ocfs2: dlmglue: clean up timestamp handling

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.

Link: http://lkml.kernel.org/r/20180619155826.4106487-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 178cb9e6772ac2c3135ecfe822081ad1820399e1..7c835824247eb7a64446467b03080f07f67aa90e 100644 (file)
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2123,10 +2123,10 @@ 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);
@@ -2142,7 +2142,6 @@ 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);
 
@@ -2163,15 +2162,12 @@ 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);
@@ -2180,7 +2176,7 @@ out:
        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;
@@ -2189,7 +2185,6 @@ 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;
@@ -2217,15 +2212,12 @@ 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);
 }