make lookup_one_len() safe to use with directory locked shared

Al Viro · Al Viro · commit 8613a209ffa6 · 2018-04-06T16:45:33.000-04:00
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
diff --git a/fs/namei.c b/fs/namei.c
@@ -2471,6 +2471,7 @@ static int lookup_one_len_common(const char *name, struct dentry *base,
  */
 struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 {
+	struct dentry *dentry;
 	struct qstr this;
 	int err;
 
@@ -2480,7 +2481,8 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
 	if (err)
 		return ERR_PTR(err);
 
-	return __lookup_hash(&this, base, 0);
+	dentry = lookup_dcache(&this, base, 0);
+	return dentry ? dentry : __lookup_slow(&this, base, 0);
 }
 EXPORT_SYMBOL(lookup_one_len);
 

Original file line number	Diff line number	Diff line change
`@@ -2471,6 +2471,7 @@ static int lookup_one_len_common(const char name, struct dentry base,`
`2471`	`2471`	`*/`
`2472`	`2472`	`struct dentry lookup_one_len(const char name, struct dentry *base, int len)`
`2473`	`2473`	`{`
	`2474`	`+ struct dentry *dentry;`
`2474`	`2475`	`struct qstr this;`
`2475`	`2476`	`int err;`
`2476`	`2477`
`@@ -2480,7 +2481,8 @@ struct dentry lookup_one_len(const char name, struct dentry *base, int len)`
`2480`	`2481`	`if (err)`
`2481`	`2482`	`return ERR_PTR(err);`
`2482`	`2483`
`2483`		`- return __lookup_hash(&this, base, 0);`
	`2484`	`+ dentry = lookup_dcache(&this, base, 0);`
	`2485`	`+ return dentry ? dentry : __lookup_slow(&this, base, 0);`
`2484`	`2486`	`}`
`2485`	`2487`	`EXPORT_SYMBOL(lookup_one_len);`
`2486`	`2488`