[PATCH v2 3/6] xfs: add xfs_mount sysfs kobject

Brian Foster
2014-06-27T12:07:04Z

Embed a base kobject into xfs_mount. This creates a kobject associated
with each XFS mount and a subdirectory in sysfs with the name of the
filesystem. The subdirectory lifecycle matches that of the mount. Also
add the new xfs_sysfs.[c,h] source files with some XFS sysfs
infrastructure to facilitate attribute creation.

Note that there are currently no attributes exported as part of the
xfs_mount kobject. It exists solely to serve as a per-mount container
for child objects.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/Makefile | 1 +
fs/xfs/xfs_linux.h | 11 +++++++++++
fs/xfs/xfs_mount.c | 14 ++++++++++++-
fs/xfs/xfs_mount.h | 1 +
fs/xfs/xfs_sysfs.c | 49 +++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_sysfs.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 133 insertions(+), 1 deletion(-)
create mode 100644 fs/xfs/xfs_sysfs.c
create mode 100644 fs/xfs/xfs_sysfs.h

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 0dfa26d..d617999 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -86,6 +86,7 @@ xfs-y += xfs_aops.o \
xfs_mru_cache.o \
xfs_super.o \
xfs_symlink.o \
+ xfs_sysfs.o \
xfs_trans.o \
xfs_xattr.o \
kmem.o \
diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
index f59b966..8312771 100644
--- a/fs/xfs/xfs_linux.h
+++ b/fs/xfs/xfs_linux.h
@@ -191,6 +191,17 @@ typedef __uint64_t __psunsigned_t;
#define MAX(a,b) (max(a,b))
#define howmany(x, y) (((x)+((y)-1))/(y))

+/*
+ * XFS wrapper structure for sysfs support. It depends on external data
+ * structures and is embedded in various internal data structures to implement
+ * the XFS sysfs object heirarchy. Define it here for broad access throughout
+ * the codebase.
+ */
+struct xfs_kobj {
+ struct kobject kobject;
+ struct completion complete;
+};
+
/* Kernel uid/gid conversion. These are used to convert to/from the on disk
* uid_t/gid_t types to the kuid_t/kgid_t types that the kernel uses internally.
* The conversion here is type only, the value will remain the same since we
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 4e9dd4a..c8a328e 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -42,6 +42,7 @@
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_dinode.h"
+#include "xfs_sysfs.h"

#ifdef HAVE_PERCPU_SB
@@ -60,6 +61,8 @@ static DEFINE_MUTEX(xfs_uuid_table_mutex);
static int xfs_uuid_table_size;
static uuid_t *xfs_uuid_table;

+extern struct kset *xfs_kset;
+
/*
* See if the UUID is unique among mounted XFS filesystems.
* Mount fails if UUID is nil or a FS with the same UUID is already mounted.
@@ -731,10 +734,15 @@ xfs_mountfs(

xfs_set_maxicount(mp);

- error = xfs_uuid_mount(mp);
+ mp->m_kobj.kobject.kset = xfs_kset;
+ error = xfs_sysfs_init(&mp->m_kobj, &xfs_mp_ktype, NULL, mp->m_fsname);
if (error)
goto out;

+ error = xfs_uuid_mount(mp);
+ if (error)
+ goto out_remove_sysfs;
+
/*
* Set the minimum read and write sizes
*/
@@ -989,6 +997,8 @@ xfs_mountfs(
xfs_da_unmount(mp);
out_remove_uuid:
xfs_uuid_unmount(mp);
+ out_remove_sysfs:
+ xfs_sysfs_del(&mp->m_kobj);
out:
return error;
}
@@ -1071,6 +1081,8 @@ xfs_unmountfs(
xfs_errortag_clearall(mp, 0);
#endif
xfs_free_perag(mp);
+
+ xfs_sysfs_del(&mp->m_kobj);
}

int
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 7295a0b..b0447c8 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -166,6 +166,7 @@ typedef struct xfs_mount {
on the next remount,rw */
int64_t m_low_space[XFS_LOWSP_MAX];
/* low free space thresholds */
+ struct xfs_kobj m_kobj;

struct workqueue_struct *m_data_workqueue;
struct workqueue_struct *m_unwritten_workqueue;
diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
new file mode 100644
index 0000000..ae9aa7a
--- /dev/null
+++ b/fs/xfs/xfs_sysfs.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2014 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * This program 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.
+ *
+ * This program is distributed in the hope that it would 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, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "xfs.h"
+#include "xfs_sysfs.h"
+
+struct xfs_sysfs_attr {
+ struct attribute attr;
+ ssize_t (*show)(char *buf, void *data);
+ ssize_t (*store)(const char *buf, size_t count, void *data);
+};
+
+static inline struct xfs_sysfs_attr *
+to_attr(struct attribute *attr)
+{
+ return container_of(attr, struct xfs_sysfs_attr, attr);
+}
+
+#define XFS_SYSFS_ATTR_RW(name) \
+ static struct xfs_sysfs_attr xfs_sysfs_attr_##name = __ATTR_RW(name)
+#define XFS_SYSFS_ATTR_RO(name) \
+ static struct xfs_sysfs_attr xfs_sysfs_attr_##name = __ATTR_RO(name)
+
+#define ATTR_LIST(name) &xfs_sysfs_attr_##name.attr
+
+/*
+ * xfs_mount kobject. This currently has no attributes and thus no need for show
+ * and store helpers. The mp kobject serves as the per-mount parent object that
+ * is identified by the fsname under sysfs.
+ */
+
+struct kobj_type xfs_mp_ktype = {
+ .release = xfs_sysfs_release,
+};
diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h
new file mode 100644
index 0000000..438976b
--- /dev/null
+++ b/fs/xfs/xfs_sysfs.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2014 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * This program 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.
+ *
+ * This program is distributed in the hope that it would 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, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef __XFS_SYSFS_H__
+#define __XFS_SYSFS_H__
+
+extern struct kobj_type xfs_mp_ktype; /* xfs_mount */
+
+static inline struct xfs_kobj *
+to_kobj(struct kobject *kobject)
+{
+ return container_of(kobject, struct xfs_kobj, kobject);
+}
+
+static inline void
+xfs_sysfs_release(struct kobject *kobject)
+{
+ struct xfs_kobj *kobj = to_kobj(kobject);
+ complete(&kobj->complete);
+}
+
+static inline int
+xfs_sysfs_init(
+ struct xfs_kobj *kobj,
+ struct kobj_type *ktype,
+ struct xfs_kobj *p_kobj,
+ const char *name)
+{
+ init_completion(&kobj->complete);
+ return kobject_init_and_add(&kobj->kobject, ktype, &p_kobj->kobject,
+ "%s", name);
+}
+
+static inline void
+xfs_sysfs_del(
+ struct xfs_kobj *kobj)
+{
+ kobject_del(&kobj->kobject);
+ kobject_put(&kobj->kobject);
+ wait_for_completion(&kobj->complete);
+}
+
+#endif /* __XFS_SYSFS_H__ */