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SubjectRe: [Ocfs2-devel] [PATCH] ocfs2: dlmglue: clean up timestamp handling


On 06-19 17:58, Arnd Bergmann wrote:
> The handling of timestamps outside of the 1970..2038 range in the dlm
> glue is rather inconsistent: on 32-bit architectures, this has always
> wrapped around to negative timestamps in the 1902..1969 range, while on
> 64-bit kernels all timestamps are interpreted as positive 34 bit numbers
> in the 1970..2514 year range.
>
> Now that the VFS code handles 64-bit timestamps on all architectures,
> we can make the behavior more consistent here, and return the same result
> that we had on 64-bit already, making the file system y2038 safe in the
> process. Outside of dlmglue, it already uses 64-bit on-disk timestamps
> anway, so that part is fine.
>
> For consistency, I'm changing ocfs2_pack_timespec() to clamp
> anything outside of the supported range to the minimum and maximum
> values. This avoids a possible ambiguity of values before 1970
> in particular, which used to be interpreted as times at the end of the
> 2514 range previously.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Will all values written to LVB be the same with or without the patch?
I am considering the situation where in a cluster some machines have this
patch and some don't. Depending on that, this may require a version
change.

> ---
> fs/ocfs2/dlmglue.c | 26 +++++++++-----------------
> 1 file changed, 9 insertions(+), 17 deletions(-)
>
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 0ff424c6d17c..50610a9ed9f4 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -2121,10 +2121,10 @@ static void ocfs2_downconvert_on_unlock(struct ocfs2_super *osb,
>
> /* LVB only has room for 64 bits of time here so we pack it for
> * now. */
> -static u64 ocfs2_pack_timespec(struct timespec *spec)
> +static u64 ocfs2_pack_timespec(struct timespec64 *spec)
> {
> u64 res;
> - u64 sec = spec->tv_sec;
> + u64 sec = clamp_t(time64_t, spec->tv_sec, 0, 0x3ffffffffull);
> u32 nsec = spec->tv_nsec;
>
> res = (sec << OCFS2_SEC_SHIFT) | (nsec & OCFS2_NSEC_MASK);
> @@ -2140,7 +2140,6 @@ static void __ocfs2_stuff_meta_lvb(struct inode *inode)
> struct ocfs2_inode_info *oi = OCFS2_I(inode);
> struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
> struct ocfs2_meta_lvb *lvb;
> - struct timespec ts;
>
> lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
>
> @@ -2161,15 +2160,12 @@ static void __ocfs2_stuff_meta_lvb(struct inode *inode)
> lvb->lvb_igid = cpu_to_be32(i_gid_read(inode));
> lvb->lvb_imode = cpu_to_be16(inode->i_mode);
> lvb->lvb_inlink = cpu_to_be16(inode->i_nlink);
> - ts = timespec64_to_timespec(inode->i_atime);
> lvb->lvb_iatime_packed =
> - cpu_to_be64(ocfs2_pack_timespec(&ts));
> - ts = timespec64_to_timespec(inode->i_ctime);
> + cpu_to_be64(ocfs2_pack_timespec(&inode->i_atime));
> lvb->lvb_ictime_packed =
> - cpu_to_be64(ocfs2_pack_timespec(&ts));
> - ts = timespec64_to_timespec(inode->i_mtime);
> + cpu_to_be64(ocfs2_pack_timespec(&inode->i_ctime));
> lvb->lvb_imtime_packed =
> - cpu_to_be64(ocfs2_pack_timespec(&ts));
> + cpu_to_be64(ocfs2_pack_timespec(&inode->i_mtime));
> lvb->lvb_iattr = cpu_to_be32(oi->ip_attr);
> lvb->lvb_idynfeatures = cpu_to_be16(oi->ip_dyn_features);
> lvb->lvb_igeneration = cpu_to_be32(inode->i_generation);
> @@ -2178,7 +2174,7 @@ static void __ocfs2_stuff_meta_lvb(struct inode *inode)
> mlog_meta_lvb(0, lockres);
> }
>
> -static void ocfs2_unpack_timespec(struct timespec *spec,
> +static void ocfs2_unpack_timespec(struct timespec64 *spec,
> u64 packed_time)
> {
> spec->tv_sec = packed_time >> OCFS2_SEC_SHIFT;
> @@ -2187,7 +2183,6 @@ static void ocfs2_unpack_timespec(struct timespec *spec,
>
> static void ocfs2_refresh_inode_from_lvb(struct inode *inode)
> {
> - struct timespec ts;
> struct ocfs2_inode_info *oi = OCFS2_I(inode);
> struct ocfs2_lock_res *lockres = &oi->ip_inode_lockres;
> struct ocfs2_meta_lvb *lvb;
> @@ -2215,15 +2210,12 @@ static void ocfs2_refresh_inode_from_lvb(struct inode *inode)
> i_gid_write(inode, be32_to_cpu(lvb->lvb_igid));
> inode->i_mode = be16_to_cpu(lvb->lvb_imode);
> set_nlink(inode, be16_to_cpu(lvb->lvb_inlink));
> - ocfs2_unpack_timespec(&ts,
> + ocfs2_unpack_timespec(&inode->i_atime,
> be64_to_cpu(lvb->lvb_iatime_packed));
> - inode->i_atime = timespec_to_timespec64(ts);
> - ocfs2_unpack_timespec(&ts,
> + ocfs2_unpack_timespec(&inode->i_mtime,
> be64_to_cpu(lvb->lvb_imtime_packed));
> - inode->i_mtime = timespec_to_timespec64(ts);
> - ocfs2_unpack_timespec(&ts,
> + ocfs2_unpack_timespec(&inode->i_ctime,
> be64_to_cpu(lvb->lvb_ictime_packed));
> - inode->i_ctime = timespec_to_timespec64(ts);
> spin_unlock(&oi->ip_lock);
> }
>
> --
> 2.9.0
>
>
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel@oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel

--
Goldwyn

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