Compute and verify the checksum of the block bitmap; this checksum is stored in
the block group descriptor.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/ext4/balloc.c | 43 ++++++++++++++++++++++++++++++++++---------
fs/ext4/ext4.h | 7 ++++++-
fs/ext4/ialloc.c | 5 +++++
fs/ext4/mballoc.c | 34 ++++++++++++++++++++++++++++++++++
4 files changed, 79 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index f8224ad..36d3020 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -105,6 +105,10 @@ 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_bitmap_csum_set(sb, block_group,
+ &gdp->bg_block_bitmap_csum, bh,
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) /
+ 8);
return 0;
}
memset(bh->b_data, 0, sb->s_blocksize);
@@ -175,6 +179,11 @@ 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_bitmap_csum_set(sb, block_group,
+ &gdp->bg_block_bitmap_csum, bh,
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 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 +241,10 @@ 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 +321,12 @@ 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 +345,7 @@ 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 +362,27 @@ 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_bitmap_csum_verify(sb, block_group,
+ desc->bg_block_bitmap_csum, bh,
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 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/ext4.h b/fs/ext4/ext4.h
index 248cbd2..df149b3 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -269,7 +269,8 @@ struct ext4_group_desc
__le16 bg_free_inodes_count_lo;/* Free inodes count */
__le16 bg_used_dirs_count_lo; /* Directories count */
__le16 bg_flags; /* EXT4_BG_flags (INODE_UNINIT, etc) */
- __u32 bg_reserved[2]; /* Likely block/inode bitmap checksum */
+ __u32 bg_reserved[1]; /* unclaimed */
+ __le32 bg_block_bitmap_csum; /* crc32c(uuid+group+bbitmap) */
__le16 bg_itable_unused_lo; /* Unused inodes count */
__le16 bg_checksum; /* crc16(sb_uuid+group+desc) */
__le32 bg_block_bitmap_hi; /* Blocks bitmap block MSB */
@@ -1731,6 +1732,10 @@ void ext4_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
__le32 *csum, 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 53faffc..a335d19 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -984,6 +984,11 @@ 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_bitmap_csum_set(sb, group,
+ &gdp->bg_block_bitmap_csum,
+ block_bitmap_bh,
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) /
+ 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..8dc3055 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -895,6 +895,33 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
if (bh[i] && !buffer_uptodate(bh[i]))
goto out;
+ for (i = 0; i < groups_per_page; i++) {
+ struct ext4_group_desc *desc;
+
+ if (!bh[i] || !bh[i]->b_end_io)
+ continue;
+ desc = ext4_get_group_desc(sb, first_group + i, NULL);
+ if (!desc)
+ goto out;
+
+ if (buffer_verified(bh[i]))
+ continue;
+ ext4_lock_group(sb, first_group + i);
+ if (!ext4_valid_block_bitmap(sb, desc, first_group + i,
+ bh[i]) ||
+ !ext4_bitmap_csum_verify(sb, first_group + i,
+ desc->bg_block_bitmap_csum, bh[i],
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) /
+ 8)) {
+ ext4_unlock_group(sb, first_group + i);
+ ext4_error(sb, "Corrupt block bitmap, group = %u",
+ first_group + i);
+ goto out;
+ }
+ ext4_unlock_group(sb, first_group + i);
+ set_buffer_verified(bh[i]);
+ }
+
err = 0;
first_block = page->index * blocks_per_page;
for (i = 0; i < blocks_per_page; i++) {
@@ -2829,6 +2856,9 @@ 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_bitmap_csum_set(sb, ac->ac_b_ex.fe_group,
+ &gdp->bg_block_bitmap_csum, bitmap_bh,
+ (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 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 +4668,8 @@ do_more:
ret = ext4_free_blks_count(sb, gdp) + count;
ext4_free_blks_set(sb, gdp, ret);
+ ext4_bitmap_csum_set(sb, block_group, &gdp->bg_block_bitmap_csum,
+ bitmap_bh, (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 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 +4812,8 @@ 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_bitmap_csum_set(sb, block_group, &desc->bg_block_bitmap_csum,
+ bitmap_bh, (EXT4_BLOCKS_PER_GROUP(sb) + 7) / 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);
--
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