From 6f61076406251626be39651d114fac412b1e0c39 Mon Sep 17 00:00:00 2001 From: Louis Rilling Date: Mon, 16 Jun 2008 19:00:58 +0200 Subject: configfs: Introduce configfs_dirent_lock This patch introduces configfs_dirent_lock spinlock to protect configfs_dirent traversals against linkage mutations (add/del/move). This will allow configfs_detach_prep() to avoid locking i_mutexes. Locking rules for configfs_dirent linkage mutations are the same plus the requirement of taking configfs_dirent_lock. For configfs_dirent walking, one can either take appropriate i_mutex as before, or take configfs_dirent_lock. The spinlock could actually be a mutex, but the critical sections are either O(1) or should not be too long (default groups walking in last patch). ChangeLog: - Clarify the comment on configfs_dirent_lock usage - Move sd->s_element init before linking the new dirent - In lseek(), do not release configfs_dirent_lock before the dirent is relinked. Signed-off-by: Louis Rilling Signed-off-by: Joel Becker --- fs/configfs/inode.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/configfs/inode.c') diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c index b9a1d810346..4803ccc9448 100644 --- a/fs/configfs/inode.c +++ b/fs/configfs/inode.c @@ -247,7 +247,9 @@ void configfs_hash_and_remove(struct dentry * dir, const char * name) if (!sd->s_element) continue; if (!strcmp(configfs_get_name(sd), name)) { + spin_lock(&configfs_dirent_lock); list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); configfs_drop_dentry(sd, dir); configfs_put(sd); break; -- cgit v1.2.3