From: Christoph Hellwig hch@lst.de
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: Christoph Hellwig hch@lst.de Reviewed-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Anna Schumaker Anna.Schumaker@Netapp.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com (cherry picked from commit 25edbcac6e32eab345e470d56ca9974a577b878b) --- fs/nfs/pagelist.c | 77 ---------------------------------------- fs/nfs/write.c | 74 ++++++++++++++++++++++++++++++++++---- include/linux/nfs_page.h | 1 - 3 files changed, 68 insertions(+), 84 deletions(-)
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 317cedfa52bf..99e756139a5d 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -167,83 +167,6 @@ nfs_page_group_lock_head(struct nfs_page *req) return head; }
-/* - * 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 diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 8e21caae4cae..eaf712d9d905 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -547,6 +547,57 @@ nfs_join_page_group(struct nfs_page *head, struct inode *inode) 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 * @page: the page used to lookup the "page group" of nfs_page structures @@ -566,7 +617,7 @@ static struct nfs_page * nfs_lock_and_join_requests(struct page *page) { struct inode *inode = page_file_mapping(page)->host; - struct nfs_page *head; + struct nfs_page *head, *subreq; int ret;
/* @@ -578,16 +629,27 @@ nfs_lock_and_join_requests(struct page *page) if (IS_ERR_OR_NULL(head)) return head;
+ 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); - if (ret < 0) { - nfs_unlock_and_release_request(head); - return ERR_PTR(ret); + 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_join_page_group(head, inode); + nfs_page_group_unlock(head);
+ nfs_join_page_group(head, inode); return head; + +out_unlock: + nfs_unlock_and_release_request(head); + return ERR_PTR(ret); }
static void nfs_write_error(struct nfs_page *req, int error) diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index ba7e2e4b0926..d7a08d18a6c5 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -144,7 +144,6 @@ 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 struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req); -extern int nfs_page_group_lock_subrequests(struct nfs_page *head); extern void nfs_join_page_group(struct nfs_page *head, struct inode *inode); extern int nfs_page_group_lock(struct nfs_page *); extern void nfs_page_group_unlock(struct nfs_page *);