Commit 010054a5 authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
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filemap: Add a version of folio_end_writeback that ignores dropbehind 



Filesystems such as NFS may need to defer dropbehind until after their
2-stage writes are done. This adds a helper
folio_end_writeback_no_dropbehind() that allows them to release the
writeback flag without immediately dropping the folio.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <anna.schumaker@oracle.com>
parent 24bbd533

include/linux/pagemap.h

+1 −0
Original line number Diff line number Diff line
@@ -1221,6 +1221,7 @@ void folio_wait_writeback(struct folio *folio); 
int folio_wait_writeback_killable(struct folio *folio);

void end_page_writeback(struct page *page);

void folio_end_writeback(struct folio *folio);

void folio_end_writeback_no_dropbehind(struct folio *folio);

void folio_end_dropbehind(struct folio *folio);

void folio_wait_stable(struct folio *folio);

void __folio_mark_dirty(struct folio *folio, struct address_space *, int warn);

mm/filemap.c

+23 −6
Original line number Diff line number Diff line
@@ -1628,14 +1628,15 @@ void folio_end_dropbehind(struct folio *folio) 
EXPORT_SYMBOL_GPL(folio_end_dropbehind);



/**

 * folio_end_writeback - End writeback against a folio.

 * folio_end_writeback_no_dropbehind - End writeback against a folio.

 * @folio: The folio.

 *

 * The folio must actually be under writeback.

 * This call is intended for filesystems that need to defer dropbehind.

 *

 * Context: May be called from process or interrupt context.

 */

void folio_end_writeback(struct folio *folio)

void folio_end_writeback_no_dropbehind(struct folio *folio)

{

	VM_BUG_ON_FOLIO(!folio_test_writeback(folio), folio);
@@ -1651,6 +1652,25 @@ void folio_end_writeback(struct folio *folio) 
		folio_rotate_reclaimable(folio);

	}



	if (__folio_end_writeback(folio))

		folio_wake_bit(folio, PG_writeback);



	acct_reclaim_writeback(folio);

}

EXPORT_SYMBOL_GPL(folio_end_writeback_no_dropbehind);



/**

 * folio_end_writeback - End writeback against a folio.

 * @folio: The folio.

 *

 * The folio must actually be under writeback.

 *

 * Context: May be called from process or interrupt context.

 */

void folio_end_writeback(struct folio *folio)

{

	VM_BUG_ON_FOLIO(!folio_test_writeback(folio), folio);



	/*

	 * Writeback does not hold a folio reference of its own, relying

	 * on truncation to wait for the clearing of PG_writeback.
@@ -1658,11 +1678,8 @@ void folio_end_writeback(struct folio *folio) 
	 * reused before the folio_wake_bit().

	 */

	folio_get(folio);

	if (__folio_end_writeback(folio))

		folio_wake_bit(folio, PG_writeback);



	folio_end_writeback_no_dropbehind(folio);

	folio_end_dropbehind(folio);

	acct_reclaim_writeback(folio);

	folio_put(folio);

}

EXPORT_SYMBOL(folio_end_writeback);