From fe0f726c9fb626b1092a9ea3bf75f57f2eed676e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 4 Nov 2019 15:54:30 -0800 Subject: kernfs: combine ino/id lookup functions into kernfs_find_and_get_node_by_id() kernfs_find_and_get_node_by_ino() looks the kernfs_node matching the specified ino. On top of that, kernfs_get_node_by_id() and kernfs_fh_get_inode() implement full ID matching by testing the rest of ID. On surface, confusingly, the two are slightly different in that the latter uses 0 gen as wildcard while the former doesn't - does it mean that the latter can't uniquely identify inodes w/ 0 gen? In practice, this is a distinction without a difference because generation number starts at 1. There are no actual IDs with 0 gen, so it can always safely used as wildcard. Let's simplify the code by renaming kernfs_find_and_get_node_by_ino() to kernfs_find_and_get_node_by_id(), moving all lookup logics into it, and removing now unnecessary kernfs_get_node_by_id(). Signed-off-by: Tejun Heo Reviewed-by: Greg Kroah-Hartman --- fs/kernfs/dir.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'fs/kernfs/dir.c') diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index c67afb591e5b..5dcf19d4adbc 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -696,17 +696,22 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent, } /* - * kernfs_find_and_get_node_by_ino - get kernfs_node from inode number + * kernfs_find_and_get_node_by_id - get kernfs_node from node id * @root: the kernfs root - * @ino: inode number + * @id: the target node id + * + * @id's lower 32bits encode ino and upper gen. If the gen portion is + * zero, all generations are matched. * * RETURNS: * NULL on failure. Return a kernfs node with reference counter incremented */ -struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, - unsigned int ino) +struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root, + u64 id) { struct kernfs_node *kn; + ino_t ino = kernfs_id_ino(id); + u32 gen = kernfs_id_gen(id); spin_lock(&kernfs_idr_lock); @@ -714,6 +719,10 @@ struct kernfs_node *kernfs_find_and_get_node_by_ino(struct kernfs_root *root, if (!kn) goto err_unlock; + /* 0 matches all generations */ + if (unlikely(gen && kernfs_gen(kn) != gen)) + goto err_unlock; + /* * ACTIVATED is protected with kernfs_mutex but it was clear when * @kn was added to idr and we just wanna see it set. No need to -- cgit v1.2.3