From: Rui Wang <r@hev.cc>
To: linux-mm@kvack.org
Cc: Guoqi <chenguoqic@163.com>, Huacai Chen <chenhuacai@loongson.cn>,
Rui Wang <kernel@hev.cc>
Subject: [RFC PATCH] mm/shmem: Fix undo range for failed fallocate
Date: Tue, 1 Nov 2022 11:22:48 +0800 [thread overview]
Message-ID: <20221101032248.819360-1-kernel@hev.cc> (raw)
This patch fixes data loss caused by the fallocate system
call interrupted by a signal.
Bug: https://lore.kernel.org/linux-mm/33b85d82.7764.1842e9ab207.Coremail.chenguoqic@163.com/
Fixes: b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios")
Reported-by: Guoqi Chen <chenguoqic@163.com>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Rui Wang <kernel@hev.cc>
---
mm/shmem.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/mm/shmem.c b/mm/shmem.c
index bc9b84602eec..8c8dce34eafc 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -948,11 +948,13 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT);
if (folio) {
same_folio = lend < folio_pos(folio) + folio_size(folio);
- folio_mark_dirty(folio);
- if (!truncate_inode_partial_folio(folio, lstart, lend)) {
- start = folio->index + folio_nr_pages(folio);
- if (same_folio)
- end = folio->index;
+ if (!unfalloc || !folio_test_uptodate(folio)) {
+ folio_mark_dirty(folio);
+ if (!truncate_inode_partial_folio(folio, lstart, lend)) {
+ start = folio->index + folio_nr_pages(folio);
+ if (same_folio)
+ end = folio->index;
+ }
}
folio_unlock(folio);
folio_put(folio);
@@ -962,9 +964,11 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
if (!same_folio)
folio = shmem_get_partial_folio(inode, lend >> PAGE_SHIFT);
if (folio) {
- folio_mark_dirty(folio);
- if (!truncate_inode_partial_folio(folio, lstart, lend))
- end = folio->index;
+ if (!unfalloc || !folio_test_uptodate(folio)) {
+ folio_mark_dirty(folio);
+ if (!truncate_inode_partial_folio(folio, lstart, lend))
+ end = folio->index;
+ }
folio_unlock(folio);
folio_put(folio);
}
--
2.38.1
next reply other threads:[~2022-11-01 3:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-01 3:22 Rui Wang [this message]
2022-11-02 14:41 ` [RFC PATCH] mm/shmem: Fix undo range for failed fallocate Matthew Wilcox
2022-11-03 7:52 ` hev
2022-11-19 14:45 ` hev
2022-11-19 20:20 ` Matthew Wilcox
2022-11-23 4:02 ` Hugh Dickins
2022-12-05 0:45 ` Hugh Dickins
2022-12-05 0:51 ` [PATCH] tmpfs: fix data loss from " Hugh Dickins
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