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From: Wen Yang <wenyang@linux.alibaba.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>
Cc: Xunlei Pang <xlpang@linux.alibaba.com>,
	linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	stable@vger.kernel.org, Wen Yang <wenyang@linux.alibaba.com>
Subject: [PATCH 07/10] proc: Generalize proc_sys_prune_dcache into proc_prune_siblings_dcache
Date: Fri,  4 Dec 2020 02:32:01 +0800	[thread overview]
Message-ID: <20201203183204.63759-8-wenyang@linux.alibaba.com> (raw)
In-Reply-To: <20201203183204.63759-1-wenyang@linux.alibaba.com>

From: "Eric W. Biederman" <ebiederm@xmission.com>

[ Upstream commit 26dbc60f385ff9cff475ea2a3bad02e80fd6fa43 ]

This prepares the way for allowing the pid part of proc to use this
dcache pruning code as well.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org> # 4.9.x
(proc: fix up cherry-pick conflicts for 26dbc60f385f)
Signed-off-by: Wen Yang <wenyang@linux.alibaba.com>
---
 fs/proc/inode.c       | 38 ++++++++++++++++++++++++++++++++++++++
 fs/proc/internal.h    |  1 +
 fs/proc/proc_sysctl.c | 35 +----------------------------------
 3 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 14d9c1d..920c761 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -101,6 +101,44 @@ void __init proc_init_inodecache(void)
 					     init_once);
 }
 
+void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
+{
+	struct inode *inode;
+	struct proc_inode *ei;
+	struct hlist_node *node;
+	struct super_block *sb;
+
+	rcu_read_lock();
+	for (;;) {
+		node = hlist_first_rcu(inodes);
+		if (!node)
+			break;
+		ei = hlist_entry(node, struct proc_inode, sibling_inodes);
+		spin_lock(lock);
+		hlist_del_init_rcu(&ei->sibling_inodes);
+		spin_unlock(lock);
+
+		inode = &ei->vfs_inode;
+		sb = inode->i_sb;
+		if (!atomic_inc_not_zero(&sb->s_active))
+			continue;
+		inode = igrab(inode);
+		rcu_read_unlock();
+		if (unlikely(!inode)) {
+			deactivate_super(sb);
+			rcu_read_lock();
+			continue;
+		}
+
+		d_prune_aliases(inode);
+		iput(inode);
+		deactivate_super(sb);
+
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+}
+
 static int proc_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct super_block *sb = root->d_sb;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 409b5c5..9bc44a1 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -200,6 +200,7 @@ struct pde_opener {
 extern const struct inode_operations proc_pid_link_inode_operations;
 
 extern void proc_init_inodecache(void);
+void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
 extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
 extern int proc_fill_super(struct super_block *, void *data, int flags);
 extern void proc_entry_rundown(struct proc_dir_entry *);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 671490e..f19063b 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -262,40 +262,7 @@ static void unuse_table(struct ctl_table_header *p)
 
 static void proc_sys_prune_dcache(struct ctl_table_header *head)
 {
-	struct inode *inode;
-	struct proc_inode *ei;
-	struct hlist_node *node;
-	struct super_block *sb;
-
-	rcu_read_lock();
-	for (;;) {
-		node = hlist_first_rcu(&head->inodes);
-		if (!node)
-			break;
-		ei = hlist_entry(node, struct proc_inode, sibling_inodes);
-		spin_lock(&sysctl_lock);
-		hlist_del_init_rcu(&ei->sibling_inodes);
-		spin_unlock(&sysctl_lock);
-
-		inode = &ei->vfs_inode;
-		sb = inode->i_sb;
-		if (!atomic_inc_not_zero(&sb->s_active))
-			continue;
-		inode = igrab(inode);
-		rcu_read_unlock();
-		if (unlikely(!inode)) {
-			deactivate_super(sb);
-			rcu_read_lock();
-			continue;
-		}
-
-		d_prune_aliases(inode);
-		iput(inode);
-		deactivate_super(sb);
-
-		rcu_read_lock();
-	}
-	rcu_read_unlock();
+	proc_prune_siblings_dcache(&head->inodes, &sysctl_lock);
 }
 
 /* called under sysctl_lock, will reacquire if has to wait */
-- 
1.8.3.1


  parent reply	other threads:[~2020-12-03 18:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-03 18:31 [PATCH 00/10] Cover letter: fix a race in release_task when flushing the dentry Wen Yang
2020-12-03 18:31 ` [PATCH 01/10] clone: add CLONE_PIDFD Wen Yang
2021-01-04 13:03   ` Greg Kroah-Hartman
2021-01-04 13:13     ` Christian Brauner
2021-01-04 13:17       ` Greg Kroah-Hartman
2021-01-04 13:19         ` Christian Brauner
2020-12-03 18:31 ` [PATCH 02/10] pidfd: add polling support Wen Yang
2020-12-03 18:31 ` [PATCH 03/10] proc: Pass file mode to proc_pid_make_inode Wen Yang
2020-12-03 18:31 ` [PATCH 04/10] proc: Better ownership of files for non-dumpable tasks in user namespaces Wen Yang
2020-12-03 18:31 ` [PATCH 05/10] proc: use %u for pid printing and slightly less stack Wen Yang
2020-12-03 20:08   ` Alexey Dobriyan
2020-12-03 18:32 ` [PATCH 06/10] proc: Rename in proc_inode rename sysctl_inodes sibling_inodes Wen Yang
2020-12-03 18:32 ` Wen Yang [this message]
2020-12-03 18:32 ` [PATCH 08/10] proc: Clear the pieces of proc_inode that proc_evict_inode cares about Wen Yang
2020-12-03 18:32 ` [PATCH 09/10] proc: Use d_invalidate in proc_prune_siblings_dcache Wen Yang
2020-12-03 18:32 ` [PATCH 10/10] proc: Use a list of inodes to flush from proc Wen Yang
2020-12-17  2:26 ` [PATCH 00/10] Cover letter: fix a race in release_task when flushing the dentry Wen Yang
2020-12-31  9:22   ` Greg Kroah-Hartman
2021-01-04  4:15     ` Wen Yang

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