| From | David Howells <> | Subject | [PATCH 43/73] union-mount: Process negative dentries in __lookup_union() [ver #2] | Date | Tue, 21 Feb 2012 18:02:53 +0000 |
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From: Valerie Aurora <vaurora@redhat.com>
Whiteouts end a union lookup. So do opaque directories, unless specific fallthru entry exists for this name.
Original-author: Valerie Aurora <vaurora@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> ---
fs/namei.c | 22 +++++++++++++++++++++- 1 files changed, 21 insertions(+), 1 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c index 8caed86..009d9b5 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1163,11 +1163,31 @@ 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);
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