[PATCH 09/13] xfstests: enable large fs testing on ext4

[Dave Chinner <david@fromorbit.com>]

From: Dave Chinner <dchinner@redhat.com>

Now that setting up large filesystem testing on sparse loopback
devices uses a generic method for filling the filesystem, extent
support to ext4 filesystems.

ext4 is slightly more complex to fill as it does not support files
larger than 16TB. Hence a slightly more complex method of using
multiple smaller files to fill the space is necessary.

WARNING: be prepeared for ext4 to take forever to prepare large
filesystems as allocation of large amounts of space (especially as
it approaches ENOSPC) is can take minutes rather than milliseconds

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
---
 common.rc |   90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)

diff --git a/common.rc b/common.rc
index 1026572..690c6a3 100644
--- a/common.rc
+++ b/common.rc
@@ -366,6 +366,93 @@ _scratch_mkfs_xfs()
     return $mkfs_status
 }
 
+_setup_large_ext4_fs()
+{
+	fs_size=$1
+	local tmp_dir=/tmp/
+
+	[ "$LARGE_SCRATCH_DEV" != yes ] && return 0
+	[ -z "$SCRATCH_DEV_EMPTY_SPACE" ] && SCRATCH_DEV_EMPTY_SPACE=0
+	[ $SCRATCH_DEV_EMPTY_SPACE -ge $fs_size ] && return 0
+
+	# Default free space in the FS is 50GB, but you can specify more via
+	# SCRATCH_DEV_EMPTY_SPACE
+	space_to_consume=$(($fs_size - 50*1024*1024*1024 - $SCRATCH_DEV_EMPTY_SPACE))
+
+	# mount the filesystem and create 16TB - 4KB files until we consume
+	# all the necessary space.
+	_scratch_mount 2>&1 >$tmp_dir/mnt.err
+	local status=$?
+	if [ $status -ne 0 ]; then
+		echo "mount failed"
+		cat $tmp_dir/mnt.err >&2
+		rm -f $tmp_dir/mnt.err
+		return $status
+	fi
+	rm -f $tmp_dir/mnt.err
+
+	file_size=$((16*1024*1024*1024*1024 - 4096))
+	nfiles=0
+	while [ $space_to_consume -gt $file_size ]; do
+
+		xfs_io -F -f \
+			-c "truncate $file_size" \
+			-c "falloc -k 0 $file_size" \
+			$SCRATCH_MNT/.use_space.$nfiles 2>&1
+		status=$?
+		if [ $status -ne 0 ]; then
+			break;
+		fi
+
+		space_to_consume=$(( $space_to_consume - $file_size ))
+		nfiles=$(($nfiles + 1))
+	done
+
+	# consume the remaining space.
+	if [ $space_to_consume -gt 0 ]; then
+		xfs_io -F -f \
+			-c "truncate $space_to_consume" \
+			-c "falloc -k 0 $space_to_consume" \
+			$SCRATCH_MNT/.use_space.$nfiles 2>&1
+		status=$?
+	fi
+
+	umount $SCRATCH_MNT
+	if [ $status -ne 0 ]; then
+		echo "large file prealloc failed"
+		cat $tmp_dir/mnt.err >&2
+		return $status
+	fi
+	return 0
+}
+_scratch_mkfs_ext4()
+{
+	local tmp_dir=/tmp/
+
+	/sbin/mkfs -t $FSTYP -- $MKFS_OPTIONS $* $SCRATCH_DEV \
+			2>$tmp_dir.mkfserr 1>$tmp_dir.mkfsstd
+	local mkfs_status=$?
+
+	if [ $mkfs_status -eq 0 -a "$LARGE_SCRATCH_DEV" = yes ]; then
+		# manually parse the mkfs output to get the fs size in bytes
+		fs_size=`cat $tmp_dir.mkfsstd | awk ' \
+			/^Block size/ { split($2, a, "="); bs = a[2] ; } \
+			/ inodes, / { blks = $3 } \
+			/reserved for the super user/ { resv = $1 } \
+			END { fssize = bs * blks - resv; print fssize }'`
+
+		_setup_large_ext4_fs $fs_size
+		mkfs_status=$?
+	fi
+
+	# output stored mkfs output
+	cat $tmp_dir.mkfserr >&2
+	cat $tmp_dir.mkfsstd
+	rm -f $tmp_dir.mkfserr $tmp_dir.mkfsstd
+
+	return $mkfs_status
+}
+
 _scratch_mkfs()
 {
     case $FSTYP in
@@ -381,6 +468,9 @@ _scratch_mkfs()
     btrfs)
         $MKFS_BTRFS_PROG $MKFS_OPTIONS $* $SCRATCH_DEV > /dev/null
 	;;
+    ext4)
+	_scratch_mkfs_ext4 $*
+	;;
     *)
 	yes | $MKFS_PROG -t $FSTYP -- $MKFS_OPTIONS $* $SCRATCH_DEV
 	;;
-- 
1.7.10.4

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