1 files changed, 94 insertions, 0 deletions

diff --git a/fs/btrfs/tree-checker.c b/fs/btrfs/tree-checker.c
index d7f4a3468945..ae4361cc6db5 100644
--- a/fs/btrfs/tree-checker.c
+++ b/fs/btrfs/tree-checker.c
@@ -678,6 +678,97 @@ static int check_dev_item(struct btrfs_fs_info *fs_info,
         return 0;
 }
 
+/* Inode item error output has the same format as dir_item_err() */
+#define inode_item_err(fs_info, eb, slot, fmt, ...)                     \
+        dir_item_err(fs_info, eb, slot, fmt, __VA_ARGS__)
+
+static int check_inode_item(struct btrfs_fs_info *fs_info,
+                            struct extent_buffer *leaf,
+                            struct btrfs_key *key, int slot)
+{
+        struct btrfs_inode_item *iitem;
+        u64 super_gen = btrfs_super_generation(fs_info->super_copy);
+        u32 valid_mask = (S_IFMT | S_ISUID | S_ISGID | S_ISVTX | 0777);
+        u32 mode;
+
+        if ((key->objectid < BTRFS_FIRST_FREE_OBJECTID ||
+             key->objectid > BTRFS_LAST_FREE_OBJECTID) &&
+            key->objectid != BTRFS_ROOT_TREE_DIR_OBJECTID &&
+            key->objectid != BTRFS_FREE_INO_OBJECTID) {
+                generic_err(fs_info, leaf, slot,
+        "invalid key objectid: has %llu expect %llu or [%llu, %llu] or %llu",
+                            key->objectid, BTRFS_ROOT_TREE_DIR_OBJECTID,
+                            BTRFS_FIRST_FREE_OBJECTID,
+                            BTRFS_LAST_FREE_OBJECTID,
+                            BTRFS_FREE_INO_OBJECTID);
+                return -EUCLEAN;
+        }
+        if (key->offset != 0) {
+                inode_item_err(fs_info, leaf, slot,
+                        "invalid key offset: has %llu expect 0",
+                        key->offset);
+                return -EUCLEAN;
+        }
+        iitem = btrfs_item_ptr(leaf, slot, struct btrfs_inode_item);
+
+        /* Here we use super block generation + 1 to handle log tree */
+        if (btrfs_inode_generation(leaf, iitem) > super_gen + 1) {
+                inode_item_err(fs_info, leaf, slot,
+                        "invalid inode generation: has %llu expect (0, %llu]",
+                               btrfs_inode_generation(leaf, iitem),
+                               super_gen + 1);
+                return -EUCLEAN;
+        }
+        /* Note for ROOT_TREE_DIR_ITEM, mkfs could set its transid 0 */
+        if (btrfs_inode_transid(leaf, iitem) > super_gen + 1) {
+                inode_item_err(fs_info, leaf, slot,
+                        "invalid inode generation: has %llu expect [0, %llu]",
+                               btrfs_inode_transid(leaf, iitem), super_gen + 1);
+                return -EUCLEAN;
+        }
+
+        /*
+         * For size and nbytes it's better not to be too strict, as for dir
+         * item its size/nbytes can easily get wrong, but doesn't affect
+         * anything in the fs. So here we skip the check.
+         */
+        mode = btrfs_inode_mode(leaf, iitem);
+        if (mode & ~valid_mask) {
+                inode_item_err(fs_info, leaf, slot,
+                               "unknown mode bit detected: 0x%x",
+                               mode & ~valid_mask);
+                return -EUCLEAN;
+        }
+
+        /*
+         * S_IFMT is not bit mapped so we can't completely rely on is_power_of_2,
+         * but is_power_of_2() can save us from checking FIFO/CHR/DIR/REG.
+         * Only needs to check BLK, LNK and SOCKS
+         */
+        if (!is_power_of_2(mode & S_IFMT)) {
+                if (!S_ISLNK(mode) && !S_ISBLK(mode) && !S_ISSOCK(mode)) {
+                        inode_item_err(fs_info, leaf, slot,
+                        "invalid mode: has 0%o expect valid S_IF* bit(s)",
+                                       mode & S_IFMT);
+                        return -EUCLEAN;
+                }
+        }
+        if (S_ISDIR(mode) && btrfs_inode_nlink(leaf, iitem) > 1) {
+                inode_item_err(fs_info, leaf, slot,
+                       "invalid nlink: has %u expect no more than 1 for dir",
+                        btrfs_inode_nlink(leaf, iitem));
+                return -EUCLEAN;
+        }
+        if (btrfs_inode_flags(leaf, iitem) & ~BTRFS_INODE_FLAG_MASK) {
+                inode_item_err(fs_info, leaf, slot,
+                               "unknown flags detected: 0x%llx",
+                               btrfs_inode_flags(leaf, iitem) &
+                               ~BTRFS_INODE_FLAG_MASK);
+                return -EUCLEAN;
+        }
+        return 0;
+}
+
 /*
  * Common point to switch the item-specific validation.
  */
@@ -711,6 +802,9 @@ static int check_leaf_item(struct btrfs_fs_info *fs_info,
         case BTRFS_DEV_ITEM_KEY:
                 ret = check_dev_item(fs_info, leaf, key, slot);
                 break;
+        case BTRFS_INODE_ITEM_KEY:
+                ret = check_inode_item(fs_info, leaf, key, slot);
+                break;
         }
         return ret;
 }