1 files changed, 19 insertions, 8 deletions

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index fd5ea4facc62..092d150643c1 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -211,9 +211,10 @@ static void ovl_put_super(struct super_block *sb)
 
         dput(ufs->indexdir);
         dput(ufs->workdir);
-        ovl_inuse_unlock(ufs->workbasedir);
+        if (ufs->workdir_locked)
+                ovl_inuse_unlock(ufs->workbasedir);
         dput(ufs->workbasedir);
-        if (ufs->upper_mnt)
+        if (ufs->upper_mnt && ufs->upperdir_locked)
                 ovl_inuse_unlock(ufs->upper_mnt->mnt_root);
         mntput(ufs->upper_mnt);
         for (i = 0; i < ufs->numlower; i++)
@@ -881,9 +882,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
                         goto out_put_upperpath;
 
                 err = -EBUSY;
-                if (!ovl_inuse_trylock(upperpath.dentry)) {
-                        pr_err("overlayfs: upperdir is in-use by another mount\n");
+                if (ovl_inuse_trylock(upperpath.dentry)) {
+                        ufs->upperdir_locked = true;
+                } else if (ufs->config.index) {
+                        pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n");
                         goto out_put_upperpath;
+                } else {
+                        pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
                 }
 
                 err = ovl_mount_dir(ufs->config.workdir, &workpath);
@@ -901,9 +906,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
                 }
 
                 err = -EBUSY;
-                if (!ovl_inuse_trylock(workpath.dentry)) {
-                        pr_err("overlayfs: workdir is in-use by another mount\n");
+                if (ovl_inuse_trylock(workpath.dentry)) {
+                        ufs->workdir_locked = true;
+                } else if (ufs->config.index) {
+                        pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n");
                         goto out_put_workpath;
+                } else {
+                        pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
                 }
 
                 ufs->workbasedir = workpath.dentry;
@@ -1156,11 +1165,13 @@ out_put_lowerpath:
 out_free_lowertmp:
         kfree(lowertmp);
 out_unlock_workdentry:
-        ovl_inuse_unlock(workpath.dentry);
+        if (ufs->workdir_locked)
+                ovl_inuse_unlock(workpath.dentry);
 out_put_workpath:
         path_put(&workpath);
 out_unlock_upperdentry:
-        ovl_inuse_unlock(upperpath.dentry);
+        if (ufs->upperdir_locked)
+                ovl_inuse_unlock(upperpath.dentry);
 out_put_upperpath:
         path_put(&upperpath);
 out_free_config: