GFS2: add support for rename2 and RENAME_EXCHANGE

gfs2 now uses the rename2 directory iop, and supports the
RENAME_EXCHANGE flag (as well as RENAME_NOREPLACE, which the vfs
takes care of).

Signed-off-by: Benjamin Marzinski <bmarzins redhat com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/inode.c

@@ -1306,6 +1306,35 @@ static int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to)
 	return error;
 }
 
+/**
+ * update_moved_ino - Update an inode that's being moved
+ * @ip: The inode being moved
+ * @ndip: The parent directory of the new filename
+ * @dir_rename: True of ip is a directory
+ *
+ * Returns: errno
+ */
+
+static int update_moved_ino(struct gfs2_inode *ip, struct gfs2_inode *ndip,
+			    int dir_rename)
+{
+	int error;
+	struct buffer_head *dibh;
+
+	if (dir_rename)
+		return gfs2_dir_mvino(ip, &gfs2_qdotdot, ndip, DT_DIR);
+
+	error = gfs2_meta_inode_buffer(ip, &dibh);
+	if (error)
+		return error;
+	ip->i_inode.i_ctime = CURRENT_TIME;
+	gfs2_trans_add_meta(ip->i_gl, dibh);
+	gfs2_dinode_out(ip, dibh->b_data);
+	brelse(dibh);
+	return 0;
+}
+
+
 /**
  * gfs2_rename - Rename a file
  * @odir: Parent directory of old file name
@@ -1354,7 +1383,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 
 		if (S_ISDIR(ip->i_inode.i_mode)) {
 			dir_rename = 1;
-			/* don't move a dirctory into it's subdir */
+			/* don't move a directory into its subdir */
 			error = gfs2_ok_to_move(ip, ndip);
 			if (error)
 				goto out_gunlock_r;
@@ -1494,20 +1523,9 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	if (nip)
 		error = gfs2_unlink_inode(ndip, ndentry);
 
-	if (dir_rename) {
-		error = gfs2_dir_mvino(ip, &gfs2_qdotdot, ndip, DT_DIR);
-		if (error)
-			goto out_end_trans;
-	} else {
-		struct buffer_head *dibh;
-		error = gfs2_meta_inode_buffer(ip, &dibh);
+	error = update_moved_ino(ip, ndip, dir_rename);
 	if (error)
 		goto out_end_trans;
-		ip->i_inode.i_ctime = CURRENT_TIME;
-		gfs2_trans_add_meta(ip->i_gl, dibh);
-		gfs2_dinode_out(ip, dibh->b_data);
-		brelse(dibh);
-	}
 
 	error = gfs2_dir_del(odip, odentry);
 	if (error)
@@ -1538,6 +1556,161 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	return error;
 }
 
+/**
+ * gfs2_exchange - exchange two files
+ * @odir: Parent directory of old file name
+ * @odentry: The old dentry of the file
+ * @ndir: Parent directory of new file name
+ * @ndentry: The new dentry of the file
+ * @flags: The rename flags
+ *
+ * Returns: errno
+ */
+
+static int gfs2_exchange(struct inode *odir, struct dentry *odentry,
+			 struct inode *ndir, struct dentry *ndentry,
+			 unsigned int flags)
+{
+	struct gfs2_inode *odip = GFS2_I(odir);
+	struct gfs2_inode *ndip = GFS2_I(ndir);
+	struct gfs2_inode *oip = GFS2_I(odentry->d_inode);
+	struct gfs2_inode *nip = GFS2_I(ndentry->d_inode);
+	struct gfs2_sbd *sdp = GFS2_SB(odir);
+	struct gfs2_holder ghs[5], r_gh = { .gh_gl = NULL, };
+	unsigned int num_gh;
+	unsigned int x;
+	umode_t old_mode = oip->i_inode.i_mode;
+	umode_t new_mode = nip->i_inode.i_mode;
+	int error;
+
+	error = gfs2_rindex_update(sdp);
+	if (error)
+		return error;
+
+	if (odip != ndip) {
+		error = gfs2_glock_nq_init(sdp->sd_rename_gl, LM_ST_EXCLUSIVE,
+					   0, &r_gh);
+		if (error)
+			goto out;
+
+		if (S_ISDIR(old_mode)) {
+			/* don't move a directory into its subdir */
+			error = gfs2_ok_to_move(oip, ndip);
+			if (error)
+				goto out_gunlock_r;
+		}
+
+		if (S_ISDIR(new_mode)) {
+			/* don't move a directory into its subdir */
+			error = gfs2_ok_to_move(nip, odip);
+			if (error)
+				goto out_gunlock_r;
+		}
+	}
+
+	num_gh = 1;
+	gfs2_holder_init(odip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
+	if (odip != ndip) {
+		gfs2_holder_init(ndip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+		num_gh++;
+	}
+	gfs2_holder_init(oip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+	num_gh++;
+
+	gfs2_holder_init(nip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + num_gh);
+	num_gh++;
+
+	for (x = 0; x < num_gh; x++) {
+		error = gfs2_glock_nq(ghs + x);
+		if (error)
+			goto out_gunlock;
+	}
+
+	error = -ENOENT;
+	if (oip->i_inode.i_nlink == 0 || nip->i_inode.i_nlink == 0)
+		goto out_gunlock;
+
+	error = gfs2_unlink_ok(odip, &odentry->d_name, oip);
+	if (error)
+		goto out_gunlock;
+	error = gfs2_unlink_ok(ndip, &ndentry->d_name, nip);
+	if (error)
+		goto out_gunlock;
+
+	if (S_ISDIR(old_mode)) {
+		error = gfs2_permission(odentry->d_inode, MAY_WRITE);
+		if (error)
+			goto out_gunlock;
+	}
+	if (S_ISDIR(new_mode)) {
+		error = gfs2_permission(ndentry->d_inode, MAY_WRITE);
+		if (error)
+			goto out_gunlock;
+	}
+	error = gfs2_trans_begin(sdp, 4 * RES_DINODE + 4 * RES_LEAF, 0);
+	if (error)
+		goto out_gunlock;
+
+	error = update_moved_ino(oip, ndip, S_ISDIR(old_mode));
+	if (error)
+		goto out_end_trans;
+
+	error = update_moved_ino(nip, odip, S_ISDIR(new_mode));
+	if (error)
+		goto out_end_trans;
+
+	error = gfs2_dir_mvino(ndip, &ndentry->d_name, oip,
+			       IF2DT(old_mode));
+	if (error)
+		goto out_end_trans;
+
+	error = gfs2_dir_mvino(odip, &odentry->d_name, nip,
+			       IF2DT(new_mode));
+	if (error)
+		goto out_end_trans;
+
+	if (odip != ndip) {
+		if (S_ISDIR(new_mode) && !S_ISDIR(old_mode)) {
+			inc_nlink(&odip->i_inode);
+			drop_nlink(&ndip->i_inode);
+		} else if (S_ISDIR(old_mode) && !S_ISDIR(new_mode)) {
+			inc_nlink(&ndip->i_inode);
+			drop_nlink(&odip->i_inode);
+		}
+	}
+	mark_inode_dirty(&ndip->i_inode);
+	if (odip != ndip)
+		mark_inode_dirty(&odip->i_inode);
+
+out_end_trans:
+	gfs2_trans_end(sdp);
+out_gunlock:
+	while (x--) {
+		gfs2_glock_dq(ghs + x);
+		gfs2_holder_uninit(ghs + x);
+	}
+out_gunlock_r:
+	if (r_gh.gh_gl)
+		gfs2_glock_dq_uninit(&r_gh);
+out:
+	return error;
+}
+
+static int gfs2_rename2(struct inode *odir, struct dentry *odentry,
+			struct inode *ndir, struct dentry *ndentry,
+			unsigned int flags)
+{
+	flags &= ~RENAME_NOREPLACE;
+
+	if (flags & ~RENAME_EXCHANGE)
+		return -EINVAL;
+
+	if (flags & RENAME_EXCHANGE)
+		return gfs2_exchange(odir, odentry, ndir, ndentry, flags);
+
+	return gfs2_rename(odir, odentry, ndir, ndentry);
+}
+
 /**
  * gfs2_follow_link - Follow a symbolic link
  * @dentry: The dentry of the link
@@ -1943,7 +2116,7 @@ const struct inode_operations gfs2_dir_iops = {
 	.mkdir = gfs2_mkdir,
 	.rmdir = gfs2_unlink,
 	.mknod = gfs2_mknod,
-	.rename = gfs2_rename,
+	.rename2 = gfs2_rename2,
 	.permission = gfs2_permission,
 	.setattr = gfs2_setattr,
 	.getattr = gfs2_getattr,