It's possible for us to issue a lookup to revalidate a dentry
concurrently with a rename. If done in the right order, then we could
end up processing dentry info in the reply that no longer reflects the
state of the dentry.
If req->r_dentry->d_name differs from the one in the trace, then just
ignore the trace in the reply. We only need to do this however if the
parent's i_rwsem is not held.
Reported-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/ceph/inode.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index b33ba16f7ae8..e1ac10f960dd 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1163,6 +1163,20 @@ static int splice_dentry(struct dentry **pdn, struct inode *in)
return 0;
}
+static bool
+d_name_cmp(struct dentry *dentry, const char *name, size_t len)
+{
+ int ret;
+
+ /* take d_lock to ensure dentry->d_name stability */
+ spin_lock(&dentry->d_lock);
+ ret = dentry->d_name.len - len;
+ if (!ret)
+ ret = memcmp(dentry->d_name.name, name, len);
+ spin_unlock(&dentry->d_lock);
+ return ret;
+}
+
/*
* Incorporate results into the local cache. This is either just
* one inode, or a directory, dentry, and possibly linked-to inode (e.g.,
@@ -1412,7 +1426,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
err = splice_dentry(&req->r_dentry, in);
if (err < 0)
goto done;
- } else if (rinfo->head->is_dentry) {
+ } else if (rinfo->head->is_dentry &&
+ !d_name_cmp(req->r_dentry, rinfo->dname, rinfo->dname_len)) {
struct ceph_vino *ptvino = NULL;
if ((le32_to_cpu(rinfo->diri.in->cap.caps) & CEPH_CAP_FILE_SHARED) ||
--
2.20.1
