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new helpers: kern_path_create/user_path_create
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combination of kern_path_parent() and lookup_create().  Does *not*
expose struct nameidata to caller.  Syscalls converted to that...

Signed-off-by: Al Viro <[email protected]>
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Al Viro committed Jul 20, 2011
1 parent 49084c3 commit dae6ad8
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Showing 4 changed files with 106 additions and 137 deletions.
154 changes: 76 additions & 78 deletions fs/namei.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2311,6 +2311,35 @@ struct dentry *lookup_create(struct nameidata *nd, int is_dir)
}
EXPORT_SYMBOL_GPL(lookup_create);

struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir)
{
struct nameidata nd;
struct dentry *res;
int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
if (error)
return ERR_PTR(error);
res = lookup_create(&nd, is_dir);
if (IS_ERR(res)) {
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
}
*path = nd.path;
return res;
}
EXPORT_SYMBOL(kern_path_create);

struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir)
{
char *tmp = getname(pathname);
struct dentry *res;
if (IS_ERR(tmp))
return ERR_CAST(tmp);
res = kern_path_create(dfd, tmp, path, is_dir);
putname(tmp);
return res;
}
EXPORT_SYMBOL(user_path_create);

int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
int error = may_create(dir, dentry);
Expand Down Expand Up @@ -2359,54 +2388,46 @@ static int may_mknod(mode_t mode)
SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode,
unsigned, dev)
{
int error;
char *tmp;
struct dentry *dentry;
struct nameidata nd;
struct path path;
int error;

if (S_ISDIR(mode))
return -EPERM;

error = user_path_parent(dfd, filename, &nd, &tmp);
if (error)
return error;
dentry = user_path_create(dfd, filename, &path, 0);
if (IS_ERR(dentry))
return PTR_ERR(dentry);

dentry = lookup_create(&nd, 0);
if (IS_ERR(dentry)) {
error = PTR_ERR(dentry);
goto out_unlock;
}
if (!IS_POSIXACL(nd.path.dentry->d_inode))
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = may_mknod(mode);
if (error)
goto out_dput;
error = mnt_want_write(nd.path.mnt);
error = mnt_want_write(path.mnt);
if (error)
goto out_dput;
error = security_path_mknod(&nd.path, dentry, mode, dev);
error = security_path_mknod(&path, dentry, mode, dev);
if (error)
goto out_drop_write;
switch (mode & S_IFMT) {
case 0: case S_IFREG:
error = vfs_create(nd.path.dentry->d_inode,dentry,mode,NULL);
error = vfs_create(path.dentry->d_inode,dentry,mode,NULL);
break;
case S_IFCHR: case S_IFBLK:
error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,
error = vfs_mknod(path.dentry->d_inode,dentry,mode,
new_decode_dev(dev));
break;
case S_IFIFO: case S_IFSOCK:
error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0);
error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
break;
}
out_drop_write:
mnt_drop_write(nd.path.mnt);
mnt_drop_write(path.mnt);
out_dput:
dput(dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
putname(tmp);
mutex_unlock(&path.dentry->d_inode->i_mutex);
path_put(&path);

return error;
}
Expand Down Expand Up @@ -2439,38 +2460,29 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)

SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode)
{
int error = 0;
char * tmp;
struct dentry *dentry;
struct nameidata nd;

error = user_path_parent(dfd, pathname, &nd, &tmp);
if (error)
goto out_err;
struct path path;
int error;

dentry = lookup_create(&nd, 1);
error = PTR_ERR(dentry);
dentry = user_path_create(dfd, pathname, &path, 1);
if (IS_ERR(dentry))
goto out_unlock;
return PTR_ERR(dentry);

if (!IS_POSIXACL(nd.path.dentry->d_inode))
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
error = mnt_want_write(nd.path.mnt);
error = mnt_want_write(path.mnt);
if (error)
goto out_dput;
error = security_path_mkdir(&nd.path, dentry, mode);
error = security_path_mkdir(&path, dentry, mode);
if (error)
goto out_drop_write;
error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode);
error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
out_drop_write:
mnt_drop_write(nd.path.mnt);
mnt_drop_write(path.mnt);
out_dput:
dput(dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
putname(tmp);
out_err:
mutex_unlock(&path.dentry->d_inode->i_mutex);
path_put(&path);
return error;
}

Expand Down Expand Up @@ -2730,38 +2742,31 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
{
int error;
char *from;
char *to;
struct dentry *dentry;
struct nameidata nd;
struct path path;

from = getname(oldname);
if (IS_ERR(from))
return PTR_ERR(from);

error = user_path_parent(newdfd, newname, &nd, &to);
if (error)
goto out_putname;

dentry = lookup_create(&nd, 0);
dentry = user_path_create(newdfd, newname, &path, 0);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_unlock;
goto out_putname;

error = mnt_want_write(nd.path.mnt);
error = mnt_want_write(path.mnt);
if (error)
goto out_dput;
error = security_path_symlink(&nd.path, dentry, from);
error = security_path_symlink(&path, dentry, from);
if (error)
goto out_drop_write;
error = vfs_symlink(nd.path.dentry->d_inode, dentry, from);
error = vfs_symlink(path.dentry->d_inode, dentry, from);
out_drop_write:
mnt_drop_write(nd.path.mnt);
mnt_drop_write(path.mnt);
out_dput:
dput(dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
path_put(&nd.path);
putname(to);
mutex_unlock(&path.dentry->d_inode->i_mutex);
path_put(&path);
out_putname:
putname(from);
return error;
Expand Down Expand Up @@ -2826,11 +2831,9 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
int, newdfd, const char __user *, newname, int, flags)
{
struct dentry *new_dentry;
struct nameidata nd;
struct path old_path;
struct path old_path, new_path;
int how = 0;
int error;
char *to;

if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0)
return -EINVAL;
Expand All @@ -2852,32 +2855,27 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
if (error)
return error;

error = user_path_parent(newdfd, newname, &nd, &to);
if (error)
goto out;
error = -EXDEV;
if (old_path.mnt != nd.path.mnt)
goto out_release;
new_dentry = lookup_create(&nd, 0);
new_dentry = user_path_create(newdfd, newname, &new_path, 0);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out_unlock;
error = mnt_want_write(nd.path.mnt);
goto out;

error = -EXDEV;
if (old_path.mnt != new_path.mnt)
goto out_dput;
error = mnt_want_write(new_path.mnt);
if (error)
goto out_dput;
error = security_path_link(old_path.dentry, &nd.path, new_dentry);
error = security_path_link(old_path.dentry, &new_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_path.dentry, new_path.dentry->d_inode, new_dentry);
out_drop_write:
mnt_drop_write(nd.path.mnt);
mnt_drop_write(new_path.mnt);
out_dput:
dput(new_dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
out_release:
path_put(&nd.path);
putname(to);
mutex_unlock(&new_path.dentry->d_inode->i_mutex);
path_put(&new_path);
out:
path_put(&old_path);

Expand Down
49 changes: 11 additions & 38 deletions fs/ocfs2/refcounttree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4368,25 +4368,6 @@ static inline int ocfs2_may_create(struct inode *dir, struct dentry *child)
return inode_permission(dir, MAY_WRITE | MAY_EXEC);
}

/* copied from user_path_parent. */
static int ocfs2_user_path_parent(const char __user *path,
struct nameidata *nd, char **name)
{
char *s = getname(path);
int error;

if (IS_ERR(s))
return PTR_ERR(s);

error = kern_path_parent(s, nd);
if (error)
putname(s);
else
*name = s;

return error;
}

/**
* ocfs2_vfs_reflink - Create a reference-counted link
*
Expand Down Expand Up @@ -4460,10 +4441,8 @@ int ocfs2_reflink_ioctl(struct inode *inode,
bool preserve)
{
struct dentry *new_dentry;
struct nameidata nd;
struct path old_path;
struct path old_path, new_path;
int error;
char *to = NULL;

if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)))
return -EOPNOTSUPP;
Expand All @@ -4474,39 +4453,33 @@ int ocfs2_reflink_ioctl(struct inode *inode,
return error;
}

error = ocfs2_user_path_parent(newname, &nd, &to);
if (error) {
new_dentry = user_path_create(AT_FDCWD, newname, &new_path, 0);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry)) {
mlog_errno(error);
goto out;
}

error = -EXDEV;
if (old_path.mnt != nd.path.mnt)
goto out_release;
new_dentry = lookup_create(&nd, 0);
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry)) {
if (old_path.mnt != new_path.mnt) {
mlog_errno(error);
goto out_unlock;
goto out_dput;
}

error = mnt_want_write(nd.path.mnt);
error = mnt_want_write(new_path.mnt);
if (error) {
mlog_errno(error);
goto out_dput;
}

error = ocfs2_vfs_reflink(old_path.dentry,
nd.path.dentry->d_inode,
new_path.dentry->d_inode,
new_dentry, preserve);
mnt_drop_write(nd.path.mnt);
mnt_drop_write(new_path.mnt);
out_dput:
dput(new_dentry);
out_unlock:
mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
out_release:
path_put(&nd.path);
putname(to);
mutex_unlock(&new_path.dentry->d_inode->i_mutex);
path_put(&new_path);
out:
path_put(&old_path);

Expand Down
2 changes: 2 additions & 0 deletions include/linux/namei.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -74,6 +74,8 @@ extern int user_path_at(int, const char __user *, unsigned, struct path *);

extern int kern_path(const char *, unsigned, struct path *);

extern struct dentry *kern_path_create(int, const char *, struct path *, int);
extern struct dentry *user_path_create(int, const char __user *, struct path *, int);
extern int kern_path_parent(const char *, struct nameidata *);
extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
const char *, unsigned int, struct nameidata *);
Expand Down
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