Hi Tao,
One question inline (below):
On 07/13/2015 05:06 AM, Peng Tao wrote:
> 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@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/nfs4file.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/nfs.h | 4 ++
> 2 files changed, 106 insertions(+)
>
> diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
> index dcd39d4..dfa6620 100644
> --- a/fs/nfs/nfs4file.c
> +++ b/fs/nfs/nfs4file.c
> @@ -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 "internal.h"
> @@ -166,8 +167,104 @@ 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) {
Why is the order of inode numbers important?
Thanks,
Anna
> + 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,
> @@ -190,4 +287,9 @@ 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 */
> };
> diff --git a/include/uapi/linux/nfs.h b/include/uapi/linux/nfs.h
> index 5199a36..d85748d 100644
> --- a/include/uapi/linux/nfs.h
> +++ b/include/uapi/linux/nfs.h
> @@ -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
>
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
