[PATCH 05/12] generic/562: handle ENOSPC while cloning gracefully

Darrick J. Wong
2024-11-18T23:02:42Z

From: Darrick J. Wong <djwong@kernel.org>

This test creates a couple of patterned files on a tiny filesystem,
fragments the free space, clones one patterned file to the other, and
checks that the entire file was cloned.

However, this test doesn't work on a 64k fsblock filesystem because
we've used up all the free space reservation for the rmapbt, and that
causes the FICLONE to error out with ENOSPC partway through. Hence we
need to detect the ENOSPC and _notrun the test.

That said, it turns out that XFS has been silently dropping error codes
if we managed to make some progress cloning extents. That's ok if the
operation has REMAP_FILE_CAN_SHORTEN like copy_file_range does, but
FICLONE/FICLONERANGE do not permit partial results, so the dropped error
codes is actually an error.

Therefore, this testcase now becomes a regression test for the patch to
fix that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
tests/generic/562 | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/tests/generic/562 b/tests/generic/562
index 91360c4154a6a2..62899945003513 100755
--- a/tests/generic/562
+++ b/tests/generic/562
@@ -15,6 +15,9 @@ _begin_fstest auto clone punch
. ./common/filter
. ./common/reflink

+test "$FSTYP" = "xfs" && \
+ _fixed_by_kernel_commit XXXXXXXXXX "xfs: don't drop errno values when we fail to ficlone the entire range"
+
_require_scratch_reflink
_require_test_program "punch-alternating"
_require_xfs_io_command "fpunch"
@@ -48,8 +51,11 @@ while true; do
done

# Now clone file bar into file foo. This is supposed to succeed and not fail
-# with ENOSPC for example.
-_reflink $SCRATCH_MNT/bar $SCRATCH_MNT/foo >>$seqres.full
+# with ENOSPC for example. However, XFS will sometimes run out of space.
+_reflink $SCRATCH_MNT/bar $SCRATCH_MNT/foo >>$seqres.full 2> $tmp.err
+cat $tmp.err
+grep -q 'No space left on device' $tmp.err && \
+ _notrun "ran out of space while cloning"

# Unmount and mount the filesystem again to verify the operation was durably
# persisted.