Commit 25edbcac authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Anna Schumaker
Browse files

nfs: fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests 



Fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests to
prepare for future changes to this code, and move the helpers to write.c
as well.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent c3f22357

fs/nfs/pagelist.c

+0 −77
Original line number Diff line number Diff line
@@ -187,83 +187,6 @@ nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx) 
}

EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);



/*

 * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req

 * @head: head request of page group, must be holding head lock

 * @req: request that couldn't lock and needs to wait on the req bit lock

 *

 * This is a helper function for nfs_lock_and_join_requests

 * returns 0 on success, < 0 on error.

 */

static void

nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)

{

	struct nfs_page *tmp;



	/* relinquish all the locks successfully grabbed this run */

	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {

		if (!kref_read(&tmp->wb_kref))

			continue;

		nfs_unlock_and_release_request(tmp);

	}

}



/*

 * nfs_page_group_lock_subreq -  try to lock a subrequest

 * @head: head request of page group

 * @subreq: request to lock

 *

 * This is a helper function for nfs_lock_and_join_requests which

 * must be called with the head request and page group both locked.

 * On error, it returns with the page group unlocked.

 */

static int

nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)

{

	int ret;



	if (!kref_get_unless_zero(&subreq->wb_kref))

		return 0;

	while (!nfs_lock_request(subreq)) {

		nfs_page_group_unlock(head);

		ret = nfs_wait_on_request(subreq);

		if (!ret)

			ret = nfs_page_group_lock(head);

		if (ret < 0) {

			nfs_unroll_locks(head, subreq);

			nfs_release_request(subreq);

			return ret;

		}

	}

	return 0;

}



/*

 * nfs_page_group_lock_subrequests -  try to lock the subrequests

 * @head: head request of page group

 *

 * This is a helper function for nfs_lock_and_join_requests which

 * must be called with the head request locked.

 */

int nfs_page_group_lock_subrequests(struct nfs_page *head)

{

	struct nfs_page *subreq;

	int ret;



	ret = nfs_page_group_lock(head);

	if (ret < 0)

		return ret;

	/* lock each request in the page group */

	for (subreq = head->wb_this_page; subreq != head;

			subreq = subreq->wb_this_page) {

		ret = nfs_page_group_lock_subreq(head, subreq);

		if (ret < 0)

			return ret;

	}

	nfs_page_group_unlock(head);

	return 0;

}



/*

 * nfs_page_set_headlock - set the request PG_HEADLOCK

 * @req: request that is to be locked

fs/nfs/write.c

+64 −3
Original line number Diff line number Diff line
@@ -478,6 +478,57 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo, 
	nfs_destroy_unlinked_subrequests(destroy_list, head, inode);

}



/*

 * nfs_unroll_locks -  unlock all newly locked reqs and wait on @req

 * @head: head request of page group, must be holding head lock

 * @req: request that couldn't lock and needs to wait on the req bit lock

 *

 * This is a helper function for nfs_lock_and_join_requests

 * returns 0 on success, < 0 on error.

 */

static void

nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)

{

	struct nfs_page *tmp;



	/* relinquish all the locks successfully grabbed this run */

	for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {

		if (!kref_read(&tmp->wb_kref))

			continue;

		nfs_unlock_and_release_request(tmp);

	}

}



/*

 * nfs_page_group_lock_subreq -  try to lock a subrequest

 * @head: head request of page group

 * @subreq: request to lock

 *

 * This is a helper function for nfs_lock_and_join_requests which

 * must be called with the head request and page group both locked.

 * On error, it returns with the page group unlocked.

 */

static int

nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)

{

	int ret;



	if (!kref_get_unless_zero(&subreq->wb_kref))

		return 0;

	while (!nfs_lock_request(subreq)) {

		nfs_page_group_unlock(head);

		ret = nfs_wait_on_request(subreq);

		if (!ret)

			ret = nfs_page_group_lock(head);

		if (ret < 0) {

			nfs_unroll_locks(head, subreq);

			nfs_release_request(subreq);

			return ret;

		}

	}

	return 0;

}



/*

 * nfs_lock_and_join_requests - join all subreqs to the head req

 * @folio: the folio used to lookup the "page group" of nfs_page structures
@@ -496,7 +547,7 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo, 
static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)

{

	struct inode *inode = folio->mapping->host;

	struct nfs_page *head;

	struct nfs_page *head, *subreq;

	struct nfs_commit_info cinfo;

	int ret;
@@ -526,10 +577,20 @@ static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio) 
	if (ret < 0)

		goto out_unlock;



	ret = nfs_page_group_lock(head);

	if (ret < 0)

		goto out_unlock;



	/* lock each request in the page group */

	ret = nfs_page_group_lock_subrequests(head);

	for (subreq = head->wb_this_page;

	     subreq != head;

	     subreq = subreq->wb_this_page) {

		ret = nfs_page_group_lock_subreq(head, subreq);

		if (ret < 0)

			goto out_unlock;

	}



	nfs_page_group_unlock(head);



	nfs_init_cinfo_from_inode(&cinfo, inode);

	nfs_join_page_group(head, &cinfo, inode);

include/linux/nfs_page.h

+0 −1
Original line number Diff line number Diff line
@@ -155,7 +155,6 @@ extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, 
extern  int nfs_wait_on_request(struct nfs_page *);

extern	void nfs_unlock_request(struct nfs_page *req);

extern	void nfs_unlock_and_release_request(struct nfs_page *);

extern	int nfs_page_group_lock_subrequests(struct nfs_page *head);

extern void nfs_join_page_group(struct nfs_page *head,

				struct nfs_commit_info *cinfo,

				struct inode *inode);