From 60545d0d4610b02e55f65d141c95b18ccf855b6e Mon Sep 17 00:00:00 2001
From: Al Viro
Date: Fri, 7 Jun 2013 01:20:27 -0400
Subject: [O_TMPFILE] it's still short a few helpers, but infrastructure should
 be OK now...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/namei.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

(limited to 'fs/namei.c')

diff --git a/fs/namei.c b/fs/namei.c
index 402eda351d07..778e253e3d48 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2902,6 +2902,61 @@ stale_open:
 	goto retry_lookup;
 }
 
+static int do_tmpfile(int dfd, struct filename *pathname,
+		struct nameidata *nd, int flags,
+		const struct open_flags *op,
+		struct file *file, int *opened)
+{
+	static const struct qstr name = QSTR_INIT("/", 1);
+	struct dentry *dentry, *child;
+	struct inode *dir;
+	int error = path_lookupat(dfd, pathname->name,
+				  flags | LOOKUP_DIRECTORY, nd);
+	if (unlikely(error))
+		return error;
+	error = mnt_want_write(nd->path.mnt);
+	if (unlikely(error))
+		goto out;
+	/* we want directory to be writable */
+	error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC);
+	if (error)
+		goto out2;
+	dentry = nd->path.dentry;
+	dir = dentry->d_inode;
+	if (!dir->i_op->tmpfile) {
+		error = -EOPNOTSUPP;
+		goto out2;
+	}
+	child = d_alloc(dentry, &name);
+	if (unlikely(!child)) {
+		error = -ENOMEM;
+		goto out2;
+	}
+	nd->flags &= ~LOOKUP_DIRECTORY;
+	nd->flags |= op->intent;
+	dput(nd->path.dentry);
+	nd->path.dentry = child;
+	error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode);
+	if (error)
+		goto out2;
+	audit_inode(pathname, nd->path.dentry, 0);
+	error = may_open(&nd->path, op->acc_mode, op->open_flag);
+	if (error)
+		goto out2;
+	file->f_path.mnt = nd->path.mnt;
+	error = finish_open(file, nd->path.dentry, NULL, opened);
+	if (error)
+		goto out2;
+	error = open_check_o_direct(file);
+	if (error)
+		fput(file);
+out2:
+	mnt_drop_write(nd->path.mnt);
+out:
+	path_put(&nd->path);
+	return error;
+}
+
 static struct file *path_openat(int dfd, struct filename *pathname,
 		struct nameidata *nd, const struct open_flags *op, int flags)
 {
@@ -2917,6 +2972,11 @@ static struct file *path_openat(int dfd, struct filename *pathname,
 
 	file->f_flags = op->open_flag;
 
+	if (unlikely(file->f_flags & O_TMPFILE)) {
+		error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened);
+		goto out;
+	}
+
 	error = path_init(dfd, pathname->name, flags | LOOKUP_PARENT, nd, &base);
 	if (unlikely(error))
 		goto out;
-- 
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