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Thu, 21 Jan 2021 13:23:21 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 10LDFjEG106643; Thu, 21 Jan 2021 13:21:21 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3030.oracle.com with ESMTP id 3668rexr9n-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 21 Jan 2021 13:21:21 +0000 Received: from userp3030.oracle.com (userp3030.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 10LDKZJF123118; Thu, 21 Jan 2021 13:21:20 GMT Received: from gmananth-linux.oraclecorp.com (dhcp-10-166-171-141.vpn.oracle.com [10.166.171.141]) by userp3030.oracle.com with ESMTP id 3668rexq88-5; Thu, 21 Jan 2021 13:21:20 +0000 From: Gautham Ananthakrishna To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: viro@zeniv.linux.org.uk, matthew.wilcox@oracle.com, khlebnikov@yandex-team.ru, gautham.ananthakrishna@oracle.com Subject: [PATCH RFC 4/6] dcache: stop walking siblings if remaining dentries all negative Date: Thu, 21 Jan 2021 18:49:43 +0530 Message-Id: <1611235185-1685-5-git-send-email-gautham.ananthakrishna@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1611235185-1685-1-git-send-email-gautham.ananthakrishna@oracle.com> References: <1611235185-1685-1-git-send-email-gautham.ananthakrishna@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9870 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 priorityscore=1501 adultscore=0 impostorscore=0 mlxlogscore=999 spamscore=0 suspectscore=0 phishscore=0 clxscore=1015 bulkscore=0 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2101210072 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Konstantin Khlebnikov Most walkers are interested only in positive dentries. Changes in simple_* libfs helpers are mostly cosmetic: it shouldn't cache negative dentries unless uses d_delete other than always_delete_dentry(). Signed-off-by: Konstantin Khlebnikov Signed-off-by: Gautham Ananthakrishna --- fs/dcache.c | 9 +++++++++ fs/libfs.c | 3 +++ 2 files changed, 12 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index 894e6da..492a42f 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1459,6 +1459,8 @@ static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry) struct check_mount *info = data; struct path path = { .mnt = info->mnt, .dentry = dentry }; + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; if (likely(!d_mountpoint(dentry))) return D_WALK_CONTINUE; if (__path_is_mountpoint(&path)) { @@ -1705,6 +1707,10 @@ void shrink_dcache_for_umount(struct super_block *sb) static enum d_walk_ret find_submount(void *_data, struct dentry *dentry) { struct dentry **victim = _data; + + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; + if (d_mountpoint(dentry)) { __dget_dlock(dentry); *victim = dentry; @@ -3174,6 +3180,9 @@ static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry) { struct dentry *root = data; if (dentry != root) { + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; + if (d_unhashed(dentry) || !dentry->d_inode) return D_WALK_SKIP; diff --git a/fs/libfs.c b/fs/libfs.c index 7124c2e..15d5ecf 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -410,6 +410,9 @@ int simple_empty(struct dentry *dentry) spin_lock(&dentry->d_lock); list_for_each_entry(child, &dentry->d_subdirs, d_child) { + if (d_is_tail_negative(child)) + break; + spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); if (simple_positive(child)) { spin_unlock(&child->d_lock);