From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Fri, 14 Aug 2015 16:48:18 +0000 (-0700)
Subject: 3.14-stable patches
X-Git-Tag: v3.10.87~13
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b2a6b5c3f39bce639ccfc991a32c76ff6ea7e462;p=thirdparty%2Fkernel%2Fstable-queue.git

3.14-stable patches

added patches:
	fold-try_prune_one_dentry.patch
---

diff --git a/queue-3.14/fold-try_prune_one_dentry.patch b/queue-3.14/fold-try_prune_one_dentry.patch
new file mode 100644
index 00000000000..46d9f3bbda2
--- /dev/null
+++ b/queue-3.14/fold-try_prune_one_dentry.patch
@@ -0,0 +1,115 @@
+From 5c47e6d0ad608987b91affbcf7d1fc12dfbe8fb4 Mon Sep 17 00:00:00 2001
+From: Al Viro <viro@zeniv.linux.org.uk>
+Date: Tue, 29 Apr 2014 16:13:18 -0400
+Subject: fold try_prune_one_dentry()
+
+From: Al Viro <viro@zeniv.linux.org.uk>
+
+commit 5c47e6d0ad608987b91affbcf7d1fc12dfbe8fb4 upstream.
+
+Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/dcache.c |   75 ++++++++++++++++++++----------------------------------------
+ 1 file changed, 25 insertions(+), 50 deletions(-)
+
+--- a/fs/dcache.c
++++ b/fs/dcache.c
+@@ -788,47 +788,9 @@ restart:
+ }
+ EXPORT_SYMBOL(d_prune_aliases);
+ 
+-/*
+- * Try to throw away a dentry - free the inode, dput the parent.
+- * Requires dentry->d_lock is held, and dentry->d_count == 0.
+- * Releases dentry->d_lock.
+- *
+- * This may fail if locks cannot be acquired no problem, just try again.
+- */
+-static struct dentry * try_prune_one_dentry(struct dentry *dentry)
+-	__releases(dentry->d_lock)
+-{
+-	struct dentry *parent;
+-
+-	parent = dentry_kill(dentry, 0);
+-	/*
+-	 * If dentry_kill returns NULL, we have nothing more to do.
+-	 * if it returns the same dentry, trylocks failed. In either
+-	 * case, just loop again.
+-	 *
+-	 * Otherwise, we need to prune ancestors too. This is necessary
+-	 * to prevent quadratic behavior of shrink_dcache_parent(), but
+-	 * is also expected to be beneficial in reducing dentry cache
+-	 * fragmentation.
+-	 */
+-	if (!parent)
+-		return NULL;
+-	if (parent == dentry)
+-		return dentry;
+-
+-	/* Prune ancestors. */
+-	dentry = parent;
+-	while (dentry) {
+-		if (lockref_put_or_lock(&dentry->d_lockref))
+-			return NULL;
+-		dentry = dentry_kill(dentry, 1);
+-	}
+-	return NULL;
+-}
+-
+ static void shrink_dentry_list(struct list_head *list)
+ {
+-	struct dentry *dentry;
++	struct dentry *dentry, *parent;
+ 
+ 	rcu_read_lock();
+ 	for (;;) {
+@@ -864,22 +826,35 @@ static void shrink_dentry_list(struct li
+ 		}
+ 		rcu_read_unlock();
+ 
++		parent = dentry_kill(dentry, 0);
+ 		/*
+-		 * If 'try_to_prune()' returns a dentry, it will
+-		 * be the same one we passed in, and d_lock will
+-		 * have been held the whole time, so it will not
+-		 * have been added to any other lists. We failed
+-		 * to get the inode lock.
+-		 *
+-		 * We just add it back to the shrink list.
++		 * If dentry_kill returns NULL, we have nothing more to do.
+ 		 */
+-		dentry = try_prune_one_dentry(dentry);
+-
+-		rcu_read_lock();
+-		if (dentry) {
++		if (!parent) {
++			rcu_read_lock();
++			continue;
++		}
++		if (unlikely(parent == dentry)) {
++			/*
++			 * trylocks have failed and d_lock has been held the
++			 * whole time, so it could not have been added to any
++			 * other lists. Just add it back to the shrink list.
++			 */
++			rcu_read_lock();
+ 			d_shrink_add(dentry, list);
+ 			spin_unlock(&dentry->d_lock);
++			continue;
+ 		}
++		/*
++		 * We need to prune ancestors too. This is necessary to prevent
++		 * quadratic behavior of shrink_dcache_parent(), but is also
++		 * expected to be beneficial in reducing dentry cache
++		 * fragmentation.
++		 */
++		dentry = parent;
++		while (dentry && !lockref_put_or_lock(&dentry->d_lockref))
++			dentry = dentry_kill(dentry, 1);
++		rcu_read_lock();
+ 	}
+ 	rcu_read_unlock();
+ }
diff --git a/queue-3.14/series b/queue-3.14/series
index 930341d8450..faaa532ba6f 100644
--- a/queue-3.14/series
+++ b/queue-3.14/series
@@ -31,3 +31,4 @@ signalfd-fix-information-leak-in-signalfd_copyinfo.patch
 signal-fix-information-leak-in-copy_siginfo_to_user.patch
 signal-fix-information-leak-in-copy_siginfo_from_user32.patch
 fold-d_kill-and-d_free.patch
+fold-try_prune_one_dentry.patch