lookup_open(): put the dentry fed to ->lookup() or ->atomic_open() into in-lookup...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index b9dde84..b84e6b2 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2842,6 +2842,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
        error = dir->i_op->atomic_open(dir, dentry, file,
                                       open_to_namei_flags(open_flag),
                                       mode, opened);
+       d_lookup_done(dentry);
        if (!error) {
                /*
                 * We didn't have the inode before the open, so check open
@@ -2903,23 +2904,36 @@ static int lookup_open(struct nameidata *nd, struct path *path,
        int open_flag = op->open_flag;
        struct dentry *dentry;
        int error, create_error = 0;
-       bool need_lookup = false;
        umode_t mode = op->mode;
+       DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 
        if (unlikely(IS_DEADDIR(dir_inode)))
                return -ENOENT;
 
        *opened &= ~FILE_CREATED;
-       dentry = lookup_dcache(&nd->last, dir, nd->flags);
-       if (IS_ERR(dentry))
-               return PTR_ERR(dentry);
+       dentry = d_lookup(dir, &nd->last);
+       for (;;) {
+               if (!dentry) {
+                       dentry = d_alloc_parallel(dir, &nd->last, &wq);
+                       if (IS_ERR(dentry))
+                               return PTR_ERR(dentry);
+               }
+               if (d_in_lookup(dentry))
+                       break;
 
-       if (!dentry) {
-               dentry = d_alloc(dir, &nd->last);
-               if (unlikely(!dentry))
-                       return -ENOMEM;
-               need_lookup = true;
-       } else if (dentry->d_inode) {
+               if (!(dentry->d_flags & DCACHE_OP_REVALIDATE))
+                       break;
+
+               error = d_revalidate(dentry, nd->flags);
+               if (likely(error > 0))
+                       break;
+               if (error)
+                       goto out_dput;
+               d_invalidate(dentry);
+               dput(dentry);
+               dentry = NULL;
+       }
+       if (dentry->d_inode) {
                /* Cached positive dentry: will open in f_op->open */
                goto out_no_open;
        }
@@ -2968,9 +2982,10 @@ static int lookup_open(struct nameidata *nd, struct path *path,
        }
 
 no_open:
-       if (need_lookup) {
+       if (d_in_lookup(dentry)) {
                struct dentry *res = dir_inode->i_op->lookup(dir_inode, dentry,
                                                             nd->flags);
+               d_lookup_done(dentry);
                if (unlikely(res)) {
                        if (IS_ERR(res)) {
                                error = PTR_ERR(res);