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ovl: simplify ovl_check_empty_and_clear()

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Filter out non-whiteout non-upper entries from list of merge dir entries
while checking if merge dir is empty in ovl_check_empty_dir().
The remaining work for ovl_clear_empty() is to clear all entries on the
list.

[amir: split patch from rmdir bug fix]

Signed-off-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:
zhangyi (F) 2017-10-31 22:57:00 +02:00 committed by Miklos Szeredi
parent b79e05aaa1
commit 95e598e7ac
2 changed files with 22 additions and 10 deletions
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5
fs/overlayfs/dir.c
View file

@ -300,7 +300,6 @@ static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
{
int err;
struct dentry *ret = NULL;
enum ovl_path_type type = ovl_path_type(dentry);
LIST_HEAD(list);
err = ovl_check_empty_dir(dentry, &list);
@ -313,13 +312,13 @@ static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
* When removing an empty opaque directory, then it makes no sense to
* replace it with an exact replica of itself.
*
* If no upperdentry then skip clearing whiteouts.
* If upperdentry has whiteouts, clear them.
*
* Can race with copy-up, since we don't hold the upperdir mutex.
* Doesn't matter, since copy-up can't create a non-empty directory
* from an empty one.
*/
if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
if (!list_empty(&list))
ret = ovl_clear_empty(dentry, &list);
out_free:

27
fs/overlayfs/readdir.c
View file

@ -26,6 +26,7 @@ struct ovl_cache_entry {
struct list_head l_node;
struct rb_node node;
struct ovl_cache_entry *next_maybe_whiteout;
bool is_upper;
bool is_whiteout;
char name[];
};
@ -158,6 +159,7 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
/* Defer setting d_ino for upper entry to ovl_iterate() */
if (ovl_calc_d_ino(rdd, p))
p->ino = 0;
p->is_upper = rdd->is_upper;
p->is_whiteout = false;
if (d_type == DT_CHR) {
@ -851,7 +853,7 @@ const struct file_operations ovl_dir_operations = {
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
{
int err;
struct ovl_cache_entry *p;
struct ovl_cache_entry *p, *n;
struct rb_root root = RB_ROOT;
err = ovl_dir_read_merged(dentry, list, &root);
@ -860,18 +862,29 @@ int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
err = 0;
list_for_each_entry(p, list, l_node) {
if (p->is_whiteout)
continue;
list_for_each_entry_safe(p, n, list, l_node) {
/*
* Select whiteouts in upperdir, they should
* be cleared when deleting this directory.
*/
if (p->is_whiteout) {
if (p->is_upper)
continue;
goto del_entry;
}
if (p->name[0] == '.') {
if (p->len == 1)
continue;
goto del_entry;
if (p->len == 2 && p->name[1] == '.')
continue;
goto del_entry;
}
err = -ENOTEMPTY;
break;
del_entry:
list_del(&p->l_node);
kfree(p);
}
return err;
@ -885,7 +898,7 @@ void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
list_for_each_entry(p, list, l_node) {
struct dentry *dentry;
if (!p->is_whiteout)
if (WARN_ON(!p->is_whiteout || !p->is_upper))
continue;
dentry = lookup_one_len(p->name, upper, p->len);