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>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index 4d54c60ceee4..0310b16a7238 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -52,9 +52,15 @@ void ocfs2_dentry_attach_gen(struct dentry *dentry)
 static int ocfs2_dentry_revalidate(struct dentry *dentry,
                                    struct nameidata *nd)
 {
-        struct inode *inode = dentry->d_inode;
+        struct inode *inode;
         int ret = 0;    /* if all else fails, just return false */
-        struct ocfs2_super *osb = OCFS2_SB(dentry->d_sb);
+        struct ocfs2_super *osb;
+
+        if (nd->flags & LOOKUP_RCU)
+                return -ECHILD;
+
+        inode = dentry->d_inode;
+        osb = OCFS2_SB(dentry->d_sb);
 
         mlog_entry("(0x%p, '%.*s')\n", dentry,
                    dentry->d_name.len, dentry->d_name.name);