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SubjectRe: [PATCH v6] e2fsck: Correct ext4 dates generated by old kernels.
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Is this version good, or should I make some more improvements?

On Thu, 2013-11-14 at 16:06 -0500, David Turner wrote:
> Not sure what the official subject line format is for revising only
> one of N patches, so I'm trying this one. Let me now if it is wrong.
>
> On Thu, 2013-11-14 at 02:15 -0800, Mark Harris wrote:
> > > + * mis-encoded.
> > > + */
> > > +#define EXT4_EXTRA_NEGATIVE_DATE_CUTOFF 5 * (1ULL << 32)
> >
> > Wouldn't 2242 be 0x200000000ULL, i.e. 2 * (1ULL << 32)?
>
> Actually, it would be 2 * (1LL << 32), because we later use it in a
> comparison with a signed value.
>
> --
> 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).
>
> Signed-off-by: David Turner <novalis@novalis.org>
> ---
> e2fsck/pass1.c | 41 +++++++++++++++++++++++++++++++++++++++++
> e2fsck/problem.c | 4 ++++
> e2fsck/problem.h | 4 ++++
> 3 files changed, 49 insertions(+)
>
> diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
> index ab23e42..e19855f 100644
> --- a/e2fsck/pass1.c
> +++ b/e2fsck/pass1.c
> @@ -348,6 +348,24 @@ fix:
> EXT2_INODE_SIZE(sb), "pass1");
> }
>
> +#define EXT4_EPOCH_BITS 2
> +#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
> +
> +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, 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 +406,29 @@ 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, 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, 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, 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 897693a..b212d00 100644
> --- a/e2fsck/problem.c
> +++ b/e2fsck/problem.c
> @@ -1018,6 +1018,10 @@ static struct e2fsck_problem problem_table[] = {
> N_("@i %i, end of extent exceeds allowed value\n\t(logical @b %c, physical @b %b, len %N)\n"),
> PROMPT_CLEAR, 0 },
>
> + /* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970 dates. */
> + { PR_1_EA_TIME_OUT_OF_RANGE,
> + N_("Timestamp(s) on @i %i beyond 2310-04-04 are likely pre-1970 dates.\n"),
> + PROMPT_FIX | PR_PREEN_OK | PR_NO_OK, 0 },
>
> /* Pass 1b errors */
>
> diff --git a/e2fsck/problem.h b/e2fsck/problem.h
> index ae1ed26..3710638 100644
> --- a/e2fsck/problem.h
> +++ b/e2fsck/problem.h
> @@ -593,6 +593,10 @@ struct problem_context {
> #define PR_1_EXTENT_INDEX_START_INVALID 0x01006D
>
> #define PR_1_EXTENT_END_OUT_OF_BOUNDS 0x01006E
> +
> +/* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970 dates. */
> +#define PR_1_EA_TIME_OUT_OF_RANGE 0x01006F
> +
> /*
> * Pass 1b errors
> */




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