fs: rcu-walk aware d_revalidate method
Require filesystems be aware of .d_revalidate being called in rcu-walk
mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning
-ECHILD from all implementations.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 3e076ca..ea9120a 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -239,9 +239,13 @@
static int sysfs_dentry_revalidate(struct dentry *dentry, struct nameidata *nd)
{
- struct sysfs_dirent *sd = dentry->d_fsdata;
+ struct sysfs_dirent *sd;
int is_dir;
+ if (nd->flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ sd = dentry->d_fsdata;
mutex_lock(&sysfs_mutex);
/* The sysfs dirent has been deleted */