f2fs: avoid abnormal behavior on broken symlink
When f2fs_symlink was triggered and checkpoint was done before syncing its
link path, f2fs can get broken symlink like "xxx -> \0\0\0".
This incurs abnormal path_walk by VFS.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 9f0eec4..407dde3 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -14,6 +14,7 @@
#include <linux/sched.h>
#include <linux/ctype.h>
#include <linux/dcache.h>
+#include <linux/namei.h>
#include "f2fs.h"
#include "node.h"
@@ -295,6 +296,23 @@
return err;
}
+static void *f2fs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+ struct page *page;
+
+ page = page_follow_link_light(dentry, nd);
+ if (IS_ERR(page))
+ return page;
+
+ /* this is broken symlink case */
+ if (*nd_get_link(nd) == 0) {
+ kunmap(page);
+ page_cache_release(page);
+ return ERR_PTR(-ENOENT);
+ }
+ return page;
+}
+
static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
const char *symname)
{
@@ -790,7 +808,7 @@
const struct inode_operations f2fs_symlink_inode_operations = {
.readlink = generic_readlink,
- .follow_link = page_follow_link_light,
+ .follow_link = f2fs_follow_link,
.put_link = page_put_link,
.getattr = f2fs_getattr,
.setattr = f2fs_setattr,