[PATCH] ext4/307: Calculate donor size to avoid failures for 64k bs

[Ojaswin Mujoo <ojaswin@linux.ibm.com>]

Hard coding donor size to 250M causes the following failure in e4compat

e4compact.c:68: do_defrag_range: Assertion `donor->length >= len' failed.
./common/rc: line 4616: 1583182 Aborted                 (core dumped)

The issue is that e4compat asserts that the stat.st_size of all files
combined shouldn't be more than that of the donor file. In case of 64k
blocksize, fsstress often creates sparse files which have >3G size even
though their disk utilization is <100M. Since donor file is not big
enough, this trips e4compat causing the failure.

Fix this by dynamically calculating the donor file size based on the
size of all files. Also, make some changes to avoid future ENOSPC like
reducing the -n passed to fsstress to keep the size around 2G and making
sure we use the whole SCRATCH disk instead of 500M.

While we are at it, add some new lines to make the code bit more
readable.

Reported-by: Disha Goel <disgoel@linux.ibm.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
---
 tests/ext4/307 | 41 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/tests/ext4/307 b/tests/ext4/307
index 1f0e42ca..7e7fb9c8 100755
--- a/tests/ext4/307
+++ b/tests/ext4/307
@@ -12,24 +12,57 @@ _begin_fstest auto ioctl rw defrag prealloc
 # Import common functions.
 . ./common/filter
 . ./common/defrag
+
+# Get the total of stat.st_size of each file to determine the
+# size of donor file. We use st_size here instead of blocks used
+# because thats what e4compat.c checks against.
+get_bytes_used() {
+	local filelist="$1"
+	local total=0
+	local blksz=$(_get_block_size $SCRATCH_MNT)
+
+	while IFS= read -r f; do
+		echo -n "File: $f: " >> $seqres.full
+		[[ -z "$f" ]] && continue
+
+		if [[ -f "$f" ]]; then
+			local bytes
+			bytes=$(stat -c %s "$f")
+			total=$((total + bytes))
+			echo $bytes >> $seqres.full
+		fi
+	done < "$filelist"
+
+	echo "Total bytes: $total" >> $seqres.full
+	echo $total
+}
+
 # Disable all sync operations to get higher load
 FSSTRESS_AVOID="$FSSTRESS_AVOID -ffsync=0 -fsync=0 -ffdatasync=0"
 _workout()
 {
+	local blksz=$(_get_block_size $SCRATCH_MNT)
+
 	echo ""
 	echo "Run fsstress"
 	out=$SCRATCH_MNT/fsstress.$$
-	args=`_scale_fsstress_args -p4 -n999 -f setattr=1 -d $out`
+	args=`_scale_fsstress_args -p4 -n500 -f setattr=1 -d $out`
 	echo "fsstress $args" >> $seqres.full
 	_run_fsstress $args
+
 	find $out -type f > $out.list
 	cat $out.list | xargs  md5sum > $out.md5sum
-	usage=`du -sch $out | tail -n1 | gawk '{ print $1 }'`
+
+	bytes=`get_bytes_used $out.list`
+	echo "Total bytes used: $bytes" >> $seqres.full
+
 	echo "Allocate donor file"
-	$XFS_IO_PROG -c "falloc 0 250M" -f $SCRATCH_MNT/donor | _filter_xfs_io
+	$XFS_IO_PROG -c "falloc 0 $bytes" -f $SCRATCH_MNT/donor | _filter_xfs_io
+
 	echo "Perform compacting"
 	cat $out.list | run_check $here/src/e4compact \
 		-i -v -f $SCRATCH_MNT/donor  >> $seqres.full 2>&1
+
 	echo "Check data"
 	run_check md5sum -c $out.md5sum
 }
@@ -41,7 +74,7 @@ _require_scratch
 _require_defrag
 _require_xfs_io_command "falloc"
 
-_scratch_mkfs_sized $((512 * 1024 * 1024)) >> $seqres.full 2>&1
+_scratch_mkfs >> $seqres.full 2>&1
 _scratch_mount
 
 _workout
-- 
2.52.0