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authorDan Williams <dan.j.williams@intel.com>2016-01-28 20:25:31 -0800
committerDan Williams <dan.j.williams@intel.com>2016-01-30 13:35:32 -0800
commitd1a5f2b4d8a125943dcb6b032fc7eaefc2c78296 (patch)
treeafdd4251d10cbcf34b00bd4f33adb27996881cc6 /block/partition-generic.c
parent9f4736fe7ca804aa79b5916221bb13dfc6221a0f (diff)
downloadlinux-0-day-d1a5f2b4d8a125943dcb6b032fc7eaefc2c78296.tar.gz
block: use DAX for partition table reads
Avoid populating pagecache when the block device is in DAX mode. Otherwise these page cache entries collide with the fsync/msync implementation and break data durability guarantees. Cc: Jan Kara <jack@suse.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com> Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Matthew Wilcox <willy@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'block/partition-generic.c')
-rw-r--r--block/partition-generic.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/block/partition-generic.c b/block/partition-generic.c
index 746935a..fefd01b 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -16,6 +16,7 @@
#include <linux/kmod.h>
#include <linux/ctype.h>
#include <linux/genhd.h>
+#include <linux/dax.h>
#include <linux/blktrace_api.h>
#include "partitions/check.h"
@@ -550,13 +551,24 @@ int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
return 0;
}
-unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
+static struct page *read_pagecache_sector(struct block_device *bdev, sector_t n)
{
struct address_space *mapping = bdev->bd_inode->i_mapping;
+
+ return read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
+ NULL);
+}
+
+unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
+{
struct page *page;
- page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
- NULL);
+ /* don't populate page cache for dax capable devices */
+ if (IS_DAX(bdev->bd_inode))
+ page = read_dax_sector(bdev, n);
+ else
+ page = read_pagecache_sector(bdev, n);
+
if (!IS_ERR(page)) {
if (PageError(page))
goto fail;