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Subject[PATCH] f2fs: initialize page->private when using for our internal use
Date
We need to guarantee it's initially zero. Otherwise, it'll hurt entire flag
operations.

Fixes: b763f3bedc2d ("f2fs: restructure f2fs page.private layout")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/data.c | 2 ++
fs/f2fs/f2fs.h | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3a01a1b50104..d2cf48c5a2e4 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3819,6 +3819,8 @@ int f2fs_migrate_page(struct address_space *mapping,
get_page(newpage);
}

+ /* guarantee to start from no stale private field */
+ set_page_private(newpage, 0);
if (PagePrivate(page)) {
set_page_private(newpage, page_private(page));
SetPagePrivate(newpage);
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 65befc68d88e..ee8eb33e2c25 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1331,7 +1331,8 @@ enum {
#define PAGE_PRIVATE_GET_FUNC(name, flagname) \
static inline bool page_private_##name(struct page *page) \
{ \
- return test_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)) && \
+ return PagePrivate(page) && \
+ test_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)) && \
test_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \
}

@@ -1341,6 +1342,7 @@ static inline void set_page_private_##name(struct page *page) \
if (!PagePrivate(page)) { \
get_page(page); \
SetPagePrivate(page); \
+ set_page_private(page, 0); \
} \
set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); \
set_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \
@@ -1392,6 +1394,7 @@ static inline void set_page_private_data(struct page *page, unsigned long data)
if (!PagePrivate(page)) {
get_page(page);
SetPagePrivate(page);
+ set_page_private(page, 0);
}
set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page));
page_private(page) |= data << PAGE_PRIVATE_MAX;
--
2.32.0.93.g670b81a890-goog
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