[PATCH] reiser4: implement ->rename2() of struct inode_operations.

[Ivan Shapovalov <intelfx100@gmail.com>]

For now, only support the basic case of flags == 0.
Also support the case of flags == RENAME_NOREPLACE, because it is a no-op for
local filesystems (destination existence is already checked by VFS).

Thus no functional changes to the existing code.

Signed-off-by: Ivan Shapovalov <intelfx100@gmail.com>
---

Could you please estimate whether it would be hard to also implement the
RENAME_EXCHANGE flag? It is defined as follows:

	Atomically exchange oldpath and newpath. Both pathnames must exist but may
	be of different types (e.g., one could be a non-empty directory and the other
	a symbolic link).

If there are no caveats, I'll try to do it as a kind of a junior job...

 fs/reiser4/plugin/inode_ops_rename.c | 47 ++++++++++++++++++++++++++++++------
 fs/reiser4/plugin/object.c           |  2 +-
 fs/reiser4/plugin/object.h           |  5 ++--
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/fs/reiser4/plugin/inode_ops_rename.c b/fs/reiser4/plugin/inode_ops_rename.c
index 4d461dc..6744e14 100644
--- a/fs/reiser4/plugin/inode_ops_rename.c
+++ b/fs/reiser4/plugin/inode_ops_rename.c
@@ -288,7 +288,7 @@ int reiser4_find_entry(struct inode *, struct dentry *, lock_handle * ,
 	       znode_lock_mode, reiser4_dir_entry_desc *);
 int reiser4_update_dir(struct inode *);
 
-/* this is common implementation of vfs's rename method of struct
+/* this is common implementation of vfs's rename2 method of struct
    inode_operations
    See comments in the body.
 
@@ -299,12 +299,13 @@ int reiser4_update_dir(struct inode *);
    entry. This should be re-considered when more than one different
    directory plugin will be implemented.
 */
-int reiser4_rename_common(struct inode *old_dir /* directory where @old
-						 * is located */ ,
-			  struct dentry *old_name /* old name */ ,
-			  struct inode *new_dir /* directory where @new
-						 * is located */ ,
-			  struct dentry *new_name/* new name */)
+int reiser4_rename2_common(struct inode *old_dir /* directory where @old
+						  * is located */ ,
+			   struct dentry *old_name /* old name */ ,
+			   struct inode *new_dir /* directory where @new
+						  * is located */ ,
+			   struct dentry *new_name /* new name */ ,
+			   unsigned flags /* specific flags */)
 {
 	/* From `The Open Group Base Specifications Issue 6'
 
@@ -384,6 +385,26 @@ int reiser4_rename_common(struct inode *old_dir /* directory where @old
 	   [N/A]
 
 	 */
+
+	/* From Documentation/filesystems/vfs.txt:
+
+	   rename2: this has an additional flags argument compared to rename.
+		f no flags are supported by the filesystem then this method
+		need not be implemented.  If some flags are supported then the
+		filesystem must return -EINVAL for any unsupported or unknown
+		flags.  Currently the following flags are implemented:
+		(1) RENAME_NOREPLACE: this flag indicates that if the target
+		of the rename exists the rename should fail with -EEXIST
+		instead of replacing the target.  The VFS already checks for
+		existence, so for local filesystems the RENAME_NOREPLACE
+		implementation is equivalent to plain rename.
+		(2) RENAME_EXCHANGE: exchange source and target.  Both must
+		exist; this is checked by the VFS.  Unlike plain rename,
+		source and target may be of different type.
+	 */
+
+	static const unsigned supported_flags = RENAME_NOREPLACE;
+
 	reiser4_context *ctx;
 	int result;
 	int is_dir;		/* is @old_name directory */
@@ -405,6 +426,18 @@ int reiser4_rename_common(struct inode *old_dir /* directory where @old
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
 
+	/*
+	 * Check rename2() flags.
+	 *
+	 * "If some flags are supported then the filesystem must return
+	 * -EINVAL for any unsupported or unknown flags."
+	 *
+	 * We support:
+	 * - RENAME_NOREPLACE (no-op)
+	 */
+	if (flags & supported_flags != flags)
+		return RETERR(-EINVAL);
+
 	old_entry = kzalloc(3 * sizeof(*old_entry) + 2 * sizeof(*new_lh) +
 			    sizeof(*dotdot_name) + sizeof(*dataonstack),
 			    reiser4_ctx_gfp_mask_get());
diff --git a/fs/reiser4/plugin/object.c b/fs/reiser4/plugin/object.c
index 553f1e2..1b86408 100644
--- a/fs/reiser4/plugin/object.c
+++ b/fs/reiser4/plugin/object.c
@@ -241,7 +241,7 @@ static struct inode_operations directory_i_ops = {
 	.mkdir = reiser4_mkdir_common,
 	.rmdir = reiser4_unlink_common,
 	.mknod = reiser4_mknod_common,
-	.rename = reiser4_rename_common,
+	.rename2 = reiser4_rename2_common,
 	.permission = reiser4_permission_common,
 	.setattr = reiser4_setattr_common,
 	.getattr = reiser4_getattr_common
diff --git a/fs/reiser4/plugin/object.h b/fs/reiser4/plugin/object.h
index 80aef3e..f8a5133 100644
--- a/fs/reiser4/plugin/object.h
+++ b/fs/reiser4/plugin/object.h
@@ -22,8 +22,9 @@ int reiser4_symlink_common(struct inode *parent, struct dentry *dentry,
 		   const char *linkname);
 int reiser4_mknod_common(struct inode *parent, struct dentry *dentry,
 		 umode_t mode, dev_t rdev);
-int reiser4_rename_common(struct inode *old_dir, struct dentry *old_name,
-			  struct inode *new_dir, struct dentry *new_name);
+int reiser4_rename2_common(struct inode *old_dir, struct dentry *old_name,
+			   struct inode *new_dir, struct dentry *new_name,
+			   unsigned flags);
 void *reiser4_follow_link_common(struct dentry *, struct nameidata *data);
 int reiser4_permission_common(struct inode *, int mask);
 int reiser4_setattr_common(struct dentry *, struct iattr *);
-- 
2.3.1