[PATCH v7 8/8] fsdax: add exception for reflinked files

From: Shiyang Ruan
Date: Fri Sep 24 2021 - 09:20:24 EST


For reflinked files, one dax page may be associated more than once with
different fime mapping and index. It will report warning. Now, since
we have introduced dax-RMAP for this case and also have to keep its
functionality for other filesystems who are not support rmap, I add this
exception here.

Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
---
fs/dax.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 2536c105ec7f..1a57211b1bc9 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -352,9 +352,10 @@ static void dax_associate_entry(void *entry, struct address_space *mapping,
for_each_mapped_pfn(entry, pfn) {
struct page *page = pfn_to_page(pfn);

- WARN_ON_ONCE(page->mapping);
- page->mapping = mapping;
- page->index = index + i++;
+ if (!page->mapping) {
+ page->mapping = mapping;
+ page->index = index + i++;
+ }
}
}

@@ -370,9 +371,10 @@ static void dax_disassociate_entry(void *entry, struct address_space *mapping,
struct page *page = pfn_to_page(pfn);

WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
- WARN_ON_ONCE(page->mapping && page->mapping != mapping);
- page->mapping = NULL;
- page->index = 0;
+ if (page->mapping == mapping) {
+ page->mapping = NULL;
+ page->index = 0;
+ }
}
}

--
2.33.0