gfs_pio_stat() may change st_mtime/st_atime, if it's called against a never accessed 0-byte file

[gfarm-admin]

Probably this is since the beginning of the gfarm-2.0.0.
And currently the fix for this problem hasn't been scheduled, because it's not known that this causes a severe problem.

NOTE: this problem can be fixed by making gfmd REOPEN protocol return st_mtime/st_atime, and letting gfsd call futimes(2), if the underlying local filesystem supports same or finer time resolution with the corresponding metadata.

Reported by: n-soda

Original Ticket: gfarm/tickets/958

[gfarm-admin]

Original comment by: n-soda

[gfarm-admin]

a regression test for this problem is added in [r10155] as regress/regress/lib/libgfarm/gfarm/gfs_pio_stat/gfs_pio_stat_mtime.sh

Original comment by: n-soda

[gfarm-admin]

• Description has changed:

Diff:

--- old
+++ new
@@ -1,2 +1,4 @@
 Probably this is since the beginning of the gfarm-2.0.0.
 And currently the fix for this problem hasn't been scheduled, because it's not known that this causes a severe problem. 
+
+NOTE: this problem can be fixed by making gfmd REOPEN protocol return st_mtime/st_atime, and letting gfsd call futimes(2)

Original comment by: n-soda

[gfarm-admin]

• Description has changed:

Diff:

--- old
+++ new
@@ -1,4 +1,4 @@
 Probably this is since the beginning of the gfarm-2.0.0.
 And currently the fix for this problem hasn't been scheduled, because it's not known that this causes a severe problem. 
 
-NOTE: this problem can be fixed by making gfmd REOPEN protocol return st_mtime/st_atime, and letting gfsd call futimes(2)
+NOTE: this problem can be fixed by making gfmd REOPEN protocol return st_mtime/st_atime, and letting gfsd call futimes(2), if the underlying local filesystem supports same or finer time resolution with the corresponding metadata.

Original comment by: n-soda

[gfarm-admin]

• Milestone: gfarm-2.6.11 --> gfarm-2.6.26

Original comment by: n-soda