3 files changed, 44 insertions, 15 deletions

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 32e9282893c9..aeaefd2a551b 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -131,9 +131,6 @@ static int ovl_open(struct inode *inode, struct file *file)
         if (IS_ERR(realfile))
                 return PTR_ERR(realfile);
 
-        /* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */
-        file->f_mapping = realfile->f_mapping;
-
         file->private_data = realfile;
 
         return 0;
@@ -334,6 +331,25 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
         return ret;
 }
 
+static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
+{
+        struct fd real;
+        const struct cred *old_cred;
+        int ret;
+
+        ret = ovl_real_fdget(file, &real);
+        if (ret)
+                return ret;
+
+        old_cred = ovl_override_creds(file_inode(file)->i_sb);
+        ret = vfs_fadvise(real.file, offset, len, advice);
+        revert_creds(old_cred);
+
+        fdput(real);
+
+        return ret;
+}
+
 static long ovl_real_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
 {
@@ -502,6 +518,7 @@ const struct file_operations ovl_file_operations = {
         .fsync          = ovl_fsync,
         .mmap           = ovl_mmap,
         .fallocate      = ovl_fallocate,
+        .fadvise        = ovl_fadvise,
         .unlocked_ioctl = ovl_ioctl,
         .compat_ioctl   = ovl_compat_ioctl,
 
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index e0bb217c01e2..b6ac545b5a32 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -467,6 +467,10 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                 return -EOPNOTSUPP;
 
         old_cred = ovl_override_creds(inode->i_sb);
+
+        if (fieinfo->fi_flags & FIEMAP_FLAG_SYNC)
+                filemap_write_and_wait(realinode->i_mapping);
+
         err = realinode->i_op->fiemap(realinode, fieinfo, start, len);
         revert_creds(old_cred);
 
@@ -500,6 +504,11 @@ static const struct inode_operations ovl_special_inode_operations = {
         .update_time    = ovl_update_time,
 };
 
+const struct address_space_operations ovl_aops = {
+        /* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */
+        .direct_IO              = noop_direct_IO,
+};
+
 /*
  * It is possible to stack overlayfs instance on top of another
  * overlayfs instance as lower layer. We need to annonate the
@@ -571,6 +580,7 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
         case S_IFREG:
                 inode->i_op = &ovl_file_inode_operations;
                 inode->i_fop = &ovl_file_operations;
+                inode->i_mapping->a_ops = &ovl_aops;
                 break;
 
         case S_IFDIR:
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 2e0fc93c2c06..30adc9d408a0 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -982,16 +982,6 @@ static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath)
         if (err)
                 goto out;
 
-        err = -EBUSY;
-        if (ovl_inuse_trylock(upperpath->dentry)) {
-                ofs->upperdir_locked = true;
-        } else if (ofs->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;
-        } else {
-                pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
-        }
-
         upper_mnt = clone_private_mount(upperpath);
         err = PTR_ERR(upper_mnt);
         if (IS_ERR(upper_mnt)) {
@@ -1002,6 +992,17 @@ static int ovl_get_upper(struct ovl_fs *ofs, struct path *upperpath)
         /* Don't inherit atime flags */
         upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
         ofs->upper_mnt = upper_mnt;
+
+        err = -EBUSY;
+        if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) {
+                ofs->upperdir_locked = true;
+        } else if (ofs->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;
+        } else {
+                pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
+        }
+
         err = 0;
 out:
         return err;
@@ -1101,8 +1102,10 @@ static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
                 goto out;
         }
 
+        ofs->workbasedir = dget(workpath.dentry);
+
         err = -EBUSY;
-        if (ovl_inuse_trylock(workpath.dentry)) {
+        if (ovl_inuse_trylock(ofs->workbasedir)) {
                 ofs->workdir_locked = true;
         } else if (ofs->config.index) {
                 pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n");
@@ -1111,7 +1114,6 @@ static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
                 pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
         }
 
-        ofs->workbasedir = dget(workpath.dentry);
         err = ovl_make_workdir(ofs, &workpath);
         if (err)
                 goto out;