1 files changed, 88 insertions, 20 deletions

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index 8580831ed237..4bc1f68243c1 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -27,9 +27,14 @@
 #include <linux/parser.h>
 #include <linux/magic.h>
 #include <linux/slab.h>
+#include <linux/srcu.h>
+
+#include "internal.h"
 
 #define DEBUGFS_DEFAULT_MODE    0700
 
+DEFINE_SRCU(debugfs_srcu);
+
 static struct vfsmount *debugfs_mount;
 static int debugfs_mount_count;
 static bool debugfs_registered;
@@ -39,7 +44,8 @@ static struct inode *debugfs_get_inode(struct super_block *sb)
         struct inode *inode = new_inode(sb);
         if (inode) {
                 inode->i_ino = get_next_ino();
-                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+                inode->i_atime = inode->i_mtime =
+                        inode->i_ctime = current_fs_time(sb);
         }
         return inode;
 }
@@ -294,6 +300,37 @@ static struct dentry *end_creating(struct dentry *dentry)
         return dentry;
 }
 
+static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
+                                struct dentry *parent, void *data,
+                                const struct file_operations *proxy_fops,
+                                const struct file_operations *real_fops)
+{
+        struct dentry *dentry;
+        struct inode *inode;
+
+        if (!(mode & S_IFMT))
+                mode |= S_IFREG;
+        BUG_ON(!S_ISREG(mode));
+        dentry = start_creating(name, parent);
+
+        if (IS_ERR(dentry))
+                return NULL;
+
+        inode = debugfs_get_inode(dentry->d_sb);
+        if (unlikely(!inode))
+                return failed_creating(dentry);
+
+        inode->i_mode = mode;
+        inode->i_private = data;
+
+        inode->i_fop = proxy_fops;
+        dentry->d_fsdata = (void *)real_fops;
+
+        d_instantiate(dentry, inode);
+        fsnotify_create(d_inode(dentry->d_parent), dentry);
+        return end_creating(dentry);
+}
+
 /**
  * debugfs_create_file - create a file in the debugfs filesystem
  * @name: a pointer to a string containing the name of the file to create.
@@ -324,29 +361,52 @@ struct dentry *debugfs_create_file(const char *name, umode_t mode,
                                    struct dentry *parent, void *data,
                                    const struct file_operations *fops)
 {
-        struct dentry *dentry;
-        struct inode *inode;
 
-        if (!(mode & S_IFMT))
-                mode |= S_IFREG;
-        BUG_ON(!S_ISREG(mode));
-        dentry = start_creating(name, parent);
-
-        if (IS_ERR(dentry))
-                return NULL;
+        return __debugfs_create_file(name, mode, parent, data,
+                                fops ? &debugfs_full_proxy_file_operations :
+                                        &debugfs_noop_file_operations,
+                                fops);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_file);
 
-        inode = debugfs_get_inode(dentry->d_sb);
-        if (unlikely(!inode))
-                return failed_creating(dentry);
+/**
+ * debugfs_create_file_unsafe - create a file in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ *
+ * debugfs_create_file_unsafe() is completely analogous to
+ * debugfs_create_file(), the only difference being that the fops
+ * handed it will not get protected against file removals by the
+ * debugfs core.
+ *
+ * It is your responsibility to protect your struct file_operation
+ * methods against file removals by means of debugfs_use_file_start()
+ * and debugfs_use_file_finish(). ->open() is still protected by
+ * debugfs though.
+ *
+ * Any struct file_operations defined by means of
+ * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
+ * thus, may be used here.
+ */
+struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
+                                   struct dentry *parent, void *data,
+                                   const struct file_operations *fops)
+{
 
-        inode->i_mode = mode;
-        inode->i_fop = fops ? fops : &debugfs_file_operations;
-        inode->i_private = data;
-        d_instantiate(dentry, inode);
-        fsnotify_create(d_inode(dentry->d_parent), dentry);
-        return end_creating(dentry);
+        return __debugfs_create_file(name, mode, parent, data,
+                                fops ? &debugfs_open_proxy_file_operations :
+                                        &debugfs_noop_file_operations,
+                                fops);
 }
-EXPORT_SYMBOL_GPL(debugfs_create_file);
+EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
 
 /**
  * debugfs_create_file_size - create a file in the debugfs filesystem
@@ -461,7 +521,11 @@ struct dentry *debugfs_create_automount(const char *name,
         inode->i_flags |= S_AUTOMOUNT;
         inode->i_private = data;
         dentry->d_fsdata = (void *)f;
+        /* directory inodes start off with i_nlink == 2 (for "." entry) */
+        inc_nlink(inode);
         d_instantiate(dentry, inode);
+        inc_nlink(d_inode(dentry->d_parent));
+        fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
         return end_creating(dentry);
 }
 EXPORT_SYMBOL(debugfs_create_automount);
@@ -565,6 +629,8 @@ void debugfs_remove(struct dentry *dentry)
         inode_unlock(d_inode(parent));
         if (!ret)
                 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+
+        synchronize_srcu(&debugfs_srcu);
 }
 EXPORT_SYMBOL_GPL(debugfs_remove);
 
@@ -642,6 +708,8 @@ void debugfs_remove_recursive(struct dentry *dentry)
         if (!__debugfs_remove(child, parent))
                 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
         inode_unlock(d_inode(parent));
+
+        synchronize_srcu(&debugfs_srcu);
 }
 EXPORT_SYMBOL_GPL(debugfs_remove_recursive);