ocfs2: Add ioctl for reflink.

The ioctl will take 3 parameters: old_path, new_path and
preserve and call vfs_reflink. It is useful when we backport
reflink features to old kernels.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
This commit is contained in:
Tao Ma 2009-09-21 11:25:14 +08:00 committed by Joel Becker
parent 64871b8d62
commit bd50873dc7
4 changed files with 193 additions and 0 deletions

View file

@ -22,6 +22,7 @@
#include "ocfs2_fs.h"
#include "ioctl.h"
#include "resize.h"
#include "refcounttree.h"
#include <linux/ext2_fs.h>
@ -116,6 +117,9 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
int status;
struct ocfs2_space_resv sr;
struct ocfs2_new_group_input input;
struct reflink_arguments args;
const char *old_path, *new_path;
bool preserve;
switch (cmd) {
case OCFS2_IOC_GETFLAGS:
@ -161,6 +165,15 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return -EFAULT;
return ocfs2_group_add(inode, &input);
case OCFS2_IOC_REFLINK:
if (copy_from_user(&args, (struct reflink_arguments *)arg,
sizeof(args)))
return -EFAULT;
old_path = (const char *)(unsigned long)args.old_path;
new_path = (const char *)(unsigned long)args.new_path;
preserve = (args.preserve != 0);
return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
default:
return -ENOTTY;
}
@ -183,6 +196,7 @@ long ocfs2_compat_ioctl(struct file *file, unsigned cmd, unsigned long arg)
case OCFS2_IOC_GROUP_EXTEND:
case OCFS2_IOC_GROUP_ADD:
case OCFS2_IOC_GROUP_ADD64:
case OCFS2_IOC_REFLINK:
break;
default:
return -ENOIOCTLCMD;

View file

@ -301,6 +301,15 @@ struct ocfs2_new_group_input {
#define OCFS2_IOC_GROUP_ADD _IOW('o', 2,struct ocfs2_new_group_input)
#define OCFS2_IOC_GROUP_ADD64 _IOW('o', 3,struct ocfs2_new_group_input)
/* Used to pass 2 file names to reflink. */
struct reflink_arguments {
__u64 old_path;
__u64 new_path;
__u64 preserve;
};
#define OCFS2_IOC_REFLINK _IOW('o', 4, struct reflink_arguments)
/*
* Journal Flags (ocfs2_dinode.id1.journal1.i_flags)
*/

View file

@ -42,6 +42,11 @@
#include <linux/writeback.h>
#include <linux/pagevec.h>
#include <linux/swap.h>
#include <linux/security.h>
#include <linux/fsnotify.h>
#include <linux/quotaops.h>
#include <linux/namei.h>
#include <linux/mount.h>
struct ocfs2_cow_context {
struct inode *inode;
@ -4145,3 +4150,164 @@ out:
return error;
}
/*
* Below here are the bits used by OCFS2_IOC_REFLINK() to fake
* sys_reflink(). This will go away when vfs_reflink() exists in
* fs/namei.c.
*/
/* copied from may_create in VFS. */
static inline int ocfs2_may_create(struct inode *dir, struct dentry *child)
{
if (child->d_inode)
return -EEXIST;
if (IS_DEADDIR(dir))
return -ENOENT;
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 = path_lookup(s, LOOKUP_PARENT, nd);
if (error)
putname(s);
else
*name = s;
return error;
}
/**
* ocfs2_vfs_reflink - Create a reference-counted link
*
* @old_dentry: source dentry + inode
* @dir: directory to create the target
* @new_dentry: target dentry
* @preserve: if true, preserve all file attributes
*/
int ocfs2_vfs_reflink(struct dentry *old_dentry, struct inode *dir,
struct dentry *new_dentry, bool preserve)
{
struct inode *inode = old_dentry->d_inode;
int error;
if (!inode)
return -ENOENT;
error = ocfs2_may_create(dir, new_dentry);
if (error)
return error;
if (dir->i_sb != inode->i_sb)
return -EXDEV;
/*
* A reflink to an append-only or immutable file cannot be created.
*/
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
return -EPERM;
/* Only regular files can be reflinked. */
if (!S_ISREG(inode->i_mode))
return -EPERM;
/*
* If the caller wants to preserve ownership, they require the
* rights to do so.
*/
if (preserve) {
if ((current_fsuid() != inode->i_uid) && !capable(CAP_CHOWN))
return -EPERM;
if (!in_group_p(inode->i_gid) && !capable(CAP_CHOWN))
return -EPERM;
}
/*
* If the caller is modifying any aspect of the attributes, they
* are not creating a snapshot. They need read permission on the
* file.
*/
if (!preserve) {
error = inode_permission(inode, MAY_READ);
if (error)
return error;
}
mutex_lock(&inode->i_mutex);
vfs_dq_init(dir);
error = ocfs2_reflink(old_dentry, dir, new_dentry, preserve);
mutex_unlock(&inode->i_mutex);
if (!error)
fsnotify_create(dir, new_dentry);
return error;
}
/*
* Most codes are copied from sys_linkat.
*/
int ocfs2_reflink_ioctl(struct inode *inode,
const char __user *oldname,
const char __user *newname,
bool preserve)
{
struct dentry *new_dentry;
struct nameidata nd;
struct path old_path;
int error;
char *to = NULL;
if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)))
return -EOPNOTSUPP;
error = user_path_at(AT_FDCWD, oldname, 0, &old_path);
if (error) {
mlog_errno(error);
return error;
}
error = ocfs2_user_path_parent(newname, &nd, &to);
if (error) {
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)) {
mlog_errno(error);
goto out_unlock;
}
error = mnt_want_write(nd.path.mnt);
if (error) {
mlog_errno(error);
goto out_dput;
}
error = ocfs2_vfs_reflink(old_path.dentry,
nd.path.dentry->d_inode,
new_dentry, preserve);
mnt_drop_write(nd.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);
out:
path_put(&old_path);
return error;
}

View file

@ -99,4 +99,8 @@ int ocfs2_increase_refcount(handle_t *handle,
u64 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_reflink_ioctl(struct inode *inode,
const char __user *oldname,
const char __user *newname,
bool preserve);
#endif /* OCFS2_REFCOUNTTREE_H */