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Commit 41a246d1 authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Theodore Ts'o
Browse files

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: default avatarDarrick J. Wong <djwong@us.ibm.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 814525f4

fs/ext4/bitmap.c

+39 −0
Original line number Diff line number Diff line
@@ -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);

}

fs/ext4/ext4.h

+20 −0
Original line number Diff line number Diff line
@@ -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) |

fs/ext4/ialloc.c

+29 −5
Original line number Diff line number Diff line
@@ -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 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode, 
		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 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode, 
			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);

	}

fs/ext4/resize.c

+47 −0
Original line number Diff line number Diff line
@@ -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));