Re: [PATCH 0/7] Configurable error behavior [V3]

Brian Foster
2016-05-05T14:11:10Z

On Wed, May 04, 2016 at 05:43:13PM +0200, Carlos Maiolino wrote:
> This is the new revision of this patchset, according to last comments.
>
> This patchset is aimed to implement a configurable error behavior in XFS, and
> most of the design has been done by Dave, so, that's why I kept his signed-off
> in the patches.
>
> This new revision has the detailed changelog written on each patch, but the
> major changes are:
>
> - Detailed changelog by-patch and description fixed to become
> (hopefuly) more clear
> - kept fail_at_unmount as a sysfs attribute
>
>
> Regarding fail_at_unmount, I left it almost exactly as Dave's design, giving his
> comments on the last revision, although, I still think there is no need to keep
> it as a per-error granularity, so, I was wondering if a single, global option in
> /sys/fs/xfs/<dev>/error/fail_at_unmount wouldn't suffice, but, this will require
> a new place to store the value inside kernel, instead of keeping it inside
> struct xfs_error_cfg, or maybe use the same structure but use it outside of the
> m_error_cfg array?
>

I agree with regard to the granularity of fail_at_unmount. This was
brought up previously:

http://oss.sgi.com/archives/xfs/2016-02/msg00558.html

... and I haven't heard a use case for per-error granularity.

I suggest just to pull it out of the error classification stuff entirely
and place it under xfs_mount. E.g., at the same level as "fail_writes"
(but not a DEBUG mode only option).

I'm also wondering whether we need more mechanism for the
fail_at_unmount behavior. For example, instead of defining
XFS_MOUNT_UNMOUNTING, could we just call a function that resets
max_retries (of each class) to 0 in the unmount path? Then maybe call
the mount tunable retry_on_unmount or something like that. Thoughts?

Brian

> First 6 patches are ready, the fail_at_unmount one, need to be re-worked if we
> want it in a less granular way, but until now I don't think we reached any
> decision about how it should be implemented.
>
> fs/xfs/xfs_buf.h | 22 ++++
> fs/xfs/xfs_buf_item.c | 126 ++++++++++++++--------
> fs/xfs/xfs_mount.c | 19 +++-
> fs/xfs/xfs_mount.h | 32 ++++++
> fs/xfs/xfs_sysfs.c | 283 +++++++++++++++++++++++++++++++++++++++++++++++++-
> fs/xfs/xfs_sysfs.h | 3 +
> 6 files changed, 437 insertions(+), 48 deletions(-)
>
> --
> 2.4.11
>
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