From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit e55fd011549eae01a230e3cace6f4d031b6a3453 upstream.
... into trylocks and everything else. The latter (actual killing)
is __dentry_kill().
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
fs/dcache.c | 62 +++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 36 insertions(+), 26 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index c7085b971290..7575aeec1740 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -463,36 +463,12 @@ void d_drop(struct dentry *dentry)
}
EXPORT_SYMBOL(d_drop);
-/*
- * Finish off a dentry we've decided to kill.
- * dentry->d_lock must be held, returns with it unlocked.
- * If ref is non-zero, then decrement the refcount too.
- * Returns dentry requiring refcount drop, or NULL if we're done.
- */
-static struct dentry *
-dentry_kill(struct dentry *dentry, int unlock_on_failure)
- __releases(dentry->d_lock)
+static void __dentry_kill(struct dentry *dentry)
{
- struct inode *inode;
struct dentry *parent = NULL;
bool can_free = true;
-
- inode = dentry->d_inode;
- if (inode && !spin_trylock(&inode->i_lock)) {
-relock:
- if (unlock_on_failure) {
- spin_unlock(&dentry->d_lock);
- cpu_relax();
- }
- return dentry; /* try again with same dentry */
- }
if (!IS_ROOT(dentry))
parent = dentry->d_parent;
- if (parent && !spin_trylock(&parent->d_lock)) {
- if (inode)
- spin_unlock(&inode->i_lock);
- goto relock;
- }
/*
* The dentry is now unrecoverably dead to the world.
@@ -536,10 +512,44 @@ relock:
can_free = false;
}
spin_unlock(&dentry->d_lock);
-out:
if (likely(can_free))
dentry_free(dentry);
+}
+
+/*
+ * Finish off a dentry we've decided to kill.
+ * dentry->d_lock must be held, returns with it unlocked.
+ * If ref is non-zero, then decrement the refcount too.
+ * Returns dentry requiring refcount drop, or NULL if we're done.
+ */
+static struct dentry *
+dentry_kill(struct dentry *dentry, int unlock_on_failure)
+ __releases(dentry->d_lock)
+{
+ struct inode *inode = dentry->d_inode;
+ struct dentry *parent = NULL;
+
+ if (inode && unlikely(!spin_trylock(&inode->i_lock)))
+ goto failed;
+
+ if (!IS_ROOT(dentry)) {
+ parent = dentry->d_parent;
+ if (unlikely(!spin_trylock(&parent->d_lock))) {
+ if (inode)
+ spin_unlock(&inode->i_lock);
+ goto failed;
+ }
+ }
+
+ __dentry_kill(dentry);
return parent;
+
+failed:
+ if (unlock_on_failure) {
+ spin_unlock(&dentry->d_lock);
+ cpu_relax();
+ }
+ return dentry; /* try again with same dentry */
}
/*
--
2.1.2
--
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