[2/3] common: add helper to count number of exclusive extents in a file

Commit Message

Filipe Manana Nov. 5, 2019, 2:56 p.m. UTC

From: Filipe Manana <[e-mail]>

Add a new helper that is similar to _count_extents() except that extents
that are shared several times by the file with itself (reflinked at
different file offsets) are accounted 1 time only, instead of N times.

This is motivated by a subsequent test for btrfs that will use this new
helper, to verify that send streams are issuing reflink operations.

Signed-off-by: Filipe Manana <[e-mail]>
---
 common/rc | 9 +++++++++
 1 file changed, 9 insertions(+)

Patch

diff --git a/common/rc b/common/rc
index 238ffef9..3c412178 100644
--- a/common/rc
+++ b/common/rc
@@ -3202,6 +3202,15 @@  _count_extents()
 	$XFS_IO_PROG -r -c "fiemap" $1 | tail -n +2 | grep -v hole | wc -l
 }
 
+# Similar to _count_extents() but if any extent is shared multiples times in
+# the file (reflinked to different file offsets), it is accounted as 1 extent
+# instead of N extents.
+_count_exclusive_extents()
+{
+	$XFS_IO_PROG -r -c "fiemap" $1 | tail -n +2 | grep -v hole | \
+		cut -d ' ' -f 3 | sort | uniq | wc -l
+}
+
 _count_holes()
 {
 	$XFS_IO_PROG -r -c "fiemap" $1 | tail -n +2 | grep hole | wc -l