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ovl: fix inconsistent d_ino for legacy merge dir

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For a merge dir that was copied up before v4.12 or that was hand crafted
offline (e.g. mkdir {upper/lower}/dir), upper dir does not contain the
'trusted.overlay.origin' xattr.  In that case, stat(2) on the merge dir
returns the lower dir st_ino, but getdents(2) returns the upper dir d_ino.

After this change, on merge dir lookup, missing origin xattr on upper
dir will be fixed and 'impure' xattr will be fixed on parent of the legacy
merge dir.

Suggested-by: zhangyi (F) <yi.zhang@huawei.com>
Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein
2018-01-03 19:34:45 +02:00
committed by Miklos Szeredi
parent a5a927a7c8
commit 9678e63030
3 changed files with 37 additions and 2 deletions
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33
fs/overlayfs/namei.c
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@@ -584,6 +584,27 @@ static int ovl_find_layer(struct ovl_fs *ofs, struct ovl_path *path)
return i;
}
/* Fix missing 'origin' xattr */
static int ovl_fix_origin(struct dentry *dentry, struct dentry *lower,
struct dentry *upper)
{
int err;
if (ovl_check_origin_xattr(upper))
return 0;
err = ovl_want_write(dentry);
if (err)
return err;
err = ovl_set_origin(dentry, lower, upper);
if (!err)
err = ovl_set_impure(dentry->d_parent, upper->d_parent);
ovl_drop_write(dentry);
return err;
}
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
@@ -674,6 +695,18 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (!this)
continue;
/*
* If no origin fh is stored in upper of a merge dir, store fh
* of lower dir and set upper parent "impure".
*/
if (upperdentry && !ctr && !ofs->noxattr) {
err = ovl_fix_origin(dentry, this, upperdentry);
if (err) {
dput(this);
goto out_put;
}
}
stack[ctr].dentry = this;
stack[ctr].layer = lower.layer;
ctr++;