[PATCH] tests/9p: reduce xattr size to 1k

[PATCH] tests/9p: reduce xattr size to 1k

[Christian Schoenebeck]

On host systems with ext4 and ea_inode capability not enabled, the max. size
for xattr values is slightly below 4k, which caused the new xattr tests to
fail on such host systems.

Reduce the xattr size for our tests to 1k to prevent them to fail on such
host systems.

Reported-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Fixes: 04a62cdfe8 ("tests/9p: add 3 xattr FID limit test cases (local fs driver)")
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
---
 tests/qtest/virtio-9p-test.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
index cfd3c02da4..938b5a4717 100644
--- a/tests/qtest/virtio-9p-test.c
+++ b/tests/qtest/virtio-9p-test.c
@@ -38,11 +38,17 @@
 /*
  * xattr size to be used for xattr tests
  *
- * 64k is the max. xattr size supported by the Linux kernel, However btrfs
- * for instance supports only 16219 bytes. So let's be conservative and
- * just use 8k for the xattr tests.
+ * 64k is the max. xattr size supported by the Linux kernel on high-level VFS
+ * layer. However filesystems impose their own limits:
+ *
+ * - btrfs: 16219 bytes
+ *
+ * - ext4: blocksize - 56 bytes (~4KB) if no ea_inode capability enabled,
+ *         64k if ea_inode enabled
+ *
+ * So let's be conservative and just use 1k for the xattr tests.
  */
-#define TEST_XATTR_SIZE (8 * 1024)
+#define TEST_XATTR_SIZE (1 * 1024)
 
 static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
 {
-- 
2.47.3

Re: [PATCH] tests/9p: reduce xattr size to 1k

[Pierrick Bouvier]

On 7/3/2026 8:26 AM, Christian Schoenebeck wrote:
> On host systems with ext4 and ea_inode capability not enabled, the max. size
> for xattr values is slightly below 4k, which caused the new xattr tests to
> fail on such host systems.
> 
> Reduce the xattr size for our tests to 1k to prevent them to fail on such
> host systems.
> 
> Reported-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> Fixes: 04a62cdfe8 ("tests/9p: add 3 xattr FID limit test cases (local fs driver)")
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>  tests/qtest/virtio-9p-test.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
Tested-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>

Looks good for me, and fix the failure observed.
In case you want the test to be more complete, you may try to detect
ea_node presence, and adapt the size to it.

Regards,
Pierrick

Re: [PATCH] tests/9p: reduce xattr size to 1k

[Christian Schoenebeck]

On Monday, 6 July 2026 23:15:38 CEST Pierrick Bouvier wrote:
> On 7/3/2026 8:26 AM, Christian Schoenebeck wrote:
> > On host systems with ext4 and ea_inode capability not enabled, the max.
> > size for xattr values is slightly below 4k, which caused the new xattr
> > tests to fail on such host systems.
> > 
> > Reduce the xattr size for our tests to 1k to prevent them to fail on such
> > host systems.
> > 
> > Reported-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> > Fixes: 04a62cdfe8 ("tests/9p: add 3 xattr FID limit test cases (local fs
> > driver)") Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> > ---
> > 
> >  tests/qtest/virtio-9p-test.c | 14 ++++++++++----
> >  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> Reviewed-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> Tested-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> 
> Looks good for me, and fix the failure observed.

Good, thanks!

> In case you want the test to be more complete, you may try to detect
> ea_node presence, and adapt the size to it.

No need ATM. These tests actually don't require large xattr values right now.

/Christian

Re: [PATCH] tests/9p: reduce xattr size to 1k

[Christian Schoenebeck]

On Friday, 3 July 2026 17:26:08 CEST Christian Schoenebeck wrote:
> On host systems with ext4 and ea_inode capability not enabled, the max. size
> for xattr values is slightly below 4k, which caused the new xattr tests to
> fail on such host systems.
> 
> Reduce the xattr size for our tests to 1k to prevent them to fail on such
> host systems.
> 
> Reported-by: Pierrick Bouvier <pierrick.bouvier@oss.qualcomm.com>
> Fixes: 04a62cdfe8 ("tests/9p: add 3 xattr FID limit test cases (local fs
> driver)") Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>  tests/qtest/virtio-9p-test.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)

Queued on 9p.next:
https://github.com/cschoenebeck/qemu/commits/9p.next

Thanks!

/Christian