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Commit e55fd011 authored by Al Viro's avatar Al Viro
Browse files

split dentry_kill() 



... into trylocks and everything else.  The latter (actual killing)
is __dentry_kill().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 64fd72e0

fs/dcache.c

+36 −26
Original line number Diff line number Diff line
@@ -441,36 +441,12 @@ 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.
@@ -514,10 +490,44 @@ dentry_kill(struct dentry *dentry, int unlock_on_failure) 
		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 */

}



/*