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c index fa3af81ac565..5813e7f2e2c6 100644 --- a/fs/ext4/bitmap.c +++ b/fs/ext4/bitmap.c @@ -29,3 +29,42 @@ unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars) #endif /* EXT4FS_DEBUG */ +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) +{ + __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_inode_bitmap_csum_lo); + calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); + if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) { + hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi); + provided |= (hi << 16); + } else + calculated &= 0xFFFF; + + return provided == calculated; +} + +void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + struct buffer_head *bh, int sz) +{ + __u32 csum; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return; + + csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); + gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); + if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) + gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16); +} diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index ca96401b4b81..7f0ff88f32ba 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -317,6 +317,13 @@ struct ext4_group_desc __u32 bg_reserved; }; +#define EXT4_BG_INODE_BITMAP_CSUM_HI_END \ + (offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \ + sizeof(__le16)) +#define EXT4_BG_BLOCK_BITMAP_CSUM_HI_END \ + (offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \ + sizeof(__le16)) + /* * Structure of a flex block group info */ @@ -1844,6 +1851,12 @@ struct mmpd_data { /* bitmap.c */ extern unsigned int ext4_count_free(struct buffer_head *, unsigned); +void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + struct ext4_group_desc *gdp, + struct buffer_head *bh, int sz); +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); /* balloc.c */ extern unsigned int ext4_block_group(struct super_block *sb, @@ -2094,6 +2107,13 @@ extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group, extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group, struct ext4_group_desc *gdp); +static inline int ext4_has_group_desc_csum(struct super_block *sb) +{ + return EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_GDT_CSUM | + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM); +} + static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es) { return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) | diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 8207dfab2682..fb897ec183c8 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -82,12 +82,17 @@ 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_inode_bitmap_csum_set(sb, block_group, gdp, bh, + EXT4_INODES_PER_GROUP(sb) / 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_inode_bitmap_csum_set(sb, block_group, gdp, bh, + EXT4_INODES_PER_GROUP(sb) / 8); + gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); return EXT4_INODES_PER_GROUP(sb); } @@ -128,12 +133,12 @@ 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); @@ -141,6 +146,7 @@ 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; @@ -154,7 +160,7 @@ 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 reading @@ -171,6 +177,20 @@ 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_inode_bitmap_csum_verify(sb, block_group, desc, bh, + EXT4_INODES_PER_GROUP(sb) / 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; } @@ -276,6 +296,8 @@ 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_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh, + EXT4_INODES_PER_GROUP(sb) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp); ext4_unlock_group(sb, block_group); @@ -751,7 +773,7 @@ got: goto fail; /* Update the relevant bg descriptor fields */ - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { + if (ext4_has_group_desc_csum(sb)) { int free; struct ext4_group_info *grp = ext4_get_group_info(sb, group); @@ -782,7 +804,9 @@ got: atomic_inc(&sbi->s_flex_groups[f].used_dirs); } } - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { + if (ext4_has_group_desc_csum(sb)) { + ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh, + EXT4_INODES_PER_GROUP(sb) / 8); gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); ext4_unlock_group(sb, group); } diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index e0374757a94b..7810cac241e1 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1069,6 +1069,47 @@ static int ext4_add_new_descs(handle_t *handle, struct super_block *sb, return err; } +static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block) +{ + struct buffer_head *bh = sb_getblk(sb, block); + if (!bh) + return NULL; + + if (bitmap_uptodate(bh)) + return bh; + + lock_buffer(bh); + if (bh_submit_read(bh) < 0) { + unlock_buffer(bh); + brelse(bh); + return NULL; + } + unlock_buffer(bh); + + return bh; +} + +static int ext4_set_bitmap_checksums(struct super_block *sb, + ext4_group_t group, + struct ext4_group_desc *gdp, + struct ext4_new_group_data *group_data) +{ + struct buffer_head *bh; + + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 0; + + bh = ext4_get_bitmap(sb, group_data->inode_bitmap); + if (!bh) + return -EIO; + ext4_inode_bitmap_csum_set(sb, group, gdp, bh, + EXT4_INODES_PER_GROUP(sb) / 8); + brelse(bh); + + return 0; +} + /* * ext4_setup_new_descs() will set up the group descriptor descriptors of a flex bg */ @@ -1101,6 +1142,12 @@ static int ext4_setup_new_descs(handle_t *handle, struct super_block *sb, memset(gdp, 0, EXT4_DESC_SIZE(sb)); ext4_block_bitmap_set(sb, gdp, group_data->block_bitmap); ext4_inode_bitmap_set(sb, gdp, group_data->inode_bitmap); + err = ext4_set_bitmap_checksums(sb, group, gdp, group_data); + if (err) { + ext4_std_error(sb, err); + break; + } + ext4_inode_table_set(sb, gdp, group_data->inode_table); ext4_free_group_clusters_set(sb, gdp, EXT4_B2C(sbi, group_data->free_blocks_count)); -- 2.39.2