[PATCH vfs-2.6 2/6] vfs: add d_ancestor() (e2761a11) · Commits · 戴 / test

fs/dcache.c

+23 −22

Original line number	Diff line number	Diff line
		@@ -1720,18 +1720,23 @@ void d_move(struct dentry * dentry, struct dentry * target)
		spin_unlock(&dcache_lock);
		}

		/*
		* Helper that returns 1 if p1 is a parent of p2, else 0
		/**
		* d_ancestor - search for an ancestor
		* @p1: ancestor dentry
		* @p2: child dentry
		*
		* Returns the ancestor dentry of p2 which is a child of p1, if p1 is
		* an ancestor of p2, else NULL.
		*/
		static int d_isparent(struct dentry p1, struct dentry p2)
		struct dentry d_ancestor(struct dentry p1, struct dentry *p2)
		{
		struct dentry *p;

		for (p = p2; !IS_ROOT(p); p = p->d_parent) {
		if (p->d_parent == p1)
		return 1;
		return p;
		}
		return 0;
		return NULL;
		}

		/*
		@@ -1755,7 +1760,7 @@ static struct dentry __d_unalias(struct dentry dentry, struct dentry *alias)

		/* Check for loops */
		ret = ERR_PTR(-ELOOP);
		if (d_isparent(alias, dentry))
		if (d_ancestor(alias, dentry))
		goto out_err;

		/* See lock_rename() */
		@@ -2158,28 +2163,24 @@ out:
		int is_subdir(struct dentry new_dentry, struct dentry old_dentry)
		{
		int result;
		struct dentry * saved = new_dentry;
		unsigned long seq;

		/* need rcu_readlock to protect against the d_parent trashing due to
		* d_move
		/* FIXME: This is old behavior, needed? Please check callers. */
		if (new_dentry == old_dentry)
		return 1;

		/*
		* Need rcu_readlock to protect against the d_parent trashing
		* due to d_move
		*/
		rcu_read_lock();
		do {
		/* for restarting inner loop in case of seq retry */
		new_dentry = saved;
		result = 0;
		seq = read_seqbegin(&rename_lock);
		for (;;) {
		if (new_dentry != old_dentry) {
		if (IS_ROOT(new_dentry))
		break;
		new_dentry = new_dentry->d_parent;
		continue;
		}
		if (d_ancestor(old_dentry, new_dentry))
		result = 1;
		break;
		}
		else
		result = 0;
		} while (read_seqretry(&rename_lock, seq));
		rcu_read_unlock();

fs/namei.c

+10 −12

Original line number	Diff line number	Diff line
		@@ -1454,21 +1454,19 @@ struct dentry lock_rename(struct dentry p1, struct dentry *p2)

		mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex);

		for (p = p1; !IS_ROOT(p); p = p->d_parent) {
		if (p->d_parent == p2) {
		p = d_ancestor(p2, p1);
		if (p) {
		mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD);
		return p;
		}
		}

		for (p = p2; !IS_ROOT(p); p = p->d_parent) {
		if (p->d_parent == p1) {
		p = d_ancestor(p1, p2);
		if (p) {
		mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
		return p;
		}
		}

		mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
		mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);

include/linux/dcache.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -287,6 +287,7 @@ static inline struct dentry d_add_unique(struct dentry entry, struct inode *in

		/* used for rename() and baskets */
		extern void d_move(struct dentry , struct dentry );
		extern struct dentry d_ancestor(struct dentry , struct dentry *);

		/* appendix may either be NULL or be used for transname suffixes */
		extern struct dentry * d_lookup(struct dentry , struct qstr );

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