From 7c8d469877b16d2c1cecf101a0abb7b218db85bc Mon Sep 17 00:00:00 2001 From: Nicolai Stange Date: Tue, 31 Oct 2017 00:15:47 +0100 Subject: debugfs: add support for more elaborate ->d_fsdata Currently, the user provided fops, "real_fops", are stored directly into ->d_fsdata. In order to be able to store more per-file state and thus prepare for more granular file removal protection, wrap the real_fops into a dynamically allocated container struct, debugfs_fsdata. A struct debugfs_fsdata gets allocated at file creation and freed from the newly intoduced ->d_release(). Finally, move the implementation of debugfs_real_fops() out of the public debugfs header such that struct debugfs_fsdata's declaration can be kept private. Signed-off-by: Nicolai Stange Signed-off-by: Greg Kroah-Hartman --- fs/debugfs/file.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'fs/debugfs/file.c') diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 6dabc4a10396..b6f5ddab66bf 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -97,6 +97,18 @@ EXPORT_SYMBOL_GPL(debugfs_use_file_finish); #define F_DENTRY(filp) ((filp)->f_path.dentry) +const struct file_operations *debugfs_real_fops(const struct file *filp) + __must_hold(&debugfs_srcu) +{ + struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata; + /* + * Neither the pointer to the struct file_operations, nor its + * contents ever change -- srcu_dereference() is not needed here. + */ + return fsd->real_fops; +} +EXPORT_SYMBOL_GPL(debugfs_real_fops); + static int open_proxy_open(struct inode *inode, struct file *filp) { const struct dentry *dentry = F_DENTRY(filp); -- cgit v1.2.3