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authorTejun Heo <tj@kernel.org>2014-02-03 23:09:12 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-08 03:52:48 +0400
commitd35258ef702cca0c4e66d799f8e38b78c02ce8a5 (patch)
treef3d98795cf620ad32edd4df982d015cfeedd1a97 /fs/sysfs
parentb9c9dad0c457d32cf8c7d2e413463c8414c7a7a7 (diff)
downloadlinux-d35258ef702cca0c4e66d799f8e38b78c02ce8a5.tar.xz
kernfs: allow nodes to be created in the deactivated state
Currently, kernfs_nodes are made visible to userland on creation, which makes it difficult for kernfs users to atomically succeed or fail creation of multiple nodes. In addition, if something fails after creating some nodes, the created nodes might already be in use and their active refs need to be drained for removal, which has the potential to introduce tricky reverse locking dependency on active_ref depending on how the error path is synchronized. This patch introduces per-root flag KERNFS_ROOT_CREATE_DEACTIVATED. If set, all nodes under the root are created in the deactivated state and stay invisible to userland until explicitly enabled by the new kernfs_activate() API. Also, nodes which have never been activated are guaranteed to bypass draining on removal thus allowing error paths to not worry about lockding dependency on active_ref draining. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/sysfs')
-rw-r--r--fs/sysfs/mount.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 6211230814fd..5c7fdd9c6811 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -62,7 +62,7 @@ int __init sysfs_init(void)
{
int err;
- sysfs_root = kernfs_create_root(NULL, NULL);
+ sysfs_root = kernfs_create_root(NULL, 0, NULL);
if (IS_ERR(sysfs_root))
return PTR_ERR(sysfs_root);