Re: [pve-devel] [PATCH ceph reef-stable-8] bluefs: fix OSD crash caused by incorrect alignment assertion

["Kefu Chai" <k.chai@proxmox.com>]

Hi Thomas, 

Could you help review this change at your convenience?

On Wed Jan 7, 2026 at 6:41 PM CST, Kefu Chai wrote:
> A regression was introduced in PR #62174 that added a `ceph_assert()`
> statement which incorrectly assumes alloc_unit is always aligned. This
> causes OSD crashes when the assertion fails.
>
> This cherry-pick removes the faulty assertion, resolving the crash while
> maintaining correct functionality for both aligned and unaligned alloc_unit
> values.
>
> Cherry-picked from: https://github.com/ceph/ceph/pull/66056
>
> References:
> - Upstream issue: https://tracker.ceph.com/issues/71235
> - Introduced by: https://github.com/ceph/ceph/pull/62174
>
> Fixes: #7211
>
> Signed-off-by: Kefu Chai <k.chai@proxmox.com>
> ---
>  ...BlueFS-truncate-accept-wierd-alloc_u.patch | 41 +++++++++++++++++++
>  1 file changed, 41 insertions(+)
>  create mode 100644 patches/0018-os-bluestore-In-BlueFS-truncate-accept-wierd-alloc_u.patch
>
> diff --git a/patches/0018-os-bluestore-In-BlueFS-truncate-accept-wierd-alloc_u.patch b/patches/0018-os-bluestore-In-BlueFS-truncate-accept-wierd-alloc_u.patch
> new file mode 100644
> index 00000000000..b2507924523
> --- /dev/null
> +++ b/patches/0018-os-bluestore-In-BlueFS-truncate-accept-wierd-alloc_u.patch
> @@ -0,0 +1,41 @@
> +From 87c90994b2f0c4274208028367cc8f376d0b1d6e Mon Sep 17 00:00:00 2001
> +From: Adam Kupczyk <akupczyk@ibm.com>
> +Date: Tue, 11 Mar 2025 10:52:15 +0000
> +Subject: [PATCH] os/bluestore: In BlueFS::truncate accept wierd alloc_unit
> +
> +The alignment of extents might not reflect current alloc_unit[bdev].
> +It might be caused be either fallback to alternate AU size for SLOW,
> +or change of allocation unit in DB or WAL.
> +In such cases, truncation just leaves extent untouched.
> +
> +Fixes: https://tracker.ceph.com/issues/71235
> +
> +Signed-off-by: Adam Kupczyk <akupczyk@ibm.com>
> +(cherry picked from commit 0da7a2a58c207b97c9bcf4a1dfcd9d09f0e9b954)
> +---
> + src/os/bluestore/BlueFS.cc | 8 +++++---
> + 1 file changed, 5 insertions(+), 3 deletions(-)
> +
> +diff --git a/src/os/bluestore/BlueFS.cc b/src/os/bluestore/BlueFS.cc
> +index 3e7955f6433..93dc6e4753a 100644
> +--- a/src/os/bluestore/BlueFS.cc
> ++++ b/src/os/bluestore/BlueFS.cc
> +@@ -3736,10 +3736,12 @@ int BlueFS::truncate(FileWriter *h, uint64_t offset)/*_WF_L*/
> +         changed_extents = true;
> +         ++p;
> +       } else {
> +-        // cut_off > p->length means that we misaligned the extent
> +-        ceph_assert(cut_off == p->length);
> ++        // Usually cut_off == p->length.
> ++        // Case cut_off > p->length means that we misaligned the extent
> ++        // or alloc size changed in the meantime.
> ++        // In both cases just leave extent untouched.
> +         fnode.allocated = (offset - x_off) + p->length;
> +-        ++p; // leave extent untouched
> ++        ++p;
> +       }
> +       while (p != fnode.extents.end()) {
> +         dirty.pending_release[p->bdev].insert(p->offset, p->length);
> +-- 
> +2.47.3
> +



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