[PATCH 16/23] initramfs: simplify clean_rootfs

Christoph Hellwig
2020-07-14T19:09:31Z

Just use d_genocide instead of iterating through the root directory with
cumbersome userspace-like APIs. This also ensures we actually remove files
that are not direct children of the root entry, which the old code failed
to do.

Fixes: df52092f3c97 ("fastboot: remove duplicate unpack_to_rootfs()")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
init/initramfs.c | 46 +++++-----------------------------------------
1 file changed, 5 insertions(+), 41 deletions(-)

diff --git a/init/initramfs.c b/init/initramfs.c
index d10404625c31f0..d42ec8329cd840 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -11,6 +11,7 @@
#include <linux/utime.h>
#include <linux/file.h>
#include <linux/memblock.h>
+#include <linux/namei.h>

static ssize_t __init xwrite(int fd, const char *p, size_t count)
{
@@ -572,51 +573,14 @@ static inline bool kexec_free_initrd(void)
#endif /* CONFIG_KEXEC_CORE */

#ifdef CONFIG_BLK_DEV_RAM
-#define BUF_SIZE 1024
static void __init clean_rootfs(void)
{
- int fd;
- void *buf;
- struct linux_dirent64 *dirp;
- int num;
+ struct path path;

- fd = ksys_open("/", O_RDONLY, 0);
- WARN_ON(fd < 0);
- if (fd < 0)
- return;
- buf = kzalloc(BUF_SIZE, GFP_KERNEL);
- WARN_ON(!buf);
- if (!buf) {
- ksys_close(fd);
+ if (kern_path("/", 0, &path))
return;
- }
-
- dirp = buf;
- num = ksys_getdents64(fd, dirp, BUF_SIZE);
- while (num > 0) {
- while (num > 0) {
- struct kstat st;
- int ret;
-
- ret = vfs_lstat(dirp->d_name, &st);
- WARN_ON_ONCE(ret);
- if (!ret) {
- if (S_ISDIR(st.mode))
- ksys_rmdir(dirp->d_name);
- else
- ksys_unlink(dirp->d_name);
- }
-
- num -= dirp->d_reclen;
- dirp = (void *)dirp + dirp->d_reclen;
- }
- dirp = buf;
- memset(buf, 0, BUF_SIZE);
- num = ksys_getdents64(fd, dirp, BUF_SIZE);
- }
-
- ksys_close(fd);
- kfree(buf);
+ d_genocide(path.dentry);
+ path_put(&path);
}

static void __init populate_initrd_image(char *err)
--
2.27.0