From: Baolin Wang <baolin.wang@linux.alibaba.com>
To: "David Hildenbrand (Arm)" <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Gregory Price <gourry@gourry.net>, Zi Yan <ziy@nvidia.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>,
Ying Huang <ying.huang@linux.alibaba.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Michal Hocko <mhocko@suse.com>, Hugh Dickins <hughd@google.com>,
Lukas Czerner <lczerner@redhat.com>,
Carlos Maiolino <cmaiolino@redhat.com>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Daniel Verkamp <dverkamp@chromium.org>,
Jeff Xu <jeffxu@google.com>, Muchun Song <muchun.song@linux.dev>,
Oscar Salvador <osalvador@suse.de>,
David Stevens <stevensd@chromium.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
William Kucharski <william.kucharski@oracle.com>,
Chris Li <chrisl@kernel.org>, Kairui Song <kasong@tencent.com>,
Nhat Pham <nphamcs@gmail.com>, Miaohe Lin <linmiaohe@huawei.com>,
Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 10/16] mm/shmem: discard whole new large folios on fallocate rollback
Date: Tue, 27 Oct 2026 15:26:10 +0800 [thread overview]
Message-ID: <e1aa3fb6-a557-420d-88b5-9864ddfcec2f@linux.alibaba.com> (raw)
In-Reply-To: <20261026-fixes_shmem-v1-10-703206d5fa0c@kernel.org>
On 10/26/26 5:40 PM, David Hildenbrand (Arm) wrote:
> When undoing a failed fallocate(), shmem_undo_range() must discard each
> newly allocated folio. Its second scan instead passes large
> folios to truncate_inode_partial_folio(), which does not necessarily
> discard the entire large folio, but instead tries splitting it to
> discard only the requested range.
>
> For example, with huge=always, a failed allocation starting at offset
> 4 KiB can leave page 0 allocated in an otherwise empty file.
>
> Discard the whole folio when unfalloc is set. Note that we enter this
> path only for folios that are not uptodate, and can consequently be
> dropped without losing any data.
>
> Fixes: 55ac8bbe358b ("mm/shmem: fix race in shmem_undo_range w/THP")
> Cc: stable@vger.kernel.org
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
> ---
Good catch. LGTM.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
next prev parent reply other threads:[~2026-10-27 7:26 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-26 9:40 [PATCH 00/16] mm/shmem: various (urgent?) fixes David Hildenbrand (Arm)
2026-10-26 9:40 ` [PATCH 01/16] mm/mempolicy: charge shared policy nodes David Hildenbrand (Arm)
2026-10-26 13:38 ` Pedro Falcato
2026-10-26 15:44 ` Kiryl Shutsemau
2026-10-26 18:10 ` Zi Yan
2026-10-27 2:57 ` Baolin Wang
2026-10-26 9:40 ` [PATCH 02/16] tmpfs: keep the quota soft limits of an unused id David Hildenbrand (Arm)
2026-10-26 10:53 ` Jan Kara
2026-10-26 11:00 ` David Hildenbrand (Arm)
2026-10-26 9:40 ` [PATCH 03/16] tmpfs: preserve explicitly disabled quota limits David Hildenbrand (Arm)
2026-10-26 13:37 ` Jan Kara
2026-10-26 9:40 ` [PATCH 04/16] mm/shmem: honour F_SEAL_EXEC when an ACL is set David Hildenbrand (Arm)
2026-10-26 13:48 ` Pedro Falcato
2026-10-26 15:52 ` Kiryl Shutsemau
2026-10-26 19:07 ` Zi Yan
2026-10-27 3:45 ` Baolin Wang
2026-10-26 9:40 ` [PATCH 05/16] hugetlbfs: enforce F_SEAL_EXEC in setattr David Hildenbrand (Arm)
2026-10-26 13:49 ` Pedro Falcato
2026-10-26 15:55 ` Kiryl Shutsemau
2026-10-26 19:08 ` Zi Yan
2026-10-26 9:40 ` [PATCH 06/16] mm/shmem: hold off eviction in shmem_writeout() David Hildenbrand (Arm)
2026-10-26 15:14 ` Pedro Falcato
2026-10-26 18:44 ` Nhat Pham
2026-10-26 16:13 ` Kiryl Shutsemau
2026-10-26 18:32 ` Nhat Pham
2026-10-27 5:44 ` Baolin Wang
2026-10-26 9:40 ` [PATCH 07/16] mm/shmem: avoid moving the truncation start backwards David Hildenbrand (Arm)
2026-10-26 16:30 ` Kiryl Shutsemau
2026-10-26 19:21 ` Zi Yan
2026-10-26 21:13 ` David Hildenbrand (Arm)
2026-10-26 22:39 ` Zi Yan
2026-10-26 23:16 ` Zi Yan
2026-10-26 23:24 ` David Hildenbrand (Arm)
2026-10-26 23:28 ` Zi Yan
2026-10-26 23:30 ` David Hildenbrand (Arm)
2026-10-26 9:40 ` [PATCH 08/16] mm/shmem: stop retrying folios that cannot be split David Hildenbrand (Arm)
2026-10-26 16:36 ` Kiryl Shutsemau
2026-10-26 17:08 ` David Hildenbrand (Arm)
2026-10-26 17:59 ` Kiryl Shutsemau
2026-10-27 1:34 ` Zi Yan
2026-10-26 9:40 ` [PATCH 09/16] mm/shmem: preserve data in clean folios when splitting fails David Hildenbrand (Arm)
2026-10-26 17:12 ` Kiryl Shutsemau
2026-10-27 6:35 ` Baolin Wang
2026-10-27 2:00 ` Zi Yan
2026-10-26 9:40 ` [PATCH 10/16] mm/shmem: discard whole new large folios on fallocate rollback David Hildenbrand (Arm)
2026-10-26 17:15 ` Kiryl Shutsemau
2026-10-27 2:12 ` Zi Yan
2026-10-27 7:26 ` Baolin Wang [this message]
2026-10-26 9:40 ` [PATCH 11/16] mm/shmem: rescan after nonuniform folio splitting David Hildenbrand (Arm)
2026-10-26 17:26 ` Kiryl Shutsemau
2026-10-27 2:34 ` Zi Yan
2026-10-27 2:32 ` Zi Yan
2026-10-27 8:00 ` Baolin Wang
2026-10-26 9:40 ` [PATCH 12/16] mm/shmem: fix truncate hang in large swap entry David Hildenbrand (Arm)
2026-10-26 17:39 ` Kiryl Shutsemau
2026-10-26 9:40 ` [PATCH 13/16] mm/shmem: preserve allocation errors when swapping in large entries David Hildenbrand (Arm)
2026-10-26 17:49 ` Kiryl Shutsemau
2026-10-26 9:40 ` [PATCH 14/16] mm/shmem: fix truncate loop after boundary swapin failure David Hildenbrand (Arm)
2026-10-26 17:53 ` Kiryl Shutsemau
2026-10-26 9:40 ` [PATCH 15/16] mm/shmem: fix accounting of swapin-error markers David Hildenbrand (Arm)
2026-10-26 9:40 ` [PATCH 16/16] mm/shmem: fix truncation of files containing only " David Hildenbrand (Arm)
2026-10-26 11:11 ` [PATCH 00/16] mm/shmem: various (urgent?) fixes Baolin Wang
2026-10-26 12:12 ` David Hildenbrand (Arm)
2026-10-26 13:23 ` Kairui Song
2026-10-26 20:08 ` Gregory Price
2026-10-26 21:09 ` David Hildenbrand (Arm)
2026-10-26 21:24 ` Gregory Price (Meta)
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