On 2025/8/13 22:53, Greg Kroah-Hartman wrote:

On Wed, Aug 13, 2025 at 08:01:51PM +0530, Naresh Kamboju wrote:

quoted

Hi Greg,

quoted

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2)

The following list of LTP syscalls failure noticed on qemu-arm64 with
stable-rc 6.16.1-rc1 with CONFIG_ARM64_64K_PAGES=y build configuration.

Most failures report ENOSPC (28) or mkswap errors, which may be related
to disk space handling in the 64K page configuration on qemu-arm64.

The issue is reproducible on multiple runs.

* qemu-arm64, ltp-syscalls - 64K page size test failures list,

  - fallocate04
  - fallocate05
  - fdatasync03
  - fsync01
  - fsync04
  - ioctl_fiemap01
  - swapoff01
  - swapoff02
  - swapon01
  - swapon02
  - swapon03
  - sync01
  - sync_file_range02
  - syncfs01

Reproducibility:
 - 64K config above listed test fails
 - 4K config above listed test pass.

Regression Analysis:
- New regression? yes

Regression from 6.16?  Or just from 6.15.y?

Based on available data, the issue is not present in v6.16 or v6.15.

Anders, bisected this regression and found,

  ext4: correct the reserved credits for extent conversion
    [ Upstream commit 95ad8ee45cdbc321c135a2db895d48b374ef0f87 ]

Report lore link,

https://lore.kernel.org/stable/CA+G9fYtBnCSa2zkaCn-oZKYz8jz5FZj0HS7DjSfMeamq3AXqNg@mail.gmail.com/ (local)

Great, and that's also affecting 6.17-rc1 so we are "bug compatible"?
:)

Hi,

This issue has already fixed in 6.17-rc1 through this series:

https://lore.kernel.org/linux-ext4/20250707140814.542883-1-yi.zhang@huaweicloud.com/ (local)


To fix this issue in 6.16, it's necessary to backport the whole series
instead of just pick 5137d6c8906b ("ext4: fix insufficient credits
calculation in ext4_meta_trans_blocks()") and 95ad8ee45cdb {"ext4: correct
the reserved credits for extent conversion").  Otherwise, this will make
the problem more likely to occur.

Thanks,
Yi.