ext4: calculate and verify inode checksums
This patch introduces to ext4 the ability to calculate and verify inode checksums. This requires the use of a new ro compatibility flag and some accompanying e2fsprogs patches to provide the relevant features in tune2fs and e2fsck. The inode generation changes have been integrated into this patch. Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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@ -915,6 +915,9 @@ struct ext4_inode_info {
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*/
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tid_t i_sync_tid;
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tid_t i_datasync_tid;
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/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
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__u32 i_csum_seed;
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};
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/*
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@ -850,6 +850,19 @@ got:
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inode->i_generation = sbi->s_next_generation++;
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spin_unlock(&sbi->s_next_gen_lock);
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/* Precompute checksum seed for inode metadata */
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if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
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__u32 csum;
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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__le32 inum = cpu_to_le32(inode->i_ino);
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__le32 gen = cpu_to_le32(inode->i_generation);
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csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
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sizeof(inum));
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ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
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sizeof(gen));
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}
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ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
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ext4_set_inode_state(inode, EXT4_STATE_NEW);
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111
fs/ext4/inode.c
111
fs/ext4/inode.c
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@ -47,6 +47,73 @@
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#define MPAGE_DA_EXTENT_TAIL 0x01
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static __u32 ext4_inode_csum(struct inode *inode, struct ext4_inode *raw,
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struct ext4_inode_info *ei)
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{
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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__u16 csum_lo;
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__u16 csum_hi = 0;
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__u32 csum;
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csum_lo = raw->i_checksum_lo;
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raw->i_checksum_lo = 0;
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
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EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi)) {
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csum_hi = raw->i_checksum_hi;
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raw->i_checksum_hi = 0;
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}
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csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)raw,
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EXT4_INODE_SIZE(inode->i_sb));
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raw->i_checksum_lo = csum_lo;
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
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EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
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raw->i_checksum_hi = csum_hi;
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return csum;
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}
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static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
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struct ext4_inode_info *ei)
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{
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__u32 provided, calculated;
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if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
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cpu_to_le32(EXT4_OS_LINUX) ||
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!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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return 1;
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provided = le16_to_cpu(raw->i_checksum_lo);
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calculated = ext4_inode_csum(inode, raw, ei);
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
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EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
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provided |= ((__u32)le16_to_cpu(raw->i_checksum_hi)) << 16;
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else
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calculated &= 0xFFFF;
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return provided == calculated;
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}
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static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
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struct ext4_inode_info *ei)
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{
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__u32 csum;
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if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
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cpu_to_le32(EXT4_OS_LINUX) ||
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!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
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return;
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csum = ext4_inode_csum(inode, raw, ei);
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raw->i_checksum_lo = cpu_to_le16(csum & 0xFFFF);
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE &&
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EXT4_FITS_IN_INODE(raw, ei, i_checksum_hi))
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raw->i_checksum_hi = cpu_to_le16(csum >> 16);
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}
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static inline int ext4_begin_ordered_truncate(struct inode *inode,
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loff_t new_size)
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{
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@ -3644,6 +3711,39 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
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if (ret < 0)
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goto bad_inode;
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raw_inode = ext4_raw_inode(&iloc);
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
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ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
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if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
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EXT4_INODE_SIZE(inode->i_sb)) {
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EXT4_ERROR_INODE(inode, "bad extra_isize (%u != %u)",
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EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize,
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EXT4_INODE_SIZE(inode->i_sb));
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ret = -EIO;
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goto bad_inode;
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}
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} else
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ei->i_extra_isize = 0;
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/* Precompute checksum seed for inode metadata */
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if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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__u32 csum;
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__le32 inum = cpu_to_le32(inode->i_ino);
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__le32 gen = raw_inode->i_generation;
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csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
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sizeof(inum));
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ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
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sizeof(gen));
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}
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if (!ext4_inode_csum_verify(inode, raw_inode, ei)) {
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EXT4_ERROR_INODE(inode, "checksum invalid");
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ret = -EIO;
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goto bad_inode;
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}
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inode->i_mode = le16_to_cpu(raw_inode->i_mode);
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inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
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inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
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@ -3721,12 +3821,6 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
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}
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if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
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ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
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if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
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EXT4_INODE_SIZE(inode->i_sb)) {
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ret = -EIO;
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goto bad_inode;
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}
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if (ei->i_extra_isize == 0) {
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/* The extra space is currently unused. Use it. */
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ei->i_extra_isize = sizeof(struct ext4_inode) -
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@ -3738,8 +3832,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
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if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
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ext4_set_inode_state(inode, EXT4_STATE_XATTR);
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}
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} else
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ei->i_extra_isize = 0;
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}
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EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
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EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
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@ -3963,6 +4056,8 @@ static int ext4_do_update_inode(handle_t *handle,
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raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
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}
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ext4_inode_csum_set(inode, raw_inode, ei);
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BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
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rc = ext4_handle_dirty_metadata(handle, NULL, bh);
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if (!err)
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@ -152,6 +152,13 @@ flags_out:
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if (!inode_owner_or_capable(inode))
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return -EPERM;
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if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
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ext4_warning(sb, "Setting inode version is not "
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"supported with metadata_csum enabled.");
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return -ENOTTY;
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}
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err = mnt_want_write_file(filp);
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if (err)
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return err;
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