[PATCH 2/3] f2fs: do sanity check on xattr node footer in f2fs_get_xnode_page()

[Chao Yu <chao@kernel.org>]

This patch introduces a new wrapper f2fs_get_xnode_page(), then, caller
can use it to load xattr block to page cache, meanwhile it will do sanity
check on xattr node footer.

Signed-off-by: Chao Yu <chao@kernel.org>
---
 fs/f2fs/f2fs.h  |  1 +
 fs/f2fs/node.c  | 14 ++++++++++++--
 fs/f2fs/node.h  |  1 +
 fs/f2fs/xattr.c |  4 ++--
 4 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 74a80bb06f06..38016d24e59c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3704,6 +3704,7 @@ void f2fs_ra_node_page(struct f2fs_sb_info *sbi, nid_t nid);
 struct page *f2fs_get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid);
 struct folio *f2fs_get_inode_folio(struct f2fs_sb_info *sbi, pgoff_t ino);
 struct page *f2fs_get_inode_page(struct f2fs_sb_info *sbi, pgoff_t ino);
+struct page *f2fs_get_xnode_page(struct f2fs_sb_info *sbi, pgoff_t xnid);
 struct page *f2fs_get_node_page_ra(struct page *parent, int start);
 int f2fs_move_node_page(struct page *node_page, int gc_type);
 void f2fs_flush_inline_data(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index ee5daa6f7408..5be8badc6261 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1245,7 +1245,7 @@ int f2fs_truncate_xattr_node(struct inode *inode)
 	if (!nid)
 		return 0;
 
-	npage = f2fs_get_node_page(sbi, nid);
+	npage = f2fs_get_xnode_page(sbi, nid);
 	if (IS_ERR(npage))
 		return PTR_ERR(npage);
 
@@ -1461,7 +1461,9 @@ static int sanity_check_node_footer(struct f2fs_sb_info *sbi,
 					enum node_type ntype)
 {
 	if (unlikely(nid != nid_of_node(page) ||
-		(ntype == NODE_TYPE_INODE && !IS_INODE(page)))) {
+		(ntype == NODE_TYPE_INODE && !IS_INODE(page)) ||
+		(ntype == NODE_TYPE_XATTR &&
+		!f2fs_has_xattr_block(ofs_of_node(page))))) {
 		f2fs_warn(sbi, "inconsistent node block, node_type:%d, nid:%lu, "
 			  "node_footer[nid:%u,ino:%u,ofs:%u,cpver:%llu,blkaddr:%u]",
 			  ntype, nid, nid_of_node(page), ino_of_node(page),
@@ -1551,6 +1553,14 @@ struct page *f2fs_get_inode_page(struct f2fs_sb_info *sbi, pgoff_t ino)
 	return &folio->page;
 }
 
+struct page *f2fs_get_xnode_page(struct f2fs_sb_info *sbi, pgoff_t xnid)
+{
+	struct folio *folio = __get_node_folio(sbi, xnid, NULL, 0,
+						NODE_TYPE_XATTR);
+
+	return &folio->page;
+}
+
 struct page *f2fs_get_node_page_ra(struct page *parent, int start)
 {
 	struct f2fs_sb_info *sbi = F2FS_P_SB(parent);
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index 5079c6a2298d..103a437e6425 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -56,6 +56,7 @@ enum {
 enum node_type {
 	NODE_TYPE_REGULAR,
 	NODE_TYPE_INODE,
+	NODE_TYPE_XATTR,
 };
 
 /*
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index d5b42e1005d8..c691b35618ad 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -303,7 +303,7 @@ static int read_xattr_block(struct inode *inode, void *txattr_addr)
 	void *xattr_addr;
 
 	/* The inode already has an extended attribute block. */
-	xpage = f2fs_get_node_page(sbi, xnid);
+	xpage = f2fs_get_xnode_page(sbi, xnid);
 	if (IS_ERR(xpage))
 		return PTR_ERR(xpage);
 
@@ -475,7 +475,7 @@ static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
 
 	/* write to xattr node block */
 	if (F2FS_I(inode)->i_xattr_nid) {
-		xpage = f2fs_get_node_page(sbi, F2FS_I(inode)->i_xattr_nid);
+		xpage = f2fs_get_xnode_page(sbi, F2FS_I(inode)->i_xattr_nid);
 		if (IS_ERR(xpage)) {
 			err = PTR_ERR(xpage);
 			f2fs_alloc_nid_failed(sbi, new_nid);
-- 
2.48.1