From patchwork Sat Apr 16 00:55:27 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 8860641 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id EDB57BF29F for ; Sat, 16 Apr 2016 00:57:46 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D72D52026C for ; Sat, 16 Apr 2016 00:57:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A593B20259 for ; Sat, 16 Apr 2016 00:57:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752537AbcDPA4Y (ORCPT ); Fri, 15 Apr 2016 20:56:24 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:39595 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752758AbcDPAza (ORCPT ); Fri, 15 Apr 2016 20:55:30 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1arEWH-0008Ii-6Z; Sat, 16 Apr 2016 00:55:29 +0000 From: Al Viro To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 15/15] parallel lookups: actual switch to rwsem Date: Sat, 16 Apr 2016 01:55:27 +0100 Message-Id: <1460768127-31822-15-git-send-email-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.7.3 In-Reply-To: <20160416005232.GV25498@ZenIV.linux.org.uk> References: <20160416005232.GV25498@ZenIV.linux.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Al Viro ta-da! The main issue is the lack of down_write_killable(), so the places like readdir.c switched to plain inode_lock(); once killable variants of rwsem primitives appear, that'll be dealt with. lockdep side also might need more work Signed-off-by: Al Viro --- fs/btrfs/ioctl.c | 16 ++++++++++------ fs/configfs/inode.c | 2 +- fs/dcache.c | 9 +++++---- fs/gfs2/ops_fstype.c | 2 +- fs/inode.c | 12 ++++++------ fs/namei.c | 4 ++-- fs/ocfs2/inode.c | 2 +- fs/overlayfs/readdir.c | 4 +++- fs/readdir.c | 7 ++++--- include/linux/fs.h | 12 ++++++------ 10 files changed, 39 insertions(+), 31 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 053e677..db1e830 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -837,9 +837,11 @@ static noinline int btrfs_mksubvol(struct path *parent, struct dentry *dentry; int error; - error = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); - if (error == -EINTR) - return error; + inode_lock_nested(dir, I_MUTEX_PARENT); + // XXX: should've been + // mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); + // if (error == -EINTR) + // return error; dentry = lookup_one_len(name, parent->dentry, namelen); error = PTR_ERR(dentry); @@ -2366,9 +2368,11 @@ static noinline int btrfs_ioctl_snap_destroy(struct file *file, goto out; - err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); - if (err == -EINTR) - goto out_drop_write; + inode_lock_nested(dir, I_MUTEX_PARENT); + // XXX: should've been + // err = mutex_lock_killable_nested(&dir->i_mutex, I_MUTEX_PARENT); + // if (err == -EINTR) + // goto out_drop_write; dentry = lookup_one_len(vol_args->name, parent, namelen); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index 03d124a..0387968 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -156,7 +156,7 @@ static void configfs_set_inode_lock_class(struct configfs_dirent *sd, if (depth > 0) { if (depth <= ARRAY_SIZE(default_group_class)) { - lockdep_set_class(&inode->i_mutex, + lockdep_set_class(&inode->i_rwsem, &default_group_class[depth - 1]); } else { /* diff --git a/fs/dcache.c b/fs/dcache.c index 5965588..d110040 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2911,7 +2911,8 @@ struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) static int __d_unalias(struct inode *inode, struct dentry *dentry, struct dentry *alias) { - struct mutex *m1 = NULL, *m2 = NULL; + struct mutex *m1 = NULL; + struct rw_semaphore *m2 = NULL; int ret = -ESTALE; /* If alias and dentry share a parent, then no extra locks required */ @@ -2922,15 +2923,15 @@ static int __d_unalias(struct inode *inode, if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) goto out_err; m1 = &dentry->d_sb->s_vfs_rename_mutex; - if (!inode_trylock(alias->d_parent->d_inode)) + if (!down_read_trylock(&alias->d_parent->d_inode->i_rwsem)) goto out_err; - m2 = &alias->d_parent->d_inode->i_mutex; + m2 = &alias->d_parent->d_inode->i_rwsem; out_unalias: __d_move(alias, dentry, false); ret = 0; out_err: if (m2) - mutex_unlock(m2); + up_read(m2); if (m1) mutex_unlock(m1); return ret; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index c09c63d..4546360 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -824,7 +824,7 @@ static int init_inodes(struct gfs2_sbd *sdp, int undo) * i_mutex on quota files is special. Since this inode is hidden system * file, we are safe to define locking ourselves. */ - lockdep_set_class(&sdp->sd_quota_inode->i_mutex, + lockdep_set_class(&sdp->sd_quota_inode->i_rwsem, &gfs2_quota_imutex_key); error = gfs2_rindex_update(sdp); diff --git a/fs/inode.c b/fs/inode.c index 4b884f7..4ccbc21 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -166,8 +166,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode) spin_lock_init(&inode->i_lock); lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key); - mutex_init(&inode->i_mutex); - lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key); + init_rwsem(&inode->i_rwsem); + lockdep_set_class(&inode->i_rwsem, &sb->s_type->i_mutex_key); atomic_set(&inode->i_dio_count, 0); @@ -925,13 +925,13 @@ void lockdep_annotate_inode_mutex_key(struct inode *inode) struct file_system_type *type = inode->i_sb->s_type; /* Set new key only if filesystem hasn't already changed it */ - if (lockdep_match_class(&inode->i_mutex, &type->i_mutex_key)) { + if (lockdep_match_class(&inode->i_rwsem, &type->i_mutex_key)) { /* * ensure nobody is actually holding i_mutex */ - mutex_destroy(&inode->i_mutex); - mutex_init(&inode->i_mutex); - lockdep_set_class(&inode->i_mutex, + // mutex_destroy(&inode->i_mutex); + init_rwsem(&inode->i_rwsem); + lockdep_set_class(&inode->i_rwsem, &type->i_mutex_dir_key); } } diff --git a/fs/namei.c b/fs/namei.c index eb879d6..877e9ef 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1607,7 +1607,7 @@ static struct dentry *lookup_slow(const struct qstr *name, struct inode *inode = dir->d_inode; DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); - inode_lock(inode); + down_read(&inode->i_rwsem); /* Don't go there if it's already dead */ if (unlikely(IS_DEADDIR(inode))) goto out; @@ -1638,7 +1638,7 @@ again: } } out: - inode_unlock(inode); + up_read(&inode->i_rwsem); return dentry; } diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c index 12f4a9e..0748777 100644 --- a/fs/ocfs2/inode.c +++ b/fs/ocfs2/inode.c @@ -262,7 +262,7 @@ static int ocfs2_init_locked_inode(struct inode *inode, void *opaque) inode->i_ino = args->fi_ino; OCFS2_I(inode)->ip_blkno = args->fi_blkno; if (args->fi_sysfile_type != 0) - lockdep_set_class(&inode->i_mutex, + lockdep_set_class(&inode->i_rwsem, &ocfs2_sysfile_lock_key[args->fi_sysfile_type]); if (args->fi_sysfile_type == USER_QUOTA_SYSTEM_INODE || args->fi_sysfile_type == GROUP_QUOTA_SYSTEM_INODE || diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 6ec1e43..da186ee 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -218,7 +218,9 @@ static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd) cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); old_cred = override_creds(override_cred); - err = mutex_lock_killable(&dir->d_inode->i_mutex); + inode_lock(dir->d_inode); + err = 0; + // XXX: err = mutex_lock_killable(&dir->d_inode->i_mutex); if (!err) { while (rdd->first_maybe_whiteout) { p = rdd->first_maybe_whiteout; diff --git a/fs/readdir.c b/fs/readdir.c index e69ef3b..bf583e8 100644 --- a/fs/readdir.c +++ b/fs/readdir.c @@ -32,9 +32,10 @@ int iterate_dir(struct file *file, struct dir_context *ctx) if (res) goto out; - res = mutex_lock_killable(&inode->i_mutex); - if (res) - goto out; + inode_lock(inode); + // res = mutex_lock_killable(&inode->i_mutex); + // if (res) + // goto out; res = -ENOENT; if (!IS_DEADDIR(inode)) { diff --git a/include/linux/fs.h b/include/linux/fs.h index 0a32045..313ad28 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -647,7 +647,7 @@ struct inode { /* Misc */ unsigned long i_state; - struct mutex i_mutex; + struct rw_semaphore i_rwsem; unsigned long dirtied_when; /* jiffies of first dirtying */ unsigned long dirtied_time_when; @@ -734,27 +734,27 @@ enum inode_i_mutex_lock_class static inline void inode_lock(struct inode *inode) { - mutex_lock(&inode->i_mutex); + down_write(&inode->i_rwsem); } static inline void inode_unlock(struct inode *inode) { - mutex_unlock(&inode->i_mutex); + up_write(&inode->i_rwsem); } static inline int inode_trylock(struct inode *inode) { - return mutex_trylock(&inode->i_mutex); + return down_write_trylock(&inode->i_rwsem); } static inline int inode_is_locked(struct inode *inode) { - return mutex_is_locked(&inode->i_mutex); + return rwsem_is_locked(&inode->i_rwsem); } static inline void inode_lock_nested(struct inode *inode, unsigned subclass) { - mutex_lock_nested(&inode->i_mutex, subclass); + down_write_nested(&inode->i_rwsem, subclass); } void lock_two_nondirectories(struct inode *, struct inode*);