diff options
| author | Shiyang Ruan <ruansy.fnst@fujitsu.com> | 2022-06-03 13:37:31 +0800 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-07-17 17:14:31 -0700 |
| commit | 6061b69b9a550a2ab84e805d0d2315ba6215f112 (patch) | |
| tree | 13fbbd096ab532eb801081d70582d688439c5c91 /include/linux/page-flags.h | |
| parent | 6f643c57d57c56d4677bc05f1fca2ef3f249797c (diff) | |
fsdax: set a CoW flag when associate reflink mappings
Introduce a PAGE_MAPPING_DAX_COW flag to support association with CoW file
mappings. In this case, since the dax-rmap has already took the
responsibility to look up for shared files by given dax page, the
page->mapping is no longer to used for rmap but for marking that this dax
page is shared. And to make sure disassociation works fine, we use
page->index as refcount, and clear page->mapping to the initial state when
page->index is decreased to 0.
With the help of this new flag, it is able to distinguish normal case and
CoW case, and keep the warning in normal case.
Link: https://lkml.kernel.org/r/20220603053738.1218681-8-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.wiliams@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Cc: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 82719d33c0f1..f2ff65f1bf83 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -661,6 +661,12 @@ PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) #define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) #define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) +/* + * Different with flags above, this flag is used only for fsdax mode. It + * indicates that this page->mapping is now under reflink case. + */ +#define PAGE_MAPPING_DAX_COW 0x1 + static __always_inline bool folio_mapping_flags(struct folio *folio) { return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; |