Hi,

This patch rearranges the sysfs interface to more closely match
GFS2, plus it adds an object release mechanism, as described in
kernel/Documentation/kobject.txt

rhbz#788694

Regards,

Bob Peterson
Red Hat File Systems

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
gfs-kernel/src/gfs/ops_fstype.c | 27 +++++++++++++++++++--------
gfs-kernel/src/gfs/ops_fstype.h | 1 -
gfs-kernel/src/gfs/ops_super.c | 6 +-----
gfs-kernel/src/gfs/sys.c | 14 ++++++++++++++
4 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/gfs-kernel/src/gfs/ops_fstype.c b/gfs-kernel/src/gfs/ops_fstype.c
index 34d9fa4..7104a2d 100644
--- a/gfs-kernel/src/gfs/ops_fstype.c
+++ b/gfs-kernel/src/gfs/ops_fstype.c
@@ -682,12 +682,24 @@ static int fill_super(struct super_block *sb, void *data, int silent)
goto fail;
}
error = init_names(sdp, silent);
- if (error)
- goto fail;
+ if (error) {
+ /* In this case, we haven't initialized sysfs, so we have to
+ manually free the sdp. */
+ vfree(sdp);
+ sb->s_fs_info = NULL;
+ return error;
+ }

error = gfs_sys_fs_add(sdp);
+ /*
+ * If we hit an error here, gfs2_sys_fs_add will have called function
+ * kobject_put which causes the sysfs usage count to go to zero, which
+ * causes sysfs to call function gfs2_sbd_release, which frees sdp.
+ * Subsequent error paths here will call gfs_sys_fs_del, which also
+ * kobject_put to free sdp.
+ */
if (error)
- goto fail;
+ return error;

/* Mount an inter-node lock module, check for local optimizations */

@@ -746,17 +758,16 @@ fail_locking:
fail_lm:
gfs_gl_hash_clear(sdp, TRUE);
gfs_lm_unmount(sdp);
+fail_sys:
gfs_clear_dirty_j(sdp);
while (invalidate_inodes(sb))
yield();

-fail_sys:
- gfs_sys_fs_del(sdp);
-
fail:
- vfree(sdp);
+ /* gfs_sys_fs_del must be the last thing we do, since it causes
+ * sysfs to call function gfs2_sbd_release, which frees sdp. */
+ gfs_sys_fs_del(sdp);
sb->s_fs_info = NULL;
-
return error;
}

diff --git a/gfs-kernel/src/gfs/ops_fstype.h b/gfs-kernel/src/gfs/ops_fstype.h
index 8f6f0f7..d31225e 100644
--- a/gfs-kernel/src/gfs/ops_fstype.h
+++ b/gfs-kernel/src/gfs/ops_fstype.h
@@ -16,7 +16,6 @@

int gfs_sys_init(void);
void gfs_sys_uninit(void);
-void gfs_sys_fs_del(struct gfs_sbd *sdp);
int gfs_test_bdev_super(struct super_block *sb, void *data);
int gfs_set_bdev_super(struct super_block *sb, void *data);
int init_names(struct gfs_sbd *sdp, int silent);
diff --git a/gfs-kernel/src/gfs/ops_super.c b/gfs-kernel/src/gfs/ops_super.c
index 1fa7faf..c111a2e 100644
--- a/gfs-kernel/src/gfs/ops_super.c
+++ b/gfs-kernel/src/gfs/ops_super.c
@@ -167,17 +167,13 @@ gfs_put_super(struct super_block *sb)

/* At this point, we're through participating in the lockspace */

- gfs_sys_fs_del(sdp);
-
gfs_clear_dirty_j(sdp);

/* Get rid of any extra inodes */
while (invalidate_inodes(sb))
yield();

- vfree(sdp);
-
- set_v2sdp(sb, NULL);
+ gfs_sys_fs_del(sdp);
}

/**
diff --git a/gfs-kernel/src/gfs/sys.c b/gfs-kernel/src/gfs/sys.c
index 81fe82b..3079cae 100644
--- a/gfs-kernel/src/gfs/sys.c
+++ b/gfs-kernel/src/gfs/sys.c
@@ -20,6 +20,7 @@
#include <linux/buffer_head.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
+#include <linux/vmalloc.h>
#include <asm/uaccess.h>

#include "gfs.h"
@@ -75,12 +76,20 @@ static ssize_t gfs_attr_store(struct kobject *kobj, struct attribute *attr,
return a->store ? a->store(sdp, buf, len) : len;
}

+static void gfs_sbd_release(struct kobject *kobj)
+{
+ struct gfs_sbd *sdp = container_of(kobj, struct gfs_sbd, sd_kobj);
+
+ vfree(sdp);
+}
+
static struct sysfs_ops gfs_attr_ops = {
.show = gfs_attr_show,
.store = gfs_attr_store,
};

static struct kobj_type gfs_ktype = {
+ .release = gfs_sbd_release,
.default_attrs = gfs_attrs,
.sysfs_ops = &gfs_attr_ops,
};
@@ -93,6 +102,7 @@ static struct kset gfs_kset = {

int gfs_sys_fs_add(struct gfs_sbd *sdp)
{
+ struct super_block *sb;
int error;

sdp->sd_kobj.kset = &gfs_kset;
@@ -109,6 +119,10 @@ int gfs_sys_fs_add(struct gfs_sbd *sdp)
return 0;

fail:
+ printk("GFS: error %d adding sysfs files", error);
+ sb = sdp->sd_vfs;
+ vfree(sdp);
+ sb->s_fs_info = NULL;
return error;
}