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Message-Id: <1323812733-7520-1-git-send-email-andi@firstfloor.org>
Date: Tue, 13 Dec 2011 13:45:32 -0800
From: Andi Kleen <andi@...stfloor.org>
To: greg@...ah.com
Cc: linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 1/3] DEBUGFS: Automatically create parents for debugfs files v2
From: Andi Kleen <ak@...ux.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.
v2: Comment fixes based on review comments.
v3: satisfy the kernel community's white space obsession.
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
fs/debugfs/inode.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 60 insertions(+), 2 deletions(-)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index f3a257d..0081ac0 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -146,6 +146,55 @@ 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) {
+ /*
+ * When the parent already exists, this will error out.
+ * Ignore that error. We'll just look the dentry up below.
+ */
+ 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 +202,7 @@ 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 +211,7 @@ 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);
@@ -185,12 +236,17 @@ 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;
}
/**
* debugfs_create_file - create a file in the debugfs filesystem
* @name: a pointer to a string containing the name of the file to create.
+ * This can also contain directories (dir/file), in this case missing
+ * directories will be automatically created.
* @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 paramater is NULL, then the
@@ -243,7 +299,8 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
/**
* debugfs_create_dir - create a directory in the debugfs filesystem
* @name: a pointer to a string containing the name of the directory to
- * create.
+ * create. This can also contain directories (dir/file), in this case
+ * missing directories will be automatically created.
* @parent: a pointer to the parent dentry for this file. This should be a
* directory dentry if set. If this paramater is NULL, then the
* directory will be created in the root of the debugfs filesystem.
@@ -269,7 +326,8 @@ EXPORT_SYMBOL_GPL(debugfs_create_dir);
/**
* debugfs_create_symlink- create a symbolic link in the debugfs filesystem
* @name: a pointer to a string containing the name of the symbolic link to
- * create.
+ * create. This can also contain directories (dir/file), in this case
+ * missing directories will be automatically created
* @parent: a pointer to the parent dentry for this symbolic link. This
* should be a directory dentry if set. If this paramater is NULL,
* then the symbolic link will be created in the root of the debugfs
--
1.7.7.3
--
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