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Commit 7f6d5b52 authored by Ross Zwisler's avatar Ross Zwisler Committed by Linus Torvalds
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dax: move writeback calls into the filesystems 



Previously calls to dax_writeback_mapping_range() for all DAX filesystems
(ext2, ext4 & xfs) were centralized in filemap_write_and_wait_range().

dax_writeback_mapping_range() needs a struct block_device, and it used
to get that from inode->i_sb->s_bdev.  This is correct for normal inodes
mounted on ext2, ext4 and XFS filesystems, but is incorrect for DAX raw
block devices and for XFS real-time files.

Instead, call dax_writeback_mapping_range() directly from the filesystem
->writepages function so that it can supply us with a valid block
device.  This also fixes DAX code to properly flush caches in response
to sync(2).

Signed-off-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 20a90f58

fs/block_dev.c

+12 −1
Original line number Diff line number Diff line
@@ -1697,13 +1697,24 @@ static int blkdev_releasepage(struct page *page, gfp_t wait) 
	return try_to_free_buffers(page);

}



static int blkdev_writepages(struct address_space *mapping,

			     struct writeback_control *wbc)

{

	if (dax_mapping(mapping)) {

		struct block_device *bdev = I_BDEV(mapping->host);



		return dax_writeback_mapping_range(mapping, bdev, wbc);

	}

	return generic_writepages(mapping, wbc);

}



static const struct address_space_operations def_blk_aops = {

	.readpage	= blkdev_readpage,

	.readpages	= blkdev_readpages,

	.writepage	= blkdev_writepage,

	.write_begin	= blkdev_write_begin,

	.write_end	= blkdev_write_end,

	.writepages	= generic_writepages,

	.writepages	= blkdev_writepages,

	.releasepage	= blkdev_releasepage,

	.direct_IO	= blkdev_direct_IO,

	.is_dirty_writeback = buffer_check_dirty_writeback,

fs/dax.c

+7 −5
Original line number Diff line number Diff line
@@ -484,11 +484,10 @@ static int dax_writeback_one(struct block_device *bdev, 
 * end]. This is required by data integrity operations to ensure file data is

 * on persistent storage prior to completion of the operation.

 */

int dax_writeback_mapping_range(struct address_space *mapping, loff_t start,

		loff_t end)

int dax_writeback_mapping_range(struct address_space *mapping,

		struct block_device *bdev, struct writeback_control *wbc)

{

	struct inode *inode = mapping->host;

	struct block_device *bdev = inode->i_sb->s_bdev;

	pgoff_t start_index, end_index, pmd_index;

	pgoff_t indices[PAGEVEC_SIZE];

	struct pagevec pvec;
@@ -499,8 +498,11 @@ int dax_writeback_mapping_range(struct address_space *mapping, loff_t start, 
	if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))

		return -EIO;



	start_index = start >> PAGE_CACHE_SHIFT;

	end_index = end >> PAGE_CACHE_SHIFT;

	if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL)

		return 0;



	start_index = wbc->range_start >> PAGE_CACHE_SHIFT;

	end_index = wbc->range_end >> PAGE_CACHE_SHIFT;

	pmd_index = DAX_PMD_INDEX(start_index);



	rcu_read_lock();

fs/ext2/inode.c

+8 −0
Original line number Diff line number Diff line
@@ -876,6 +876,14 @@ ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset) 
static int

ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)

{

#ifdef CONFIG_FS_DAX

	if (dax_mapping(mapping)) {

		return dax_writeback_mapping_range(mapping,

						   mapping->host->i_sb->s_bdev,

						   wbc);

	}

#endif



	return mpage_writepages(mapping, wbc, ext2_get_block);

}

fs/ext4/inode.c

+4 −0
Original line number Diff line number Diff line
@@ -2478,6 +2478,10 @@ static int ext4_writepages(struct address_space *mapping, 


	trace_ext4_writepages(inode, wbc);



	if (dax_mapping(mapping))

		return dax_writeback_mapping_range(mapping, inode->i_sb->s_bdev,

						   wbc);



	/*

	 * No pages to write? This is mainly a kludge to avoid starting

	 * a transaction for special inodes like journal inode on last iput()

fs/xfs/xfs_aops.c

+4 −0
Original line number Diff line number Diff line
@@ -1208,6 +1208,10 @@ xfs_vm_writepages( 
	struct writeback_control *wbc)

{

	xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);

	if (dax_mapping(mapping))

		return dax_writeback_mapping_range(mapping,

				xfs_find_bdev_for_inode(mapping->host), wbc);



	return generic_writepages(mapping, wbc);

}