// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2023 Red Hat
*/
#include "packer.h"
#include <linux/atomic.h>
#include <linux/blkdev.h>
#include "logger.h"
#include "memory-alloc.h"
#include "permassert.h"
#include "string-utils.h"
#include "admin-state.h"
#include "completion.h"
#include "constants.h"
#include "data-vio.h"
#include "dedupe.h"
#include "encodings.h"
#include "io-submitter.h"
#include "physical-zone.h"
#include "status-codes.h"
#include "vdo.h"
#include "vio.h"
static const struct version_number COMPRESSED_BLOCK_1_0 = {
.major_version = 1,
.minor_version = 0,
};
#define COMPRESSED_BLOCK_1_0_SIZE (4 + 4 + (2 * VDO_MAX_COMPRESSION_SLOTS))
/**
* vdo_get_compressed_block_fragment() - Get a reference to a compressed fragment from a compressed
* block.
* @mapping_state [in] The mapping state for the look up.
* @compressed_block [in] The compressed block that was read from disk.
* @fragment_offset [out] The offset of the fragment within a compressed block.
* @fragment_size [out] The size of the fragment.
*
* Return: If a valid compressed fragment is found, VDO_SUCCESS; otherwise, VDO_INVALID_FRAGMENT if
* the fragment is invalid.
*/
int vdo_get_compressed_block_fragment(enum block_mapping_state mapping_state,
struct compressed_block *block,
u16 *fragment_offset, u16 *fragment_size)
{
u16 compressed_size;
u16 offset = 0;
unsigned int i;
u8 slot;
struct version_number version;
if (!vdo_is_state_compressed(mapping_state))
return VDO_INVALID_FRAGMENT;
version = vdo_unpack_version_number(block->header.version);
if (!vdo_are_same_version(version, COMPRESSED_BLOCK_1_0))
return VDO_INVALID_FRAGMENT;
slot = mapping_state - VDO_MAPPING_STATE_COMPRESSED_BASE;
if (slot >= VDO_MAX_COMPRESSION_SLOTS)
return VDO_INVALID_FRAGMENT;
compressed_size = __le16_to_cpu(block->header.sizes[slot]);
for (i = 0; i < slot; i++) {
offset += __le16_to_cpu(block->header.sizes[i]);
if (offset >= VDO_COMPRESSED_BLOCK_DATA_SIZE)
return VDO_INVALID_FRAGMENT;
}
if ((offset + compressed_size) > VDO_COMPRESSED_BLOCK_DATA_SIZE)
return VDO_INVALID_FRAGMENT;
*fragment_offset = offset;
*fragment_size = compressed_size;
return VDO_SUCCESS;
}
/**
* assert_on_packer_thread() - Check that we are on the packer thread.
* @packer: The packer.
* @caller: The function which is asserting.
*/
static inline void assert_on_packer_thread(struct packer *packer, const char *caller)
{
VDO_ASSERT_LOG_ONLY((vdo_get_callback_thread_id() == packer->thread_id),
"%s() called from packer thread", caller);
}
/**
* insert_in_sorted_list() - Insert a bin to the list.
* @packer: The packer.
* @bin: The bin to move to its sorted position.
*
* The list is in ascending order of free space. Since all bins are already in the list, this
* actually moves the bin to the correct position in the list.
*/
static void insert_in_sorted_list(struct packer *packer, struct packer_bin *bin)
{
struct packer_bin *active_bin;
list_for_each_entry(active_bin, &packer->bins, list)
if (active_bin->free_space > bin->free_space) {
list_move_tail(&bin->list, &active_bin->list);
return;
}
list_move_tail(&bin->list, &packer->bins);
}
/**
* make_bin() - Allocate a bin and put it into the packer's list.
* @packer: The packer.
*/
static int __must_check make_bin(struct packer *packer)
{
struct packer_bin *bin;
int result;
result = vdo_allocate_extended(struct packer_bin, VDO_MAX_COMPRESSION_SLOTS,
struct vio *, __func__, &bin);
if (result != VDO_SUCCESS)
return result;
bin->free_space = VDO_COMPRESSED_BLOCK_DATA_SIZE;
INIT_LIST_HEAD(&bin->list);
list_add_tail(&bin->list, &packer->bins);
return VDO_SUCCESS;
}
/**
* vdo_make_packer() - Make a new block packer.
*
* @vdo: The vdo to which this packer belongs.
* @bin_count: The number of partial bins to keep in memory.
* @packer_ptr: A pointer to hold the new packer.
*
* Return: VDO_SUCCESS or an error
*/
int vdo_make_packer(struct vdo *vdo, block_count_t bin_count, struct packer **packer_ptr)
{
struct packer *packer;
block_count_t i;
int result;
result = vdo_allocate(1, struct packer, __func__, &packer);
if (result != VDO_SUCCESS)
return result;
packer->thread_id = vdo->thread_config.packer_thread;
packer->size = bin_count;
INIT_LIST_HEAD(&packer->bins);
vdo_set_admin_state_code(&packer->state, VDO_ADMIN_STATE_NORMAL_OPERATION);
for (i = 0; i < bin_count; i++) {
result = make_bin(packer);
if (result != VDO_SUCCESS) {
vdo_free_packer(packer);
return result;
}
}
/*
* The canceled bin can hold up to half the number of user vios. Every canceled vio in the
* bin must have a canceler for which it is waiting, and any canceler will only have
* canceled one lock holder at a time.
*/
result = vdo_allocate_extended(struct packer_bin, MAXIMUM_VDO_USER_VIOS / 2,
struct vio *, __func__, &packer->canceled_bin);
if (result != VDO_SUCCESS) {
vdo_free_packer(packer);
return result;
}
result = vdo_make_default_thread(vdo, packer->thread_id);
if (result != VDO_SUCCESS) {
vdo_free_packer(packer);
return result;
}
*packer_ptr = packer;
return VDO_SUCCESS;
}
/**
* vdo_free_packer() - Free a block packer.
* @packer: The packer to free.
*/
void vdo_free_packer(struct packer *packer)
{
struct packer_bin *bin, *tmp;
if (packer == NULL)
return;
list_for_each_entry_safe(bin, tmp, &packer->bins, list) {
list_del_init(&bin->list);
vdo_free(bin);
}
vdo_free(vdo_forget(packer->canceled_bin));
vdo_free(packer);
}
/**
* get_packer_from_data_vio() - Get the packer from a data_vio.
* @data_vio: The data_vio.
*
* Return: The packer from the VDO to which the data_vio belongs.
*/
static inline struct packer *get_packer_from_data_vio(struct data_vio *data_vio)
{
return vdo_from_data_vio(data_vio)->packer;
}
/**
* vdo_get_packer_statistics() - Get the current statistics from the packer.
* @packer: The packer to query.
*
* Return: a copy of the current statistics for the packer.
*/
struct packer_statistics vdo_get_packer_statistics(const struct packer *packer)
{
const struct packer_statistics *stats = &packer->statistics;
return (struct packer_statistics) {
.compressed_fragments_written = READ_ONCE(stats->compressed_fragments_written),
.compressed_blocks_written = READ_ONCE(stats->compressed_blocks_written),
.compressed_fragments_in_packer = READ_ONCE(stats->compressed_fragments_in_packer),
};
}
/**
* abort_packing() - Abort packing a data_vio.
* @data_vio: The data_vio to abort.
*/
static void abort_packing(struct data_vio *data_vio)
{
struct packer *packer = get_packer_from_data_vio(data_vio);
WRITE_ONCE(packer->statistics.compressed_fragments_in_packer,
packer->statistics.compressed_fragments_in_packer - 1);
write_data_vio(data_vio);
}
/**
* release_compressed_write_waiter() - Update a data_vio for which a successful compressed write
* has completed and send it on its way.
* @data_vio: The data_vio to release.
* @allocation: The allocation to which the compressed block was written.
*/
static void release_compressed_write_waiter(struct data_vio *data_vio,
struct allocation *allocation)
{
data_vio->new_mapped = (struct zoned_pbn) {
.pbn = allocation->pbn,
.zone = allocation->zone,
.state = data_vio->compression.slot + VDO_MAPPING_STATE_COMPRESSED_BASE,
};
vdo_share_compressed_write_lock(data_vio, allocation->lock);
update_metadata_for_data_vio_write(data_vio, allocation->lock);
}
/**
* finish_compressed_write() - Finish a compressed block write.
* @completion: The compressed write completion.
*
* This callback is registered in continue_after_allocation().
*/
static void finish_compressed_write(struct vdo_completion *completion)
{
struct data_vio *agent = as_data_vio(completion);
struct data_vio *client, *next;
assert_data_vio_in_allocated_zone(agent);
/*
* Process all the non-agent waiters first to ensure that the pbn lock can not be released
* until all of them have had a chance to journal their increfs.
*/
for (client = agent->compression.next_in_batch; client != NULL; client = next) {
next = client->compression.next_in_batch;
release_compressed_write_waiter(client, &agent->allocation);
}
completion->error_handler = handle_data_vio_error;
release_compressed_write_waiter(agent, &agent->allocation);
}
static void handle_compressed_write_error(struct vdo_completion *completion)
{
struct data_vio *agent = as_data_vio(completion);
struct allocation *allocation = &agent->allocation;
struct data_vio *client, *next;
if (vdo_requeue_completion_if_needed(completion, allocation->zone->thread_id))
return;
update_vio_error_stats(as_vio(completion),
"Completing compressed write vio for physical block %llu with error",
(unsigned long long) allocation->pbn);
for (client = agent->compression.next_in_batch; client != NULL; client = next) {
next = client->compression.next_in_batch;
write_data_vio(client);
}
/* Now that we've released the batch from the packer, forget the error and continue on. */
vdo_reset_completion(completion);
completion->error_handler = handle_data_vio_error;
write_data_vio(agent);
}
/**
* add_to_bin() - Put a data_vio in a specific packer_bin in which it will definitely fit.
* @bin: The bin in which to put the data_vio.
* @data_vio: The data_vio to add.
*/
static void add_to_bin(struct packer_bin *bin, struct data_vio *data_vio)
{
data_vio->compression.bin = bin;
data_vio->compression.slot = bin->slots_used;
bin->incoming[bin->slots_used++] = data_vio;
}
/**
* remove_from_bin() - Get the next data_vio whose compression has not been canceled from a bin.
* @packer: The packer.
* @bin: The bin from which to get a data_vio.
*
* Any canceled data_vios will be moved to the canceled bin.
* Return: An uncanceled data_vio from the bin or NULL if there are none.
*/
static struct data_vio *remove_from_bin(struct packer *packer, struct packer_bin *bin)
{
while (bin->slots_used > 0) {
struct data_vio *data_vio = bin->incoming[--bin->slots_used];
if (!advance_data_vio_compression_stage(data_vio).may_not_compress) {
data_vio->compression.bin = NULL;
return data_vio;
}
add_to_bin(packer->canceled_bin, data_vio);
}
/* The bin is now empty. */
bin->free_space = VDO_COMPRESSED_BLOCK_DATA_SIZE;
return NULL;
}
/**
* initialize_compressed_block() - Initialize a compressed block.
* @block: The compressed block to initialize.
* @size: The size of the agent's fragment.
*
* This method initializes the compressed block in the compressed write agent. Because the
* compressor already put the agent's compressed fragment at the start of the compressed block's
* data field, it needn't be copied. So all we need do is initialize the header and set the size of
* the agent's fragment.
*/
static void initialize_compressed_block(struct compressed_block *block, u16 size)
{
/*
* Make sure the block layout isn't accidentally changed by changing the length of the
* block header.
*/
BUILD_BUG_ON(sizeof(struct compressed_block_header) != COMPRESSED_BLOCK_1_0_SIZE);
block->header.version = vdo_pack_version_number(COMPRESSED_BLOCK_1_0);
block->header.sizes[0] = __cpu_to_le16(size);
}
/**
* pack_fragment() - Pack a data_vio's fragment into the compressed block in which it is already
* known to fit.
* @compression: The agent's compression_state to pack in to.
* @data_vio: The data_vio to pack.
* @offset: The offset into the compressed block at which to pack the fragment.
* @compressed_block: The compressed block which will be written out when batch is fully packed.
*
* Return: The new amount of space used.
*/
static block_size_t __must_check pack_fragment(struct compression_state *compression,
struct data_vio *data_vio,
block_size_t offset, slot_number_t slot,
struct compressed_block *block)
{
struct compression_state *to_pack = &data_vio->compression;
char *fragment = to_pack->block->data;
to_pack->next_in_batch = compression->next_in_batch;
compression->next_in_batch = data_vio;
to_pack->slot = slot;
block->header.sizes[slot] = __cpu_to_le16(to_pack->size);
memcpy(&block->data[offset], fragment, to_pack->size);
return (offset + to_pack->size);
}
/**
* compressed_write_end_io() - The bio_end_io for a compressed block write.
* @bio: The bio for the compressed write.
*/
static void compressed_write_end_io(struct bio *bio)
{
struct data_vio *data_vio = vio_as_data_vio(bio->bi_private);
vdo_count_completed_bios(bio);
set_data_vio_allocated_zone_callback(data_vio, finish_compressed_write);
continue_data_vio_with_error(data_vio, blk_status_to_errno(bio->bi_status));
}
/**
* write_bin() - Write out a bin.
* @packer: The packer.
* @bin: The bin to write.
*/
static void write_bin(struct packer *packer, struct packer_bin *bin)
{
int result;
block_size_t offset;
slot_number_t slot = 1;
struct compression_state *compression;
struct compressed_block *block;
struct data_vio *agent = remove_from_bin(packer, bin);
struct data_vio *client;
struct packer_statistics *stats;
if (agent == NULL)
return;
compression = &agent->compression;
compression->slot = 0;
block = compression->block;
initialize_compressed_block(block, compression->size);
offset = compression->size;
while ((client = remove_from_bin(packer, bin)) != NULL)
offset = pack_fragment(compression, client, offset, slot++, block);
/*
* If the batch contains only a single vio, then we save nothing by saving the compressed
* form. Continue processing the single vio in the batch.
*/
if (slot == 1) {
abort_packing(agent);
return;
}
if (slot < VDO_MAX_COMPRESSION_SLOTS) {
/* Clear out the sizes of the unused slots */
memset(&block->header.sizes[slot], 0,
(VDO_MAX_COMPRESSION_SLOTS - slot) * sizeof(__le16));
}
agent->vio.completion.error_handler = handle_compressed_write_error;
if (vdo_is_read_only(vdo_from_data_vio(agent))) {
continue_data_vio_with_error(agent, VDO_READ_ONLY);
return;
}
result = vio_reset_bio(&agent->vio, (char *) block, compressed_write_end_io,
REQ_OP_WRITE, agent->allocation.pbn);
if (result != VDO_SUCCESS) {
continue_data_vio_with_error(agent, result);
return;
}
/*
* Once the compressed write is submitted, the fragments are no longer in the packer, so
* update stats now.
*/
stats = &packer->statistics;
WRITE_ONCE(stats->compressed_fragments_in_packer,
(stats->compressed_fragments_in_packer - slot));
WRITE_ONCE(stats->compressed_fragments_written,
(stats->compressed_fragments_written + slot));
WRITE_ONCE(stats->compressed_blocks_written,
stats->compressed_blocks_written + 1);
vdo_submit_data_vio(agent);
}
/**
* add_data_vio_to_packer_bin() - Add a data_vio to a bin's incoming queue
* @packer: The packer.
* @bin: The bin to which to add the data_vio.
* @data_vio: The data_vio to add to the bin's queue.
*
* Adds a data_vio to a bin's incoming queue, handles logical space change, and calls physical
* space processor.
*/
static void add_data_vio_to_packer_bin(struct packer *packer, struct packer_bin *bin,
struct data_vio *data_vio)
{
/* If the selected bin doesn't have room, start a new batch to make room. */
if (bin->free_space < data_vio->compression.size)
write_bin(packer, bin);
add_to_bin(bin, data_vio);
bin->free_space -= data_vio->compression.size;
/* If we happen to exactly fill the bin, start a new batch. */
if ((bin->slots_used == VDO_MAX_COMPRESSION_SLOTS) ||
(bin->free_space == 0))
write_bin(packer, bin);
/* Now that we've finished changing the free space, restore the sort order. */
insert_in_sorted_list(packer, bin);
}
/**
* select_bin() - Select the bin that should be used to pack the compressed data in a data_vio with
* other data_vios.
* @packer: The packer.
* @data_vio: The data_vio.
*/
static struct packer_bin * __must_check select_bin(struct packer *packer,
struct data_vio *data_vio)
{
/*
* First best fit: select the bin with the least free space that has enough room for the
* compressed data in the data_vio.
*/
struct packer_bin *bin, *fullest_bin;
list_for_each_entry(bin, &packer->bins, list) {
if (bin->free_space >= data_vio->compression.size)
return bin;
}
/*
* None of the bins have enough space for the data_vio. We're not allowed to create new
* bins, so we have to overflow one of the existing bins. It's pretty intuitive to select
* the fullest bin, since that "wastes" the least amount of free space in the compressed
* block. But if the space currently used in the fullest bin is smaller than the compressed
* size of the incoming block, it seems wrong to force that bin to write when giving up on
* compressing the incoming data_vio would likewise "waste" the least amount of free space.
*/
fullest_bin = list_first_entry(&packer->bins, struct packer_bin, list);
if (data_vio->compression.size >=
(VDO_COMPRESSED_BLOCK_DATA_SIZE - fullest_bin->free_space))
return NULL;
/*
* The fullest bin doesn't have room, but writing it out and starting a new batch with the
* incoming data_vio will increase the packer's free space.
*/
return fullest_bin;
}
/**
* vdo_attempt_packing() - Attempt to rewrite the data in this data_vio as part of a compressed
* block.
* @data_vio: The data_vio to pack.
*/
void vdo_attempt_packing(struct data_vio *data_vio)
{
int result;
struct packer_bin *bin;
struct data_vio_compression_status status = get_data_vio_compression_status(data_vio);
struct packer *packer = get_packer_from_data_vio(data_vio);
assert_on_packer_thread(packer, __func__);
result = VDO_ASSERT((status.stage == DATA_VIO_COMPRESSING),
"attempt to pack data_vio not ready for packing, stage: %u",
status.stage);
if (result != VDO_SUCCESS)
return;
/*
* Increment whether or not this data_vio will be packed or not since abort_packing()
* always decrements the counter.
*/
WRITE_ONCE(packer->statistics.compressed_fragments_in_packer,
packer->statistics.compressed_fragments_in_packer + 1);
/*
* If packing of this data_vio is disallowed for administrative reasons, give up before
* making any state changes.
*/
if (!vdo_is_state_normal(&packer->state) ||
(data_vio->flush_generation < packer->flush_generation)) {
abort_packing(data_vio);
return;
}
/*
* The advance_data_vio_compression_stage() check here verifies that the data_vio is
* allowed to be compressed (if it has already been canceled, we'll fall out here). Once
* the data_vio is in the DATA_VIO_PACKING state, it must be guaranteed to be put in a bin
* before any more requests can be processed by the packer thread. Otherwise, a canceling
* data_vio could attempt to remove the canceled data_vio from the packer and fail to
* rendezvous with it. Thus, we must call select_bin() first to ensure that we will
* actually add the data_vio to a bin before advancing to the DATA_VIO_PACKING stage.
*/
bin = select_bin(packer, data_vio);
if ((bin == NULL) ||
(advance_data_vio_compression_stage(data_vio).stage != DATA_VIO_PACKING)) {
abort_packing(data_vio);
return;
}
add_data_vio_to_packer_bin(packer, bin, data_vio);
}
/**
* check_for_drain_complete() - Check whether the packer has drained.
* @packer: The packer.
*/
static void check_for_drain_complete(struct packer *packer)
{
if (vdo_is_state_draining(&packer->state) && (packer->canceled_bin->slots_used == 0))
vdo_finish_draining(&packer->state);
}
/**
* write_all_non_empty_bins() - Write out all non-empty bins on behalf of a flush or suspend.
* @packer: The packer being flushed.
*/
static void write_all_non_empty_bins(struct packer *packer)
{
struct packer_bin *bin;
list_for_each_entry(bin, &packer->bins, list)
write_bin(packer, bin);
/*
* We don't need to re-sort the bin here since this loop will make every bin have
* the same amount of free space, so every ordering is sorted.
*/
check_for_drain_complete(packer);
}
/**
* vdo_flush_packer() - Request that the packer flush asynchronously.
* @packer: The packer to flush.
*
* All bins with at least two compressed data blocks will be written out, and any solitary pending
* VIOs will be released from the packer. While flushing is in progress, any VIOs submitted to
* vdo_attempt_packing() will be continued immediately without attempting to pack them.
*/
void vdo_flush_packer(struct packer *packer)
{
assert_on_packer_thread(packer, __func__);
if (vdo_is_state_normal(&packer->state))
write_all_non_empty_bins(packer);
}
/**
* vdo_remove_lock_holder_from_packer() - Remove a lock holder from the packer.
* @completion: The data_vio which needs a lock held by a data_vio in the packer. The data_vio's
* compression.lock_holder field will point to the data_vio to remove.
*/
void vdo_remove_lock_holder_from_packer(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
struct packer *packer = get_packer_from_data_vio(data_vio);
struct data_vio *lock_holder;
struct packer_bin *bin;
slot_number_t slot;
assert_data_vio_in_packer_zone(data_vio);
lock_holder = vdo_forget(data_vio->compression.lock_holder);
bin = lock_holder->compression.bin;
VDO_ASSERT_LOG_ONLY((bin != NULL), "data_vio in packer has a bin");
slot = lock_holder->compression.slot;
bin->slots_used--;
if (slot < bin->slots_used) {
bin->incoming[slot] = bin->incoming[bin->slots_used];
bin->incoming[slot]->compression.slot = slot;
}
lock_holder->compression.bin = NULL;
lock_holder->compression.slot = 0;
if (bin != packer->canceled_bin) {
bin->free_space += lock_holder->compression.size;
insert_in_sorted_list(packer, bin);
}
abort_packing(lock_holder);
check_for_drain_complete(packer);
}
/**
* vdo_increment_packer_flush_generation() - Increment the flush generation in the packer.
* @packer: The packer.
*
* This will also cause the packer to flush so that any VIOs from previous generations will exit
* the packer.
*/
void vdo_increment_packer_flush_generation(struct packer *packer)
{
assert_on_packer_thread(packer, __func__);
packer->flush_generation++;
vdo_flush_packer(packer);
}
/**
* initiate_drain() - Initiate a drain.
*
* Implements vdo_admin_initiator_fn.
*/
static void initiate_drain(struct admin_state *state)
{
struct packer *packer = container_of(state, struct packer, state);
write_all_non_empty_bins(packer);
}
/**
* vdo_drain_packer() - Drain the packer by preventing any more VIOs from entering the packer and
* then flushing.
* @packer: The packer to drain.
* @completion: The completion to finish when the packer has drained.
*/
void vdo_drain_packer(struct packer *packer, struct vdo_completion *completion)
{
assert_on_packer_thread(packer, __func__);
vdo_start_draining(&packer->state, VDO_ADMIN_STATE_SUSPENDING, completion,
initiate_drain);
}
/**
* vdo_resume_packer() - Resume a packer which has been suspended.
* @packer: The packer to resume.
* @parent: The completion to finish when the packer has resumed.
*/
void vdo_resume_packer(struct packer *packer, struct vdo_completion *parent)
{
assert_on_packer_thread(packer, __func__);
vdo_continue_completion(parent, vdo_resume_if_quiescent(&packer->state));
}
static void dump_packer_bin(const struct packer_bin *bin, bool canceled)
{
if (bin->slots_used == 0)
/* Don't dump empty bins. */
return;
vdo_log_info(" %sBin slots_used=%u free_space=%zu",
(canceled ? "Canceled" : ""), bin->slots_used, bin->free_space);
/*
* FIXME: dump vios in bin->incoming? The vios should have been dumped from the vio pool.
* Maybe just dump their addresses so it's clear they're here?
*/
}
/**
* vdo_dump_packer() - Dump the packer.
* @packer: The packer.
*
* Context: dumps in a thread-unsafe fashion.
*/
void vdo_dump_packer(const struct packer *packer)
{
struct packer_bin *bin;
vdo_log_info("packer");
vdo_log_info(" flushGeneration=%llu state %s packer_bin_count=%llu",
(unsigned long long) packer->flush_generation,
vdo_get_admin_state_code(&packer->state)->name,
(unsigned long long) packer->size);
list_for_each_entry(bin, &packer->bins, list)
dump_packer_bin(bin, false);
dump_packer_bin(packer->canceled_bin, true);
}
Codebase Browser
linux