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Commit b30d2f04 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Refactor nfs_page_find_head_request() 



Split out the 2 cases so that we can treat the locking differently.
The issue is that the locking in the pageswapcache cache is highly
linked to the commit list locking.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent bd37d6fc

fs/nfs/write.c

+30 −12
Original line number Diff line number Diff line
@@ -170,20 +170,41 @@ nfs_page_private_request(struct page *page) 
 * returns matching head request with reference held, or NULL if not found.

 */

static struct nfs_page *

nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page)

nfs_page_find_private_request(struct page *page)

{

	struct inode *inode = page_file_mapping(page)->host;

	struct nfs_page *req;



	if (!PagePrivate(page))

		return NULL;

	spin_lock(&inode->i_lock);

	req = nfs_page_private_request(page);

	if (!req && unlikely(PageSwapCache(page)))

	if (req) {

		WARN_ON_ONCE(req->wb_head != req);

		kref_get(&req->wb_kref);

	}

	spin_unlock(&inode->i_lock);

	return req;

}



static struct nfs_page *

nfs_page_find_swap_request(struct page *page)

{

	struct inode *inode = page_file_mapping(page)->host;

	struct nfs_inode *nfsi = NFS_I(inode);

	struct nfs_page *req = NULL;

	if (!PageSwapCache(page))

		return NULL;

	spin_lock(&inode->i_lock);

	if (PageSwapCache(page)) {

		req = nfs_page_search_commits_for_head_request_locked(nfsi,

			page);



		if (req) {

			WARN_ON_ONCE(req->wb_head != req);

			kref_get(&req->wb_kref);

		}



	}

	spin_unlock(&inode->i_lock);

	return req;

}
@@ -194,14 +215,11 @@ nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page) 
 */

static struct nfs_page *nfs_page_find_head_request(struct page *page)

{

	struct inode *inode = page_file_mapping(page)->host;

	struct nfs_page *req = NULL;

	struct nfs_page *req;



	if (PagePrivate(page) || PageSwapCache(page)) {

		spin_lock(&inode->i_lock);

		req = nfs_page_find_head_request_locked(NFS_I(inode), page);

		spin_unlock(&inode->i_lock);

	}

	req = nfs_page_find_private_request(page);

	if (!req)

		req = nfs_page_find_swap_request(page);

	return req;

}