lkml.org 
[lkml]   [2011]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/3] DEBUGFS: Automatically create parents for debugfs files
Date
From: Andi Kleen <ak@linux.intel.com>

Allow passing path names to debugfs_create* and automatically create
the parents. This makes it much simpler for the caller to create hierarchies.

The way the reference counts are handled is admittedly a bit ugly.

There is no way to clean them up currently other than to delete the tree,
but that doesn't seem like a big problem for debugfs to leave
behind a few empty directories.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
fs/debugfs/inode.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 51 insertions(+), 0 deletions(-)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index f3a257d..7ea9a6c 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -146,6 +146,52 @@ static struct file_system_type debug_fs_type = {
.kill_sb = kill_litter_super,
};

+/*
+ * Created parents stay around later. Sorry, but it shouldn't be a big issue.
+ */
+static const char *create_parents(const char *name, struct dentry *parent,
+ struct dentry **pp, int *ref)
+{
+ char fn[strlen(name) + 1];
+ char *tail;
+ char *s, *p;
+ struct dentry *new_parent, *dentry, *old_parent = NULL;
+
+ strcpy(fn, name);
+ tail = strrchr(fn, '/');
+ if (!tail)
+ return name;
+ tail++;
+
+ s = fn;
+ while ((p = strsep(&s, "/")) != NULL && p != tail) {
+ /* ignore error here */
+ dentry = debugfs_create_dir(p, parent);
+
+ /* Is it there now? */
+ mutex_lock(&parent->d_inode->i_mutex);
+ new_parent = lookup_one_len(p, parent, strlen(p));
+ mutex_unlock(&parent->d_inode->i_mutex);
+
+ if (!PTR_ERR(dentry))
+ dput(dentry);
+ if (IS_ERR(new_parent))
+ return NULL;
+ if (old_parent)
+ dput(old_parent);
+ if (parent != *pp)
+ old_parent = parent;
+ parent = new_parent;
+ }
+ if (parent) {
+ *ref = 1;
+ *pp = parent;
+ }
+ if (old_parent)
+ dput(old_parent);
+ return strrchr(name, '/') + 1;
+}
+
static int debugfs_create_by_name(const char *name, mode_t mode,
struct dentry *parent,
struct dentry **dentry,
@@ -153,6 +199,7 @@ static int debugfs_create_by_name(const char *name, mode_t mode,
const struct file_operations *fops)
{
int error = 0;
+ int ref = 0;

/* If the parent is not specified, we create it in the root.
* We need the root dentry to do this, which is in the super
@@ -161,6 +208,7 @@ static int debugfs_create_by_name(const char *name, mode_t mode,
*/
if (!parent)
parent = debugfs_mount->mnt_sb->s_root;
+ name = create_parents(name, parent, &parent, &ref);

*dentry = NULL;
mutex_lock(&parent->d_inode->i_mutex);
@@ -185,6 +233,9 @@ static int debugfs_create_by_name(const char *name, mode_t mode,
error = PTR_ERR(*dentry);
mutex_unlock(&parent->d_inode->i_mutex);

+ if (ref)
+ dput(parent);
+
return error;
}

--
1.7.4.4


\
 
 \ /
  Last update: 2011-12-02 19:51    [W:0.194 / U:0.616 seconds]
©2003-2014 Jasper Spaans. Advertise on this site