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Commit bea51b30 authored by Peng Tao's avatar Peng Tao Committed by Trond Myklebust
Browse files

nfs42: add NFS_IOC_CLONE ioctl 



It can be called by user space to CLONE two files.
Follow btrfs lead and define NFS_IOC_CLONE same as BTRFS_IOC_CLONE.
Thus we don't mess up userspace with too many ioctls.

Signed-off-by: default avatarPeng Tao <tao.peng@primarydata.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent e5341f3a

fs/nfs/nfs4file.c

+102 −0
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
 *  Copyright (C) 1992  Rick Sladkey

 */

#include <linux/fs.h>

#include <linux/file.h>

#include <linux/falloc.h>

#include <linux/nfs_fs.h>

#include "delegation.h"
@@ -192,8 +193,104 @@ static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t 
		return nfs42_proc_deallocate(filep, offset, len);

	return nfs42_proc_allocate(filep, offset, len);

}



static noinline long

nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd,

		  u64 src_off, u64 dst_off, u64 count)

{

	struct inode *dst_inode = file_inode(dst_file);

	struct fd src_file;

	struct inode *src_inode;

	int ret;



	/* dst file must be opened for writing */

	if (!(dst_file->f_mode & FMODE_WRITE))

		return -EINVAL;



	ret = mnt_want_write_file(dst_file);

	if (ret)

		return ret;



	src_file = fdget(srcfd);

	if (!src_file.file) {

		ret = -EBADF;

		goto out_drop_write;

	}



	src_inode = file_inode(src_file.file);



	/* src and dst must be different files */

	ret = -EINVAL;

	if (src_inode == dst_inode)

		goto out_fput;



	/* src file must be opened for reading */

	if (!(src_file.file->f_mode & FMODE_READ))

		goto out_fput;



	/* src and dst must be regular files */

	ret = -EISDIR;

	if (!S_ISREG(src_inode->i_mode) || !S_ISREG(dst_inode->i_mode))

		goto out_fput;



	ret = -EXDEV;

	if (src_file.file->f_path.mnt != dst_file->f_path.mnt ||

	    src_inode->i_sb != dst_inode->i_sb)

		goto out_fput;



	/* XXX: do we lock at all? what if server needs CB_RECALL_LAYOUT? */

	if (dst_inode < src_inode) {

		mutex_lock_nested(&dst_inode->i_mutex, I_MUTEX_PARENT);

		mutex_lock_nested(&src_inode->i_mutex, I_MUTEX_CHILD);

	} else {

		mutex_lock_nested(&src_inode->i_mutex, I_MUTEX_PARENT);

		mutex_lock_nested(&dst_inode->i_mutex, I_MUTEX_CHILD);

	}



	/* flush all pending writes on both src and dst so that server

	 * has the latest data */

	ret = nfs_sync_inode(src_inode);

	if (ret)

		goto out_unlock;

	ret = nfs_sync_inode(dst_inode);

	if (ret)

		goto out_unlock;



	ret = nfs42_proc_clone(src_file.file, dst_file, src_off, dst_off, count);



	/* truncate inode page cache of the dst range so that future reads can fetch

	 * new data from server */

	if (!ret)

		truncate_inode_pages_range(&dst_inode->i_data, dst_off, dst_off + count - 1);



out_unlock:

	if (dst_inode < src_inode) {

		mutex_unlock(&src_inode->i_mutex);

		mutex_unlock(&dst_inode->i_mutex);

	} else {

		mutex_unlock(&dst_inode->i_mutex);

		mutex_unlock(&src_inode->i_mutex);

	}

out_fput:

	fdput(src_file);

out_drop_write:

	mnt_drop_write_file(dst_file);

	return ret;

}

#endif /* CONFIG_NFS_V4_2 */



long nfs4_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	switch (cmd) {

#ifdef CONFIG_NFS_V4_2

	case NFS_IOC_CLONE:

		return nfs42_ioctl_clone(file, arg, 0, 0, 0);

#endif

	}



	return -ENOTTY;

}



const struct file_operations nfs4_file_operations = {

#ifdef CONFIG_NFS_V4_2

	.llseek		= nfs4_file_llseek,
@@ -216,4 +313,9 @@ const struct file_operations nfs4_file_operations = { 
#endif /* CONFIG_NFS_V4_2 */

	.check_flags	= nfs_check_flags,

	.setlease	= simple_nosetlease,

#ifdef CONFIG_COMPAT

	.unlocked_ioctl = nfs4_ioctl,

#else

	.compat_ioctl	= nfs4_ioctl,

#endif /* CONFIG_COMPAT */

};

include/uapi/linux/nfs.h

+4 −0
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ 


#define NFS_PIPE_DIRNAME "nfs"



/* NFS ioctls */

/* Let's follow btrfs lead on CLONE to avoid messing userspace */

#define NFS_IOC_CLONE	_IOW(0x94, 9, int)



/*

 * NFS stats. The good thing with these values is that NFSv3 errors are

 * a superset of NFSv2 errors (with the exception of NFSERR_WFLUSH which