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Diffstat (limited to 'fs/btrfs/subpage.c')
-rw-r--r--fs/btrfs/subpage.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index c9b3821957f7..cb4f97833dc3 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -448,8 +448,25 @@ void btrfs_subpage_set_writeback(const struct btrfs_fs_info *fs_info,
spin_lock_irqsave(&bfs->lock, flags);
bitmap_set(bfs->bitmaps, start_bit, len >> fs_info->sectorsize_bits);
+
+ /*
+ * Don't clear the TOWRITE tag when starting writeback on a still-dirty
+ * folio. Doing so can cause WB_SYNC_ALL writepages() to overlook it,
+ * assume writeback is complete, and exit too early — violating sync
+ * ordering guarantees.
+ */
if (!folio_test_writeback(folio))
- folio_start_writeback(folio);
+ __folio_start_writeback(folio, true);
+ if (!folio_test_dirty(folio)) {
+ struct address_space *mapping = folio_mapping(folio);
+ XA_STATE(xas, &mapping->i_pages, folio->index);
+ unsigned long flags;
+
+ xas_lock_irqsave(&xas, flags);
+ xas_load(&xas);
+ xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE);
+ xas_unlock_irqrestore(&xas, flags);
+ }
spin_unlock_irqrestore(&bfs->lock, flags);
}