diff options
| -rw-r--r-- | fs/nfs/pagelist.c | 74 | ||||
| -rw-r--r-- | fs/nfs/write.c | 91 | ||||
| -rw-r--r-- | include/linux/nfs_page.h | 1 |
3 files changed, 95 insertions, 71 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index f535a92403bf..261236157e33 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -131,6 +131,80 @@ 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 and page group both locked. + * On error, it returns with the page group unlocked. + */ +int nfs_page_group_lock_subrequests(struct nfs_page *head) +{ + struct nfs_page *subreq; + int 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; + } + 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 a6d7926b0653..832cf57ea442 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -380,34 +380,6 @@ static void nfs_end_page_writeback(struct nfs_page *req) } /* - * nfs_unroll_locks_and_wait - unlock all newly locked reqs and wait on @req - * - * this is a helper function for nfs_lock_and_join_requests - * - * @inode - inode associated with request page group, must be holding inode lock - * @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 - * - * NOTE: this must be called holding page_group bit lock - * which will be released before returning. - * - * returns 0 on success, < 0 on error. - */ -static void -nfs_unroll_locks(struct inode *inode, 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_destroy_unlinked_subrequests - destroy recently unlinked subrequests * * @destroy_list - request list (using wb_this_page) terminated by @old_head @@ -487,7 +459,7 @@ nfs_lock_and_join_requests(struct page *page) struct inode *inode = page_file_mapping(page)->host; struct nfs_page *head, *subreq; struct nfs_page *destroy_list = NULL; - unsigned int total_bytes; + unsigned int pgbase, off, bytes; int ret; try_again: @@ -520,49 +492,30 @@ try_again: goto release_request; /* lock each request in the page group */ - total_bytes = head->wb_bytes; + ret = nfs_page_group_lock_subrequests(head); + if (ret < 0) + goto release_request; + + pgbase = head->wb_pgbase; + bytes = head->wb_bytes; + off = head->wb_offset; for (subreq = head->wb_this_page; subreq != head; subreq = subreq->wb_this_page) { - - if (!kref_get_unless_zero(&subreq->wb_kref)) { - if (subreq->wb_offset == head->wb_offset + total_bytes) - total_bytes += subreq->wb_bytes; - continue; - } - - while (!nfs_lock_request(subreq)) { - /* - * Unlock page to allow nfs_page_group_sync_on_bit() - * to succeed - */ - 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(inode, head, subreq); - nfs_release_request(subreq); - goto release_request; - } - } - /* - * Subrequests are always contiguous, non overlapping - * and in order - but may be repeated (mirrored writes). - */ - if (subreq->wb_offset == (head->wb_offset + total_bytes)) { - /* keep track of how many bytes this group covers */ - total_bytes += subreq->wb_bytes; - } else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset || - ((subreq->wb_offset + subreq->wb_bytes) > - (head->wb_offset + total_bytes)))) { - nfs_page_group_unlock(head); - nfs_unroll_locks(inode, head, subreq); - nfs_unlock_and_release_request(subreq); - ret = -EIO; - goto release_request; + /* Subrequests should always form a contiguous range */ + if (pgbase > subreq->wb_pgbase) { + off -= pgbase - subreq->wb_pgbase; + bytes += pgbase - subreq->wb_pgbase; + pgbase = subreq->wb_pgbase; } + bytes = max(subreq->wb_pgbase + subreq->wb_bytes + - pgbase, bytes); } + /* Set the head request's range to cover the former page group */ + head->wb_pgbase = pgbase; + head->wb_bytes = bytes; + head->wb_offset = off; + /* Now that all requests are locked, make sure they aren't on any list. * Commit list removal accounting is done after locks are dropped */ subreq = head; @@ -576,10 +529,6 @@ try_again: /* destroy list will be terminated by head */ destroy_list = head->wb_this_page; head->wb_this_page = head; - - /* change head request to cover whole range that - * the former page group covered */ - head->wb_bytes = total_bytes; } /* Postpone destruction of this request */ diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h index 7e9419d74b86..dd205bc6bc58 100644 --- a/include/linux/nfs_page.h +++ b/include/linux/nfs_page.h @@ -139,6 +139,7 @@ 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 int nfs_page_group_lock(struct nfs_page *); extern void nfs_page_group_unlock(struct nfs_page *); extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int); |