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authorTejun Heo <tj@kernel.org>2015-08-18 23:54:55 +0200
committerJens Axboe <axboe@fb.com>2015-08-19 00:49:15 +0200
commit9acee9c551f045d2c5b5261aa587331423fd7d92 (patch)
tree16f0ecafd4f842d6352dd85913283a262a8e56f0 /fs/kernfs
parentwriteback: explain why @inode is allowed to be NULL for inode_congested() (diff)
downloadlinux-9acee9c551f045d2c5b5261aa587331423fd7d92.tar.xz
linux-9acee9c551f045d2c5b5261aa587331423fd7d92.zip
kernfs: implement kernfs_path_len()
Add a function to determine the path length of a kernfs node. This for now will be used by writeback tracepoint updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 2d48d28e1640..91e004518237 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -92,6 +92,29 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
}
/**
+ * kernfs_path_len - determine the length of the full path of a given node
+ * @kn: kernfs_node of interest
+ *
+ * The returned length doesn't include the space for the terminating '\0'.
+ */
+size_t kernfs_path_len(struct kernfs_node *kn)
+{
+ size_t len = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+
+ do {
+ len += strlen(kn->name) + 1;
+ kn = kn->parent;
+ } while (kn && kn->parent);
+
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+
+ return len;
+}
+
+/**
* kernfs_path - build full path of a given node
* @kn: kernfs_node of interest
* @buf: buffer to copy @kn's name into