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ext4: calculate and verify checksums for inode bitmaps

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Compute and verify the checksum of the inode bitmap; the checkum is
stored in the block group descriptor.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2012-04-29 18:33:10 -04:00 committed by Theodore Ts'o
parent 814525f4df
commit 41a246d1ff
4 changed files with 135 additions and 5 deletions
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39
fs/ext4/bitmap.c
View file

@ -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);
}

20
fs/ext4/ext4.h
View file

@ -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) |

34
fs/ext4/ialloc.c
View file

@ -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);
}

47
fs/ext4/resize.c
View file

@ -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));