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ext4: make block group checksums use metadata_csum algorithm

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metadata_csum supersedes uninit_bg.  Convert the ROCOMPAT uninit_bg
flag check to a helper function that covers both, and make the
checksum calculation algorithm use either crc16 or the metadata_csum
chosen algorithm depending on which flag is set.  Print a warning if
we try to mount a filesystem with both feature flags set.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong
2012-04-29 18:45:10 -04:00
committed by Theodore Ts'o
parent cc8e94fd12
commit feb0ab32a5
7 changed files with 75 additions and 49 deletions
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79
fs/ext4/super.c
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@@ -1952,43 +1952,69 @@ failed:
return 0;
}
__le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
struct ext4_group_desc *gdp)
static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
struct ext4_group_desc *gdp)
{
int offset;
__u16 crc = 0;
__le32 le_group = cpu_to_le32(block_group);
if (sbi->s_es->s_feature_ro_compat &
cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
int offset = offsetof(struct ext4_group_desc, bg_checksum);
__le32 le_group = cpu_to_le32(block_group);
if ((sbi->s_es->s_feature_ro_compat &
cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
/* Use new metadata_csum algorithm */
__u16 old_csum;
__u32 csum32;
crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
crc = crc16(crc, (__u8 *)gdp, offset);
offset += sizeof(gdp->bg_checksum); /* skip checksum */
/* for checksum of struct ext4_group_desc do the rest...*/
if ((sbi->s_es->s_feature_incompat &
cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
offset < le16_to_cpu(sbi->s_es->s_desc_size))
crc = crc16(crc, (__u8 *)gdp + offset,
le16_to_cpu(sbi->s_es->s_desc_size) -
offset);
old_csum = gdp->bg_checksum;
gdp->bg_checksum = 0;
csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group,
sizeof(le_group));
csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp,
sbi->s_desc_size);
gdp->bg_checksum = old_csum;
crc = csum32 & 0xFFFF;
goto out;
}
/* old crc16 code */
offset = offsetof(struct ext4_group_desc, bg_checksum);
crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
crc = crc16(crc, (__u8 *)gdp, offset);
offset += sizeof(gdp->bg_checksum); /* skip checksum */
/* for checksum of struct ext4_group_desc do the rest...*/
if ((sbi->s_es->s_feature_incompat &
cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
offset < le16_to_cpu(sbi->s_es->s_desc_size))
crc = crc16(crc, (__u8 *)gdp + offset,
le16_to_cpu(sbi->s_es->s_desc_size) -
offset);
out:
return cpu_to_le16(crc);
}
int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
int ext4_group_desc_csum_verify(struct super_block *sb, __u32 block_group,
struct ext4_group_desc *gdp)
{
if ((sbi->s_es->s_feature_ro_compat &
cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
(gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
if (ext4_has_group_desc_csum(sb) &&
(gdp->bg_checksum != ext4_group_desc_csum(EXT4_SB(sb),
block_group, gdp)))
return 0;
return 1;
}
void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group,
struct ext4_group_desc *gdp)
{
if (!ext4_has_group_desc_csum(sb))
return;
gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp);
}
/* Called at mount-time, super-block is locked */
static int ext4_check_descriptors(struct super_block *sb,
ext4_group_t *first_not_zeroed)
@@ -2043,7 +2069,7 @@ static int ext4_check_descriptors(struct super_block *sb,
return 0;
}
ext4_lock_group(sb, i);
if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
if (!ext4_group_desc_csum_verify(sb, i, gdp)) {
ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
"Checksum for group %u failed (%u!=%u)",
i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
@@ -3069,6 +3095,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
goto cantfind_ext4;
sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
/* Warn if metadata_csum and gdt_csum are both set. */
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
ext4_warning(sb, KERN_INFO "metadata_csum and uninit_bg are "
"redundant flags; please run fsck.");
/* Check for a known checksum algorithm */
if (!ext4_verify_csum_type(sb, es)) {
ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
@@ -4400,7 +4433,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
struct ext4_group_desc *gdp =
ext4_get_group_desc(sb, g, NULL);
if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
if (!ext4_group_desc_csum_verify(sb, g, gdp)) {
ext4_msg(sb, KERN_ERR,
"ext4_remount: Checksum for group %u failed (%u!=%u)",
g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),