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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: hch@infradead.org, viro@zeniv.linux.org.uk, adilger@sun.com,
	corbet@lwn.net, neilb@suse.de, npiggin@kernel.dk,
	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" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH -V22 06/14] fs: Don't allow to create hardlink for deleted file
Date: Fri, 29 Oct 2010 15:27:15 +0530	[thread overview]
Message-ID: <1288346243-12211-7-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1288346243-12211-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

Add inode->i_nlink == 0 check in VFS. Some of the file systems
do this internally. A followup patch will remove those instance.
This is needed to ensure that with link by handle we don't allow
to create hardlink of an unlinked file. The check also prevent a race
between unlink and link

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 fs/namei.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index ea6656e..9c8d4cc 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2620,7 +2620,11 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 		return error;
 
 	mutex_lock(&inode->i_mutex);
-	error = dir->i_op->link(old_dentry, dir, new_dentry);
+	/* Make sure we don't allow creating hardlink to an unlinked file */
+	if (inode->i_nlink == 0)
+		error =  -ENOENT;
+	else
+		error = dir->i_op->link(old_dentry, dir, new_dentry);
 	mutex_unlock(&inode->i_mutex);
 	if (!error)
 		fsnotify_link(dir, inode, new_dentry);
-- 
1.7.1

  parent reply	other threads:[~2010-10-29  9:57 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-29  9:57 [PATCH -V22 00/14] Generic name to handle and open by handle syscalls Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 01/14] exportfs: Return the minimum required handle size Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 02/14] vfs: Add name to file handle conversion support Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 03/14] vfs: Add open by file handle support Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 04/14] vfs: Add handle based readlink syscall Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 05/14] vfs: Add handle based stat syscall Aneesh Kumar K.V
2010-10-29  9:57 ` Aneesh Kumar K.V [this message]
2010-10-29  9:57 ` [PATCH -V22 07/14] fs: Remove i_nlink check from file system link callback Aneesh Kumar K.V
2010-10-29 10:19   ` [Updated PATCH " Aneesh Kumar K. V
2010-10-29  9:57 ` [PATCH -V22 08/14] vfs: Add handle based link syscall Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 09/14] x86: Add new syscalls for x86_32 Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 10/14] x86: Add new syscalls for x86_64 Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 11/14] unistd.h: Add new syscalls numbers to asm-generic Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 12/14] vfs: Export file system uuid via /proc/<pid>/mountinfo Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 13/14] ext3: Copy fs UUID to superblock Aneesh Kumar K.V
2010-10-29  9:57 ` [PATCH -V22 14/14] ext4: " Aneesh Kumar K.V

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