[PATCH] ext4/060: Skip for dax devices on non-4k page sizes

[PATCH] ext4/060: Skip for dax devices on non-4k page sizes

[Ojaswin Mujoo]

This test tries to trigger an ext4 corruption by resizing past the
meta_bg size (8GB on 4k blocksize) in ext4. Since the test is sensistive
to the size and FS layout it hardcodes the 4kb blocksize ignoring user's
$MKFS_OPTIONS. While this is okay for most cases it fails for dax based
filesystems where system pagesize is non-4k.

One way to work past this is to make the test blocksize agnostic, but
since we still need the disk to be as big as the meta_bg size, this
means for blocksize=64kb filesystems we need a scratch disk of ~4TB
which is not feasible.

Hence, just skip the test if fsdax is used in a non-4k page size system.

Reported-by: Disha Goel <disgoel@linux.ibm.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
---
 tests/ext4/060 | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/ext4/060 b/tests/ext4/060
index b8cc542f..565f8601 100755
--- a/tests/ext4/060
+++ b/tests/ext4/060
@@ -17,6 +17,10 @@ _begin_fstest auto resize quick
 _exclude_fs ext2
 _exclude_fs ext3
 
+if __scratch_uses_fsdax && [[ $(_get_page_size) -ne 4096 ]]; then
+    _notrun "Test does not support dax on non-4k pagesize systems"
+fi
+
 _fixed_by_kernel_commit a6b3bfe176e8 \
 	"ext4: fix corruption during on-line resize"
 
-- 
2.49.0

Re: [PATCH] ext4/060: Skip for dax devices on non-4k page sizes

[Theodore Ts'o]

On Sat, Oct 11, 2025 at 07:17:08PM +0530, Ojaswin Mujoo wrote:
> This test tries to trigger an ext4 corruption by resizing past the
> meta_bg size (8GB on 4k blocksize) in ext4. Since the test is sensistive
> to the size and FS layout it hardcodes the 4kb blocksize ignoring user's
> $MKFS_OPTIONS. While this is okay for most cases it fails for dax based
> filesystems where system pagesize is non-4k.
> 
> One way to work past this is to make the test blocksize agnostic, but
> since we still need the disk to be as big as the meta_bg size, this
> means for blocksize=64kb filesystems we need a scratch disk of ~4TB
> which is not feasible.
> 
> Hence, just skip the test if fsdax is used in a non-4k page size system.
> 
> Reported-by: Disha Goel <disgoel@linux.ibm.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Makes sense to me.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>