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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: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Peng Tao 2015-09-26 02:24:36 +08:00 committed by Trond Myklebust
parent e5341f3a57
commit bea51b30b2
2 changed files with 106 additions and 0 deletions
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102
fs/nfs/nfs4file.c
View File

@ -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 */
};

4
include/uapi/linux/nfs.h
View File

@ -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