From 2d96afc8f70ef86c66a0b5d80c24a27d6dd13df3 Mon Sep 17 00:00:00 2001
From: Toshi Kani <toshi.kani@hpe.com>
Date: Tue, 10 May 2016 10:23:53 -0600
Subject: block: Add bdev_dax_supported() for dax mount checks

DAX imposes additional requirements to a device.  Add
bdev_dax_supported() which performs all the precondition checks
necessary for filesystem to mount the device with dax option.

Also add a new check to verify if a partition is aligned by 4KB.
When a partition is unaligned, any dax read/write access fails,
except for metadata update.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@fb.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Boaz Harrosh <boaz@plexistor.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 include/linux/blkdev.h | 1 +
 1 file changed, 1 insertion(+)

(limited to 'include/linux/blkdev.h')

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 78c48ab22f46..71231a55debd 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1688,6 +1688,7 @@ extern int bdev_read_page(struct block_device *, sector_t, struct page *);
 extern int bdev_write_page(struct block_device *, sector_t, struct page *,
 						struct writeback_control *);
 extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
+extern int bdev_dax_supported(struct super_block *, int);
 #else /* CONFIG_BLOCK */
 
 struct block_device;
-- 
cgit