xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ovl: introduce the inodes index dir feature

Browse Source 
Create the index dir on mount. The index dir will contain hardlinks to
upper inodes, named after the hex representation of their origin lower
inodes.

The index dir is going to be used to prevent breaking lower hardlinks
on copy up and to implement overlayfs NFS export.

Because the feature is not fully backward compat, enabling the feature
is opt-in by config/module/mount option.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein
2017-06-21 15:28:36 +03:00
committed by Miklos Szeredi
parent 6b8aa129dc
commit 02bcd15774
6 changed files with 108 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
fs/overlayfs/copy_up.c
View File

@@ -233,12 +233,13 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
return err;
}
static struct ovl_fh *ovl_encode_fh(struct dentry *lower, uuid_t *uuid)
static struct ovl_fh *ovl_encode_fh(struct dentry *lower)
{
struct ovl_fh *fh;
int fh_type, fh_len, dwords;
void *buf;
int buflen = MAX_HANDLE_SZ;
uuid_t *uuid = &lower->d_sb->s_uuid;
buf = kmalloc(buflen, GFP_TEMPORARY);
if (!buf)
@@ -283,7 +284,6 @@ out:
static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
struct dentry *upper)
{
struct super_block *sb = lower->d_sb;
const struct ovl_fh *fh = NULL;
int err;
@@ -292,9 +292,8 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
* so we can use the overlay.origin xattr to distignuish between a copy
* up and a pure upper inode.
*/
if (sb->s_export_op && sb->s_export_op->fh_to_dentry &&
!uuid_is_null(&sb->s_uuid)) {
fh = ovl_encode_fh(lower, &sb->s_uuid);
if (ovl_can_decode_fh(lower->d_sb)) {
fh = ovl_encode_fh(lower);
if (IS_ERR(fh))
return PTR_ERR(fh);
}