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Re: Review: fix test 004 to account for reserved space

To: David Chinner <dgc@xxxxxxx>
Subject: Re: Review: fix test 004 to account for reserved space
From: Tim Shimmin <tes@xxxxxxx>
Date: Sat, 16 Jun 2007 14:10:53 +1000
Cc: xfs-dev <xfs-dev@xxxxxxx>, xfs-oss <xfs@xxxxxxxxxxx>, asg-qa <asg-qa@xxxxxxxxxxxxxxxxx>
In-reply-to: <20070615062335.GO86004887@xxxxxxx>
References: <20070604063328.GT85884050@xxxxxxx> <20070615062335.GO86004887@xxxxxxx>
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Hi Dave,

Yes that looks not bad.

However, your last proposal, prompted from Nathan, was to adjust f_bavail differently than bfree to account for how much was available in the reserved block space.

struct statfs {
 long    f_type;     /* type of filesystem (see below) */
 long    f_bsize;    /* optimal transfer block size */
 long    f_blocks;   /* total data blocks in file system */
long f_bfree; /* free blocks in fs */ <------ includes reserved long f_bavail; /* free blocks avail to non-superuser */ <------ doesn't include reserved
 long    f_files;    /* total file nodes in file system */
 long    f_ffree;    /* free file nodes in fs */
 fsid_t  f_fsid;     /* file system id */
 long    f_namelen;  /* maximum length of filenames */
 long    f_spare[6]; /* spare for later */
};

And looking at df code it uses bfree in calculation of space used...
the 3rd field of df output.

df code:
---------------------------------------------------------------
    total = fsu.fsu_blocks;
    available = fsu.fsu_bavail;
    negate_available = (fsu.fsu_bavail_top_bit_set
             & (available != UINTMAX_MAX));
    available_to_root = fsu.fsu_bfree;
  }

used = UINTMAX_MAX;
negate_used = false;
if (total != UINTMAX_MAX && available_to_root != UINTMAX_MAX)
  {
    used = total - available_to_root;
    negate_used = (total < available_to_root);
  }

printf (" %*s %*s %*s ",
     width + col1_adjustment,
     df_readable (false, total,
              buf[0], input_units, output_units),
     width, df_readable (negate_used, used,
                 buf[1], input_units, output_units),
     width, df_readable (negate_available, available,
                 buf[2], input_units, output_units));
-----------------------------------------------------------------
example df output:
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda3             18864128   7476720  11387408  40% /
-------------------------------------------------------------------

And indeed we set "used" as a shell variable in test 004 from df but don't seem
to do anything with it.
I think we should check it to verify that we have set bfree correctly.

Cheers,
Tim.

David Chinner wrote:
Ping?

On Mon, Jun 04, 2007 at 04:33:28PM +1000, David Chinner wrote:
With the changes to use some space by default in only in memory
as a reserved pool, df and statfs will now output a fre block
count that is slightly different to  what is held in the superblock.

Update the qa test to account for this change.

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group

---
 xfstests/004 |   35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

Index: xfs-cmds/xfstests/004
===================================================================
--- xfs-cmds.orig/xfstests/004  2006-11-14 19:57:39.000000000 +1100
+++ xfs-cmds/xfstests/004       2007-05-04 16:38:03.957537306 +1000
@@ -67,21 +67,36 @@ xfs_db -r -c "freesp -s" $SCRATCH_DEV >$
 echo "xfs_db for $SCRATCH_DEV" >>$seq.full
 cat $tmp.xfs_db >>$seq.full
+eval `$XFS_IO_PROG -x -c resblks $SCRATCH_MNT 2>&1 \
+       | $AWK_PROG '/available/ { printf "resblks=%u\n", $5 }'`
+echo "resblks gave: resblks=$resblks" >>$seq.full
+
 # check the 'blocks' field from freesp command is OK
 # since 2.6.18, df does not report the 4 blocks per AG that cannot
 # be allocated, hence we check for that exact mismatch.
+# since ~2.6.22, reserved blocks are used by default and df does
+# not report them, hence check for an exact mismatch.
 perl -ne '
-           BEGIN       { $avail ='$avail' * 512;
-                         $answer="(no xfs_db free blocks line?)" }
-           /free blocks (\d+)$/        || next;
-           $freesp = $1 * '$dbsize';
-           if ($freesp == $avail)      { $answer = "yes"; }
-           else {
+       BEGIN   { $avail ='$avail' * 512;
+                 $answer="(no xfs_db free blocks line?)" }
+       /free blocks (\d+)$/    || next;
+       $freesp = $1 * '$dbsize';
+       if ($freesp == $avail) {
+               $answer = "yes";
+       } else {
                $avail = $avail + (('$agcount' + 1) * '$dbsize' * 4);
-               if ($freesp == $avail)  { $answer = "yes"; }
-               else                    { $answer = "no ($freesp != $avail)"; }
-           }
-           END { print "$answer\n" }
+               if ($freesp == $avail) {
+                       $answer = "yes";
+               } else {
+                       $avail = $avail + ('$resblks' * '$dbsize');
+                       if ($freesp == $avail) {
+                               $answer = "yes";
+                       } else {
+                               $answer = "no ($freesp != $avail)";
+                       }
+               }
+       }
+       END     { print "$answer\n" }
        ' <$tmp.xfs_db >$tmp.ans
 ans="`cat $tmp.ans`"
 echo "Checking blocks column same as df: $ans"



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