Commit b2e7bbb3 authored by Stephen Champion's avatar Stephen Champion Committed by Greg Kroah-Hartman
Browse files

staging: lustre: llite: handle concurrent use of cob_transient_pages 



With the lockless __generic_file_aio_write introduced in LU-1669,
ll_direct_IO_26 is no longer protected by the inode i_isem.

This renders obsoltete checks that all transient pages have been
handled before and after entry, and requires atomic access to their
counter.

Signed-off-by: default avatarStephen Champion <schamp@sgi.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5700
Reviewed-on: http://review.whamcloud.com/12179


Reviewed-by: default avatarJinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: default avatarBobi Jam <bobijam@gmail.com>
Reviewed-by: default avatarOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: default avatarJames Simmons <jsimmons@infradead.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4660dd9b

drivers/staging/lustre/lustre/llite/rw26.c

+0 −4
Original line number Diff line number Diff line
@@ -345,7 +345,6 @@ static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter) 
	struct cl_io *io;

	struct file *file = iocb->ki_filp;

	struct inode *inode = file->f_mapping->host;

	struct vvp_object *obj = cl_inode2vvp(inode);

	loff_t file_offset = iocb->ki_pos;

	ssize_t count = iov_iter_count(iter);

	ssize_t tot_bytes = 0, result = 0;
@@ -374,7 +373,6 @@ static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter) 
	io = vvp_env_io(env)->vui_cl.cis_io;

	LASSERT(io);



	LASSERT(obj->vob_transient_pages == 0);

	while (iov_iter_count(iter)) {

		struct page **pages;

		size_t offs;
@@ -422,8 +420,6 @@ static ssize_t ll_direct_IO_26(struct kiocb *iocb, struct iov_iter *iter) 
		file_offset += result;

	}

out:

	LASSERT(obj->vob_transient_pages == 0);



	if (tot_bytes > 0) {

		struct vvp_io *vio = vvp_env_io(env);

drivers/staging/lustre/lustre/llite/vvp_internal.h

+5 −4
Original line number Diff line number Diff line
@@ -217,11 +217,12 @@ struct vvp_object { 
	struct list_head	vob_pending_list;



	/**

	 * Access this counter is protected by inode->i_sem. Now that

	 * the lifetime of transient pages must be covered by inode sem,

	 * we don't need to hold any lock..

	 * Number of transient pages.  This is no longer protected by i_sem,

	 * and needs to be atomic.  This is not actually used for anything,

	 * and can probably be removed.

	 */

	int			vob_transient_pages;

	atomic_t		vob_transient_pages;



	/**

	 * Number of outstanding mmaps on this file.

	 *

drivers/staging/lustre/lustre/llite/vvp_object.c

+3 −3
Original line number Diff line number Diff line
@@ -67,8 +67,8 @@ static int vvp_object_print(const struct lu_env *env, void *cookie, 


	(*p)(env, cookie, "(%s %d %d) inode: %p ",

	     list_empty(&obj->vob_pending_list) ? "-" : "+",

	     obj->vob_transient_pages, atomic_read(&obj->vob_mmap_cnt),

	     inode);

	     atomic_read(&obj->vob_transient_pages),

	     atomic_read(&obj->vob_mmap_cnt), inode);

	if (inode) {

		lli = ll_i2info(inode);

		(*p)(env, cookie, "%lu/%u %o %u %d %p "DFID,
@@ -220,7 +220,7 @@ static int vvp_object_init0(const struct lu_env *env, 
			    const struct cl_object_conf *conf)

{

	vob->vob_inode = conf->coc_inode;

	vob->vob_transient_pages = 0;

	atomic_set(&vob->vob_transient_pages, 0);

	cl_object_page_init(&vob->vob_cl, sizeof(struct vvp_page));

	return 0;

}

drivers/staging/lustre/lustre/llite/vvp_page.c

+2 −2
Original line number Diff line number Diff line
@@ -506,7 +506,7 @@ static void vvp_transient_page_fini(const struct lu_env *env, 
	struct vvp_object *clobj = cl2vvp(clp->cp_obj);



	vvp_page_fini_common(vpg);

	clobj->vob_transient_pages--;

	atomic_dec(&clobj->vob_transient_pages);

}



static const struct cl_page_operations vvp_transient_page_ops = {
@@ -555,7 +555,7 @@ int vvp_page_init(const struct lu_env *env, struct cl_object *obj, 


		cl_page_slice_add(page, &vpg->vpg_cl, obj, index,

				  &vvp_transient_page_ops);

		clobj->vob_transient_pages++;

		atomic_inc(&clobj->vob_transient_pages);

	}

	return 0;

}