Commit 48bf2b17 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

GFS2: Something nonlinear this way comes! 



For some reason GFS2 has been missing support for non-linear
mappings. This patch fixes that, and also avoids taking any
locks for mmap in the O_NOATIME case. In fact we don't actually need
to take the lock here at all - just doing file_accessed() would be
enough, but we have to take the lock eventually and this helps
it hit disk (and thus be seen by other nodes) faster.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 4a0f9a32

fs/gfs2/ops_file.c

+16 −13
Original line number Diff line number Diff line
@@ -425,33 +425,36 @@ static struct vm_operations_struct gfs2_vm_ops = { 
	.page_mkwrite = gfs2_page_mkwrite,

};





/**

 * gfs2_mmap -

 * @file: The file to map

 * @vma: The VMA which described the mapping

 *

 * Returns: 0 or error code

 * There is no need to get a lock here unless we should be updating

 * atime. We ignore any locking errors since the only consequence is

 * a missed atime update (which will just be deferred until later).

 *

 * Returns: 0

 */



static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)

{

	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);



	if (!(file->f_flags & O_NOATIME)) {

		struct gfs2_holder i_gh;

		int error;



	gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);

		gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);

		error = gfs2_glock_nq(&i_gh);

	if (error) {

		gfs2_holder_uninit(&i_gh);

		return error;

		file_accessed(file);

		if (error == 0)

			gfs2_glock_dq_uninit(&i_gh);

	}



	vma->vm_ops = &gfs2_vm_ops;

	vma->vm_flags |= VM_CAN_NONLINEAR;



	gfs2_glock_dq_uninit(&i_gh);



	return error;

	return 0;

}



/**

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