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authorChao Yu <yuchao0@huawei.com>2019-03-06 17:30:59 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2019-03-12 18:59:19 -0700
commit240a59156d9bcfabceddb66be449e7b32fb5dc4a (patch)
tree83fdc1204a92dccad9b2dd895c56e75f2a8970ca /fs/f2fs/data.c
parent25720cc05e492467099a2d4d21a50f6ee8555cfd (diff)
downloadlinux-240a59156d9bcfabceddb66be449e7b32fb5dc4a.tar.bz2
f2fs: fix to add refcount once page is tagged PG_private
As Gao Xiang reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202749 f2fs may skip pageout() due to incorrect page reference count. The problem here is that MM defined the rule [1] very clearly that once page was set with PG_private flag, we should increment the refcount in that page, also main flows like pageout(), migrate_page() will assume there is one additional page reference count if page_has_private() returns true. But currently, f2fs won't add/del refcount when changing PG_private flag. Anyway, f2fs should follow MM's rule to make MM's related flows running as expected. [1] https://lore.kernel.org/lkml/2b19b3c4-2bc4-15fa-15cc-27a13e5c7af1@aol.com/ Reported-by: Gao Xiang <gaoxiang25@huawei.com> Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/data.c')
-rw-r--r--fs/f2fs/data.c21
1 files changed, 8 insertions, 13 deletions
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 2510e935301e..fa6318549af5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2714,8 +2714,7 @@ void f2fs_invalidate_page(struct page *page, unsigned int offset,
if (IS_ATOMIC_WRITTEN_PAGE(page))
return f2fs_drop_inmem_page(inode, page);
- set_page_private(page, 0);
- ClearPagePrivate(page);
+ f2fs_clear_page_private(page);
}
int f2fs_release_page(struct page *page, gfp_t wait)
@@ -2729,8 +2728,7 @@ int f2fs_release_page(struct page *page, gfp_t wait)
return 0;
clear_cold_data(page);
- set_page_private(page, 0);
- ClearPagePrivate(page);
+ f2fs_clear_page_private(page);
return 1;
}
@@ -2798,12 +2796,8 @@ int f2fs_migrate_page(struct address_space *mapping,
return -EAGAIN;
}
- /*
- * A reference is expected if PagePrivate set when move mapping,
- * however F2FS breaks this for maintaining dirty page counts when
- * truncating pages. So here adjusting the 'extra_count' make it work.
- */
- extra_count = (atomic_written ? 1 : 0) - page_has_private(page);
+ /* one extra reference was held for atomic_write page */
+ extra_count = atomic_written ? 1 : 0;
rc = migrate_page_move_mapping(mapping, newpage,
page, mode, extra_count);
if (rc != MIGRATEPAGE_SUCCESS) {
@@ -2824,9 +2818,10 @@ int f2fs_migrate_page(struct address_space *mapping,
get_page(newpage);
}
- if (PagePrivate(page))
- SetPagePrivate(newpage);
- set_page_private(newpage, page_private(page));
+ if (PagePrivate(page)) {
+ f2fs_set_page_private(newpage, page_private(page));
+ f2fs_clear_page_private(page);
+ }
if (mode != MIGRATE_SYNC_NO_COPY)
migrate_page_copy(newpage, page);