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Date: Tue, 24 Nov 2015 14:37:02 -0700
From: Andreas Dilger <adilger@...ger.ca>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org, David Turner <novalis@...alis.org>
Subject: Re: [PATCH] e2fsck: Correct ext4 dates generated by old kernels
On Nov 24, 2015, at 2:34 PM, Andreas Dilger <adilger@...ger.ca> wrote:
>
> From: David Turner <novalis@...alis.org>
>
> Older kernels on 64-bit machines would incorrectly encode pre-1970
> ext4 dates as post-2311 dates. Detect and correct this (assuming the
> current date is before 2242).
>
> Includes tests for this, as well as changes to debugfs to correctly
> set crtimes.
>
> Signed-off-by: David Turner <novalis@...alis.org>
>
> - ext2_fs.h: declare EXT4_EPOCH_BITS/EXT4_EPOCH_MASK like the kernel
> instead of in a separate header in an unusual location
> - problem.h: move PR_1_EA_TIME_OUT_OF_RANGE to avoid master conflict
> - problem.c: fix PR_1_EA_TIME_OUT_OF_RANGE PR_*_OK flag usage
> - f_pre_1970_date_encoding/script: run debugfs less often,
> use $MKE2FS instead of mkfs.ext4, fit within 80 columns
>
> Signed-off-by: Andreas Dilger <adilger@...ger.ca>
This is a refresh of David's patch against the current "maint" branch,
with a few fixes as described above. The PR_1_EA_TIME_OUT_OF_RANGE
value was selected to avoid conflicts with values already used on master.
Cheers, Andreas
> ---
> debugfs/set_fields.c | 2 +-
> e2fsck/pass1.c | 41 +++++++++++++++
> e2fsck/problem.c | 5 ++
> e2fsck/problem.h | 3 ++
> lib/ext2fs/ext2_fs.h | 3 ++
> tests/f_pre_1970_date_encoding/expect | 45 +++++++++++++++++
> tests/f_pre_1970_date_encoding/name | 1 +
> tests/f_pre_1970_date_encoding/script | 94 +++++++++++++++++++++++++++++++++++
> 8 files changed, 193 insertions(+), 1 deletion(-)
> create mode 100644 tests/f_pre_1970_date_encoding/expect
> create mode 100644 tests/f_pre_1970_date_encoding/name
> create mode 100644 tests/f_pre_1970_date_encoding/script
>
> diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c
> index 8297e08..8782f80 100644
> --- a/debugfs/set_fields.c
> +++ b/debugfs/set_fields.c
> @@ -212,7 +212,7 @@ static struct field_set_info inode_fields[] = {
> 4, parse_uint },
> { "atime_extra", &set_inode.i_atime_extra, NULL,
> 4, parse_uint },
> - { "crtime", &set_inode.i_crtime, NULL, 4, parse_uint },
> + { "crtime", &set_inode.i_crtime, NULL, 4, parse_time },
> { "crtime_extra", &set_inode.i_crtime_extra, NULL,
> 4, parse_uint },
> { "bmap", NULL, NULL, 4, parse_bmap, FLAG_ARRAY },
> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
> index 3bf481f..a46d344 100644
> --- a/e2fsck/pass1.c
> +++ b/e2fsck/pass1.c
> @@ -348,6 +348,21 @@ fix:
> EXT2_INODE_SIZE(sb), "pass1");
> }
>
> +static int check_inode_extra_negative_epoch(__u32 xtime, __u32 extra) {
> + return (xtime & (1 << 31)) != 0 &&
> + (extra & EXT4_EPOCH_MASK) == EXT4_EPOCH_MASK;
> +}
> +
> +#define CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, xtime) \
> + check_inode_extra_negative_epoch(inode->i_##xtime, \
> + inode->i_##xtime##_extra)
> +
> +/* When today's date is earlier than 2242, we assume that atimes,
> + * ctimes, crtimes, and mtimes with years in the range 2310..2378 are
> + * actually pre-1970 dates mis-encoded.
> + */
> +#define EXT4_EXTRA_NEGATIVE_DATE_CUTOFF 2 * (1LL << 32)
> +
> static void check_inode_extra_space(e2fsck_t ctx, struct problem_context *pctx)
> {
> struct ext2_super_block *sb = ctx->fs->super;
> @@ -388,6 +403,32 @@ static void check_inode_extra_space(e2fsck_t ctx, struct problem_context *pctx)
> /* it seems inode has an extended attribute(s) in body */
> check_ea_in_inode(ctx, pctx);
> }
> +
> + /*
> + * If the inode's extended atime (ctime, crtime, mtime) is stored in
> + * the old, invalid format, repair it.
> + */
> + if (sizeof(time_t) > 4 && ctx->now < EXT4_EXTRA_NEGATIVE_DATE_CUTOFF &&
> + (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, atime) ||
> + CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, ctime) ||
> + CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, crtime) ||
> + CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, mtime))) {
> +
> + if (!fix_problem(ctx, PR_1_EA_TIME_OUT_OF_RANGE, pctx))
> + return;
> +
> + if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, atime))
> + inode->i_atime_extra &= ~EXT4_EPOCH_MASK;
> + if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, ctime))
> + inode->i_ctime_extra &= ~EXT4_EPOCH_MASK;
> + if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, crtime))
> + inode->i_crtime_extra &= ~EXT4_EPOCH_MASK;
> + if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, mtime))
> + inode->i_mtime_extra &= ~EXT4_EPOCH_MASK;
> + e2fsck_write_inode_full(ctx, pctx->ino, pctx->inode,
> + EXT2_INODE_SIZE(sb), "pass1");
> + }
> +
> }
>
> /*
> diff --git a/e2fsck/problem.c b/e2fsck/problem.c
> index f442a33..d90e383 100644
> --- a/e2fsck/problem.c
> +++ b/e2fsck/problem.c
> @@ -987,6 +987,11 @@ static struct e2fsck_problem problem_table[] = {
> N_("@i %i logical @b %b (physical @b %c) violates cluster allocation rules.\nWill fix in pass 1B.\n"),
> PROMPT_NONE, 0 },
>
> + /* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970. */
> + { PR_1_EA_TIME_OUT_OF_RANGE,
> + N_("Timestamp(s) on @i %i beyond 2310-04-04 are likely pre-1970.\n"),
> + PROMPT_FIX, PR_PREEN_OK | PR_NO_OK },
> +
> /* Pass 1b errors */
>
> /* Pass 1B: Rescan for duplicate/bad blocks */
> diff --git a/e2fsck/problem.h b/e2fsck/problem.h
> index 212ed35..25863d3 100644
> --- a/e2fsck/problem.h
> +++ b/e2fsck/problem.h
> @@ -587,6 +587,9 @@ struct problem_context {
> /* Inode logical block is misaligned */
> #define PR_1_MISALIGNED_CLUSTER 0x010074
>
> +/* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970. */
> +#define PR_1_EA_TIME_OUT_OF_RANGE 0x010081
> +
> /*
> * Pass 1b errors
> */
> diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
> index 6c3620c..5b0eb82 100644
> --- a/lib/ext2fs/ext2_fs.h
> +++ b/lib/ext2fs/ext2_fs.h
> @@ -459,6 +459,9 @@ struct ext2_inode_large {
> __u32 i_version_hi; /* high 32 bits for 64-bit version */
> };
>
> +#define EXT4_EPOCH_BITS 2
> +#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
> +
> #define i_dir_acl i_size_high
>
> #if defined(__KERNEL__) || defined(__linux__)
> diff --git a/tests/f_pre_1970_date_encoding/expect b/tests/f_pre_1970_date_encoding/expect
> new file mode 100644
> index 0000000..1a71571
> --- /dev/null
> +++ b/tests/f_pre_1970_date_encoding/expect
> @@ -0,0 +1,45 @@
> +times for year-1909 =
> + ctime: 0x8e475440:00000003
> + atime: 0x8e475440:00000003
> + mtime: 0x8e475440:00000003
> +crtime: 0x8e475440:00000003
> +times for year-1979 =
> + ctime: 0x11db6940:00000000
> + atime: 0x11db6940:00000000
> + mtime: 0x11db6940:00000000
> +crtime: 0x11db6940:00000000
> +times for year-2039 =
> + ctime: 0x82a37b40:00000001
> + atime: 0x82a37b40:00000001
> + mtime: 0x82a37b40:00000001
> +crtime: 0x82a37b40:00000001
> +times for year-2139 =
> + ctime: 0x3e9b9940:00000001
> + atime: 0x3e9b9940:00000001
> + mtime: 0x3e9b9940:00000001
> +crtime: 0x3e9b9940:00000001
> +times for year-1909 =
> + ctime: 0x8e475440:00000000
> + atime: 0x8e475440:00000000
> + mtime: 0x8e475440:00000000
> +crtime: 0x8e475440:00000000
> +times for year-1979 =
> + ctime: 0x11db6940:00000000
> + atime: 0x11db6940:00000000
> + mtime: 0x11db6940:00000000
> +crtime: 0x11db6940:00000000
> +times for year-2039 =
> + ctime: 0x82a37b40:00000001
> + atime: 0x82a37b40:00000001
> + mtime: 0x82a37b40:00000001
> +crtime: 0x82a37b40:00000001
> +times for year-2139 =
> + ctime: 0x3e9b9940:00000001
> + atime: 0x3e9b9940:00000001
> + mtime: 0x3e9b9940:00000001
> +crtime: 0x3e9b9940:00000001
> +times for year-1909 =
> + ctime: 0x8e475440:00000003
> + atime: 0x8e475440:00000003
> + mtime: 0x8e475440:00000003
> +crtime: 0x8e475440:00000003
> diff --git a/tests/f_pre_1970_date_encoding/name b/tests/f_pre_1970_date_encoding/name
> new file mode 100644
> index 0000000..9805324
> --- /dev/null
> +++ b/tests/f_pre_1970_date_encoding/name
> @@ -0,0 +1 @@
> +correct mis-encoded pre-1970 dates
> diff --git a/tests/f_pre_1970_date_encoding/script b/tests/f_pre_1970_date_encoding/script
> new file mode 100644
> index 0000000..e6d7bbd
> --- /dev/null
> +++ b/tests/f_pre_1970_date_encoding/script
> @@ -0,0 +1,94 @@
> +if ! test -x $DEBUGFS_EXE; then
> + echo "$test_name: $test_description: skipped (no debugfs)"
> + return 0
> +fi
> +
> +OUT=$test_name.log
> +TIMESTAMPS=$test_name.timestamps.log
> +EXP=$test_dir/expect
> +FSCK_OPT=-yf
> +
> +create_file_with_xtime_and_extra() {
> + name=$1
> + time=$2
> + extra=$3
> + {
> + echo "write /dev/null $name"
> + for xtime in atime ctime mtime crtime; do
> + echo "set_inode_field $name $xtime @$time"
> + echo "set_inode_field $name ${xtime}_extra $extra"
> + done
> + } | $DEBUGFS -w -f /dev/stdin $TMPFILE >> $OUT 2>&1
> +}
> +
> +get_file_xtime_and_extra() {
> + name=$1
> + echo "times for $name =" >> $TIMESTAMPS
> + $DEBUGFS -R "stat $name" $TMPFILE 2>&1 | egrep '^( a| c| m|cr)time:' |
> + sed 's/ --.*//' >> $TIMESTAMPS
> +}
> +
> +rm -f $OUT $TIMESTAMPS
> +
> +# create an empty ext4 filesystem with 256-byte inodes for testing
> +> $TMPFILE
> +echo mkfs.ext4 -b 1024 -q -I 256 $TMPFILE 5000 >> $OUT
> +$MKE2FS -t ext4 -b 1024 -q -I 256 -F $TMPFILE 5000 >> $OUT 2>&1
> +
> +# this is a pre-1970 file encoded with the old encoding.
> +# fsck should repair this
> +create_file_with_xtime_and_extra year-1909 -1907928000 3
> +
> +# these are all already encoded correctly
> +create_file_with_xtime_and_extra year-1979 299592000 0
> +create_file_with_xtime_and_extra year-2039 2191752000 1
> +create_file_with_xtime_and_extra year-2139 5345352000 1
> +
> +# confirm that the xtime is wrong on the pre-1970 file
> +get_file_xtime_and_extra year-1909
> +
> +# and confirm that it is right on the remaining files
> +get_file_xtime_and_extra year-1979
> +get_file_xtime_and_extra year-2039
> +get_file_xtime_and_extra year-2139
> +
> +# before we repair the filesystem, save off a copy so that
> +# we can use it later
> +
> +cp -a $TMPFILE $TMPFILE.sav
> +
> +# repair the filesystem
> +E2FSCK_TIME=1386393539 $FSCK $FSCK_OPT $TMPFILE >> $OUT 2>&1
> +
> +# check that the dates and xtime_extra on the file is now correct
> +get_file_xtime_and_extra year-1909
> +
> +# check that the remaining dates have not been altered
> +get_file_xtime_and_extra year-1979
> +get_file_xtime_and_extra year-2039
> +get_file_xtime_and_extra year-2139
> +
> +# now we need to check that after the year 2242, e2fsck does not
> +# modify dates with extra_xtime=3
> +
> +# restore the unrepaired filesystem
> +mv $TMPFILE.sav $TMPFILE
> +
> +#retry the repair
> +E2FSCK_TIME=9270393539 $FSCK $FSCK_OPT $TMPFILE >> $OUT 2>&1
> +
> +# check that the 1909 file is unaltered (i.e. it has a post-2378 date)
> +get_file_xtime_and_extra year-1909
> +
> +cmp -s $TIMESTAMPS $EXP
> +status=$?
> +
> +if [ "$status" = 0 ]; then
> + echo "$test_name: $test_description: ok"
> + touch $test_name.ok
> +else
> + echo "$test_name: $test_description: failed"
> + diff $DIFF_OPTS $EXP $TIMESTAMPS > $test_name.failed
> +fi
> +
> +unset OUT TIMESTAMPS EXP FSCK_OPT
> --
> 1.8.0
>
Cheers, Andreas
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