ocfs2: correct l_next_free_rec in online check

Correct the value of l_next_free_rec to l_count during the online check,
as done in the check_el() function in ocfs2_tools.

Link: https://lkml.kernel.org/r/20250106023432.1320904-2-sunjunchao2870@gmail.com
Signed-off-by: Julian Sun <sunjunchao2870@gmail.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: jc2870

fs/ocfs2/inode.c

@@ -200,6 +200,20 @@ struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
 	return inode;
 }
 
+static int ocfs2_dinode_has_extents(struct ocfs2_dinode *di)
+{
+	/* inodes flagged with other stuff in id2 */
+	if (di->i_flags & (OCFS2_SUPER_BLOCK_FL | OCFS2_LOCAL_ALLOC_FL |
+			   OCFS2_CHAIN_FL | OCFS2_DEALLOC_FL))
+		return 0;
+	/* i_flags doesn't indicate when id2 is a fast symlink */
+	if (S_ISLNK(di->i_mode) && di->i_size && di->i_clusters == 0)
+		return 0;
+	if (di->i_dyn_features & OCFS2_INLINE_DATA_FL)
+		return 0;
+
+	return 1;
+}
 
 /*
  * here's how inodes get read from disk:
@@ -1547,6 +1561,16 @@ static int ocfs2_filecheck_repair_inode_block(struct super_block *sb,
 		     le32_to_cpu(di->i_fs_generation));
 	}
 
+	if (ocfs2_dinode_has_extents(di) &&
+	    le16_to_cpu(di->id2.i_list.l_next_free_rec) > le16_to_cpu(di->id2.i_list.l_count)) {
+		di->id2.i_list.l_next_free_rec = di->id2.i_list.l_count;
+		changed = 1;
+		mlog(ML_ERROR,
+		     "Filecheck: reset dinode #%llu: l_next_free_rec to %u\n",
+		     (unsigned long long)bh->b_blocknr,
+		     le16_to_cpu(di->id2.i_list.l_next_free_rec));
+	}
+
 	if (changed || ocfs2_validate_meta_ecc(sb, bh->b_data, &di->i_check)) {
 		ocfs2_compute_meta_ecc(sb, bh->b_data, &di->i_check);
 		mark_buffer_dirty(bh);