ceph: handle the case where a dentry has been renamed on outstanding req (4b822287) · Commits · 戴 / test

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>

fs/ceph/inode.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -1163,6 +1163,19 @@ 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.,
		@@ -1412,7 +1425,8 @@ retry_lookup:
		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) \|\|

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