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Commit 21fad313 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Trond Myklebust
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nfs: allow intra-file CLONE 



Originally CLONE didn't allow for intra-file clones, but we recently
updated the spec to support this feature which is also supported by
local Linux file systems.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 3a2e1769

fs/nfs/nfs4file.c

+14 −5
Original line number Diff line number Diff line
@@ -203,6 +203,7 @@ nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd, 
	struct fd src_file;

	struct inode *src_inode;

	unsigned int bs = server->clone_blksize;

	bool same_inode = false;

	int ret;



	/* dst file must be opened for writing */
@@ -221,10 +222,8 @@ nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd, 


	src_inode = file_inode(src_file.file);



	/* src and dst must be different files */

	ret = -EINVAL;

	if (src_inode == dst_inode)

		goto out_fput;

		same_inode = true;



	/* src file must be opened for reading */

	if (!(src_file.file->f_mode & FMODE_READ))
@@ -249,8 +248,16 @@ nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd, 
			goto out_fput;

	}



	/* verify if ranges are overlapped within the same file */

	if (same_inode) {

		if (dst_off + count > src_off && dst_off < src_off + count)

			goto out_fput;

	}



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

	if (dst_inode < src_inode) {

	if (same_inode) {

		mutex_lock(&src_inode->i_mutex);

	} else 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 {
@@ -275,7 +282,9 @@ nfs42_ioctl_clone(struct file *dst_file, unsigned long srcfd, 
		truncate_inode_pages_range(&dst_inode->i_data, dst_off, dst_off + count - 1);



out_unlock:

	if (dst_inode < src_inode) {

	if (same_inode) {

		mutex_unlock(&src_inode->i_mutex);

	} else if (dst_inode < src_inode) {

		mutex_unlock(&src_inode->i_mutex);

		mutex_unlock(&dst_inode->i_mutex);

	} else {