Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
 
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "ctree.h"
#include "volumes.h"
#include "extent_map.h"
#include "compression.h"
 
 
static struct kmem_cache *extent_map_cache;
 
int __init extent_map_init(void)
{
<------>extent_map_cache = kmem_cache_create("btrfs_extent_map",
<------><------><------>sizeof(struct extent_map), 0,
<------><------><------>SLAB_MEM_SPREAD, NULL);
<------>if (!extent_map_cache)
<------><------>return -ENOMEM;
<------>return 0;
}
 
void __cold extent_map_exit(void)
{
<------>kmem_cache_destroy(extent_map_cache);
}
 
/**
 * extent_map_tree_init - initialize extent map tree
 * @tree:		tree to initialize
 *
 * Initialize the extent tree @tree.  Should be called for each new inode
 * or other user of the extent_map interface.
 */
void extent_map_tree_init(struct extent_map_tree *tree)
{
<------>tree->map = RB_ROOT_CACHED;
<------>INIT_LIST_HEAD(&tree->modified_extents);
<------>rwlock_init(&tree->lock);
}
 
/**
 * alloc_extent_map - allocate new extent map structure
 *
 * Allocate a new extent_map structure.  The new structure is
 * returned with a reference count of one and needs to be
 * freed using free_extent_map()
 */
struct extent_map *alloc_extent_map(void)
{
<------>struct extent_map *em;
<------>em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
<------>if (!em)
<------><------>return NULL;
<------>RB_CLEAR_NODE(&em->rb_node);
<------>em->flags = 0;
<------>em->compress_type = BTRFS_COMPRESS_NONE;
<------>em->generation = 0;
<------>refcount_set(&em->refs, 1);
<------>INIT_LIST_HEAD(&em->list);
<------>return em;
}
 
/**
 * free_extent_map - drop reference count of an extent_map
 * @em:		extent map being released
 *
 * Drops the reference out on @em by one and free the structure
 * if the reference count hits zero.
 */
void free_extent_map(struct extent_map *em)
{
<------>if (!em)
<------><------>return;
<------>WARN_ON(refcount_read(&em->refs) == 0);
<------>if (refcount_dec_and_test(&em->refs)) {
<------><------>WARN_ON(extent_map_in_tree(em));
<------><------>WARN_ON(!list_empty(&em->list));
<------><------>if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
<------><------><------>kfree(em->map_lookup);
<------><------>kmem_cache_free(extent_map_cache, em);
<------>}
}
 
/* simple helper to do math around the end of an extent, handling wrap */
static u64 range_end(u64 start, u64 len)
{
<------>if (start + len < start)
<------><------>return (u64)-1;
<------>return start + len;
}
 
static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
{
<------>struct rb_node **p = &root->rb_root.rb_node;
<------>struct rb_node *parent = NULL;
<------>struct extent_map *entry = NULL;
<------>struct rb_node *orig_parent = NULL;
<------>u64 end = range_end(em->start, em->len);
<------>bool leftmost = true;
 
<------>while (*p) {
<------><------>parent = *p;
<------><------>entry = rb_entry(parent, struct extent_map, rb_node);
 
<------><------>if (em->start < entry->start) {
<------><------><------>p = &(*p)->rb_left;
<------><------>} else if (em->start >= extent_map_end(entry)) {
<------><------><------>p = &(*p)->rb_right;
<------><------><------>leftmost = false;
<------><------>} else {
<------><------><------>return -EEXIST;
<------><------>}
<------>}
 
<------>orig_parent = parent;
<------>while (parent && em->start >= extent_map_end(entry)) {
<------><------>parent = rb_next(parent);
<------><------>entry = rb_entry(parent, struct extent_map, rb_node);
<------>}
<------>if (parent)
<------><------>if (end > entry->start && em->start < extent_map_end(entry))
<------><------><------>return -EEXIST;
 
<------>parent = orig_parent;
<------>entry = rb_entry(parent, struct extent_map, rb_node);
<------>while (parent && em->start < entry->start) {
<------><------>parent = rb_prev(parent);
<------><------>entry = rb_entry(parent, struct extent_map, rb_node);
<------>}
<------>if (parent)
<------><------>if (end > entry->start && em->start < extent_map_end(entry))
<------><------><------>return -EEXIST;
 
<------>rb_link_node(&em->rb_node, orig_parent, p);
<------>rb_insert_color_cached(&em->rb_node, root, leftmost);
<------>return 0;
}
 
/*
 * search through the tree for an extent_map with a given offset.  If
 * it can't be found, try to find some neighboring extents
 */
static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
<------><------><------><------>     struct rb_node **prev_ret,
<------><------><------><------>     struct rb_node **next_ret)
{
<------>struct rb_node *n = root->rb_node;
<------>struct rb_node *prev = NULL;
<------>struct rb_node *orig_prev = NULL;
<------>struct extent_map *entry;
<------>struct extent_map *prev_entry = NULL;
 
<------>while (n) {
<------><------>entry = rb_entry(n, struct extent_map, rb_node);
<------><------>prev = n;
<------><------>prev_entry = entry;
 
<------><------>if (offset < entry->start)
<------><------><------>n = n->rb_left;
<------><------>else if (offset >= extent_map_end(entry))
<------><------><------>n = n->rb_right;
<------><------>else
<------><------><------>return n;
<------>}
 
<------>if (prev_ret) {
<------><------>orig_prev = prev;
<------><------>while (prev && offset >= extent_map_end(prev_entry)) {
<------><------><------>prev = rb_next(prev);
<------><------><------>prev_entry = rb_entry(prev, struct extent_map, rb_node);
<------><------>}
<------><------>*prev_ret = prev;
<------><------>prev = orig_prev;
<------>}
 
<------>if (next_ret) {
<------><------>prev_entry = rb_entry(prev, struct extent_map, rb_node);
<------><------>while (prev && offset < prev_entry->start) {
<------><------><------>prev = rb_prev(prev);
<------><------><------>prev_entry = rb_entry(prev, struct extent_map, rb_node);
<------><------>}
<------><------>*next_ret = prev;
<------>}
<------>return NULL;
}
 
/* check to see if two extent_map structs are adjacent and safe to merge */
static int mergable_maps(struct extent_map *prev, struct extent_map *next)
{
<------>if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
<------><------>return 0;
 
<------>/*
<------> * don't merge compressed extents, we need to know their
<------> * actual size
<------> */
<------>if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
<------><------>return 0;
 
<------>if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) ||
<------>    test_bit(EXTENT_FLAG_LOGGING, &next->flags))
<------><------>return 0;
 
<------>/*
<------> * We don't want to merge stuff that hasn't been written to the log yet
<------> * since it may not reflect exactly what is on disk, and that would be
<------> * bad.
<------> */
<------>if (!list_empty(&prev->list) || !list_empty(&next->list))
<------><------>return 0;
 
<------>ASSERT(next->block_start != EXTENT_MAP_DELALLOC &&
<------>       prev->block_start != EXTENT_MAP_DELALLOC);
 
<------>if (prev->map_lookup || next->map_lookup)
<------><------>ASSERT(test_bit(EXTENT_FLAG_FS_MAPPING, &prev->flags) &&
<------><------>       test_bit(EXTENT_FLAG_FS_MAPPING, &next->flags));
 
<------>if (extent_map_end(prev) == next->start &&
<------>    prev->flags == next->flags &&
<------>    prev->map_lookup == next->map_lookup &&
<------>    ((next->block_start == EXTENT_MAP_HOLE &&
<------>      prev->block_start == EXTENT_MAP_HOLE) ||
<------>     (next->block_start == EXTENT_MAP_INLINE &&
<------>      prev->block_start == EXTENT_MAP_INLINE) ||
<------>     (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
<------>      next->block_start == extent_map_block_end(prev)))) {
<------><------>return 1;
<------>}
<------>return 0;
}
 
static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
{
<------>struct extent_map *merge = NULL;
<------>struct rb_node *rb;
 
<------>/*
<------> * We can't modify an extent map that is in the tree and that is being
<------> * used by another task, as it can cause that other task to see it in
<------> * inconsistent state during the merging. We always have 1 reference for
<------> * the tree and 1 for this task (which is unpinning the extent map or
<------> * clearing the logging flag), so anything > 2 means it's being used by
<------> * other tasks too.
<------> */
<------>if (refcount_read(&em->refs) > 2)
<------><------>return;
 
<------>if (em->start != 0) {
<------><------>rb = rb_prev(&em->rb_node);
<------><------>if (rb)
<------><------><------>merge = rb_entry(rb, struct extent_map, rb_node);
<------><------>if (rb && mergable_maps(merge, em)) {
<------><------><------>em->start = merge->start;
<------><------><------>em->orig_start = merge->orig_start;
<------><------><------>em->len += merge->len;
<------><------><------>em->block_len += merge->block_len;
<------><------><------>em->block_start = merge->block_start;
<------><------><------>em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
<------><------><------>em->mod_start = merge->mod_start;
<------><------><------>em->generation = max(em->generation, merge->generation);
 
<------><------><------>rb_erase_cached(&merge->rb_node, &tree->map);
<------><------><------>RB_CLEAR_NODE(&merge->rb_node);
<------><------><------>free_extent_map(merge);
<------><------>}
<------>}
 
<------>rb = rb_next(&em->rb_node);
<------>if (rb)
<------><------>merge = rb_entry(rb, struct extent_map, rb_node);
<------>if (rb && mergable_maps(em, merge)) {
<------><------>em->len += merge->len;
<------><------>em->block_len += merge->block_len;
<------><------>rb_erase_cached(&merge->rb_node, &tree->map);
<------><------>RB_CLEAR_NODE(&merge->rb_node);
<------><------>em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
<------><------>em->generation = max(em->generation, merge->generation);
<------><------>free_extent_map(merge);
<------>}
}
 
/**
 * unpin_extent_cache - unpin an extent from the cache
 * @tree:	tree to unpin the extent in
 * @start:	logical offset in the file
 * @len:	length of the extent
 * @gen:	generation that this extent has been modified in
 *
 * Called after an extent has been written to disk properly.  Set the generation
 * to the generation that actually added the file item to the inode so we know
 * we need to sync this extent when we call fsync().
 */
int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
<------><------>       u64 gen)
{
<------>int ret = 0;
<------>struct extent_map *em;
<------>bool prealloc = false;
 
<------>write_lock(&tree->lock);
<------>em = lookup_extent_mapping(tree, start, len);
 
<------>WARN_ON(!em || em->start != start);
 
<------>if (!em)
<------><------>goto out;
 
<------>em->generation = gen;
<------>clear_bit(EXTENT_FLAG_PINNED, &em->flags);
<------>em->mod_start = em->start;
<------>em->mod_len = em->len;
 
<------>if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) {
<------><------>prealloc = true;
<------><------>clear_bit(EXTENT_FLAG_FILLING, &em->flags);
<------>}
 
<------>try_merge_map(tree, em);
 
<------>if (prealloc) {
<------><------>em->mod_start = em->start;
<------><------>em->mod_len = em->len;
<------>}
 
<------>free_extent_map(em);
out:
<------>write_unlock(&tree->lock);
<------>return ret;
 
}
 
void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
{
<------>clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
<------>if (extent_map_in_tree(em))
<------><------>try_merge_map(tree, em);
}
 
static inline void setup_extent_mapping(struct extent_map_tree *tree,
<------><------><------><------><------>struct extent_map *em,
<------><------><------><------><------>int modified)
{
<------>refcount_inc(&em->refs);
<------>em->mod_start = em->start;
<------>em->mod_len = em->len;
 
<------>if (modified)
<------><------>list_move(&em->list, &tree->modified_extents);
<------>else
<------><------>try_merge_map(tree, em);
}
 
static void extent_map_device_set_bits(struct extent_map *em, unsigned bits)
{
<------>struct map_lookup *map = em->map_lookup;
<------>u64 stripe_size = em->orig_block_len;
<------>int i;
 
<------>for (i = 0; i < map->num_stripes; i++) {
<------><------>struct btrfs_bio_stripe *stripe = &map->stripes[i];
<------><------>struct btrfs_device *device = stripe->dev;
 
<------><------>set_extent_bits_nowait(&device->alloc_state, stripe->physical,
<------><------><------><------> stripe->physical + stripe_size - 1, bits);
<------>}
}
 
static void extent_map_device_clear_bits(struct extent_map *em, unsigned bits)
{
<------>struct map_lookup *map = em->map_lookup;
<------>u64 stripe_size = em->orig_block_len;
<------>int i;
 
<------>for (i = 0; i < map->num_stripes; i++) {
<------><------>struct btrfs_bio_stripe *stripe = &map->stripes[i];
<------><------>struct btrfs_device *device = stripe->dev;
 
<------><------>__clear_extent_bit(&device->alloc_state, stripe->physical,
<------><------><------><------>   stripe->physical + stripe_size - 1, bits,
<------><------><------><------>   0, 0, NULL, GFP_NOWAIT, NULL);
<------>}
}
 
/**
 * add_extent_mapping - add new extent map to the extent tree
 * @tree:	tree to insert new map in
 * @em:		map to insert
 *
 * Insert @em into @tree or perform a simple forward/backward merge with
 * existing mappings.  The extent_map struct passed in will be inserted
 * into the tree directly, with an additional reference taken, or a
 * reference dropped if the merge attempt was successful.
 */
int add_extent_mapping(struct extent_map_tree *tree,
<------><------>       struct extent_map *em, int modified)
{
<------>int ret = 0;
 
<------>lockdep_assert_held_write(&tree->lock);
 
<------>ret = tree_insert(&tree->map, em);
<------>if (ret)
<------><------>goto out;
 
<------>setup_extent_mapping(tree, em, modified);
<------>if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) {
<------><------>extent_map_device_set_bits(em, CHUNK_ALLOCATED);
<------><------>extent_map_device_clear_bits(em, CHUNK_TRIMMED);
<------>}
out:
<------>return ret;
}
 
static struct extent_map *
__lookup_extent_mapping(struct extent_map_tree *tree,
<------><------><------>u64 start, u64 len, int strict)
{
<------>struct extent_map *em;
<------>struct rb_node *rb_node;
<------>struct rb_node *prev = NULL;
<------>struct rb_node *next = NULL;
<------>u64 end = range_end(start, len);
 
<------>rb_node = __tree_search(&tree->map.rb_root, start, &prev, &next);
<------>if (!rb_node) {
<------><------>if (prev)
<------><------><------>rb_node = prev;
<------><------>else if (next)
<------><------><------>rb_node = next;
<------><------>else
<------><------><------>return NULL;
<------>}
 
<------>em = rb_entry(rb_node, struct extent_map, rb_node);
 
<------>if (strict && !(end > em->start && start < extent_map_end(em)))
<------><------>return NULL;
 
<------>refcount_inc(&em->refs);
<------>return em;
}
 
/**
 * lookup_extent_mapping - lookup extent_map
 * @tree:	tree to lookup in
 * @start:	byte offset to start the search
 * @len:	length of the lookup range
 *
 * Find and return the first extent_map struct in @tree that intersects the
 * [start, len] range.  There may be additional objects in the tree that
 * intersect, so check the object returned carefully to make sure that no
 * additional lookups are needed.
 */
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
<------><------><------><------><------> u64 start, u64 len)
{
<------>return __lookup_extent_mapping(tree, start, len, 1);
}
 
/**
 * search_extent_mapping - find a nearby extent map
 * @tree:	tree to lookup in
 * @start:	byte offset to start the search
 * @len:	length of the lookup range
 *
 * Find and return the first extent_map struct in @tree that intersects the
 * [start, len] range.
 *
 * If one can't be found, any nearby extent may be returned
 */
struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
<------><------><------><------><------> u64 start, u64 len)
{
<------>return __lookup_extent_mapping(tree, start, len, 0);
}
 
/**
 * remove_extent_mapping - removes an extent_map from the extent tree
 * @tree:	extent tree to remove from
 * @em:		extent map being removed
 *
 * Removes @em from @tree.  No reference counts are dropped, and no checks
 * are done to see if the range is in use
 */
void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
{
<------>WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
<------>rb_erase_cached(&em->rb_node, &tree->map);
<------>if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
<------><------>list_del_init(&em->list);
<------>if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
<------><------>extent_map_device_clear_bits(em, CHUNK_ALLOCATED);
<------>RB_CLEAR_NODE(&em->rb_node);
}
 
void replace_extent_mapping(struct extent_map_tree *tree,
<------><------><------>    struct extent_map *cur,
<------><------><------>    struct extent_map *new,
<------><------><------>    int modified)
{
<------>WARN_ON(test_bit(EXTENT_FLAG_PINNED, &cur->flags));
<------>ASSERT(extent_map_in_tree(cur));
<------>if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags))
<------><------>list_del_init(&cur->list);
<------>rb_replace_node_cached(&cur->rb_node, &new->rb_node, &tree->map);
<------>RB_CLEAR_NODE(&cur->rb_node);
 
<------>setup_extent_mapping(tree, new, modified);
}
 
static struct extent_map *next_extent_map(struct extent_map *em)
{
<------>struct rb_node *next;
 
<------>next = rb_next(&em->rb_node);
<------>if (!next)
<------><------>return NULL;
<------>return container_of(next, struct extent_map, rb_node);
}
 
static struct extent_map *prev_extent_map(struct extent_map *em)
{
<------>struct rb_node *prev;
 
<------>prev = rb_prev(&em->rb_node);
<------>if (!prev)
<------><------>return NULL;
<------>return container_of(prev, struct extent_map, rb_node);
}
 
/*
 * Helper for btrfs_get_extent.  Given an existing extent in the tree,
 * the existing extent is the nearest extent to map_start,
 * and an extent that you want to insert, deal with overlap and insert
 * the best fitted new extent into the tree.
 */
static noinline int merge_extent_mapping(struct extent_map_tree *em_tree,
<------><------><------><------><------> struct extent_map *existing,
<------><------><------><------><------> struct extent_map *em,
<------><------><------><------><------> u64 map_start)
{
<------>struct extent_map *prev;
<------>struct extent_map *next;
<------>u64 start;
<------>u64 end;
<------>u64 start_diff;
 
<------>BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
 
<------>if (existing->start > map_start) {
<------><------>next = existing;
<------><------>prev = prev_extent_map(next);
<------>} else {
<------><------>prev = existing;
<------><------>next = next_extent_map(prev);
<------>}
 
<------>start = prev ? extent_map_end(prev) : em->start;
<------>start = max_t(u64, start, em->start);
<------>end = next ? next->start : extent_map_end(em);
<------>end = min_t(u64, end, extent_map_end(em));
<------>start_diff = start - em->start;
<------>em->start = start;
<------>em->len = end - start;
<------>if (em->block_start < EXTENT_MAP_LAST_BYTE &&
<------>    !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
<------><------>em->block_start += start_diff;
<------><------>em->block_len = em->len;
<------>}
<------>return add_extent_mapping(em_tree, em, 0);
}
 
/**
 * btrfs_add_extent_mapping - add extent mapping into em_tree
 * @fs_info - used for tracepoint
 * @em_tree - the extent tree into which we want to insert the extent mapping
 * @em_in   - extent we are inserting
 * @start   - start of the logical range btrfs_get_extent() is requesting
 * @len     - length of the logical range btrfs_get_extent() is requesting
 *
 * Note that @em_in's range may be different from [start, start+len),
 * but they must be overlapped.
 *
 * Insert @em_in into @em_tree. In case there is an overlapping range, handle
 * the -EEXIST by either:
 * a) Returning the existing extent in @em_in if @start is within the
 *    existing em.
 * b) Merge the existing extent with @em_in passed in.
 *
 * Return 0 on success, otherwise -EEXIST.
 *
 */
int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
<------><------><------>     struct extent_map_tree *em_tree,
<------><------><------>     struct extent_map **em_in, u64 start, u64 len)
{
<------>int ret;
<------>struct extent_map *em = *em_in;
 
<------>ret = add_extent_mapping(em_tree, em, 0);
<------>/* it is possible that someone inserted the extent into the tree
<------> * while we had the lock dropped.  It is also possible that
<------> * an overlapping map exists in the tree
<------> */
<------>if (ret == -EEXIST) {
<------><------>struct extent_map *existing;
 
<------><------>ret = 0;
 
<------><------>existing = search_extent_mapping(em_tree, start, len);
 
<------><------>trace_btrfs_handle_em_exist(fs_info, existing, em, start, len);
 
<------><------>/*
<------><------> * existing will always be non-NULL, since there must be
<------><------> * extent causing the -EEXIST.
<------><------> */
<------><------>if (start >= existing->start &&
<------><------>    start < extent_map_end(existing)) {
<------><------><------>free_extent_map(em);
<------><------><------>*em_in = existing;
<------><------><------>ret = 0;
<------><------>} else {
<------><------><------>u64 orig_start = em->start;
<------><------><------>u64 orig_len = em->len;
 
<------><------><------>/*
<------><------><------> * The existing extent map is the one nearest to
<------><------><------> * the [start, start + len) range which overlaps
<------><------><------> */
<------><------><------>ret = merge_extent_mapping(em_tree, existing,
<------><------><------><------><------><------>   em, start);
<------><------><------>if (ret) {
<------><------><------><------>free_extent_map(em);
<------><------><------><------>*em_in = NULL;
<------><------><------><------>WARN_ONCE(ret,
"unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n",
<------><------><------><------><------>  ret, existing->start, existing->len,
<------><------><------><------><------>  orig_start, orig_len);
<------><------><------>}
<------><------><------>free_extent_map(existing);
<------><------>}
<------>}
 
<------>ASSERT(ret == 0 || ret == -EEXIST);
<------>return ret;
}