[RFC 04/26] VFS: Make lookup_create() return a struct path

From: Jan Blunck
Date: Mon Jul 30 2007 - 12:21:16 EST


This patch changes lookup_create() into returning a struct path.

Signed-off-by: Jan Blunck <jblunck@xxxxxxx>
---
arch/powerpc/platforms/cell/spufs/inode.c | 15 ++----
fs/namei.c | 75 +++++++++++++-----------------
include/linux/dcache.h | 1
include/linux/namei.h | 1
net/unix/af_unix.c | 17 +++---
5 files changed, 50 insertions(+), 59 deletions(-)

--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -456,7 +456,7 @@ static struct file_system_type spufs_typ

long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode)
{
- struct dentry *dentry;
+ struct path path;
int ret;

ret = -EINVAL;
@@ -475,26 +475,25 @@ long spufs_create(struct nameidata *nd,
goto out;
}

- dentry = lookup_create(nd, 1);
- ret = PTR_ERR(dentry);
- if (IS_ERR(dentry))
+ ret = lookup_create(nd, 1, &path);
+ if (ret)
goto out_dir;

ret = -EEXIST;
- if (dentry->d_inode)
+ if (path.dentry->d_inode)
goto out_dput;

mode &= ~current->fs->umask;

if (flags & SPU_CREATE_GANG)
return spufs_create_gang(nd->dentry->d_inode,
- dentry, nd->mnt, mode);
+ path.dentry, path.mnt, mode);
else
return spufs_create_context(nd->dentry->d_inode,
- dentry, nd->mnt, flags, mode);
+ path.dentry, path.mnt, flags, mode);

out_dput:
- dput(dentry);
+ dput_path(&path, nd);
out_dir:
mutex_unlock(&nd->dentry->d_inode->i_mutex);
out:
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1833,10 +1833,9 @@ do_link:
*
* Returns with nd->dentry->d_inode->i_mutex locked.
*/
-struct dentry *lookup_create(struct nameidata *nd, int is_dir)
+int lookup_create(struct nameidata *nd, int is_dir, struct path *path)
{
- struct path path = { .dentry = ERR_PTR(-EEXIST) } ;
- int err;
+ int err = -EEXIST;

mutex_lock_nested(&nd->dentry->d_inode->i_mutex, I_MUTEX_PARENT);
/*
@@ -1852,11 +1851,9 @@ struct dentry *lookup_create(struct name
/*
* Do the final lookup.
*/
- err = lookup_hash(nd, &nd->last, &path);
- if (err) {
- path.dentry = ERR_PTR(err);
+ err = lookup_hash(nd, &nd->last, path);
+ if (err)
goto fail;
- }

/*
* Special case - lookup gave negative, but... we had foo/bar/
@@ -1864,16 +1861,14 @@ struct dentry *lookup_create(struct name
* all is fine. Let's be bastards - you had / on the end, you've
* been asking for (non-existent) directory. -ENOENT for you.
*/
- if (!is_dir && nd->last.name[nd->last.len] && !path.dentry->d_inode)
+ if (!is_dir && nd->last.name[nd->last.len] && !path->dentry->d_inode)
goto enoent;
- if (nd->mnt != path.mnt)
- mntput(path.mnt);
- return path.dentry;
+ return 0;
enoent:
- dput_path(&path, nd);
- path.dentry = ERR_PTR(-ENOENT);
+ dput_path(path, nd);
+ err = -ENOENT;
fail:
- return path.dentry;
+ return err;
}
EXPORT_SYMBOL_GPL(lookup_create);

@@ -1906,7 +1901,7 @@ asmlinkage long sys_mknodat(int dfd, con
{
int error = 0;
char * tmp;
- struct dentry * dentry;
+ struct path path;
struct nameidata nd;

if (S_ISDIR(mode))
@@ -1918,22 +1913,23 @@ asmlinkage long sys_mknodat(int dfd, con
error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
if (error)
goto out;
- dentry = lookup_create(&nd, 0);
- error = PTR_ERR(dentry);
+ error = lookup_create(&nd, 0, &path);

if (!IS_POSIXACL(nd.dentry->d_inode))
mode &= ~current->fs->umask;
- if (!IS_ERR(dentry)) {
+ if (!error) {
switch (mode & S_IFMT) {
case 0: case S_IFREG:
- error = vfs_create(nd.dentry->d_inode,dentry,mode,&nd);
+ error = vfs_create(nd.dentry->d_inode, path.dentry,
+ mode, &nd);
break;
case S_IFCHR: case S_IFBLK:
- error = vfs_mknod(nd.dentry->d_inode,dentry,mode,
- new_decode_dev(dev));
+ error = vfs_mknod(nd.dentry->d_inode, path.dentry,
+ mode, new_decode_dev(dev));
break;
case S_IFIFO: case S_IFSOCK:
- error = vfs_mknod(nd.dentry->d_inode,dentry,mode,0);
+ error = vfs_mknod(nd.dentry->d_inode, path.dentry,
+ mode, 0);
break;
case S_IFDIR:
error = -EPERM;
@@ -1941,7 +1937,7 @@ asmlinkage long sys_mknodat(int dfd, con
default:
error = -EINVAL;
}
- dput(dentry);
+ dput_path(&path, &nd);
}
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);
@@ -1982,7 +1978,7 @@ asmlinkage long sys_mkdirat(int dfd, con
{
int error = 0;
char * tmp;
- struct dentry *dentry;
+ struct path path;
struct nameidata nd;

tmp = getname(pathname);
@@ -1993,15 +1989,14 @@ asmlinkage long sys_mkdirat(int dfd, con
error = do_path_lookup(dfd, tmp, LOOKUP_PARENT, &nd);
if (error)
goto out;
- dentry = lookup_create(&nd, 1);
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry))
+ error = lookup_create(&nd, 1, &path);
+ if (error)
goto out_unlock;

if (!IS_POSIXACL(nd.dentry->d_inode))
mode &= ~current->fs->umask;
- error = vfs_mkdir(nd.dentry->d_inode, dentry, mode);
- dput(dentry);
+ error = vfs_mkdir(nd.dentry->d_inode, path.dentry, mode);
+ dput_path(&path, &nd);
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);
@@ -2247,7 +2242,7 @@ asmlinkage long sys_symlinkat(const char
int error = 0;
char * from;
char * to;
- struct dentry *dentry;
+ struct path path;
struct nameidata nd;

from = getname(oldname);
@@ -2261,13 +2256,12 @@ asmlinkage long sys_symlinkat(const char
error = do_path_lookup(newdfd, to, LOOKUP_PARENT, &nd);
if (error)
goto out;
- dentry = lookup_create(&nd, 0);
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry))
+ error = lookup_create(&nd, 0, &path);
+ if (error)
goto out_unlock;

- error = vfs_symlink(nd.dentry->d_inode, dentry, from, S_IALLUGO);
- dput(dentry);
+ error = vfs_symlink(nd.dentry->d_inode, path.dentry, from, S_IALLUGO);
+ dput_path(&path, &nd);
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);
@@ -2334,7 +2328,7 @@ asmlinkage long sys_linkat(int olddfd, c
int newdfd, const char __user *newname,
int flags)
{
- struct dentry *new_dentry;
+ struct path path;
struct nameidata nd, old_nd;
int error;
char * to;
@@ -2357,12 +2351,11 @@ asmlinkage long sys_linkat(int olddfd, c
error = -EXDEV;
if (old_nd.mnt != nd.mnt)
goto out_release;
- new_dentry = lookup_create(&nd, 0);
- error = PTR_ERR(new_dentry);
- if (IS_ERR(new_dentry))
+ error = lookup_create(&nd, 0, &path);
+ if (error)
goto out_unlock;
- error = vfs_link(old_nd.dentry, nd.dentry->d_inode, new_dentry);
- dput(new_dentry);
+ error = vfs_link(old_nd.dentry, nd.dentry->d_inode, path.dentry);
+ dput_path(&path, &nd);
out_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
out_release:
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -358,7 +358,6 @@ static inline int d_mountpoint(struct de

extern struct vfsmount *lookup_mnt(struct vfsmount *, struct dentry *);
extern struct vfsmount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
-extern struct dentry *lookup_create(struct nameidata *nd, int is_dir);

extern int sysctl_vfs_cache_pressure;

--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -91,6 +91,7 @@ static inline struct dentry *lookup_one_
{
return lookup_one_len_nd(name, dir, len, NULL);
}
+extern int lookup_create(struct nameidata *, int, struct path *);

extern int follow_down(struct vfsmount **, struct dentry **);
extern int follow_up(struct vfsmount **, struct dentry **);
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -749,8 +749,8 @@ static int unix_bind(struct socket *sock
struct sock *sk = sock->sk;
struct unix_sock *u = unix_sk(sk);
struct sockaddr_un *sunaddr=(struct sockaddr_un *)uaddr;
- struct dentry * dentry = NULL;
struct nameidata nd;
+ struct path path;
int err;
unsigned hash;
struct unix_address *addr;
@@ -797,9 +797,8 @@ static int unix_bind(struct socket *sock
if (err)
goto out_mknod_parent;

- dentry = lookup_create(&nd, 0);
- err = PTR_ERR(dentry);
- if (IS_ERR(dentry))
+ err = lookup_create(&nd, 0, &path);
+ if (err)
goto out_mknod_unlock;

/*
@@ -807,12 +806,11 @@ static int unix_bind(struct socket *sock
*/
mode = S_IFSOCK |
(SOCK_INODE(sock)->i_mode & ~current->fs->umask);
- err = vfs_mknod(nd.dentry->d_inode, dentry, mode, 0);
+ err = vfs_mknod(nd.dentry->d_inode, path.dentry, mode, 0);
if (err)
goto out_mknod_dput;
mutex_unlock(&nd.dentry->d_inode->i_mutex);
- dput(nd.dentry);
- nd.dentry = dentry;
+ path_to_nameidata(&path, &nd);

addr->hash = UNIX_HASH_SIZE;
}
@@ -829,7 +827,8 @@ static int unix_bind(struct socket *sock

list = &unix_socket_table[addr->hash];
} else {
- list = &unix_socket_table[dentry->d_inode->i_ino & (UNIX_HASH_SIZE-1)];
+ list = &unix_socket_table[nd.dentry->d_inode->i_ino &
+ (UNIX_HASH_SIZE-1)];
u->dentry = nd.dentry;
u->mnt = nd.mnt;
}
@@ -847,7 +846,7 @@ out:
return err;

out_mknod_dput:
- dput(dentry);
+ dput_path(&path, &nd);
out_mknod_unlock:
mutex_unlock(&nd.dentry->d_inode->i_mutex);
path_release(&nd);

--

-
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