fuse: add renameat2 support

Support RENAME_EXCHANGE and RENAME_NOREPLACE flags on the userspace ABI.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
(cherry picked from commit 1560c974dcd40a8d3f193283acd7cc6aee13dc13)
Signed-off-by: Alex Shi <alex.shi@linaro.org>

 Conflicts:
	fs/fuse/dir.c
	include/uapi/linux/fuse.h

3 files changed, 29 insertions, 8 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 6d5e45c0db77..33dec83eccfb 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -753,23 +753,26 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
 	return err;
 }
 
-static int fuse_rename(struct inode *olddir, struct dentry *oldent,
-		       struct inode *newdir, struct dentry *newent)
+static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
+			      struct inode *newdir, struct dentry *newent,
+			      unsigned int flags, int opcode, size_t argsize)
 {
 	int err;
-	struct fuse_rename_in inarg;
+	struct fuse_rename2_in inarg;
 	struct fuse_conn *fc = get_fuse_conn(olddir);
-	struct fuse_req *req = fuse_get_req_nopages(fc);
+	struct fuse_req *req;
 
+	req = fuse_get_req_nopages(fc);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
-	memset(&inarg, 0, sizeof(inarg));
+	memset(&inarg, 0, argsize);
 	inarg.newdir = get_node_id(newdir);
-	req->in.h.opcode = FUSE_RENAME;
+	inarg.flags = flags;
+	req->in.h.opcode = opcode;
 	req->in.h.nodeid = get_node_id(olddir);
 	req->in.numargs = 3;
-	req->in.args[0].size = sizeof(inarg);
+	req->in.args[0].size = argsize;
 	req->in.args[0].value = &inarg;
 	req->in.args[1].size = oldent->d_name.len + 1;
 	req->in.args[1].value = oldent->d_name.name;
@@ -783,12 +786,17 @@ static int fuse_rename(struct inode *olddir, struct dentry *oldent,
 		fuse_invalidate_attr(oldent->d_inode);
 		fuse_update_ctime(oldent->d_inode);
 
+		if (flags & RENAME_EXCHANGE) {
+			fuse_invalidate_attr(newent->d_inode);
+			fuse_update_ctime(newent->d_inode);
+		}
+
 		fuse_invalidate_attr(olddir);
 		if (olddir != newdir)
 			fuse_invalidate_attr(newdir);
 
 		/* newent will end up negative */
-		if (newent->d_inode) {
+		if (!(flags & RENAME_EXCHANGE) && newent->d_inode) {
 			fuse_invalidate_attr(newent->d_inode);
 			fuse_invalidate_entry_cache(newent);
 			fuse_update_ctime(newent->d_inode);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 1e6ad6d43051..7cc58c976780 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -544,6 +544,9 @@ struct fuse_conn {
 	/** Is fallocate not implemented by fs? */
 	unsigned no_fallocate:1;
 
+	/** Is rename with flags implemented by fs? */
+	unsigned no_rename2:1;
+
 	/** Use enhanced/automatic page cache invalidation. */
 	unsigned auto_inval_data:1;
 
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 60bb2f9f7b74..b77cf381a44b 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -93,6 +93,9 @@
  *
  * 7.22
  *  - add FUSE_ASYNC_DIO
+ *
+ * 7.23
+ *  - add FUSE_RENAME2 request
  */
 
 #ifndef _LINUX_FUSE_H
@@ -343,6 +346,7 @@ enum fuse_opcode {
 	FUSE_BATCH_FORGET  = 42,
 	FUSE_FALLOCATE     = 43,
 	FUSE_READDIRPLUS   = 44,
+	FUSE_RENAME2       = 45,
 
 	/* CUSE specific operations */
 	CUSE_INIT          = 4096,
@@ -421,6 +425,12 @@ struct fuse_rename_in {
 	uint64_t	newdir;
 };
 
+struct fuse_rename2_in {
+	uint64_t	newdir;
+	uint32_t	flags;
+	uint32_t	padding;
+};
+
 struct fuse_link_in {
 	uint64_t	oldnodeid;
 };