autofs4: eliminate d_unhashed in path walk checks (c42c7f7e) · Commits · 戴 / test

We unhash the dentry (in a subsequent patch) in ->d_revalidate() in order to send mount requests to ->lookup(). But then we can not rely on d_unhased() to give reliable results because it may be called at any time by any code path. The d_unhashed() function is used by __simple_empty() in the path walking callbacks but autofs mount point dentrys should have no directories at all so a list_empty() on d_subdirs should be (and is) sufficient. Signed-off-by:

Ian Kent <raven@themaw.net> Cc: Sage Weil <sage@newdream.net> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Yehuda Saheh <yehuda@newdream.net> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs4/root.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -133,7 +133,7 @@ static int autofs4_dir_open(struct inode inode, struct file file)
		* it.
		*/
		spin_lock(&dcache_lock);
		if (!d_mountpoint(dentry) && __simple_empty(dentry)) {
		if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
		spin_unlock(&dcache_lock);
		return -ENOENT;
		}
		@@ -257,7 +257,7 @@ static void autofs4_follow_link(struct dentry dentry, struct nameidata *nd)
		* mount it again.
		*/
		if (ino->flags & AUTOFS_INF_PENDING \|\|
		(!d_mountpoint(dentry) && __simple_empty(dentry))) {
		(!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
		spin_unlock(&dcache_lock);
		spin_unlock(&sbi->fs_lock);

		@@ -340,8 +340,7 @@ static int autofs4_revalidate(struct dentry dentry, struct nameidata nd)
		/* Check for a non-mountpoint directory with no contents */
		spin_lock(&dcache_lock);
		if (S_ISDIR(dentry->d_inode->i_mode) &&
		!d_mountpoint(dentry) &&
		__simple_empty(dentry)) {
		!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
		DPRINTK("dentry=%p %.*s, emptydir",
		dentry, dentry->d_name.len, dentry->d_name.name);
		spin_unlock(&dcache_lock);

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