+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) STRATO AG 2011. All rights reserved.
- */
-
-/*
- * This module can be used to catch cases when the btrfs kernel
- * code executes write requests to the disk that bring the file
- * system in an inconsistent state. In such a state, a power-loss
- * or kernel panic event would cause that the data on disk is
- * lost or at least damaged.
- *
- * Code is added that examines all block write requests during
- * runtime (including writes of the super block). Three rules
- * are verified and an error is printed on violation of the
- * rules:
- * 1. It is not allowed to write a disk block which is
- * currently referenced by the super block (either directly
- * or indirectly).
- * 2. When a super block is written, it is verified that all
- * referenced (directly or indirectly) blocks fulfill the
- * following requirements:
- * 2a. All referenced blocks have either been present when
- * the file system was mounted, (i.e., they have been
- * referenced by the super block) or they have been
- * written since then and the write completion callback
- * was called and no write error was indicated and a
- * FLUSH request to the device where these blocks are
- * located was received and completed.
- * 2b. All referenced blocks need to have a generation
- * number which is equal to the parent's number.
- *
- * One issue that was found using this module was that the log
- * tree on disk became temporarily corrupted because disk blocks
- * that had been in use for the log tree had been freed and
- * reused too early, while being referenced by the written super
- * block.
- *
- * The search term in the kernel log that can be used to filter
- * on the existence of detected integrity issues is
- * "btrfs: attempt".
- *
- * The integrity check is enabled via mount options. These
- * mount options are only supported if the integrity check
- * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
- *
- * Example #1, apply integrity checks to all metadata:
- * mount /dev/sdb1 /mnt -o check_int
- *
- * Example #2, apply integrity checks to all metadata and
- * to data extents:
- * mount /dev/sdb1 /mnt -o check_int_data
- *
- * Example #3, apply integrity checks to all metadata and dump
- * the tree that the super block references to kernel messages
- * each time after a super block was written:
- * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
- *
- * If the integrity check tool is included and activated in
- * the mount options, plenty of kernel memory is used, and
- * plenty of additional CPU cycles are spent. Enabling this
- * functionality is not intended for normal use. In most
- * cases, unless you are a btrfs developer who needs to verify
- * the integrity of (super)-block write requests, do not
- * enable the config option BTRFS_FS_CHECK_INTEGRITY to
- * include and compile the integrity check tool.
- *
- * Expect millions of lines of information in the kernel log with an
- * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
- * kernel config to at least 26 (which is 64MB). Usually the value is
- * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
- * changed like this before LOG_BUF_SHIFT can be set to a high value:
- * config LOG_BUF_SHIFT
- * int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
- * range 12 30
- */
-
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/mutex.h>
-#include <linux/blkdev.h>
-#include <linux/mm.h>
-#include <linux/string.h>
-#include <crypto/hash.h>
-#include "messages.h"
-#include "ctree.h"
-#include "disk-io.h"
-#include "transaction.h"
-#include "extent_io.h"
-#include "volumes.h"
-#include "print-tree.h"
-#include "locking.h"
-#include "check-integrity.h"
-#include "rcu-string.h"
-#include "compression.h"
-#include "accessors.h"
-
-#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
-#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
-#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
-#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
-#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
-#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
-#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
-#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6) /* in characters,
- * excluding " [...]" */
-#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
-
-/*
- * The definition of the bitmask fields for the print_mask.
- * They are specified with the mount option check_integrity_print_mask.
- */
-#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE 0x00000001
-#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION 0x00000002
-#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE 0x00000004
-#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE 0x00000008
-#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH 0x00000010
-#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH 0x00000020
-#define BTRFSIC_PRINT_MASK_VERBOSE 0x00000040
-#define BTRFSIC_PRINT_MASK_VERY_VERBOSE 0x00000080
-#define BTRFSIC_PRINT_MASK_INITIAL_TREE 0x00000100
-#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES 0x00000200
-#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE 0x00000400
-#define BTRFSIC_PRINT_MASK_NUM_COPIES 0x00000800
-#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS 0x00001000
-#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE 0x00002000
-
-struct btrfsic_dev_state;
-struct btrfsic_state;
-
-struct btrfsic_block {
- u32 magic_num; /* only used for debug purposes */
- unsigned int is_metadata:1; /* if it is meta-data, not data-data */
- unsigned int is_superblock:1; /* if it is one of the superblocks */
- unsigned int is_iodone:1; /* if is done by lower subsystem */
- unsigned int iodone_w_error:1; /* error was indicated to endio */
- unsigned int never_written:1; /* block was added because it was
- * referenced, not because it was
- * written */
- unsigned int mirror_num; /* large enough to hold
- * BTRFS_SUPER_MIRROR_MAX */
- struct btrfsic_dev_state *dev_state;
- u64 dev_bytenr; /* key, physical byte num on disk */
- u64 logical_bytenr; /* logical byte num on disk */
- u64 generation;
- struct btrfs_disk_key disk_key; /* extra info to print in case of
- * issues, will not always be correct */
- struct list_head collision_resolving_node; /* list node */
- struct list_head all_blocks_node; /* list node */
-
- /* the following two lists contain block_link items */
- struct list_head ref_to_list; /* list */
- struct list_head ref_from_list; /* list */
- struct btrfsic_block *next_in_same_bio;
- void *orig_bio_private;
- bio_end_io_t *orig_bio_end_io;
- blk_opf_t submit_bio_bh_rw;
- u64 flush_gen; /* only valid if !never_written */
-};
-
-/*
- * Elements of this type are allocated dynamically and required because
- * each block object can refer to and can be ref from multiple blocks.
- * The key to lookup them in the hashtable is the dev_bytenr of
- * the block ref to plus the one from the block referred from.
- * The fact that they are searchable via a hashtable and that a
- * ref_cnt is maintained is not required for the btrfs integrity
- * check algorithm itself, it is only used to make the output more
- * beautiful in case that an error is detected (an error is defined
- * as a write operation to a block while that block is still referenced).
- */
-struct btrfsic_block_link {
- u32 magic_num; /* only used for debug purposes */
- u32 ref_cnt;
- struct list_head node_ref_to; /* list node */
- struct list_head node_ref_from; /* list node */
- struct list_head collision_resolving_node; /* list node */
- struct btrfsic_block *block_ref_to;
- struct btrfsic_block *block_ref_from;
- u64 parent_generation;
-};
-
-struct btrfsic_dev_state {
- u32 magic_num; /* only used for debug purposes */
- struct block_device *bdev;
- struct btrfsic_state *state;
- struct list_head collision_resolving_node; /* list node */
- struct btrfsic_block dummy_block_for_bio_bh_flush;
- u64 last_flush_gen;
-};
-
-struct btrfsic_block_hashtable {
- struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
-};
-
-struct btrfsic_block_link_hashtable {
- struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
-};
-
-struct btrfsic_dev_state_hashtable {
- struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
-};
-
-struct btrfsic_block_data_ctx {
- u64 start; /* virtual bytenr */
- u64 dev_bytenr; /* physical bytenr on device */
- u32 len;
- struct btrfsic_dev_state *dev;
- char **datav;
- struct page **pagev;
- void *mem_to_free;
-};
-
-/* This structure is used to implement recursion without occupying
- * any stack space, refer to btrfsic_process_metablock() */
-struct btrfsic_stack_frame {
- u32 magic;
- u32 nr;
- int error;
- int i;
- int limit_nesting;
- int num_copies;
- int mirror_num;
- struct btrfsic_block *block;
- struct btrfsic_block_data_ctx *block_ctx;
- struct btrfsic_block *next_block;
- struct btrfsic_block_data_ctx next_block_ctx;
- struct btrfs_header *hdr;
- struct btrfsic_stack_frame *prev;
-};
-
-/* Some state per mounted filesystem */
-struct btrfsic_state {
- u32 print_mask;
- int include_extent_data;
- struct list_head all_blocks_list;
- struct btrfsic_block_hashtable block_hashtable;
- struct btrfsic_block_link_hashtable block_link_hashtable;
- struct btrfs_fs_info *fs_info;
- u64 max_superblock_generation;
- struct btrfsic_block *latest_superblock;
- u32 metablock_size;
- u32 datablock_size;
-};
-
-static void btrfsic_print_rem_link(const struct btrfsic_state *state,
- const struct btrfsic_block_link *l);
-static char btrfsic_get_block_type(const struct btrfsic_state *state,
- const struct btrfsic_block *block);
-static struct mutex btrfsic_mutex;
-static int btrfsic_is_initialized;
-static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
-
-
-static void btrfsic_block_free(struct btrfsic_block *b)
-{
- BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
- kfree(b);
-}
-
-static void btrfsic_block_link_free(struct btrfsic_block_link *l)
-{
- BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
- kfree(l);
-}
-
-static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
-{
- BUG_ON(!(NULL == ds ||
- BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
- kfree(ds);
-}
-
-static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
-{
- list_del(&ds->collision_resolving_node);
-}
-
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
- struct btrfsic_dev_state_hashtable *h)
-{
- const unsigned int hashval =
- dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
- struct btrfsic_dev_state *ds;
-
- list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
- if (ds->bdev->bd_dev == dev)
- return ds;
- }
-
- return NULL;
-}
-
-static void btrfsic_print_rem_link(const struct btrfsic_state *state,
- const struct btrfsic_block_link *l)
-{
- pr_info("rem %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
- l->ref_cnt,
- btrfsic_get_block_type(state, l->block_ref_from),
- l->block_ref_from->logical_bytenr,
- l->block_ref_from->dev_state->bdev,
- l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
- btrfsic_get_block_type(state, l->block_ref_to),
- l->block_ref_to->logical_bytenr,
- l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
- l->block_ref_to->mirror_num);
-}
-
-static char btrfsic_get_block_type(const struct btrfsic_state *state,
- const struct btrfsic_block *block)
-{
- if (block->is_superblock &&
- state->latest_superblock->dev_bytenr == block->dev_bytenr &&
- state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
- return 'S';
- else if (block->is_superblock)
- return 's';
- else if (block->is_metadata)
- return 'M';
- else
- return 'D';
-}
-
-void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
-{
- struct btrfsic_block *b_all, *tmp_all;
- struct btrfsic_state *state;
- struct list_head *dev_head = &fs_devices->devices;
- struct btrfs_device *device;
-
- if (!btrfsic_is_initialized)
- return;
-
- mutex_lock(&btrfsic_mutex);
-
- state = NULL;
- list_for_each_entry(device, dev_head, dev_list) {
- struct btrfsic_dev_state *ds;
-
- if (!device->bdev || !device->name)
- continue;
-
- ds = btrfsic_dev_state_hashtable_lookup(
- device->bdev->bd_dev,
- &btrfsic_dev_state_hashtable);
- if (NULL != ds) {
- state = ds->state;
- btrfsic_dev_state_hashtable_remove(ds);
- btrfsic_dev_state_free(ds);
- }
- }
-
- if (NULL == state) {
- pr_info("btrfsic: error, cannot find state information on umount!\n");
- mutex_unlock(&btrfsic_mutex);
- return;
- }
-
- /*
- * Don't care about keeping the lists' state up to date,
- * just free all memory that was allocated dynamically.
- * Free the blocks and the block_links.
- */
- list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
- all_blocks_node) {
- struct btrfsic_block_link *l, *tmp;
-
- list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
- node_ref_to) {
- if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
- btrfsic_print_rem_link(state, l);
-
- l->ref_cnt--;
- if (0 == l->ref_cnt)
- btrfsic_block_link_free(l);
- }
-
- if (b_all->is_iodone || b_all->never_written)
- btrfsic_block_free(b_all);
- else
- pr_info(
-"btrfs: attempt to free %c-block @%llu (%pg/%llu/%d) on umount which is not yet iodone!\n",
- btrfsic_get_block_type(state, b_all),
- b_all->logical_bytenr, b_all->dev_state->bdev,
- b_all->dev_bytenr, b_all->mirror_num);
- }
-
- mutex_unlock(&btrfsic_mutex);
-
- kvfree(state);
-}
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