On Fri, 2 Dec 2022 09:23:11 +0000 Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> wrote: > fsdax page is used not only when CoW, but also mapread. To make the it > easily understood, use 'share' to indicate that the dax page is shared > by more than one extent. And add helper functions to use it. > > Also, the flag needs to be renamed to PAGE_MAPPING_DAX_SHARED. > For those who are wondering what changed, I queued the below incremental patch. From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> Subject: fsdax: introduce page->share for fsdax in reflink mode Date: Fri, 2 Dec 2022 09:23:11 +0000 rename several functions Link: https://lkml.kernel.org/r/1669972991-246-1-git-send-email-ruansy.fnst@xxxxxxxxxxx Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Darrick J. Wong <djwong@xxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/dax.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/fs/dax.c~fsdax-introduce-page-share-for-fsdax-in-reflink-mode-fix +++ a/fs/dax.c @@ -334,7 +334,7 @@ static unsigned long dax_end_pfn(void *e for (pfn = dax_to_pfn(entry); \ pfn < dax_end_pfn(entry); pfn++) -static inline bool dax_mapping_is_shared(struct page *page) +static inline bool dax_page_is_shared(struct page *page) { return (unsigned long)page->mapping == PAGE_MAPPING_DAX_SHARED; } @@ -343,7 +343,7 @@ static inline bool dax_mapping_is_shared * Set the page->mapping with PAGE_MAPPING_DAX_SHARED flag, increase the * refcount. */ -static inline void dax_mapping_set_shared(struct page *page) +static inline void dax_page_bump_sharing(struct page *page) { if ((uintptr_t)page->mapping != PAGE_MAPPING_DAX_SHARED) { /* @@ -357,7 +357,7 @@ static inline void dax_mapping_set_share page->share++; } -static inline unsigned long dax_mapping_decrease_shared(struct page *page) +static inline unsigned long dax_page_drop_sharing(struct page *page) { return --page->share; } @@ -381,7 +381,7 @@ static void dax_associate_entry(void *en struct page *page = pfn_to_page(pfn); if (shared) { - dax_mapping_set_shared(page); + dax_page_bump_sharing(page); } else { WARN_ON_ONCE(page->mapping); page->mapping = mapping; @@ -402,9 +402,9 @@ static void dax_disassociate_entry(void struct page *page = pfn_to_page(pfn); WARN_ON_ONCE(trunc && page_ref_count(page) > 1); - if (dax_mapping_is_shared(page)) { + if (dax_page_is_shared(page)) { /* keep the shared flag if this page is still shared */ - if (dax_mapping_decrease_shared(page) > 0) + if (dax_page_drop_sharing(page) > 0) continue; } else WARN_ON_ONCE(page->mapping && page->mapping != mapping); _
