From feb7cbb079e63ebb7c0bd7022d2ba9c1dd15c69b Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 15 Apr 2015 13:49:55 -0700 Subject: [PATCH] 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 --- fs/f2fs/namei.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index 9f0eec4677fe..407dde3d7a92 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "f2fs.h" #include "node.h" @@ -295,6 +296,23 @@ fail: 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_dir_inode_operations = { 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,