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From: David Howells <dhowells@redhat.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Steve French <sfrench@samba.org>,
	Dominique Martinet <asmadeus@codewreck.org>
Cc: dhowells@redhat.com, Jeff Layton <jlayton@redhat.com>,
	David Wysochanski <dwysocha@redhat.com>,
	Matthew Wilcox <willy@infradead.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-cachefs@redhat.com, linux-afs@lists.infradead.org,
	linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org,
	ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 22/25] afs: Extract writeback extension into its own function
Date: Wed, 20 Jan 2021 22:25:46 +0000	[thread overview]
Message-ID: <161118154610.1232039.1765365632920504822.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <161118128472.1232039.11746799833066425131.stgit@warthog.procyon.org.uk>

Extract writeback extension into its own function to break up the writeback
function a bit.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/afs/write.c |  109 ++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 67 insertions(+), 42 deletions(-)

diff --git a/fs/afs/write.c b/fs/afs/write.c
index e1791de90478..89c804bfe253 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -490,47 +490,25 @@ static int afs_store_data(struct afs_vnode *vnode, struct iov_iter *iter,
 }
 
 /*
- * Synchronously write back the locked page and any subsequent non-locked dirty
- * pages.
+ * Extend the region to be written back to include subsequent contiguously
+ * dirty pages if possible, but don't sleep while doing so.
+ *
+ * If this page holds new content, then we can include filler zeros in the
+ * writeback.
  */
-static int afs_write_back_from_locked_page(struct address_space *mapping,
-					   struct writeback_control *wbc,
-					   struct page *primary_page,
-					   pgoff_t final_page)
+static void afs_extend_writeback(struct address_space *mapping,
+				 struct afs_vnode *vnode,
+				 long *_count,
+				 pgoff_t start,
+				 pgoff_t final_page,
+				 unsigned *_offset,
+				 unsigned *_to,
+				 bool new_content)
 {
-	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
-	struct iov_iter iter;
 	struct page *pages[8], *page;
-	unsigned long count, priv;
-	unsigned n, offset, to, f, t;
-	pgoff_t start, first, last;
-	loff_t i_size, pos, end;
-	int loop, ret;
-
-	_enter(",%lx", primary_page->index);
-
-	count = 1;
-	if (test_set_page_writeback(primary_page))
-		BUG();
-
-	/* Find all consecutive lockable dirty pages that have contiguous
-	 * written regions, stopping when we find a page that is not
-	 * immediately lockable, is not dirty or is missing, or we reach the
-	 * end of the range.
-	 */
-	start = primary_page->index;
-	priv = page_private(primary_page);
-	offset = afs_page_dirty_from(primary_page, priv);
-	to = afs_page_dirty_to(primary_page, priv);
-	trace_afs_page_dirty(vnode, tracepoint_string("store"), primary_page);
-
-	WARN_ON(offset == to);
-	if (offset == to)
-		trace_afs_page_dirty(vnode, tracepoint_string("WARN"), primary_page);
-
-	if (start >= final_page ||
-	    (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)))
-		goto no_more;
+	unsigned long count = *_count, priv;
+	unsigned offset = *_offset, to = *_to, n, f, t;
+	int loop;
 
 	start++;
 	do {
@@ -551,8 +529,7 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 
 		for (loop = 0; loop < n; loop++) {
 			page = pages[loop];
-			if (to != PAGE_SIZE &&
-			    !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))
+			if (to != PAGE_SIZE && !new_content)
 				break;
 			if (page->index > final_page)
 				break;
@@ -566,8 +543,7 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 			priv = page_private(page);
 			f = afs_page_dirty_from(page, priv);
 			t = afs_page_dirty_to(page, priv);
-			if (f != 0 &&
-			    !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) {
+			if (f != 0 && !new_content) {
 				unlock_page(page);
 				break;
 			}
@@ -593,6 +569,55 @@ static int afs_write_back_from_locked_page(struct address_space *mapping,
 	} while (start <= final_page && count < 65536);
 
 no_more:
+	*_count = count;
+	*_offset = offset;
+	*_to = to;
+}
+
+/*
+ * Synchronously write back the locked page and any subsequent non-locked dirty
+ * pages.
+ */
+static int afs_write_back_from_locked_page(struct address_space *mapping,
+					   struct writeback_control *wbc,
+					   struct page *primary_page,
+					   pgoff_t final_page)
+{
+	struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+	struct iov_iter iter;
+	unsigned long count, priv;
+	unsigned offset, to;
+	pgoff_t start, first, last;
+	loff_t i_size, pos, end;
+	bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
+	int ret;
+
+	_enter(",%lx", primary_page->index);
+
+	count = 1;
+	if (test_set_page_writeback(primary_page))
+		BUG();
+
+	/* Find all consecutive lockable dirty pages that have contiguous
+	 * written regions, stopping when we find a page that is not
+	 * immediately lockable, is not dirty or is missing, or we reach the
+	 * end of the range.
+	 */
+	start = primary_page->index;
+	priv = page_private(primary_page);
+	offset = afs_page_dirty_from(primary_page, priv);
+	to = afs_page_dirty_to(primary_page, priv);
+	trace_afs_page_dirty(vnode, tracepoint_string("store"), primary_page);
+
+	WARN_ON(offset == to);
+	if (offset == to)
+		trace_afs_page_dirty(vnode, tracepoint_string("WARN"), primary_page);
+
+	if (start < final_page &&
+	    (to == PAGE_SIZE || new_content))
+		afs_extend_writeback(mapping, vnode, &count, start, final_page,
+				     &offset, &to, new_content);
+
 	/* We now have a contiguous set of dirty pages, each with writeback
 	 * set; the first page is still locked at this point, but all the rest
 	 * have been unlocked.



  parent reply	other threads:[~2021-01-21  2:19 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20 22:21 [RFC][PATCH 00/25] Network fs helper library & fscache kiocb API David Howells
2021-01-20 22:21 ` [PATCH 01/25] iov_iter: Add ITER_XARRAY David Howells
2021-01-21 13:34   ` Matthew Wilcox
2021-01-21 14:54   ` David Howells
2021-01-20 22:21 ` [PATCH 02/25] vm: Add wait/unlock functions for PG_fscache David Howells
2021-01-20 22:21 ` [PATCH 03/25] mm: Implement readahead_control pageset expansion David Howells
2021-01-20 22:22 ` [PATCH 04/25] vfs: Export rw_verify_area() for use by cachefiles David Howells
2021-01-20 22:22 ` [PATCH 05/25] cachefiles: Drop superfluous readpages aops NULL check David Howells
2021-01-20 22:22 ` [PATCH 06/25] netfs: Make a netfs helper module David Howells
2021-01-20 22:22 ` [PATCH 07/25] netfs: Provide readahead and readpage netfs helpers David Howells
2021-01-20 22:23 ` [PATCH 08/25] netfs: Add tracepoints David Howells
2021-01-20 22:23 ` [PATCH 09/25] netfs: Gather stats David Howells
2021-01-20 22:23 ` [PATCH 10/25] netfs: Add write_begin helper David Howells
2021-01-20 22:23 ` [PATCH 11/25] netfs: Define an interface to talk to a cache David Howells
2021-01-20 22:23 ` [PATCH 12/25] fscache, cachefiles: Add alternate API to use kiocb for read/write to cache David Howells
2021-01-20 22:23 ` [PATCH 13/25] afs: Disable use of the fscache I/O routines David Howells
2021-01-20 22:24 ` [PATCH 14/25] afs: Pass page into dirty region helpers to provide THP size David Howells
2021-01-20 22:24 ` [PATCH 15/25] afs: Print the operation debug_id when logging an unexpected data version David Howells
2021-01-20 22:24 ` [PATCH 16/25] afs: Move key to afs_read struct David Howells
2021-01-20 22:24 ` [PATCH 17/25] afs: Don't truncate iter during data fetch David Howells
2021-01-20 22:24 ` [PATCH 18/25] afs: Log remote unmarshalling errors David Howells
2021-01-20 22:25 ` [PATCH 19/25] afs: Set up the iov_iter before calling afs_extract_data() David Howells
2021-01-20 22:25 ` [PATCH 20/25] afs: Use ITER_XARRAY for writing David Howells
2021-01-20 22:25 ` [PATCH 21/25] afs: Wait on PG_fscache before modifying/releasing a page David Howells
2021-01-20 22:25 ` David Howells [this message]
2021-01-20 22:25 ` [PATCH 23/25] afs: Prepare for use of THPs David Howells
2021-01-20 22:26 ` [PATCH 24/25] afs: Use the fs operation ops to handle FetchData completion David Howells
2021-01-20 22:26 ` [PATCH 25/25] afs: Use new fscache read helper API David Howells
2021-01-21 16:46 ` [RFC][PATCH 00/25] Network fs helper library & fscache kiocb API J. Bruce Fields
2021-01-21 17:02 ` David Howells
2021-01-21 17:43   ` J. Bruce Fields
2021-01-21 18:55   ` David Howells
2021-01-21 19:09     ` J. Bruce Fields
2021-01-21 20:08     ` David Howells
2021-01-22 16:01       ` J. Bruce Fields
2021-01-22 16:06       ` David Howells
2021-01-22  8:23     ` Christoph Hellwig

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