[RFC PATCH 17/35] ovl: readd fiemap

From: Miklos Szeredi
Date: Thu Apr 12 2018 - 11:09:04 EST


Implement stacked fiemap().

Need to split inode operations for regular file (which has fiemap) and
special file (which doesn't have fiemap).

Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/overlayfs/inode.c | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 3b996639e1ad..b723327501f7 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -455,6 +455,23 @@ int ovl_update_time(struct inode *inode, struct timespec *ts, int flags)
return 0;
}

+static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+ u64 start, u64 len)
+{
+ int err;
+ struct inode *realinode = ovl_inode_real(inode);
+ const struct cred *old_cred;
+
+ if (!realinode->i_op->fiemap)
+ return -EOPNOTSUPP;
+
+ old_cred = ovl_override_creds(inode->i_sb);
+ err = realinode->i_op->fiemap(realinode, fieinfo, start, len);
+ revert_creds(old_cred);
+
+ return err;
+}
+
static const struct inode_operations ovl_file_inode_operations = {
.setattr = ovl_setattr,
.permission = ovl_permission,
@@ -462,6 +479,7 @@ static const struct inode_operations ovl_file_inode_operations = {
.listxattr = ovl_listxattr,
.get_acl = ovl_get_acl,
.update_time = ovl_update_time,
+ .fiemap = ovl_fiemap,
};

static const struct inode_operations ovl_symlink_inode_operations = {
@@ -472,6 +490,15 @@ static const struct inode_operations ovl_symlink_inode_operations = {
.update_time = ovl_update_time,
};

+static const struct inode_operations ovl_special_inode_operations = {
+ .setattr = ovl_setattr,
+ .permission = ovl_permission,
+ .getattr = ovl_getattr,
+ .listxattr = ovl_listxattr,
+ .get_acl = ovl_get_acl,
+ .update_time = ovl_update_time,
+};
+
/*
* It is possible to stack overlayfs instance on top of another
* overlayfs instance as lower layer. We need to annonate the
@@ -555,7 +582,7 @@ static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
break;

default:
- inode->i_op = &ovl_file_inode_operations;
+ inode->i_op = &ovl_special_inode_operations;
init_special_inode(inode, mode, rdev);
break;
}
--
2.14.3