linux-kernel - Re: [PATCH 00/16] vfs: atomic open v4 (part 1)

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Date:	Thu, 24 May 2012 16:52:02 +0100
From:	David Howells <dhowells@...hat.com>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	dhowells@...hat.com, viro@...IV.linux.org.uk,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	hch@...radead.org, torvalds@...ux-foundation.org, mszeredi@...e.cz
Subject: Re: [PATCH 00/16] vfs: atomic open v4 (part 1)

I'd also recommend changing the "ok" and "common" labels in do_last() to
something a bit more meaningful, perhaps:

	common -> finish_open
	ok -> finish_open_may_want_write

Also, does it make sense to combine:

	if (!S_ISREG(nd->inode->i_mode))
		will_truncate = 0;

with:

	int will_truncate = open_flag & O_TRUNC;

up at the top of the function.

As the code stands, if ->atomic_open() opens the file but does not create it,
handle_truncate() will be called on it even if it is not a regular file,
whereas by the normal path, it won't.

I would also be tempted to move the body of:

	if (filp == ERR_PTR(-EOPENSTALE) && save_parent.dentry && !retried) {
		BUG_ON(save_parent.dentry != dir);
		path_put(&nd->path);
		nd->path = save_parent;
		nd->inode = dir->d_inode;
		save_parent.mnt = NULL;
		save_parent.dentry = NULL;
		if (want_write) {
			mnt_drop_write(nd->path.mnt);
			want_write = 0;
		}
		retried = true;
		goto retry_lookup;
	}

before the retry_lookup label and then goto around it from the preceding
if-else statement or place it at the bottom to make the "common:" block simpler
to read.  Also, you could nest the if (filp == ERR_PTR(-EOPENSTALE)...) inside
if (IS_ERR(filp)).

Can I also suggest being consistent about the use of int v bool?  "created"
and "retried" are bool, but "will_truncate", "want_write" and "symlink_ok" are
not.  Granted some of this is likely inherited from the previous incarnation.

David
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