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, serue@us.ibm.com, neilb@suse.de,
hooanon05@yahoo.co.jp, bfields@fieldses.org
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 11/11] vfs: Support null pathname in linkat
Date: Thu, 3 Jun 2010 21:38:41 +0530 [thread overview]
Message-ID: <1275581321-5861-12-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1275581321-5861-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
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 <aneesh.kumar@linux.vnet.ibm.com>
---
fs/namei.c | 31 +++++++++++++++++++++++--------
1 files changed, 23 insertions(+), 8 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 417bf53..8b1cc23 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2533,16 +2533,27 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
{
struct dentry *new_dentry;
struct nameidata nd;
- struct path old_path;
+ struct path old_path, *old_pathp;
+ struct file *file = NULL;
int error;
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(olddfd);
+ 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;
@@ -2550,7 +2561,7 @@ 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);
@@ -2559,10 +2570,11 @@ 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:
@@ -2573,7 +2585,10 @@ out_release:
path_put(&nd.path);
putname(to);
out:
- path_put(&old_path);
+ if (file)
+ fput(file);
+ else
+ path_put(&old_path);
return error;
}
--
1.7.1.236.g81fa0
prev parent reply other threads:[~2010-06-03 16:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-03 16:08 [PATCH -V13 0/11] Generic name to handle and open by handle syscalls Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 01/11] exportfs: Return the minimum required handle size Aneesh Kumar K.V
2010-06-03 16:17 ` Aneesh Kumar K. V
2010-06-03 16:08 ` [PATCH 02/11] vfs: Add name to file handle conversion support Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 03/11] vfs: Add open by file handle support Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 04/11] vfs: Allow handle based open on symlinks Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 05/11] vfs: Support null pathname in readlink Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 06/11] ext4: Copy fs UUID to superblock Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 07/11] x86: Add new syscalls for x86_32 Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 08/11] x86: Add new syscalls for x86_64 Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 09/11] ext3: Copy fs UUID to superblock Aneesh Kumar K.V
2010-06-03 16:08 ` [PATCH 10/11] vfs: Support null pathname in faccessat Aneesh Kumar K.V
2010-06-03 16:08 ` Aneesh Kumar K.V [this message]
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