WORM: Write Once Read Many times xlator support

This xlator will allow files to be opened for write in append mode
only. Mount with --worm(glusterfs) or -o worm (mount) option to
enable worm xlator

Change-Id: I1be02fcf2aee2182ea2c66b514357918136fabeb
BUG: 3166
Reviewed-on: http://review.gluster.com/23
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@gluster.com>

5 files changed, 480 insertions, 221 deletions

diff --git a/xlators/features/read-only/src/Makefile.am b/xlators/features/read-only/src/Makefile.am
index 15f49966ff7..588d00cf48b 100644
--- a/xlators/features/read-only/src/Makefile.am
+++ b/xlators/features/read-only/src/Makefile.am
@@ -1,11 +1,19 @@
-xlator_LTLIBRARIES = read-only.la
+xlator_LTLIBRARIES = read-only.la worm.la
+
 xlatordir = $(libdir)/glusterfs/$(PACKAGE_VERSION)/xlator/features
 
+noinst_HEADERS = read-only-common.h
+
 read_only_la_LDFLAGS = -module -avoidversion
 
 read_only_la_SOURCES = read-only.c
 read_only_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la 
 
+worm_la_LDFLAGS = -module -avoidversion
+
+worm_la_SOURCES = read-only-common.c worm.c
+worm_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la
+
 AM_CFLAGS = -fPIC -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE -Wall -D$(GF_HOST_OS) \
 	-I$(top_srcdir)/libglusterfs/src -shared -nostartfiles $(GF_CFLAGS)
 
diff --git a/xlators/features/read-only/src/read-only-common.c b/xlators/features/read-only/src/read-only-common.c
new file mode 100644
index 00000000000..5e4949ee0c2
--- /dev/null
+++ b/xlators/features/read-only/src/read-only-common.c
@@ -0,0 +1,246 @@
+/*
+  Copyright (c) 2008-2011 Gluster, Inc. <http://www.gluster.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "defaults.h"
+
+int32_t
+ro_xattrop (call_frame_t *frame, xlator_t *this, loc_t *loc,
+            gf_xattrop_flags_t flags, dict_t *dict)
+{
+        STACK_UNWIND_STRICT (xattrop, frame, -1, EROFS, NULL);
+        return 0;
+}
+
+int32_t
+ro_fxattrop (call_frame_t *frame, xlator_t *this,
+             fd_t *fd, gf_xattrop_flags_t flags, dict_t *dict)
+{
+        STACK_UNWIND_STRICT (fxattrop, frame, -1, EROFS, NULL);
+        return 0;
+}
+
+int32_t
+ro_entrylk (call_frame_t *frame, xlator_t *this, const char *volume,
+            loc_t *loc, const char *basename, entrylk_cmd cmd,
+            entrylk_type type)
+{
+        STACK_UNWIND_STRICT (entrylk, frame, -1, EROFS);
+        return 0;
+}
+
+int32_t
+ro_fentrylk (call_frame_t *frame, xlator_t *this, const char *volume,
+             fd_t *fd, const char *basename, entrylk_cmd cmd, entrylk_type type)
+{
+        STACK_UNWIND_STRICT (fentrylk, frame, -1, EROFS);
+        return 0;
+}
+
+int32_t
+ro_inodelk (call_frame_t *frame, xlator_t *this, const char *volume,
+            loc_t *loc, int32_t cmd, struct gf_flock *lock)
+{
+        STACK_UNWIND_STRICT (inodelk, frame, -1, EROFS);
+        return 0;
+}
+
+int32_t
+ro_finodelk (call_frame_t *frame, xlator_t *this, const char *volume,
+             fd_t *fd, int32_t cmd, struct gf_flock *lock)
+{
+        STACK_UNWIND_STRICT (finodelk, frame, -1, EROFS);
+        return 0;
+}
+
+int32_t
+ro_lk (call_frame_t *frame, xlator_t *this, fd_t *fd, int cmd,
+       struct gf_flock *flock)
+{
+        STACK_UNWIND_STRICT (lk, frame, -1, EROFS, NULL);
+        return 0;
+}
+
+int32_t
+ro_setattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
+            struct iatt *stbuf, int32_t valid)
+{
+        STACK_UNWIND_STRICT (setattr, frame, -1, EROFS, NULL, NULL);
+	return 0;
+}
+
+int32_t
+ro_fsetattr (call_frame_t *frame, xlator_t *this, fd_t *fd,
+             struct iatt *stbuf, int32_t valid)
+{
+        STACK_UNWIND_STRICT (fsetattr, frame, -1, EROFS, NULL, NULL);
+        return 0;
+}
+
+
+int32_t
+ro_truncate (call_frame_t *frame, xlator_t *this, loc_t *loc, off_t offset)
+{
+        STACK_UNWIND_STRICT (truncate, frame, -1, EROFS, NULL, NULL);
+	return 0;
+}
+
+int32_t
+ro_ftruncate (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset)
+{
+        STACK_UNWIND_STRICT (ftruncate, frame, -1, EROFS, NULL, NULL);
+	return 0;
+}
+
+int
+ro_mknod (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          dev_t rdev, dict_t *params)
+{
+        STACK_UNWIND_STRICT (mknod, frame, -1, EROFS, NULL, NULL, NULL, NULL);
+        return 0;
+}
+
+
+int
+ro_mkdir (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          dict_t *params)
+{
+        STACK_UNWIND_STRICT (mkdir, frame, -1, EROFS, NULL, NULL, NULL, NULL);
+        return 0;
+}
+
+int32_t
+ro_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc)
+{
+        STACK_UNWIND_STRICT (unlink, frame, -1, EROFS, NULL, NULL);
+        return 0;
+}
+
+
+int
+ro_rmdir (call_frame_t *frame, xlator_t *this, loc_t *loc, int flags)
+{
+        STACK_UNWIND_STRICT (rmdir, frame, -1, EROFS, NULL, NULL);
+        return 0;
+}
+
+
+int
+ro_symlink (call_frame_t *frame, xlator_t *this, const char *linkpath,
+            loc_t *loc, dict_t *params)
+{
+        STACK_UNWIND_STRICT (symlink, frame, -1, EROFS, NULL, NULL, NULL, NULL);
+        return 0;
+}
+
+
+
+int32_t
+ro_rename (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc)
+{
+        STACK_UNWIND_STRICT (rename, frame, -1, EROFS, NULL, NULL, NULL, NULL,
+                             NULL);
+        return 0;
+}
+
+
+int32_t
+ro_link (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc)
+{
+        STACK_UNWIND_STRICT (link, frame, -1, EROFS, NULL, NULL, NULL, NULL);
+        return 0;
+}
+
+int32_t
+ro_create (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+           mode_t mode, fd_t *fd, dict_t *params)
+{
+        STACK_UNWIND_STRICT (create, frame, -1, EROFS, NULL, NULL, NULL,
+                             NULL, NULL);
+        return 0;
+}
+
+
+static int32_t
+ro_open_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
+             int32_t op_errno, fd_t *fd)
+{
+	STACK_UNWIND_STRICT (open, frame, op_ret, op_errno, fd);
+	return 0;
+}
+
+int32_t
+ro_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+         fd_t *fd, int32_t wbflags)
+{
+        if (((flags & O_ACCMODE) == O_WRONLY) ||
+              ((flags & O_ACCMODE) == O_RDWR)) {
+                STACK_UNWIND_STRICT (open, frame, -1, EROFS, NULL);
+                return 0;
+	}
+
+	STACK_WIND (frame, ro_open_cbk, FIRST_CHILD(this),
+                    FIRST_CHILD(this)->fops->open, loc, flags, fd, wbflags);
+	return 0;
+}
+
+int32_t
+ro_fsetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *dict,
+              int32_t flags)
+{
+        STACK_UNWIND_STRICT (fsetxattr, frame, -1, EROFS);
+	return 0;
+}
+
+int32_t
+ro_fsyncdir (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t flags)
+{
+        STACK_UNWIND_STRICT (fsyncdir, frame, -1, EROFS);
+	return 0;
+}
+
+int32_t
+ro_writev (call_frame_t *frame, xlator_t *this, fd_t *fd, struct iovec *vector,
+           int32_t count, off_t off, struct iobref *iobref)
+{
+        STACK_UNWIND_STRICT (writev, frame, -1, EROFS, NULL, NULL);
+        return 0;
+}
+
+
+int32_t
+ro_setxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict,
+             int32_t flags)
+{
+        STACK_UNWIND_STRICT (setxattr, frame, -1, EROFS);
+        return 0;
+}
+
+int32_t
+ro_removexattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
+                const char *name)
+{
+        STACK_UNWIND_STRICT (removexattr, frame, -1, EROFS);
+        return 0;
+}
diff --git a/xlators/features/read-only/src/read-only-common.h b/xlators/features/read-only/src/read-only-common.h
new file mode 100644
index 00000000000..3bc008e5978
--- /dev/null
+++ b/xlators/features/read-only/src/read-only-common.h
@@ -0,0 +1,123 @@
+/*
+  Copyright (c) 2008-2011 Gluster, Inc. <http://www.gluster.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "defaults.h"
+
+int32_t
+ro_xattrop (call_frame_t *frame, xlator_t *this, loc_t *loc,
+            gf_xattrop_flags_t flags, dict_t *dict);
+
+int32_t
+ro_fxattrop (call_frame_t *frame, xlator_t *this,
+             fd_t *fd, gf_xattrop_flags_t flags, dict_t *dict);
+
+int32_t
+ro_entrylk (call_frame_t *frame, xlator_t *this, const char *volume,
+            loc_t *loc, const char *basename, entrylk_cmd cmd,
+            entrylk_type type);
+
+int32_t
+ro_fentrylk (call_frame_t *frame, xlator_t *this, const char *volume,
+             fd_t *fd, const char *basename, entrylk_cmd cmd, entrylk_type
+             type);
+
+int32_t
+ro_inodelk (call_frame_t *frame, xlator_t *this, const char *volume,
+            loc_t *loc, int32_t cmd, struct gf_flock *lock);
+
+int32_t
+ro_finodelk (call_frame_t *frame, xlator_t *this, const char *volume,
+             fd_t *fd, int32_t cmd, struct gf_flock *lock);
+
+int32_t
+ro_lk (call_frame_t *frame, xlator_t *this, fd_t *fd, int cmd,
+       struct gf_flock *flock);
+
+int32_t
+ro_setattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
+            struct iatt *stbuf, int32_t valid);
+
+int32_t
+ro_fsetattr (call_frame_t *frame, xlator_t *this, fd_t *fd,
+             struct iatt *stbuf, int32_t valid);
+
+
+int32_t
+ro_truncate (call_frame_t *frame, xlator_t *this, loc_t *loc, off_t offset);
+
+int32_t
+ro_ftruncate (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset);
+
+int
+ro_mknod (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          dev_t rdev, dict_t *params);
+
+int
+ro_mkdir (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
+          dict_t *params);
+
+int32_t
+ro_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc);
+
+int
+ro_rmdir (call_frame_t *frame, xlator_t *this, loc_t *loc, int flags);
+
+
+int
+ro_symlink (call_frame_t *frame, xlator_t *this, const char *linkpath,
+            loc_t *loc, dict_t *params);
+
+int32_t
+ro_rename (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc);
+
+int32_t
+ro_link (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc);
+
+int32_t
+ro_create (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+           mode_t mode, fd_t *fd, dict_t *params);
+
+int32_t
+ro_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+         fd_t *fd, int32_t wbflags);
+
+int32_t
+ro_fsetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *dict,
+              int32_t flags);
+
+int32_t
+ro_fsyncdir (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t flags);
+
+int32_t
+ro_writev (call_frame_t *frame, xlator_t *this, fd_t *fd, struct iovec *vector,
+           int32_t count, off_t off, struct iobref *iobref);
+
+int32_t
+ro_setxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict,
+             int32_t flags);
+
+int32_t
+ro_removexattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
+                const char *name);
diff --git a/xlators/features/read-only/src/read-only.c b/xlators/features/read-only/src/read-only.c
index 54def698431..b11e84f24e8 100644
--- a/xlators/features/read-only/src/read-only.c
+++ b/xlators/features/read-only/src/read-only.c
@@ -24,226 +24,7 @@
 
 #include "xlator.h"
 #include "defaults.h"
-
-int32_t
-ro_xattrop (call_frame_t *frame, xlator_t *this, loc_t *loc,
-            gf_xattrop_flags_t flags, dict_t *dict)
-{
-        STACK_UNWIND_STRICT (xattrop, frame, -1, EROFS, NULL);
-        return 0;
-}
-
-int32_t
-ro_fxattrop (call_frame_t *frame, xlator_t *this,
-             fd_t *fd, gf_xattrop_flags_t flags, dict_t *dict)
-{
-        STACK_UNWIND_STRICT (fxattrop, frame, -1, EROFS, NULL);
-        return 0;
-}
-
-int32_t
-ro_entrylk (call_frame_t *frame, xlator_t *this, const char *volume,
-            loc_t *loc, const char *basename, entrylk_cmd cmd,
-            entrylk_type type)
-{
-        STACK_UNWIND_STRICT (entrylk, frame, -1, EROFS);
-        return 0;
-}
-
-int32_t
-ro_fentrylk (call_frame_t *frame, xlator_t *this, const char *volume,
-             fd_t *fd, const char *basename, entrylk_cmd cmd, entrylk_type type)
-{
-        STACK_UNWIND_STRICT (fentrylk, frame, -1, EROFS);
-        return 0;
-}
-
-int32_t
-ro_inodelk (call_frame_t *frame, xlator_t *this, const char *volume,
-            loc_t *loc, int32_t cmd, struct gf_flock *lock)
-{
-        STACK_UNWIND_STRICT (inodelk, frame, -1, EROFS);
-        return 0;
-}
-
-int32_t
-ro_finodelk (call_frame_t *frame, xlator_t *this, const char *volume,
-             fd_t *fd, int32_t cmd, struct gf_flock *lock)
-{
-        STACK_UNWIND_STRICT (finodelk, frame, -1, EROFS);
-        return 0;
-}
-
-int32_t
-ro_lk (call_frame_t *frame, xlator_t *this, fd_t *fd, int cmd,
-       struct gf_flock *flock)
-{
-        STACK_UNWIND_STRICT (lk, frame, -1, EROFS, NULL);
-        return 0;
-}
-
-int32_t
-ro_setattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
-            struct iatt *stbuf, int32_t valid)
-{
-        STACK_UNWIND_STRICT (setattr, frame, -1, EROFS, NULL, NULL);
-	return 0;
-}
-
-int32_t
-ro_fsetattr (call_frame_t *frame, xlator_t *this, fd_t *fd,
-             struct iatt *stbuf, int32_t valid)
-{
-        STACK_UNWIND_STRICT (fsetattr, frame, -1, EROFS, NULL, NULL);
-        return 0;
-}
-
-
-int32_t
-ro_truncate (call_frame_t *frame, xlator_t *this, loc_t *loc, off_t offset)
-{
-        STACK_UNWIND_STRICT (truncate, frame, -1, EROFS, NULL, NULL);
-	return 0;
-}
-
-int32_t
-ro_ftruncate (call_frame_t *frame, xlator_t *this, fd_t *fd, off_t offset)
-{
-        STACK_UNWIND_STRICT (ftruncate, frame, -1, EROFS, NULL, NULL);
-	return 0;
-}
-
-int
-ro_mknod (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
-          dev_t rdev, dict_t *params)
-{
-        STACK_UNWIND_STRICT (mknod, frame, -1, EROFS, NULL, NULL, NULL, NULL);
-        return 0;
-}
-
-
-int
-ro_mkdir (call_frame_t *frame, xlator_t *this, loc_t *loc, mode_t mode,
-          dict_t *params)
-{
-        STACK_UNWIND_STRICT (mkdir, frame, -1, EROFS, NULL, NULL, NULL, NULL);
-        return 0;
-}
-
-int32_t
-ro_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc)
-{
-        STACK_UNWIND_STRICT (unlink, frame, -1, EROFS, NULL, NULL);
-        return 0;
-}
-
-
-int
-ro_rmdir (call_frame_t *frame, xlator_t *this, loc_t *loc, int flags)
-{
-        STACK_UNWIND_STRICT (rmdir, frame, -1, EROFS, NULL, NULL);
-        return 0;
-}
-
-
-int
-ro_symlink (call_frame_t *frame, xlator_t *this, const char *linkpath,
-            loc_t *loc, dict_t *params)
-{
-        STACK_UNWIND_STRICT (symlink, frame, -1, EROFS, NULL, NULL, NULL, NULL);
-        return 0;
-}
-
-
-
-int32_t
-ro_rename (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc)
-{
-        STACK_UNWIND_STRICT (rename, frame, -1, EROFS, NULL, NULL, NULL, NULL,
-                             NULL);
-        return 0;
-}
-
-
-int32_t
-ro_link (call_frame_t *frame, xlator_t *this, loc_t *oldloc, loc_t *newloc)
-{
-        STACK_UNWIND_STRICT (link, frame, -1, EROFS, NULL, NULL, NULL, NULL);
-        return 0;
-}
-
-int32_t
-ro_create (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
-           mode_t mode, fd_t *fd, dict_t *params)
-{
-        STACK_UNWIND_STRICT (create, frame, -1, EROFS, NULL, NULL, NULL,
-                             NULL, NULL);
-        return 0;
-}
-
-
-static int32_t
-ro_open_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
-             int32_t op_errno, fd_t *fd)
-{
-	STACK_UNWIND_STRICT (open, frame, op_ret, op_errno, fd);
-	return 0;
-}
-
-int32_t
-ro_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
-         fd_t *fd, int32_t wbflags)
-{
-        if (((flags & O_ACCMODE) == O_WRONLY) ||
-              ((flags & O_ACCMODE) == O_RDWR)) {
-                STACK_UNWIND_STRICT (open, frame, -1, EROFS, NULL);
-                return 0;
-	}
-
-	STACK_WIND (frame, ro_open_cbk, FIRST_CHILD(this),
-                    FIRST_CHILD(this)->fops->open, loc, flags, fd, wbflags);
-	return 0;
-}
-
-int32_t
-ro_fsetxattr (call_frame_t *frame, xlator_t *this, fd_t *fd, dict_t *dict,
-              int32_t flags)
-{
-        STACK_UNWIND_STRICT (fsetxattr, frame, -1, EROFS);
-	return 0;
-}
-
-int32_t
-ro_fsyncdir (call_frame_t *frame, xlator_t *this, fd_t *fd, int32_t flags)
-{
-        STACK_UNWIND_STRICT (fsyncdir, frame, -1, EROFS);
-	return 0;
-}
-
-int32_t
-ro_writev (call_frame_t *frame, xlator_t *this, fd_t *fd, struct iovec *vector,
-           int32_t count, off_t off, struct iobref *iobref)
-{
-        STACK_UNWIND_STRICT (writev, frame, -1, EROFS, NULL, NULL);
-        return 0;
-}
-
-
-int32_t
-ro_setxattr (call_frame_t *frame, xlator_t *this, loc_t *loc, dict_t *dict,
-             int32_t flags)
-{
-        STACK_UNWIND_STRICT (setxattr, frame, -1, EROFS);
-        return 0;
-}
-
-int32_t
-ro_removexattr (call_frame_t *frame, xlator_t *this, loc_t *loc,
-                const char *name)
-{
-        STACK_UNWIND_STRICT (removexattr, frame, -1, EROFS);
-        return 0;
-}
+#include "read-only-common.h"
 
 int32_t
 init (xlator_t *this)
diff --git a/xlators/features/read-only/src/worm.c b/xlators/features/read-only/src/worm.c
new file mode 100644
index 00000000000..790bc3234dd
--- /dev/null
+++ b/xlators/features/read-only/src/worm.c
@@ -0,0 +1,101 @@
+/*
+  Copyright (c) 2008-2011 Gluster, Inc. <http://www.gluster.com>
+  This file is part of GlusterFS.
+
+  GlusterFS is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published
+  by the Free Software Foundation; either version 3 of the License,
+  or (at your option) any later version.
+
+  GlusterFS is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see
+  <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "xlator.h"
+#include "defaults.h"
+#include "read-only-common.h"
+
+static int32_t
+worm_open_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int32_t op_ret,
+             int32_t op_errno, fd_t *fd)
+{
+        STACK_UNWIND_STRICT (open, frame, op_ret, op_errno, fd);
+        return 0;
+}
+
+int32_t
+worm_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
+         fd_t *fd, int32_t wbflags)
+{
+        if ((((flags & O_ACCMODE) == O_WRONLY) ||
+              ((flags & O_ACCMODE) == O_RDWR)) &&
+              !(flags & O_APPEND)) {
+                STACK_UNWIND_STRICT (open, frame, -1, EROFS, NULL);
+                return 0;
+        }
+
+        STACK_WIND (frame, worm_open_cbk, FIRST_CHILD(this),
+                    FIRST_CHILD(this)->fops->open, loc, flags, fd, wbflags);
+        return 0;
+}
+
+int32_t
+init (xlator_t *this)
+{
+        if (!this->children || this->children->next) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "translator not configured with exactly one child");
+                return -1;
+        }
+
+        if (!this->parents) {
+                gf_log (this->name, GF_LOG_WARNING,
+                        "dangling volume. check volfile ");
+        }
+
+        return 0;
+}
+
+
+void
+fini (xlator_t *this)
+{
+        return;
+}
+
+struct xlator_fops fops = {
+        
+        .open        = worm_open,
+
+        .unlink      = ro_unlink,
+        .rmdir       = ro_rmdir,
+        .rename      = ro_rename,
+        .truncate    = ro_truncate,
+        .removexattr = ro_removexattr,
+        .fsyncdir    = ro_fsyncdir,
+        .xattrop     = ro_xattrop,
+        .inodelk     = ro_inodelk,
+        .finodelk    = ro_finodelk,
+        .entrylk     = ro_entrylk,
+        .fentrylk    = ro_fentrylk,
+        .lk          = ro_lk,
+};
+
+struct xlator_cbks cbks = {
+};
+
+struct volume_options options[] = {
+        { .key = {NULL} },
+};
+