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/symlink.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/configfs/symlink.c') diff --git a/fs/configfs/symlink.c b/fs/configfs/symlink.c index 2a731ef5f305..676c84c416da 100644 --- a/fs/configfs/symlink.c +++ b/fs/configfs/symlink.c @@ -169,7 +169,9 @@ int configfs_unlink(struct inode *dir, struct dentry *dentry) parent_item = configfs_get_config_item(dentry->d_parent); type = parent_item->ci_type; + spin_lock(&configfs_dirent_lock); list_del_init(&sd->s_sibling); + spin_unlock(&configfs_dirent_lock); configfs_drop_dentry(sd, dentry->d_parent); dput(dentry); configfs_put(sd); -- cgit v1.2.3