diff options
author | Darrick J. Wong <djwong@us.ibm.com> | 2012-04-29 18:33:10 -0400 |
---|---|---|
committer | Theodore Ts'o <tytso@mit.edu> | 2012-04-29 18:33:10 -0400 |
commit | 41a246d1ff75a95d2be3191ca6e6db139dc0f430 (patch) | |
tree | 0b5150f476dd69726ffe7ea1ba83832c42b441be /fs/ext4/bitmap.c | |
parent | 814525f4df50a196464ce2c7abe91f693203060f (diff) |
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>
Diffstat (limited to 'fs/ext4/bitmap.c')
-rw-r--r-- | fs/ext4/bitmap.c | 39 |
1 files changed, 39 insertions, 0 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) | |||
29 | 29 | ||
30 | #endif /* EXT4FS_DEBUG */ | 30 | #endif /* EXT4FS_DEBUG */ |
31 | 31 | ||
32 | int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, | ||
33 | struct ext4_group_desc *gdp, | ||
34 | struct buffer_head *bh, int sz) | ||
35 | { | ||
36 | __u32 hi; | ||
37 | __u32 provided, calculated; | ||
38 | struct ext4_sb_info *sbi = EXT4_SB(sb); | ||
39 | |||
40 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | ||
41 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | ||
42 | return 1; | ||
43 | |||
44 | provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo); | ||
45 | calculated = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | ||
46 | if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) { | ||
47 | hi = le16_to_cpu(gdp->bg_inode_bitmap_csum_hi); | ||
48 | provided |= (hi << 16); | ||
49 | } else | ||
50 | calculated &= 0xFFFF; | ||
51 | |||
52 | return provided == calculated; | ||
53 | } | ||
54 | |||
55 | void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group, | ||
56 | struct ext4_group_desc *gdp, | ||
57 | struct buffer_head *bh, int sz) | ||
58 | { | ||
59 | __u32 csum; | ||
60 | struct ext4_sb_info *sbi = EXT4_SB(sb); | ||
61 | |||
62 | if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, | ||
63 | EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) | ||
64 | return; | ||
65 | |||
66 | csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz); | ||
67 | gdp->bg_inode_bitmap_csum_lo = cpu_to_le16(csum & 0xFFFF); | ||
68 | if (sbi->s_desc_size >= EXT4_BG_INODE_BITMAP_CSUM_HI_END) | ||
69 | gdp->bg_inode_bitmap_csum_hi = cpu_to_le16(csum >> 16); | ||
70 | } | ||