From: Jeff Layton jlayton@kernel.org
[ Upstream commit 4b8222870032715f9d995f3eb7c7acd8379a275d ]
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.
Signed-off-by: Jeff Layton jlayton@kernel.org Reviewed-by: "Yan, Zheng" zyan@redhat.com Signed-off-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ceph/inode.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index 9d1f34d46627..5880ee20ada4 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -1152,6 +1152,19 @@ static int splice_dentry(struct dentry **pdn, struct inode *in) return 0; }
+static int 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., @@ -1401,7 +1414,8 @@ 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) ||