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Commit bd50873d authored by Tao Ma's avatar Tao Ma Committed by Joel Becker
Browse files

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: default avatarTao Ma <tao.ma@oracle.com>
parent 64871b8d

fs/ocfs2/ioctl.c

+14 −0
Original line number Diff line number Diff line
@@ -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;

fs/ocfs2/ocfs2_fs.h

+9 −0
Original line number Diff line number Diff line
@@ -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)

 */

fs/ocfs2/refcounttree.c

+166 −0
Original line number Diff line number Diff line
@@ -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 @@ static int ocfs2_reflink(struct dentry *old_dentry, struct inode *dir, 


	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;

}

fs/ocfs2/refcounttree.h

+4 −0
Original line number Diff line number Diff line
@@ -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 */