4 files changed, 23 insertions, 11 deletions

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 329a5d103846..645158dc33f1 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -435,6 +435,15 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
         if (IS_ERR_OR_NULL(result))
                 return ERR_PTR(-ESTALE);
 
+        /*
+         * If no acceptance criteria was specified by caller, a disconnected
+         * dentry is also accepatable. Callers may use this mode to query if
+         * file handle is stale or to get a reference to an inode without
+         * risking the high overhead caused by directory reconnect.
+         */
+        if (!acceptable)
+                return result;
+
         if (d_is_dir(result)) {
                 /*
                  * This request is for a directory.
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index e688cf019460..15411350a7a1 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -685,7 +685,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
         if (!ofs->upper_mnt)
                 return ERR_PTR(-EACCES);
 
-        upper = ovl_decode_real_fh(fh, ofs->upper_mnt);
+        upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true);
         if (IS_ERR_OR_NULL(upper))
                 return upper;
 
@@ -735,7 +735,7 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
         }
 
         /* Then lookup origin by fh */
-        err = ovl_check_origin_fh(ofs, fh, NULL, &stack);
+        err = ovl_check_origin_fh(ofs, fh, true, NULL, &stack);
         if (err) {
                 goto out_err;
         } else if (index) {
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 24bd387321d1..810a333d2221 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -180,7 +180,8 @@ invalid:
         goto out;
 }
 
-struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt)
+struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
+                                  bool connected)
 {
         struct dentry *real;
         int bytes;
@@ -195,7 +196,7 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt)
         bytes = (fh->len - offsetof(struct ovl_fh, fid));
         real = exportfs_decode_fh(mnt, (struct fid *)fh->fid,
                                   bytes >> 2, (int)fh->type,
-                                  ovl_acceptable, mnt);
+                                  connected ? ovl_acceptable : NULL, mnt);
         if (IS_ERR(real)) {
                 /*
                  * Treat stale file handle to lower file as "origin unknown".
@@ -319,14 +320,15 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
 }
 
 
-int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
+int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
                         struct dentry *upperdentry, struct ovl_path **stackp)
 {
         struct dentry *origin = NULL;
         int i;
 
         for (i = 0; i < ofs->numlower; i++) {
-                origin = ovl_decode_real_fh(fh, ofs->lower_layers[i].mnt);
+                origin = ovl_decode_real_fh(fh, ofs->lower_layers[i].mnt,
+                                            connected);
                 if (origin)
                         break;
         }
@@ -370,7 +372,7 @@ static int ovl_check_origin(struct ovl_fs *ofs, struct dentry *upperdentry,
         if (IS_ERR_OR_NULL(fh))
                 return PTR_ERR(fh);
 
-        err = ovl_check_origin_fh(ofs, fh, upperdentry, stackp);
+        err = ovl_check_origin_fh(ofs, fh, false, upperdentry, stackp);
         kfree(fh);
 
         if (err) {
@@ -460,7 +462,7 @@ struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index)
         if (IS_ERR_OR_NULL(fh))
                 return ERR_CAST(fh);
 
-        upper = ovl_decode_real_fh(fh, ofs->upper_mnt);
+        upper = ovl_decode_real_fh(fh, ofs->upper_mnt, true);
         kfree(fh);
 
         if (IS_ERR_OR_NULL(upper))
@@ -567,7 +569,7 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
 
         /* Check if non-dir index is orphan and don't warn before cleaning it */
         if (!d_is_dir(index) && d_inode(index)->i_nlink == 1) {
-                err = ovl_check_origin_fh(ofs, fh, index, &stack);
+                err = ovl_check_origin_fh(ofs, fh, false, index, &stack);
                 if (err)
                         goto fail;
 
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index dd6c10e5a7db..b51613b355c5 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -266,8 +266,9 @@ static inline bool ovl_is_impuredir(struct dentry *dentry)
 
 /* namei.c */
 int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
-struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt);
-int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
+struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
+                                  bool connected);
+int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
                         struct dentry *upperdentry, struct ovl_path **stackp);
 int ovl_verify_set_fh(struct dentry *dentry, const char *name,
                       struct dentry *real, bool is_upper, bool set);