f2fs: fix to detect potential corrupted nid in free_nid_list

As reported, on-disk footer.ino and footer.nid is the same and
out-of-range, let's add sanity check on f2fs_alloc_nid() to detect
any potential corruption in free_nid_list.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 27743b93e18672426e5c73b2a551eb3afadcd370..286e8a53f8e77ef78ef897654ca85e1ebf2f0def 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -27,12 +27,17 @@ static struct kmem_cache *free_nid_slab;
 static struct kmem_cache *nat_entry_set_slab;
 static struct kmem_cache *fsync_node_entry_slab;
 
+static inline bool is_invalid_nid(struct f2fs_sb_info *sbi, nid_t nid)
+{
+       return nid < F2FS_ROOT_INO(sbi) || nid >= NM_I(sbi)->max_nid;
+}
+
 /*
  * Check whether the given nid is within node id range.
  */
 int f2fs_check_nid_range(struct f2fs_sb_info *sbi, nid_t nid)
 {
-       if (unlikely(nid < F2FS_ROOT_INO(sbi) || nid >= NM_I(sbi)->max_nid)) {
+       if (unlikely(is_invalid_nid(sbi, nid))) {
                set_sbi_flag(sbi, SBI_NEED_FSCK);
                f2fs_warn(sbi, "%s: out-of-range nid=%x, run fsck to fix.",
                          __func__, nid);
@@ -2634,6 +2639,16 @@ retry:
                f2fs_bug_on(sbi, list_empty(&nm_i->free_nid_list));
                i = list_first_entry(&nm_i->free_nid_list,
                                        struct free_nid, list);
+
+               if (unlikely(is_invalid_nid(sbi, i->nid))) {
+                       spin_unlock(&nm_i->nid_list_lock);
+                       f2fs_err(sbi, "Corrupted nid %u in free_nid_list",
+                                                               i->nid);
+                       f2fs_stop_checkpoint(sbi, false,
+                                       STOP_CP_REASON_CORRUPTED_NID);
+                       return false;
+               }
+
                *nid = i->nid;
 
                __move_free_nid(sbi, i, FREE_NID, PREALLOC_NID);

diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 2f8b8bfc0e73154710d3f55c96bcfbfa43587ddb..6afb4a13b81d6525ea005aedc9fe883e57df0442 100644 (file)
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -79,6 +79,7 @@ enum stop_cp_reason {
        STOP_CP_REASON_FLUSH_FAIL,
        STOP_CP_REASON_NO_SEGMENT,
        STOP_CP_REASON_CORRUPTED_FREE_BITMAP,
+       STOP_CP_REASON_CORRUPTED_NID,
        STOP_CP_REASON_MAX,
 };