[RFC PATCH 2/3] debugfs: put private data to i_private for automount inode

Roman Pen
2015-12-10T12:47:27Z

I will need dentry->d_fsdata in the next patch.
Keep 'd_fsdata' for debugfs needs.

Signed-off-by: Roman Pen <r.peniaev@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org
---
fs/debugfs/inode.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 7bd7e19..a1d077a 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -170,6 +170,8 @@ static void debugfs_evict_inode(struct inode *inode)
clear_inode(inode);
if (S_ISLNK(inode->i_mode))
kfree(inode->i_link);
+ else if (S_ISDIR(inode->i_mode) && IS_AUTOMOUNT(inode))
+ kfree(inode->i_private);
}

static const struct super_operations debugfs_super_operations = {
@@ -179,11 +181,16 @@ static const struct super_operations debugfs_super_operations = {
.evict_inode = debugfs_evict_inode,
};

+struct automount_priv {
+ struct vfsmount *(*func)(void *);
+ void *data;
+};
+
static struct vfsmount *debugfs_automount(struct path *path)
{
- struct vfsmount *(*f)(void *);
- f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata;
- return f(d_inode(path->dentry)->i_private);
+ struct automount_priv *p = d_inode(path->dentry)->i_private;
+
+ return p->func(p->data);
}

static const struct dentry_operations debugfs_dops = {
@@ -448,19 +455,28 @@ struct dentry *debugfs_create_automount(const char *name,
void *data)
{
struct dentry *dentry = start_creating(name, parent);
+ struct automount_priv *p;
struct inode *inode;

if (IS_ERR(dentry))
return NULL;

+ p = kmalloc(sizeof(*p), GFP_KERNEL);
+ if (unlikely(!p))
+ return failed_creating(dentry);
+
+ p->func = f;
+ p->data = data;
+
inode = debugfs_get_inode(dentry->d_sb);
- if (unlikely(!inode))
+ if (unlikely(!inode)) {
+ kfree(p);
return failed_creating(dentry);
+ }

inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
inode->i_flags |= S_AUTOMOUNT;
- inode->i_private = data;
- dentry->d_fsdata = (void *)f;
+ inode->i_private = p;
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
d_instantiate(dentry, inode);
--
2.6.2