Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752183Ab0HTBwT (ORCPT ); Thu, 19 Aug 2010 21:52:19 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:35434 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751836Ab0HTBwQ (ORCPT ); Thu, 19 Aug 2010 21:52:16 -0400 From: "Aneesh Kumar K.V" To: hch@infradead.org, viro@zeniv.linux.org.uk, adilger@sun.com, corbet@lwn.net, neilb@suse.de, npiggin@suse.de, hooanon05@yahoo.co.jp, bfields@fieldses.org, miklos@szeredi.hu Cc: linux-fsdevel@vger.kernel.org, sfrench@us.ibm.com, philippe.deniel@CEA.FR, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" Subject: [PATCH -V18 07/13] vfs: Support null pathname in linkat Date: Fri, 20 Aug 2010 07:21:31 +0530 Message-Id: <1282269097-26166-8-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.0.4 In-Reply-To: <1282269097-26166-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1282269097-26166-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2880 Lines: 99 This enables to use linkat to create hardlinks from a file descriptor pointing to the file. This can be used with open_by_handle syscall that returns a file descriptor. Signed-off-by: Aneesh Kumar K.V --- fs/namei.c | 36 ++++++++++++++++++++++++++---------- 1 files changed, 26 insertions(+), 10 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 2c79363..fd9febc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2627,7 +2627,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de struct inode *inode = old_dentry->d_inode; int error; - if (!inode) + if (!inode || inode->i_nlink == 0) return -ENOENT; error = may_create(dir, new_dentry); @@ -2673,16 +2673,28 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, { struct dentry *new_dentry; struct nameidata nd; - struct path old_path; - int error; + struct path old_path, *old_pathp; + struct file *file = NULL; + int error, fput_needed; char *to; if ((flags & ~AT_SYMLINK_FOLLOW) != 0) return -EINVAL; - error = user_path_at(olddfd, oldname, - flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, - &old_path); + if (oldname == NULL && olddfd != AT_FDCWD) { + file = fget_light(olddfd, &fput_needed); + if (file) { + old_pathp = &file->f_path; + error = 0; + } else + error = -EBADF; + } else { + error = user_path_at(olddfd, oldname, + flags & AT_SYMLINK_FOLLOW ? + LOOKUP_FOLLOW : 0, + &old_path); + old_pathp = &old_path; + } if (error) return error; @@ -2690,7 +2702,7 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, if (error) goto out; error = -EXDEV; - if (old_path.mnt != nd.path.mnt) + if (old_pathp->mnt != nd.path.mnt) goto out_release; new_dentry = lookup_create(&nd, 0); error = PTR_ERR(new_dentry); @@ -2699,10 +2711,11 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, error = mnt_want_write(nd.path.mnt); if (error) goto out_dput; - error = security_path_link(old_path.dentry, &nd.path, new_dentry); + error = security_path_link(old_pathp->dentry, &nd.path, new_dentry); if (error) goto out_drop_write; - error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); + error = vfs_link(old_pathp->dentry, + nd.path.dentry->d_inode, new_dentry); out_drop_write: mnt_drop_write(nd.path.mnt); out_dput: @@ -2713,7 +2726,10 @@ out_release: path_put(&nd.path); putname(to); out: - path_put(&old_path); + if (file) + fput_light(file, fput_needed); + else + path_put(&old_path); return error; } -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/