From e2761a1167633ed943fea29002f990194923d060 Mon Sep 17 00:00:00 2001 From: OGAWA Hirofumi Date: Thu, 16 Oct 2008 07:50:28 +0900 Subject: [PATCH vfs-2.6 2/6] vfs: add d_ancestor() This adds d_ancestor() instead of d_isparent(), then use it. If new_dentry == old_dentry, is_subdir() returns 1, looks strange. "new_dentry == old_dentry" is not subdir obviously. But I'm not checking callers for now, so this keeps current behavior. Signed-off-by: OGAWA Hirofumi --- fs/dcache.c | 45 +++++++++++++++++++++++---------------------- 1 file changed, 23 insertions(+), 22 deletions(-) (limited to 'fs/dcache.c') diff --git a/fs/dcache.c b/fs/dcache.c index c6fd1f27da5..64024005da4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -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() */ @@ -2155,31 +2160,27 @@ out: * Caller must ensure that "new_dentry" is pinned before calling is_subdir() */ -int is_subdir(struct dentry * new_dentry, struct dentry * old_dentry) +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 { + 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(); -- cgit v1.2.3-18-g5258