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Commit 6e2608df authored by Dan Williams's avatar Dan Williams
Browse files

xfs, dax: introduce xfs_dax_aops 



In preparation for the dax implementation to start associating dax pages
to inodes via page->mapping, we need to provide a 'struct
address_space_operations' instance for dax. Otherwise, direct-I/O
triggers incorrect page cache assumptions and warnings like the
following:

 WARNING: CPU: 27 PID: 1783 at fs/xfs/xfs_aops.c:1468
 xfs_vm_set_page_dirty+0xf3/0x1b0 [xfs]
 [..]
 CPU: 27 PID: 1783 Comm: dma-collision Tainted: G           O 4.15.0-rc2+ #984
 [..]
 Call Trace:
  set_page_dirty_lock+0x40/0x60
  bio_set_pages_dirty+0x37/0x50
  iomap_dio_actor+0x2b7/0x3b0
  ? iomap_dio_zero+0x110/0x110
  iomap_apply+0xa4/0x110
  iomap_dio_rw+0x29e/0x3b0
  ? iomap_dio_zero+0x110/0x110
  ? xfs_file_dio_aio_read+0x7c/0x1a0 [xfs]
  xfs_file_dio_aio_read+0x7c/0x1a0 [xfs]
  xfs_file_read_iter+0xa0/0xc0 [xfs]
  __vfs_read+0xf9/0x170
  vfs_read+0xa6/0x150
  SyS_pread64+0x93/0xb0
  entry_SYSCALL_64_fastpath+0x1f/0x96

...where the default set_page_dirty() handler assumes that dirty state
is being tracked in 'struct page' flags.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: default avatarJan Kara <jack@suse.cz>
Suggested-by: default avatarDave Chinner <david@fromorbit.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 15aa8a01

fs/xfs/xfs_aops.c

+18 −16
Original line number Diff line number Diff line
@@ -1194,16 +1194,22 @@ xfs_vm_writepages( 
	int			ret;



	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);



	ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);

	if (wpc.ioend)

		ret = xfs_submit_ioend(wbc, wpc.ioend, ret);

	return ret;

}



STATIC int

xfs_dax_writepages(

	struct address_space	*mapping,

	struct writeback_control *wbc)

{

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

	return dax_writeback_mapping_range(mapping,

			xfs_find_bdev_for_inode(mapping->host), wbc);

}



/*

 * Called to move a page into cleanable state - and from there

 * to be released. The page should already be clean. We always
@@ -1367,17 +1373,6 @@ xfs_get_blocks( 
	return error;

}



STATIC ssize_t

xfs_vm_direct_IO(

	struct kiocb		*iocb,

	struct iov_iter		*iter)

{

	/*

	 * We just need the method present so that open/fcntl allow direct I/O.

	 */

	return -EINVAL;

}



STATIC sector_t

xfs_vm_bmap(

	struct address_space	*mapping,
@@ -1500,8 +1495,15 @@ const struct address_space_operations xfs_address_space_operations = { 
	.releasepage		= xfs_vm_releasepage,

	.invalidatepage		= xfs_vm_invalidatepage,

	.bmap			= xfs_vm_bmap,

	.direct_IO		= xfs_vm_direct_IO,

	.direct_IO		= noop_direct_IO,

	.migratepage		= buffer_migrate_page,

	.is_partially_uptodate  = block_is_partially_uptodate,

	.error_remove_page	= generic_error_remove_page,

};



const struct address_space_operations xfs_dax_aops = {

	.writepages		= xfs_dax_writepages,

	.direct_IO		= noop_direct_IO,

	.set_page_dirty		= noop_set_page_dirty,

	.invalidatepage		= noop_invalidatepage,

};

fs/xfs/xfs_aops.h

+1 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ struct xfs_ioend { 
};



extern const struct address_space_operations xfs_address_space_operations;

extern const struct address_space_operations xfs_dax_aops;



int	xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size);

fs/xfs/xfs_iops.c

+4 −1
Original line number Diff line number Diff line
@@ -1272,6 +1272,9 @@ xfs_setup_iops( 
	case S_IFREG:

		inode->i_op = &xfs_inode_operations;

		inode->i_fop = &xfs_file_operations;

		if (IS_DAX(inode))

			inode->i_mapping->a_ops = &xfs_dax_aops;

		else

			inode->i_mapping->a_ops = &xfs_address_space_operations;

		break;

	case S_IFDIR: