f2fs: remove the orphan block page array

As the orphan_blocks may be max to 504, so it is not security
and rigorous to store such a large array in the kernel stack
as Dan Carpenter said.
In fact, grab_meta_page has locked the page in the page cache,
and we can use find_get_page() to fetch the page safely in the
downstream, so we can remove the page array directly.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index f9d4f7d..ed82de6 100644 (file)
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -311,11 +311,10 @@ static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
        unsigned short orphan_blocks = (unsigned short)((sbi->n_orphans +
                (F2FS_ORPHANS_PER_BLOCK - 1)) / F2FS_ORPHANS_PER_BLOCK);
        struct page *page = NULL;
-       struct page *pages[orphan_blocks];
        struct orphan_inode_entry *orphan = NULL;
 
        for (index = 0; index < orphan_blocks; index++)
-               pages[index] = grab_meta_page(sbi, start_blk + index);
+               grab_meta_page(sbi, start_blk + index);
 
        index = 1;
        spin_lock(&sbi->orphan_inode_lock);
@@ -324,10 +323,12 @@ static void write_orphan_inodes(struct f2fs_sb_info *sbi, block_t start_blk)
        /* loop for each orphan inode entry and write them in Jornal block */
        list_for_each_entry(orphan, head, list) {
                if (!page) {
-                       page = pages[index - 1];
+                       page = find_get_page(META_MAPPING(sbi), start_blk++);
+                       f2fs_bug_on(!page);
                        orphan_blk =
                                (struct f2fs_orphan_block *)page_address(page);
                        memset(orphan_blk, 0, sizeof(*orphan_blk));
+                       f2fs_put_page(page, 0);
                }
 
                orphan_blk->ino[nentries++] = cpu_to_le32(orphan->ino);