Don't fail tests when the timestamp read resolution is higher than write.

Previously, if bup was able to read path timestamps at a higher
resolution than it could write them, tests would fail.  This situation
can occur (for example) when the stat() resolution is 1ns, but either
the underlying filesystem's isn't, or bup wasn't able to find
utimensat at build time.

To fix this, compute the maximum resolution of the test filesystem
(via "t/ns-timestamp-resolutions HERE"), and then limit the "bup
xstat" timestamp resolution in the tests to match via a new
--mtime-resolution argument.

For completeness, also add --atime-resolution and --ctime-resolution
arguments.

Thanks to Tim Riemenschneider <t.riemenschneider@detco.de> for
reporting the problem.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>

diff --git a/cmd/xstat-cmd.py b/cmd/xstat-cmd.py
index 11b0b58fd179e4c8a410fa2746fdfd3eaa181289..85071d21a7e232590c1079b8160fa59808587d16 100755 (executable)
--- a/cmd/xstat-cmd.py
+++ b/cmd/xstat-cmd.py
@@ -5,7 +5,25 @@
 # Public License as described in the bup LICENSE file.
 import sys, stat, errno
 from bup import metadata, options, xstat
-from bup.helpers import handle_ctrl_c, saved_errors, add_error, log
+from bup.helpers import handle_ctrl_c, parse_timestamp, saved_errors, \
+    add_error, log
+
+
+def parse_timestamp_arg(field, value):
+    res = str(value) # Undo autoconversion.
+    try:
+        res = parse_timestamp(res)
+    except ValueError, ex:
+        if ex.args:
+            o.fatal('unable to parse %s resolution "%s" (%s)'
+                    % (field, value, ex))
+        else:
+            o.fatal('unable to parse %s resolution "%s"' % (field, value))
+
+    if res != 1 and res % 10:
+        o.fatal('%s resolution "%s" must be a power of 10' % (field, value))
+    return res
+
 
 optspec = """
 bup xstat pathinfo [OPTION ...] <PATH ...>
@@ -14,6 +32,9 @@ v,verbose       increase log output (can be used more than once)
 q,quiet         don't show progress meter
 exclude-fields= exclude comma-separated fields
 include-fields= include comma-separated fields (definitive if first)
+atime-resolution=  limit s, ms, us, ns, 10ns (value must be a power of 10) [ns]
+mtime-resolution=  limit s, ms, us, ns, 10ns (value must be a power of 10) [ns]
+ctime-resolution=  limit s, ms, us, ns, 10ns (value must be a power of 10) [ns]
 """
 
 target_filename = ''
@@ -24,6 +45,10 @@ handle_ctrl_c()
 o = options.Options(optspec)
 (opt, flags, remainder) = o.parse(sys.argv[1:])
 
+atime_resolution = parse_timestamp_arg('atime', opt.atime_resolution)
+mtime_resolution = parse_timestamp_arg('mtime', opt.mtime_resolution)
+ctime_resolution = parse_timestamp_arg('ctime', opt.ctime_resolution)
+
 treat_include_fields_as_definitive = True
 for flag, value in flags:
     if flag == '--exclude-fields':
@@ -61,6 +86,12 @@ for path in remainder:
     if metadata.verbose >= 0:
         if not first_path:
             print
+        if atime_resolution != 1:
+            m.atime = (m.atime / atime_resolution) * atime_resolution
+        if mtime_resolution != 1:
+            m.mtime = (m.mtime / mtime_resolution) * mtime_resolution
+        if ctime_resolution != 1:
+            m.ctime = (m.ctime / ctime_resolution) * ctime_resolution
         print metadata.detailed_str(m, active_fields)
         first_path = False
 

diff --git a/lib/bup/helpers.py b/lib/bup/helpers.py
index c090bc0ab09e0f13a68019b32b88ba3cf5a957bf..45fcbb58cffecd317b202fb22c723d5fe37dfa8a 100644 (file)
--- a/lib/bup/helpers.py
+++ b/lib/bup/helpers.py
@@ -625,6 +625,26 @@ def mmap_readwrite_private(f, sz = 0, close=True):
                     close)
 
 
+def parse_timestamp(epoch_str):
+    """Return the number of nanoseconds since the epoch that are described
+by epoch_str (100ms, 100ns, ...); when epoch_str cannot be parsed,
+throw a ValueError that may contain additional information."""
+    ns_per = {'s' :  1000000000,
+              'ms' : 1000000,
+              'us' : 1000,
+              'ns' : 1}
+    match = re.match(r'^((?:[-+]?[0-9]+)?)(s|ms|us|ns)$', epoch_str)
+    if not match:
+        if re.match(r'^([-+]?[0-9]+)$', epoch_str):
+            raise ValueError('must include units, i.e. 100ns, 100ms, ...')
+        raise ValueError()
+    (n, units) = match.group(1, 2)
+    if not n:
+        n = 1
+    n = int(n)
+    return n * ns_per[units]
+
+
 def parse_num(s):
     """Parse data size information into a float number.
 

diff --git a/t/ns-timestamp-resolutions b/t/ns-timestamp-resolutions
new file mode 100755 (executable)
index 0000000..d1bb785
--- /dev/null
+++ b/t/ns-timestamp-resolutions
@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+
+import os, sys
+
+argv = sys.argv
+exe = os.path.realpath(argv[0])
+exepath = os.path.split(exe)[0] or '.'
+exeprefix = os.path.split(os.path.abspath(exepath))[0]
+
+# fix the PYTHONPATH to include our lib dir
+libpath = os.path.join(exepath, '..', 'lib')
+sys.path[:0] = [libpath]
+os.environ['PYTHONPATH'] = libpath + ':' + os.environ.get('PYTHONPATH', '')
+
+import bup.xstat as xstat
+from bup.helpers import handle_ctrl_c, saved_errors
+from bup import metadata, options
+
+optspec = """
+ns-timestamp-resolutions TEST_FILE_NAME
+--
+"""
+
+handle_ctrl_c()
+
+o = options.Options(optspec)
+(opt, flags, extra) = o.parse(sys.argv[1:])
+
+if len(extra) != 1:
+    o.fatal('must specify a test file name')
+
+target = extra[0]
+
+open(target, 'w').close()
+xstat.utime(target, (123456789, 123456789))
+meta = metadata.from_path(target)
+
+def ns_resolution(x):
+    n = 1;
+    while n < 10**9 and x % 10 == 0:
+        x /= 10
+        n *= 10
+    return n
+
+print ns_resolution(meta.atime), ns_resolution(meta.mtime)
+
+if saved_errors:
+    log('warning: %d errors encountered\n' % len(saved_errors))
+    sys.exit(1)

diff --git a/t/test-meta.sh b/t/test-meta.sh
index b247e7ad7be2c3d3d26074a82dc996cbb0289e3e..4f8c0c40a4c11190325fd26970c100cc6f0aad48 100755 (executable)
--- a/t/test-meta.sh
+++ b/t/test-meta.sh
@@ -7,6 +7,15 @@ set -o pipefail
 TOP="$(WVPASS pwd)" || exit $?
 export BUP_DIR="$TOP/buptest.tmp"
 
+WVPASS force-delete "$TOP/bupmeta.tmp"
+timestamp_resolutions="$(t/ns-timestamp-resolutions "$TOP/bupmeta.tmp")" \
+    || exit $?
+WVPASS rm "$TOP/bupmeta.tmp"
+atime_resolution="$(echo $timestamp_resolutions | WVPASS cut -d' ' -f 1)" \
+    || exit $?
+mtime_resolution="$(echo $timestamp_resolutions | WVPASS cut -d' ' -f 2)" \
+    || exit $?
+
 bup()
 {
     "$TOP/bup" "$@"
@@ -34,7 +43,9 @@ genstat()
         export PATH="$TOP:$PATH" # pick up bup
         # Skip atime (test elsewhere) to avoid the observer effect.
         WVPASS find . | WVPASS sort \
-            | WVPASS xargs bup xstat --exclude-fields ctime,atime,size
+            | WVPASS xargs bup xstat \
+            --mtime-resolution "$mtime_resolution"ns \
+            --exclude-fields ctime,atime,size
     )
 }