From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Jan Kara <jack@suse.cz>, Dan Williams <dan.j.williams@intel.com>,
Dave Chinner <david@fromorbit.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Christoph Hellwig <hch@lst.de>,
linux-nvdimm@lists.01.org, Jeff Moyer <jmoyer@redhat.com>,
linux-ext4@vger.kernel.org, Lukas Czerner <lczerner@redhat.com>
Subject: [PATCH v4 1/2] dax: dax_layout_busy_page() warn on !exceptional
Date: Tue, 10 Jul 2018 13:10:30 -0600 [thread overview]
Message-ID: <20180710191031.17919-2-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <20180710191031.17919-1-ross.zwisler@linux.intel.com>
Inodes using DAX should only ever have exceptional entries in their page
caches. Make this clear by warning if the iteration in
dax_layout_busy_page() ever sees a non-exceptional entry, and by adding a
comment for the pagevec_release() call which only deals with struct page
pointers.
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/dax.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/dax.c b/fs/dax.c
index 641192808bb6..897b51e41d8f 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -566,7 +566,8 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
if (index >= end)
break;
- if (!radix_tree_exceptional_entry(pvec_ent))
+ if (WARN_ON_ONCE(
+ !radix_tree_exceptional_entry(pvec_ent)))
continue;
xa_lock_irq(&mapping->i_pages);
@@ -578,6 +579,13 @@ struct page *dax_layout_busy_page(struct address_space *mapping)
if (page)
break;
}
+
+ /*
+ * We don't expect normal struct page entries to exist in our
+ * tree, but we keep these pagevec calls so that this code is
+ * consistent with the common pattern for handling pagevecs
+ * throughout the kernel.
+ */
pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
index++;
--
2.14.4
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next prev parent reply other threads:[~2018-07-10 19:10 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-10 19:10 [PATCH v4 0/2] ext4: fix DAX dma vs truncate/hole-punch Ross Zwisler
2018-07-10 19:10 ` Ross Zwisler [this message]
2018-08-10 19:52 ` [PATCH v4 1/2] dax: dax_layout_busy_page() warn on !exceptional Eric Sandeen
2018-08-10 20:33 ` Theodore Y. Ts'o
2018-08-11 2:10 ` Theodore Y. Ts'o
2018-08-13 10:12 ` Jan Kara
2018-08-13 12:46 ` Theodore Y. Ts'o
2018-08-24 15:44 ` Jan Kara
2018-08-27 16:09 ` Jan Kara
2018-07-10 19:10 ` [PATCH v4 2/2] ext4: handle layout changes to pinned DAX mappings Ross Zwisler
2018-07-11 8:17 ` [PATCH v4 0/2] ext4: fix DAX dma vs truncate/hole-punch Jan Kara
2018-07-11 15:41 ` Ross Zwisler
2018-07-25 22:28 ` Ross Zwisler
2018-07-27 16:28 ` Ross Zwisler
2018-08-06 3:55 ` Dave Chinner
2018-08-06 15:49 ` Christoph Hellwig
2018-08-06 22:25 ` Dave Chinner
2018-08-07 8:45 ` Jan Kara
2018-09-10 22:18 ` Eric Sandeen
2018-09-11 15:14 ` Jan Kara
2018-09-11 15:20 ` Jan Kara
2018-09-11 17:28 ` Theodore Y. Ts'o
2018-09-11 18:21 ` Eric Sandeen
2018-07-31 19:44 ` Ross Zwisler
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