[PATCH v5 08/19] vfs: fix mknodat to retry on ESTALE errors

[Jeff Layton <jlayton@redhat.com>]

Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
 fs/namei.c | 51 +++++++++++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index f04ba14..0a0397f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3109,34 +3109,49 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
 	struct dentry *dentry;
 	struct path path;
 	int error;
+	char *name;
+	unsigned int try = 0;
 
 	error = may_mknod(mode);
 	if (error)
 		return error;
 
-	dentry = user_path_create(dfd, filename, &path, 0);
-	if (IS_ERR(dentry))
-		return PTR_ERR(dentry);
+	name = getname(filename);
+	if (IS_ERR(name))
+		return PTR_ERR(name);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
-		mode &= ~current_umask();
-	error = security_path_mknod(&path, dentry, mode, dev);
-	if (error)
-		goto out;
-	switch (mode & S_IFMT) {
-		case 0: case S_IFREG:
-			error = vfs_create(path.dentry->d_inode,dentry,mode,true);
+	do {
+		dentry = kern_path_create(dfd, name, &path, false, try);
+		if (IS_ERR(dentry)) {
+			error = PTR_ERR(dentry);
 			break;
-		case S_IFCHR: case S_IFBLK:
-			error = vfs_mknod(path.dentry->d_inode,dentry,mode,
-					new_decode_dev(dev));
+		}
+
+		if (!IS_POSIXACL(path.dentry->d_inode))
+			mode &= ~current_umask();
+		error = security_path_mknod(&path, dentry, mode, dev);
+		if (error)
+			goto out;
+		switch (mode & S_IFMT) {
+		case 0:
+		case S_IFREG:
+			error = vfs_create(path.dentry->d_inode, dentry,
+					mode, true);
 			break;
-		case S_IFIFO: case S_IFSOCK:
-			error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
+		case S_IFCHR:
+		case S_IFBLK:
+			error = vfs_mknod(path.dentry->d_inode, dentry, mode,
+					new_decode_dev(dev));
 			break;
-	}
+		case S_IFIFO:
+		case S_IFSOCK:
+			error = vfs_mknod(path.dentry->d_inode, dentry,
+					mode, 0);
+		}
 out:
-	done_path_create(&path, dentry);
+		done_path_create(&path, dentry);
+	} while (retry_estale(error, try++));
+	putname(name);
 	return error;
 }
 
-- 
1.7.11.2