linux-ext4 - [PATCH v8 08/18] mm: clean up error handling in write_one

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Date:   Thu, 29 Jun 2017 09:19:44 -0400
From:   jlayton@...nel.org
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Al Viro <viro@...IV.linux.org.uk>, Jan Kara <jack@...e.cz>,
        tytso@....edu, axboe@...nel.dk, mawilcox@...rosoft.com,
        ross.zwisler@...ux.intel.com, corbet@....net,
        Chris Mason <clm@...com>, Josef Bacik <jbacik@...com>,
        David Sterba <dsterba@...e.com>,
        "Darrick J . Wong" <darrick.wong@...cle.com>
Cc:     Carlos Maiolino <cmaiolino@...hat.com>,
        Eryu Guan <eguan@...hat.com>,
        David Howells <dhowells@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        Liu Bo <bo.li.liu@...cle.com>, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-ext4@...r.kernel.org,
        linux-xfs@...r.kernel.org, linux-btrfs@...r.kernel.org,
        linux-block@...r.kernel.org
Subject: [PATCH v8 08/18] mm: clean up error handling in write_one_page

From: Jeff Layton <jlayton@...hat.com>

Don't try to check PageError since that's potentially racy and not
necessarily going to be set after writepage errors out.

Instead, check the mapping for an error after writepage returns.

Signed-off-by: Jeff Layton <jlayton@...hat.com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
 mm/page-writeback.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b901fe52b153..db30ce0b7d80 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2371,9 +2371,8 @@ int do_writepages(struct address_space *mapping, struct writeback_control *wbc)
  *
  * The page must be locked by the caller and will be unlocked upon return.
  *
- * write_one_page() returns a negative error code if I/O failed. Note that
- * the address_space is not marked for error. The caller must do this if
- * needed.
+ * Note that the mapping's AS_EIO/AS_ENOSPC flags will be cleared when this
+ * function returns.
  */
 int write_one_page(struct page *page)
 {
@@ -2391,15 +2390,15 @@ int write_one_page(struct page *page)
 	if (clear_page_dirty_for_io(page)) {
 		get_page(page);
 		ret = mapping->a_ops->writepage(page, &wbc);
-		if (ret == 0) {
+		if (ret == 0)
 			wait_on_page_writeback(page);
-			if (PageError(page))
-				ret = -EIO;
-		}
 		put_page(page);
 	} else {
 		unlock_page(page);
 	}
+
+	if (!ret)
+		ret = filemap_check_errors(mapping);
 	return ret;
 }
 EXPORT_SYMBOL(write_one_page);
-- 
2.13.0