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 <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index fa3af81..5813e7f 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c
@@ -29,3 +29,42 @@
#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 ca96401..7f0ff88 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -317,6 +317,13 @@
__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 @@
/* 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 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 8207dfa..fb897ec 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -82,12 +82,17 @@
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 @@
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_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 @@
*/
set_bitmap_uptodate(bh);
unlock_buffer(bh);
- return bh;
+ goto verify;
}
/*
* submit the buffer_head for reading
@@ -171,6 +177,20 @@
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 @@
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 @@
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 @@
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 e037475..7810cac 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1069,6 +1069,47 @@
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 @@
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));