ceph: pass ino# instead of old_dentry if it's disconnected

When exporting the kceph to NFS it may pass a DCACHE_DISCONNECTED
dentry for the link operation. Then it will parse this dentry as a
snapdir, and the mds will fail the link request as -EROFS.

MDS allow clients to pass a ino# instead of a path.

Link: https://tracker.ceph.com/issues/59515
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 0ced8b5..cb67ac8 100644 (file)
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1050,6 +1050,9 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
        struct ceph_mds_request *req;
        int err;
 
+       if (dentry->d_flags & DCACHE_DISCONNECTED)
+               return -EINVAL;
+
        err = ceph_wait_on_conflict_unlink(dentry);
        if (err)
                return err;
@@ -1057,8 +1060,8 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
        if (ceph_snap(dir) != CEPH_NOSNAP)
                return -EROFS;
 
-       dout("link in dir %p old_dentry %p dentry %p\n", dir,
-            old_dentry, dentry);
+       dout("link in dir %p %llx.%llx old_dentry %p:'%pd' dentry %p:'%pd'\n",
+            dir, ceph_vinop(dir), old_dentry, old_dentry, dentry, dentry);
        req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LINK, USE_AUTH_MDS);
        if (IS_ERR(req)) {
                d_drop(dentry);
@@ -1067,6 +1070,12 @@ static int ceph_link(struct dentry *old_dentry, struct inode *dir,
        req->r_dentry = dget(dentry);
        req->r_num_caps = 2;
        req->r_old_dentry = dget(old_dentry);
+       /*
+        * The old_dentry maybe a DCACHE_DISCONNECTED dentry, then we
+        * will just pass the ino# to MDSs.
+        */
+       if (old_dentry->d_flags & DCACHE_DISCONNECTED)
+               req->r_ino2 = ceph_vino(d_inode(old_dentry));
        req->r_parent = dir;
        ihold(dir);
        set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 54e3c2a..29cf002 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2570,6 +2570,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
        u64 ino1 = 0, ino2 = 0;
        int pathlen1 = 0, pathlen2 = 0;
        bool freepath1 = false, freepath2 = false;
+       struct dentry *old_dentry = NULL;
        int len;
        u16 releases;
        void *p, *end;
@@ -2587,7 +2588,10 @@ static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
        }
 
        /* If r_old_dentry is set, then assume that its parent is locked */
-       ret = set_request_path_attr(NULL, req->r_old_dentry,
+       if (req->r_old_dentry &&
+           !(req->r_old_dentry->d_flags & DCACHE_DISCONNECTED))
+               old_dentry = req->r_old_dentry;
+       ret = set_request_path_attr(NULL, old_dentry,
                              req->r_old_dentry_dir,
                              req->r_path2, req->r_ino2.ino,
                              &path2, &pathlen2, &ino2, &freepath2, true);