[PATCH 07/16] ext4: Create bitmap checksum helper functions
From: Darrick J. Wong <hidden>
Date: 2011-09-01 00:31:19
Also in:
linux-fsdevel, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
These helper functions will be used to calculate and verify the block and inode bitmap checksums. Signed-off-by: Darrick J. Wong <redacted> --- fs/ext4/bitmap.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ fs/ext4/ext4.h | 6 ++++++ 2 files changed, 50 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index fa3af81..5421152 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c@@ -9,6 +9,7 @@ #include <linux/buffer_head.h> #include <linux/jbd2.h> +#include <linux/crc32c.h> #include "ext4.h" #ifdef EXT4FS_DEBUG
@@ -29,3 +30,46 @@ unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars) #endif /* EXT4FS_DEBUG */ +__le32 ext4_bitmap_csum(struct super_block *sb, ext4_group_t group, + struct buffer_head *bh, int sz) +{ + __le32 crc; + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT) + return 0; + if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + return 0; + + group = cpu_to_le32(group); + crc = crc32c_le(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); + crc = crc32c_le(crc, (__u8 *)&group, sizeof(group)); + crc = crc32c_le(crc, (__u8 *)bh->b_data, sz); + + return cpu_to_le32(crc); +} + +int ext4_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, + __le32 provided, struct buffer_head *bh, int sz) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (sbi->s_desc_size >= EXT4_MIN_DESC_SIZE_64BIT && + EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) && + (provided != ext4_bitmap_csum(sb, group, bh, sz))) + return 0; + return 1; +} + +void ext4_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + __le32 *csum, struct buffer_head *bh, int sz) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + + if (sbi->s_desc_size >= EXT4_MIN_DESC_SIZE_64BIT && + EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) + *csum = ext4_bitmap_csum(sb, group, bh, sz); +}
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e2361cc..bc7ace1 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h@@ -1722,6 +1722,12 @@ struct mmpd_data { /* bitmap.c */ extern unsigned int ext4_count_free(struct buffer_head *, unsigned); +__le32 ext4_bitmap_csum(struct super_block *sb, ext4_group_t group, + struct buffer_head *bh, int sz); +int ext4_bitmap_csum_verify(struct super_block *sb, ext4_group_t group, + __le32 provided, struct buffer_head *bh, int sz); +void ext4_bitmap_csum_set(struct super_block *sb, ext4_group_t group, + __le32 *csum, struct buffer_head *bh, int sz); /* balloc.c */ extern unsigned int ext4_block_group(struct super_block *sb,