From patchwork Tue Aug 14 03:56:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 10565009 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EED7C1390 for ; Tue, 14 Aug 2018 03:58:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E0E412964B for ; Tue, 14 Aug 2018 03:58:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D572F29662; Tue, 14 Aug 2018 03:58:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F1C1229653 for ; Tue, 14 Aug 2018 03:58:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731128AbeHNGn1 (ORCPT ); Tue, 14 Aug 2018 02:43:27 -0400 Received: from mx2.suse.de ([195.135.220.15]:45022 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725846AbeHNGn0 (ORCPT ); Tue, 14 Aug 2018 02:43:26 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 38A12AF40; Tue, 14 Aug 2018 03:58:09 +0000 (UTC) From: NeilBrown To: Jeff Layton , Alexander Viro Date: Tue, 14 Aug 2018 13:56:52 +1000 Subject: [PATCH 1/5] fs/locks: rename some lists and pointers. Cc: "J. Bruce Fields" , Martin Wilck , linux-fsdevel@vger.kernel.org, Frank Filz , linux-kernel@vger.kernel.org Message-ID: <153421901196.24426.13628119459456277309.stgit@noble> In-Reply-To: <153421852728.24426.2111161640156686201.stgit@noble> References: <153421852728.24426.2111161640156686201.stgit@noble> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP struct file lock contains an 'fl_next' pointer which is used to point to the lock that this request is blocked waiting for. So rename it to fl_blocker. The fl_blocked list_head in an active lock is the head of a list of blocked requests. In a request it is a node in that list. These are two distinct uses, so replace with two list_heads with different names. fl_blocked is the head of a list of blocked requests fl_block is a node on that list. The two different list_heads are never used at the same time, but that will change in a future patch. Note that a tracepoint is changed to report fl_blocker instead of fl_next. Signed-off-by: NeilBrown --- fs/cifs/file.c | 2 +- fs/locks.c | 40 ++++++++++++++++++++------------------- include/linux/fs.h | 7 +++++-- include/trace/events/filelock.h | 16 ++++++++-------- 4 files changed, 35 insertions(+), 30 deletions(-) diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 8d41ca7bfcf1..066ed2e4ba96 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1092,7 +1092,7 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock) rc = posix_lock_file(file, flock, NULL); up_write(&cinode->lock_sem); if (rc == FILE_LOCK_DEFERRED) { - rc = wait_event_interruptible(flock->fl_wait, !flock->fl_next); + rc = wait_event_interruptible(flock->fl_wait, !flock->fl_blocker); if (!rc) goto try_again; posix_unblock_lock(flock); diff --git a/fs/locks.c b/fs/locks.c index db7b6917d9c5..322491e70e41 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -194,7 +194,7 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); * This lock protects the blocked_hash. Generally, if you're accessing it, you * want to be holding this lock. * - * In addition, it also protects the fl->fl_block list, and the fl->fl_next + * In addition, it also protects the fl->fl_blocked list, and the fl->fl_blocker * pointer for file_lock structures that are acting as lock requests (in * contrast to those that are acting as records of acquired locks). * @@ -203,7 +203,7 @@ static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); * protected by this lock, we can skip acquiring it iff we already hold the * flc_lock. * - * In particular, adding an entry to the fl_block list requires that you hold + * In particular, adding an entry to the fl_blocked list requires that you hold * both the flc_lock and the blocked_lock_lock (acquired in that order). * Deleting an entry from the list however only requires the file_lock_lock. */ @@ -302,6 +302,7 @@ static void locks_init_lock_heads(struct file_lock *fl) { INIT_HLIST_NODE(&fl->fl_link); INIT_LIST_HEAD(&fl->fl_list); + INIT_LIST_HEAD(&fl->fl_blocked); INIT_LIST_HEAD(&fl->fl_block); init_waitqueue_head(&fl->fl_wait); } @@ -341,6 +342,7 @@ void locks_free_lock(struct file_lock *fl) { BUG_ON(waitqueue_active(&fl->fl_wait)); BUG_ON(!list_empty(&fl->fl_list)); + BUG_ON(!list_empty(&fl->fl_blocked)); BUG_ON(!list_empty(&fl->fl_block)); BUG_ON(!hlist_unhashed(&fl->fl_link)); @@ -676,7 +678,7 @@ static void __locks_delete_block(struct file_lock *waiter) { locks_delete_global_blocked(waiter); list_del_init(&waiter->fl_block); - waiter->fl_next = NULL; + waiter->fl_blocker = NULL; } static void locks_delete_block(struct file_lock *waiter) @@ -692,16 +694,16 @@ static void locks_delete_block(struct file_lock *waiter) * it seems like the reasonable thing to do. * * Must be called with both the flc_lock and blocked_lock_lock held. The - * fl_block list itself is protected by the blocked_lock_lock, but by ensuring + * fl_blocked list itself is protected by the blocked_lock_lock, but by ensuring * that the flc_lock is also held on insertions we can avoid taking the - * blocked_lock_lock in some cases when we see that the fl_block list is empty. + * blocked_lock_lock in some cases when we see that the fl_blocked list is empty. */ static void __locks_insert_block(struct file_lock *blocker, struct file_lock *waiter) { BUG_ON(!list_empty(&waiter->fl_block)); - waiter->fl_next = blocker; - list_add_tail(&waiter->fl_block, &blocker->fl_block); + waiter->fl_blocker = blocker; + list_add_tail(&waiter->fl_block, &blocker->fl_blocked); if (IS_POSIX(blocker) && !IS_OFDLCK(blocker)) locks_insert_global_blocked(waiter); } @@ -725,18 +727,18 @@ static void locks_wake_up_blocks(struct file_lock *blocker) /* * Avoid taking global lock if list is empty. This is safe since new * blocked requests are only added to the list under the flc_lock, and - * the flc_lock is always held here. Note that removal from the fl_block + * the flc_lock is always held here. Note that removal from the fl_blocked * list does not require the flc_lock, so we must recheck list_empty() * after acquiring the blocked_lock_lock. */ - if (list_empty(&blocker->fl_block)) + if (list_empty(&blocker->fl_blocked)) return; spin_lock(&blocked_lock_lock); - while (!list_empty(&blocker->fl_block)) { + while (!list_empty(&blocker->fl_blocked)) { struct file_lock *waiter; - waiter = list_first_entry(&blocker->fl_block, + waiter = list_first_entry(&blocker->fl_blocked, struct file_lock, fl_block); __locks_delete_block(waiter); if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) @@ -887,7 +889,7 @@ static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) { if (posix_same_owner(fl, block_fl)) - return fl->fl_next; + return fl->fl_blocker; } return NULL; } @@ -1245,7 +1247,7 @@ static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) error = posix_lock_inode(inode, fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -1332,7 +1334,7 @@ int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start, error = posix_lock_inode(inode, &fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl.fl_wait, !fl.fl_next); + error = wait_event_interruptible(fl.fl_wait, !fl.fl_blocker); if (!error) { /* * If we've been sleeping someone might have @@ -1526,7 +1528,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) locks_dispose_list(&dispose); error = wait_event_interruptible_timeout(new_fl->fl_wait, - !new_fl->fl_next, break_time); + !new_fl->fl_blocker, break_time); percpu_down_read_preempt_disable(&file_rwsem); spin_lock(&ctx->flc_lock); @@ -1940,7 +1942,7 @@ static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) error = flock_lock_inode(inode, fl); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -2212,7 +2214,7 @@ static int do_lock_file_wait(struct file *filp, unsigned int cmd, error = vfs_lock_file(filp, cmd, fl, NULL); if (error != FILE_LOCK_DEFERRED) break; - error = wait_event_interruptible(fl->fl_wait, !fl->fl_next); + error = wait_event_interruptible(fl->fl_wait, !fl->fl_blocker); if (!error) continue; @@ -2583,7 +2585,7 @@ posix_unblock_lock(struct file_lock *waiter) int status = 0; spin_lock(&blocked_lock_lock); - if (waiter->fl_next) + if (waiter->fl_blocker) __locks_delete_block(waiter); else status = -ENOENT; @@ -2711,7 +2713,7 @@ static int locks_show(struct seq_file *f, void *v) lock_get_status(f, fl, iter->li_pos, ""); - list_for_each_entry(bfl, &fl->fl_block, fl_block) + list_for_each_entry(bfl, &fl->fl_blocked, fl_block) lock_get_status(f, bfl, iter->li_pos, " ->"); return 0; diff --git a/include/linux/fs.h b/include/linux/fs.h index 805bf22898cf..b168013ef99e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1002,10 +1002,13 @@ bool opens_in_grace(struct net *); * Obviously, the last two criteria only matter for POSIX locks. */ struct file_lock { - struct file_lock *fl_next; /* singly linked list for this inode */ + struct file_lock *fl_blocker; /* The lock, that is blocking us */ struct list_head fl_list; /* link into file_lock_context */ struct hlist_node fl_link; /* node in global lists */ - struct list_head fl_block; /* circular list of blocked processes */ + struct list_head fl_blocked; /* list of requests with + * ->fl_blocker pointing here */ + struct list_head fl_block; /* node in + * ->fl_blocker->fl_blocked */ fl_owner_t fl_owner; unsigned int fl_flags; unsigned char fl_type; diff --git a/include/trace/events/filelock.h b/include/trace/events/filelock.h index d1faf3597b9d..0e50f985a390 100644 --- a/include/trace/events/filelock.h +++ b/include/trace/events/filelock.h @@ -68,7 +68,7 @@ DECLARE_EVENT_CLASS(filelock_lock, __field(struct file_lock *, fl) __field(unsigned long, i_ino) __field(dev_t, s_dev) - __field(struct file_lock *, fl_next) + __field(struct file_lock *, fl_blocker) __field(fl_owner_t, fl_owner) __field(unsigned int, fl_pid) __field(unsigned int, fl_flags) @@ -82,7 +82,7 @@ DECLARE_EVENT_CLASS(filelock_lock, __entry->fl = fl ? fl : NULL; __entry->s_dev = inode->i_sb->s_dev; __entry->i_ino = inode->i_ino; - __entry->fl_next = fl ? fl->fl_next : NULL; + __entry->fl_blocker = fl ? fl->fl_blocker : NULL; __entry->fl_owner = fl ? fl->fl_owner : NULL; __entry->fl_pid = fl ? fl->fl_pid : 0; __entry->fl_flags = fl ? fl->fl_flags : 0; @@ -92,9 +92,9 @@ DECLARE_EVENT_CLASS(filelock_lock, __entry->ret = ret; ), - TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_next=0x%p fl_owner=0x%p fl_pid=%u fl_flags=%s fl_type=%s fl_start=%lld fl_end=%lld ret=%d", + TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_blocker=0x%p fl_owner=0x%p fl_pid=%u fl_flags=%s fl_type=%s fl_start=%lld fl_end=%lld ret=%d", __entry->fl, MAJOR(__entry->s_dev), MINOR(__entry->s_dev), - __entry->i_ino, __entry->fl_next, __entry->fl_owner, + __entry->i_ino, __entry->fl_blocker, __entry->fl_owner, __entry->fl_pid, show_fl_flags(__entry->fl_flags), show_fl_type(__entry->fl_type), __entry->fl_start, __entry->fl_end, __entry->ret) @@ -122,7 +122,7 @@ DECLARE_EVENT_CLASS(filelock_lease, __field(struct file_lock *, fl) __field(unsigned long, i_ino) __field(dev_t, s_dev) - __field(struct file_lock *, fl_next) + __field(struct file_lock *, fl_blocker) __field(fl_owner_t, fl_owner) __field(unsigned int, fl_flags) __field(unsigned char, fl_type) @@ -134,7 +134,7 @@ DECLARE_EVENT_CLASS(filelock_lease, __entry->fl = fl ? fl : NULL; __entry->s_dev = inode->i_sb->s_dev; __entry->i_ino = inode->i_ino; - __entry->fl_next = fl ? fl->fl_next : NULL; + __entry->fl_blocker = fl ? fl->fl_blocker : NULL; __entry->fl_owner = fl ? fl->fl_owner : NULL; __entry->fl_flags = fl ? fl->fl_flags : 0; __entry->fl_type = fl ? fl->fl_type : 0; @@ -142,9 +142,9 @@ DECLARE_EVENT_CLASS(filelock_lease, __entry->fl_downgrade_time = fl ? fl->fl_downgrade_time : 0; ), - TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_next=0x%p fl_owner=0x%p fl_flags=%s fl_type=%s fl_break_time=%lu fl_downgrade_time=%lu", + TP_printk("fl=0x%p dev=0x%x:0x%x ino=0x%lx fl_blocker=0x%p fl_owner=0x%p fl_flags=%s fl_type=%s fl_break_time=%lu fl_downgrade_time=%lu", __entry->fl, MAJOR(__entry->s_dev), MINOR(__entry->s_dev), - __entry->i_ino, __entry->fl_next, __entry->fl_owner, + __entry->i_ino, __entry->fl_blocker, __entry->fl_owner, show_fl_flags(__entry->fl_flags), show_fl_type(__entry->fl_type), __entry->fl_break_time, __entry->fl_downgrade_time)