From: Lei Chen <losemyheaven@gmail.com>
To: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Why does d_splice_alias need to check IS_ROOT?
Date: Sun, 27 May 2018 00:33:40 +0800 [thread overview]
Message-ID: <CAKEZqKJhZNoF-29ymEmAjiYfVn64q5mHrMY9sC2NZ=EDqTHjeA@mail.gmail.com> (raw)
Hello list,
I'm insteresting in how hard link and denry lookup work and their
implementation.
I know that this interface tries to connect an inode to a dentry, but
why does it need
to check whether the inode alias IS_ROOT if the inode represents a directory?
And the code process in different way according to check result. What
occasions
are they used for?
struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
{
if (S_ISDIR(inode->i_mode)) {
struct dentry *new = __d_find_any_alias(inode);
if (unlikely(new)) {
if (unlikely(d_ancestor(new, dentry))) {
/*the code here is to forbidden ancestor hard link*/
} else if (!IS_ROOT(new)) {
__d_unalias(inode, dentry, new);
} else {
__d_move(new, dentry, false);
}
}
}
}
Thanks in advance.
Regards,
Larry
next reply other threads:[~2018-05-26 16:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-26 16:33 Lei Chen [this message]
2018-05-26 17:12 ` Why does d_splice_alias need to check IS_ROOT? Al Viro
2018-05-27 11:09 ` Lei Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAKEZqKJhZNoF-29ymEmAjiYfVn64q5mHrMY9sC2NZ=EDqTHjeA@mail.gmail.com' \
--to=losemyheaven@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).