X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=blobdiff_plain;f=fs%2Fnamei.c;h=2b729d253715ba183e912fae98cfec1e68665e24;hp=29fc6a657477cf49eaa4a722f2b2da39f6c387a6;hb=65e765ab385fc1ee5568db9a2733afd165b36474;hpb=f2ca379642d7a843be972ea4167abdd3c8c9e5d1

diff --git a/fs/namei.c b/fs/namei.c
index 29fc6a657477..2b729d253715 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1555,8 +1555,6 @@ static int lookup_fast(struct nameidata *nd,
 		negative = d_is_negative(dentry);
 		if (read_seqcount_retry(&dentry->d_seq, seq))
 			return -ECHILD;
-		if (negative)
-			return -ENOENT;
 
 		/*
 		 * This sequence count validates that the parent had no
@@ -1577,6 +1575,12 @@ static int lookup_fast(struct nameidata *nd,
 				goto unlazy;
 			}
 		}
+		/*
+		 * Note: do negative dentry check after revalidation in
+		 * case that drops it.
+		 */
+		if (negative)
+			return -ENOENT;
 		path->mnt = mnt;
 		path->dentry = dentry;
 		if (likely(__follow_mount_rcu(nd, path, inode, seqp)))
@@ -1962,7 +1966,7 @@ OK:
 		if (err) {
 			const char *s = get_link(nd);
 
-			if (unlikely(IS_ERR(s)))
+			if (IS_ERR(s))
 				return PTR_ERR(s);
 			err = 0;
 			if (unlikely(!s)) {
@@ -2275,6 +2279,8 @@ EXPORT_SYMBOL(vfs_path_lookup);
  *
  * Note that this routine is purely a helper for filesystem usage and should
  * not be called by generic code.
+ *
+ * The caller must hold base->i_mutex.
  */
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {
@@ -2318,6 +2324,78 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 }
 EXPORT_SYMBOL(lookup_one_len);
 
+/**
+ * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * @name:	pathname component to lookup
+ * @base:	base directory to lookup from
+ * @len:	maximum length @len should be interpreted to
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * Unlike lookup_one_len, it should be called without the parent
+ * i_mutex held, and will take the i_mutex itself if necessary.
+ */
+struct dentry *lookup_one_len_unlocked(const char *name,
+				       struct dentry *base, int len)
+{
+	struct qstr this;
+	unsigned int c;
+	int err;
+	struct dentry *ret;
+
+	this.name = name;
+	this.len = len;
+	this.hash = full_name_hash(name, len);
+	if (!len)
+		return ERR_PTR(-EACCES);
+
+	if (unlikely(name[0] == '.')) {
+		if (len < 2 || (len == 2 && name[1] == '.'))
+			return ERR_PTR(-EACCES);
+	}
+
+	while (len--) {
+		c = *(const unsigned char *)name++;
+		if (c == '/' || c == '\0')
+			return ERR_PTR(-EACCES);
+	}
+	/*
+	 * See if the low-level filesystem might want
+	 * to use its own hash..
+	 */
+	if (base->d_flags & DCACHE_OP_HASH) {
+		int err = base->d_op->d_hash(base, &this);
+		if (err < 0)
+			return ERR_PTR(err);
+	}
+
+	err = inode_permission(base->d_inode, MAY_EXEC);
+	if (err)
+		return ERR_PTR(err);
+
+	ret = __d_lookup(base, &this);
+	if (ret)
+		return ret;
+	/*
+	 * __d_lookup() is used to try to get a quick answer and avoid the
+	 * mutex.  A false-negative does no harm.
+	 */
+	ret = __d_lookup(base, &this);
+	if (ret && ret->d_flags & DCACHE_OP_REVALIDATE) {
+		dput(ret);
+		ret = NULL;
+	}
+	if (ret)
+		return ret;
+
+	mutex_lock(&base->d_inode->i_mutex);
+	ret =  __lookup_hash(&this, base, 0);
+	mutex_unlock(&base->d_inode->i_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(lookup_one_len_unlocked);
+
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 		 struct path *path, int *empty)
 {
@@ -3376,7 +3454,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 		return ERR_PTR(-ELOOP);
 
 	filename = getname_kernel(name);
-	if (unlikely(IS_ERR(filename)))
+	if (IS_ERR(filename))
 		return ERR_CAST(filename);
 
 	set_nameidata(&nd, -1, filename);