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Subject[PATCH 28/34] union-mount: Process negative dentries in __union_lookup()
Date
Whiteouts end a union lookup.  So do opaque directories, unless
specific fallthru entry exists for this name.

Signed-off-by: Valerie Aurora <vaurora@redhat.com>
---
fs/namei.c | 23 ++++++++++++++++++++++-
1 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 8373463..f6ad8b3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -781,11 +781,32 @@ static int __lookup_union(struct nameidata *nd, struct qstr *name,
err = PTR_ERR(lower.dentry);
goto out_err;
}
- /* XXX - do nothing, lookup rule processing in later patches */
+
+ /*
+ * A negative dentry can mean several things. A plain
+ * negative dentry is ignored and lookup continues to
+ * the next layer. But a whiteout or a non-fallthru
+ * in an opaque dir covers everything below it.
+ */
+ if (!lower.dentry->d_inode) {
+ if (d_is_whiteout(lower.dentry))
+ goto out_lookup_done;
+ if (IS_OPAQUE(nd->path.dentry->d_inode) &&
+ !d_is_fallthru(lower.dentry))
+ goto out_lookup_done;
+ path_put(&lower);
+ continue;
+ }
+
+ /* XXX - do nothing, more in later patches */
path_put(&lower);
}
return 0;

+out_lookup_done:
+ path_put(&lower);
+ return 0;
+
out_err:
d_free_unions(topmost->dentry);
path_put(&lower);
--
1.6.3.3


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