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amap_smart.c
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/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/************************************************************************/
/* */
/* PROJECT : exFAT & FAT12/16/32 File System */
/* FILE : amap_smart.c */
/* PURPOSE : FAT32 Smart allocation code for sdFAT */
/* */
/*----------------------------------------------------------------------*/
/* NOTES */
/* */
/* */
/************************************************************************/
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include "sdfat.h"
#include "core.h"
#include "amap_smart.h"
/* AU list related functions */
static inline void amap_list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
/* Will be used to check if the entry is a single entry(selected) */
entry->prev = NULL;
entry->next = NULL;
}
static inline int amap_insert_to_list(AU_INFO_T *au, struct slist_head *shead)
{
struct slist_head *entry = &au->shead;
ASSERT(!entry->head);
entry->next = shead->next;
entry->head = shead;
shead->next = entry;
return 0;
}
static inline int amap_remove_from_list(AU_INFO_T *au, struct slist_head *shead)
{
struct slist_head *entry = &au->shead;
struct slist_head *iter;
BUG_ON(entry->head != shead);
iter = shead;
while (iter->next) {
if (iter->next == entry) {
// iter->next = iter->next->next
iter->next = entry->next;
entry->next = NULL;
entry->head = NULL;
return 0;
}
iter = iter->next;
}
BUG_ON("Not reachable");
}
/* Full-linear serach => Find AU with max. number of fclu */
static inline AU_INFO_T *amap_find_hot_au_largest(struct slist_head *shead)
{
struct slist_head *iter;
uint16_t max_fclu = 0;
AU_INFO_T *entry, *ret = NULL;
ASSERT(shead->head == shead); /* Singly-list condition */
ASSERT(shead->next != shead);
iter = shead->next;
while (iter) {
entry = list_entry(iter, AU_INFO_T, shead);
if (entry->free_clusters > max_fclu) {
max_fclu = entry->free_clusters;
ret = entry;
}
iter = iter->next;
}
return ret;
}
/* Find partially used AU with max. number of fclu.
* If there is no partial AU available, pick a clean one
*/
static inline AU_INFO_T *amap_find_hot_au_partial(AMAP_T *amap)
{
struct slist_head *iter;
uint16_t max_fclu = 0;
AU_INFO_T *entry, *ret = NULL;
iter = &amap->slist_hot;
ASSERT(iter->head == iter); /* Singly-list condition */
ASSERT(iter->next != iter);
iter = iter->next;
while (iter) {
entry = list_entry(iter, AU_INFO_T, shead);
if (entry->free_clusters > max_fclu) {
if (entry->free_clusters < amap->clusters_per_au) {
max_fclu = entry->free_clusters;
ret = entry;
} else {
if (!ret)
ret = entry;
}
}
iter = iter->next;
}
return ret;
}
/*
* Size-base AU management functions
*/
/*
* Add au into cold AU MAP
* au: an isolated (not in a list) AU data structure
*/
int amap_add_cold_au(AMAP_T *amap, AU_INFO_T *au)
{
FCLU_NODE_T *fclu_node = NULL;
/* Check if a single entry */
BUG_ON(au->head.prev);
/* Ignore if the au is full */
if (!au->free_clusters)
return 0;
/* Find entry */
fclu_node = NODE(au->free_clusters, amap);
/* Insert to the list */
list_add_tail(&(au->head), &(fclu_node->head));
/* Update fclu_hint (Increase) */
if (au->free_clusters > amap->fclu_hint)
amap->fclu_hint = au->free_clusters;
return 0;
}
/*
* Remove an AU from AU MAP
*/
int amap_remove_cold_au(AMAP_T *amap, AU_INFO_T *au)
{
struct list_head *prev = au->head.prev;
/* Single entries are not managed in lists */
if (!prev) {
BUG_ON(au->free_clusters > 0);
return 0;
}
/* remove from list */
amap_list_del(&(au->head));
return 0;
}
/* "Find" best fit AU
* returns NULL if there is no AU w/ enough free space.
*
* This function doesn't change AU status.
* The caller should call amap_remove_cold_au() if needed.
*/
AU_INFO_T *amap_find_cold_au_bestfit(AMAP_T *amap, uint16_t free_clusters)
{
AU_INFO_T *au = NULL;
FCLU_NODE_T *fclu_iter;
if (free_clusters <= 0 || free_clusters > amap->clusters_per_au) {
EMSG("AMAP: amap_find_cold_au_bestfit / unexpected arg. (%d)\n",
free_clusters);
return NULL;
}
fclu_iter = NODE(free_clusters, amap);
if (amap->fclu_hint < free_clusters) {
/* There is no AUs with enough free_clusters */
return NULL;
}
/* Naive Hash management (++) */
do {
if (!list_empty(&fclu_iter->head)) {
struct list_head *first = fclu_iter->head.next;
au = list_entry(first, AU_INFO_T, head);
break;
}
fclu_iter++;
} while (fclu_iter < (amap->fclu_nodes + amap->clusters_per_au));
// BUG_ON(au->free_clusters < 0);
BUG_ON(au && (au->free_clusters > amap->clusters_per_au));
return au;
}
/* "Pop" best fit AU
*
* returns NULL if there is no AU w/ enough free space.
* The returned AU will not be in the list anymore.
*/
AU_INFO_T *amap_pop_cold_au_bestfit(AMAP_T *amap, uint16_t free_clusters)
{
/* Naive implementation */
AU_INFO_T *au;
au = amap_find_cold_au_bestfit(amap, free_clusters);
if (au)
amap_remove_cold_au(amap, au);
return au;
}
/* Pop the AU with the largest free space
*
* search from 'start_fclu' to 0
* (target freecluster : -1 for each step)
* start_fclu = 0 means to search from the max. value
*/
AU_INFO_T *amap_pop_cold_au_largest(AMAP_T *amap, uint16_t start_fclu)
{
AU_INFO_T *au = NULL;
FCLU_NODE_T *fclu_iter;
if (!start_fclu)
start_fclu = amap->clusters_per_au;
if (start_fclu > amap->clusters_per_au)
start_fclu = amap->clusters_per_au;
/* Use hint (search start point) */
if (amap->fclu_hint < start_fclu)
fclu_iter = NODE(amap->fclu_hint, amap);
else
fclu_iter = NODE(start_fclu, amap);
/* Naive Hash management */
do {
if (!list_empty(&fclu_iter->head)) {
struct list_head *first = fclu_iter->head.next;
au = list_entry(first, AU_INFO_T, head);
// BUG_ON((au < amap->entries) || ((amap->entries + amap->n_au) <= au));
amap_list_del(first);
// (Hint) Possible maximum value of free clusters (among cold)
/* if it wasn't the whole search, don't update fclu_hint */
if (start_fclu == amap->clusters_per_au)
amap->fclu_hint = au->free_clusters;
break;
}
fclu_iter--;
} while (amap->fclu_nodes <= fclu_iter);
return au;
}
/*
* ===============================================
* Allocation Map related functions
* ===============================================
*/
/* Create AMAP related data structure (mount time) */
int amap_create(struct super_block *sb, u32 pack_ratio, u32 sect_per_au, u32 hidden_sect)
{
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
AMAP_T *amap;
int total_used_clusters;
int n_au_table = 0;
int i, i_clu, i_au;
int i_au_root = -1, i_au_hot_from = INT_MAX;
u32 misaligned_sect = hidden_sect;
u64 tmp;
BUG_ON(!fsi->bd_opened);
if (fsi->amap)
return -EEXIST;
/* Check conditions */
if (fsi->vol_type != FAT32) {
sdfat_msg(sb, KERN_ERR, "smart allocation is only available "
"with fat32-fs");
return -ENOTSUPP;
}
if (fsi->num_sectors < AMAP_MIN_SUPPORT_SECTORS) {
sdfat_msg(sb, KERN_ERR, "smart allocation is only available "
"with sectors above %d", AMAP_MIN_SUPPORT_SECTORS);
return -ENOTSUPP;
}
/* AU size must be a multiple of clu_size */
if ((sect_per_au <= 0) || (sect_per_au & (fsi->sect_per_clus - 1))) {
sdfat_msg(sb, KERN_ERR,
"invalid AU size (sect_per_au : %u, "
"sect_per_clus : %u) "
"please re-format for performance.",
sect_per_au, fsi->sect_per_clus);
return -EINVAL;
}
/* the start sector of this partition must be a multiple of clu_size */
if (misaligned_sect & (fsi->sect_per_clus - 1)) {
sdfat_msg(sb, KERN_ERR,
"misaligned part (start sect : %u, "
"sect_per_clus : %u) "
"please re-format for performance.",
misaligned_sect, fsi->sect_per_clus);
return -EINVAL;
}
/* data start sector must be a multiple of clu_size */
if (fsi->data_start_sector & (fsi->sect_per_clus - 1)) {
sdfat_msg(sb, KERN_ERR,
"misaligned data area (start sect : %llu, "
"sect_per_clus : %u) "
"please re-format for performance.",
fsi->data_start_sector, fsi->sect_per_clus);
return -EINVAL;
}
misaligned_sect &= (sect_per_au - 1);
/* Allocate data structrues */
amap = kzalloc(sizeof(AMAP_T), GFP_NOIO);
if (!amap)
return -ENOMEM;
amap->sb = sb;
tmp = fsi->num_sectors + misaligned_sect + sect_per_au - 1;
do_div(tmp, sect_per_au);
amap->n_au = tmp;
amap->n_clean_au = 0;
amap->n_full_au = 0;
/* Reflect block-partition align first,
* then partition-data_start align
*/
amap->clu_align_bias = (misaligned_sect / fsi->sect_per_clus);
amap->clu_align_bias += (fsi->data_start_sector >> fsi->sect_per_clus_bits) - CLUS_BASE;
amap->clusters_per_au = sect_per_au / fsi->sect_per_clus;
/* That is,
* the size of cluster is at least 4KB if the size of AU is 4MB
*/
if (amap->clusters_per_au > MAX_CLU_PER_AU) {
sdfat_log_msg(sb, KERN_INFO,
"too many clusters per AU (clus/au:%d > %d).",
amap->clusters_per_au,
MAX_CLU_PER_AU);
}
/* is it needed? why here? */
// set_sb_dirty(sb);
spin_lock_init(&amap->amap_lock);
amap->option.packing_ratio = pack_ratio;
amap->option.au_size = sect_per_au;
amap->option.au_align_factor = hidden_sect;
/* Allocate AU info table */
n_au_table = (amap->n_au + N_AU_PER_TABLE - 1) / N_AU_PER_TABLE;
amap->au_table = kmalloc(sizeof(AU_INFO_T *) * n_au_table, GFP_NOIO);
if (!amap->au_table) {
sdfat_msg(sb, KERN_ERR,
"failed to alloc amap->au_table\n");
kfree(amap);
return -ENOMEM;
}
for (i = 0; i < n_au_table; i++)
amap->au_table[i] = (AU_INFO_T *)get_zeroed_page(GFP_NOIO);
/* Allocate buckets indexed by # of free clusters */
amap->fclu_order = get_order(sizeof(FCLU_NODE_T) * amap->clusters_per_au);
// XXX: amap->clusters_per_au limitation is 512 (w/ 8 byte list_head)
sdfat_log_msg(sb, KERN_INFO, "page orders for AU nodes : %d "
"(clus_per_au : %d, node_size : %lu)",
amap->fclu_order,
amap->clusters_per_au,
(unsigned long)sizeof(FCLU_NODE_T));
if (!amap->fclu_order)
amap->fclu_nodes = (FCLU_NODE_T *)get_zeroed_page(GFP_NOIO);
else
amap->fclu_nodes = vzalloc(PAGE_SIZE << amap->fclu_order);
amap->fclu_hint = amap->clusters_per_au;
/* Hot AU list, ignored AU list */
amap->slist_hot.next = NULL;
amap->slist_hot.head = &amap->slist_hot;
amap->total_fclu_hot = 0;
amap->slist_ignored.next = NULL;
amap->slist_ignored.head = &amap->slist_ignored;
/* Strategy related vars. */
amap->cur_cold.au = NULL;
amap->cur_hot.au = NULL;
amap->n_need_packing = 0;
/* Build AMAP info */
total_used_clusters = 0; // Count # of used clusters
i_au_root = i_AU_of_CLU(amap, fsi->root_dir);
i_au_hot_from = amap->n_au - (SMART_ALLOC_N_HOT_AU - 1);
for (i = 0; i < amap->clusters_per_au; i++)
INIT_LIST_HEAD(&amap->fclu_nodes[i].head);
/*
* Thanks to kzalloc()
* amap->entries[i_au].free_clusters = 0;
* amap->entries[i_au].head.prev = NULL;
* amap->entries[i_au].head.next = NULL;
*/
/* Parse FAT table */
for (i_clu = CLUS_BASE; i_clu < fsi->num_clusters; i_clu++) {
u32 clu_data;
AU_INFO_T *au;
if (fat_ent_get(sb, i_clu, &clu_data)) {
sdfat_msg(sb, KERN_ERR,
"failed to read fat entry(%u)\n", i_clu);
goto free_and_eio;
}
if (IS_CLUS_FREE(clu_data)) {
au = GET_AU(amap, i_AU_of_CLU(amap, i_clu));
au->free_clusters++;
} else
total_used_clusters++;
}
/* Build AU list */
for (i_au = 0; i_au < amap->n_au; i_au++) {
AU_INFO_T *au = GET_AU(amap, i_au);
au->idx = i_au;
BUG_ON(au->free_clusters > amap->clusters_per_au);
if (au->free_clusters == amap->clusters_per_au)
amap->n_clean_au++;
else if (au->free_clusters == 0)
amap->n_full_au++;
/* If hot, insert to the hot list */
if (i_au >= i_au_hot_from) {
amap_add_hot_au(amap, au);
amap->total_fclu_hot += au->free_clusters;
} else if (i_au != i_au_root || SMART_ALLOC_N_HOT_AU == 0) {
/* Otherwise, insert to the free cluster hash */
amap_add_cold_au(amap, au);
}
}
/* Hot list -> (root) -> (last) -> (last - 1) -> ... */
if (i_au_root >= 0 && SMART_ALLOC_N_HOT_AU > 0) {
amap_add_hot_au(amap, GET_AU(amap, i_au_root));
amap->total_fclu_hot += GET_AU(amap, i_au_root)->free_clusters;
}
fsi->amap = amap;
fsi->used_clusters = total_used_clusters;
sdfat_msg(sb, KERN_INFO,
"AMAP: Smart allocation enabled (opt : %u / %u / %u)",
amap->option.au_size, amap->option.au_align_factor,
amap->option.packing_ratio);
/* Debug purpose - check */
//{
//u32 used_clusters;
//fat_count_used_clusters(sb, &used_clusters)
//ASSERT(used_clusters == total_used_clusters);
//}
return 0;
free_and_eio:
if (amap) {
if (amap->au_table) {
for (i = 0; i < n_au_table; i++)
free_page((unsigned long)amap->au_table[i]);
kfree(amap->au_table);
}
if (amap->fclu_nodes) {
if (!amap->fclu_order)
free_page((unsigned long)amap->fclu_nodes);
else
vfree(amap->fclu_nodes);
}
kfree(amap);
}
return -EIO;
}
/* Free AMAP related structure */
void amap_destroy(struct super_block *sb)
{
AMAP_T *amap = SDFAT_SB(sb)->fsi.amap;
int n_au_table;
if (!amap)
return;
DMSG("%s\n", __func__);
n_au_table = (amap->n_au + N_AU_PER_TABLE - 1) / N_AU_PER_TABLE;
if (amap->au_table) {
int i;
for (i = 0; i < n_au_table; i++)
free_page((unsigned long)amap->au_table[i]);
kfree(amap->au_table);
}
if (!amap->fclu_order)
free_page((unsigned long)amap->fclu_nodes);
else
vfree(amap->fclu_nodes);
kfree(amap);
SDFAT_SB(sb)->fsi.amap = NULL;
}
/*
* Check status of FS
* and change destination if needed to disable AU-aligned alloc.
* (from ALLOC_COLD_ALIGNED to ALLOC_COLD_SEQ)
*/
static inline int amap_update_dest(AMAP_T *amap, int ori_dest)
{
FS_INFO_T *fsi = &(SDFAT_SB(amap->sb)->fsi);
int n_partial_au, n_partial_freeclus;
if (ori_dest != ALLOC_COLD_ALIGNED)
return ori_dest;
/* # of partial AUs and # of clusters in those AUs */
n_partial_au = amap->n_au - amap->n_clean_au - amap->n_full_au;
n_partial_freeclus = fsi->num_clusters - fsi->used_clusters -
amap->clusters_per_au * amap->n_clean_au;
/* Status of AUs : Full / Partial / Clean
* If there are many partial (and badly fragmented) AUs,
* the throughput will decrease extremly.
*
* The follow code will treat those worst cases.
*/
/* XXX: AMAP heuristics */
if ((amap->n_clean_au * 50 <= amap->n_au) &&
(n_partial_freeclus*2) < (n_partial_au*amap->clusters_per_au)) {
/* If clean AUs are fewer than 2% of n_au (80 AUs per 16GB)
* and fragment ratio is more than 2 (AVG free_clusters=half AU)
*
* disable clean-first allocation
* enable VFAT-like sequential allocation
*/
return ALLOC_COLD_SEQ;
}
return ori_dest;
}
#define PACKING_SOFTLIMIT (amap->option.packing_ratio)
#define PACKING_HARDLIMIT (amap->option.packing_ratio * 4)
/*
* Pick a packing AU if needed.
* Otherwise just return NULL
*
* This function includes some heuristics.
*/
static inline AU_INFO_T *amap_get_packing_au(AMAP_T *amap, int dest, int num_to_wb, int *clu_to_skip)
{
AU_INFO_T *au = NULL;
if (dest == ALLOC_COLD_PACKING) {
/* ALLOC_COLD_PACKING:
* Packing-first mode for defrag.
* Optimized to save clean AU
*
* 1) best-fit AU
* 2) Smallest AU (w/ minimum free clusters)
*/
if (num_to_wb >= amap->clusters_per_au)
num_to_wb = num_to_wb % amap->clusters_per_au;
/* 이거 주석처리하면, AU size 딱 맞을때는 clean, 나머지는 작은거부터 */
if (num_to_wb == 0)
num_to_wb = 1; // Don't use clean AUs
au = amap_find_cold_au_bestfit(amap, num_to_wb);
if (au && au->free_clusters == amap->clusters_per_au && num_to_wb > 1) {
/* if au is clean then get a new partial one */
au = amap_find_cold_au_bestfit(amap, 1);
}
if (au) {
amap->n_need_packing = 0;
amap_remove_cold_au(amap, au);
return au;
}
}
/* Heuristic packing:
* This will improve QoS greatly.
*
* Count # of AU_ALIGNED allocation.
* If the number exceeds the specific threshold,
* allocate on a partial AU or generate random I/O.
*/
if ((PACKING_SOFTLIMIT > 0) &&
(amap->n_need_packing >= PACKING_SOFTLIMIT) &&
(num_to_wb < (int)amap->clusters_per_au)) {
/* Best-fit packing:
* If num_to_wb (expected number to be allocated) is smaller
* than AU_SIZE, find a best-fit AU.
*/
/* Back margin (heuristics) */
if (num_to_wb < amap->clusters_per_au / 4)
num_to_wb = amap->clusters_per_au / 4;
au = amap_find_cold_au_bestfit(amap, num_to_wb);
if (au != NULL) {
amap_remove_cold_au(amap, au);
MMSG("AMAP: packing (cnt: %d) / softlimit, "
"best-fit (num_to_wb: %d))\n",
amap->n_need_packing, num_to_wb);
if (au->free_clusters > num_to_wb) { // Best-fit search: if 문 무조건 hit
*clu_to_skip = au->free_clusters - num_to_wb;
/* otherwise don't skip */
}
amap->n_need_packing = 0;
return au;
}
}
if ((PACKING_HARDLIMIT) && amap->n_need_packing >= PACKING_HARDLIMIT) {
/* Compulsory SLC flushing:
* If there was no chance to do best-fit packing
* and the # of AU-aligned allocation exceeds HARD threshold,
* then pick a clean AU and generate a compulsory random I/O.
*/
au = amap_pop_cold_au_largest(amap, amap->clusters_per_au);
if (au) {
MMSG("AMAP: packing (cnt: %d) / hard-limit, largest)\n",
amap->n_need_packing);
if (au->free_clusters >= 96) {
*clu_to_skip = au->free_clusters / 2;
MMSG("AMAP: cluster idx re-position\n");
}
amap->n_need_packing = 0;
return au;
}
}
/* Update # of clean AU allocation */
amap->n_need_packing++;
return NULL;
}
/* Pick a target AU:
* This function should be called
* only if there are one or more free clusters in the bdev.
*/
TARGET_AU_T *amap_get_target_au(AMAP_T *amap, int dest, int num_to_wb)
{
int loop_count = 0;
retry:
if (++loop_count >= 3) {
/* No space available (or AMAP consistency error)
* This could happen because of the ignored AUs but not likely
* (because the defrag daemon will not work if there is no enough space)
*/
BUG_ON(amap->slist_ignored.next == NULL);
return NULL;
}
/* Hot clusters (DIR) */
if (dest == ALLOC_HOT) {
/* Working hot AU exist? */
if (amap->cur_hot.au == NULL || amap->cur_hot.au->free_clusters == 0) {
AU_INFO_T *au;
if (amap->total_fclu_hot == 0) {
/* No more hot AU avaialbe */
dest = ALLOC_COLD;
goto retry;
}
au = amap_find_hot_au_partial(amap);
BUG_ON(au == NULL);
BUG_ON(au->free_clusters <= 0);
amap->cur_hot.au = au;
amap->cur_hot.idx = 0;
amap->cur_hot.clu_to_skip = 0;
}
/* Now allocate on a hot AU */
return &amap->cur_hot;
}
/* Cold allocation:
* If amap->cur_cold.au has one or more free cluster(s),
* then just return amap->cur_cold
*/
if ((!amap->cur_cold.au)
|| (amap->cur_cold.idx == amap->clusters_per_au)
|| (amap->cur_cold.au->free_clusters == 0)) {
AU_INFO_T *au = NULL;
const AU_INFO_T *old_au = amap->cur_cold.au;
int n_clu_to_skip = 0;
if (old_au) {
ASSERT(!IS_AU_WORKING(old_au, amap));
/* must be NOT WORKING AU.
* (only for information gathering)
*/
}
/* Next target AU is needed:
* There are 3 possible ALLOC options for cold AU
*
* ALLOC_COLD_ALIGNED: Clean AU first, but heuristic packing is ON
* ALLOC_COLD_PACKING: Packing AU first (usually for defrag)
* ALLOC_COLD_SEQ : Sequential AU allocation (VFAT-like)
*/
/* Experimental: Modify allocation destination if needed (ALIGNED => SEQ) */
// dest = amap_update_dest(amap, dest);
if ((dest == ALLOC_COLD_SEQ) && old_au) {
int i_au = old_au->idx + 1;
while (i_au != old_au->idx) {
au = GET_AU(amap, i_au);
if ((au->free_clusters > 0) &&
!IS_AU_HOT(au, amap) &&
!IS_AU_IGNORED(au, amap)) {
MMSG("AMAP: new cold AU(%d) with %d "
"clusters (seq)\n",
au->idx, au->free_clusters);
amap_remove_cold_au(amap, au);
goto ret_new_cold;
}
i_au++;
if (i_au >= amap->n_au)
i_au = 0;
}
// no cold AUs are available => Hot allocation
dest = ALLOC_HOT;
goto retry;
}
/*
* Check if packing is needed
* (ALLOC_COLD_PACKING is treated by this function)
*/
au = amap_get_packing_au(amap, dest, num_to_wb, &n_clu_to_skip);
if (au) {
MMSG("AMAP: new cold AU(%d) with %d clusters "
"(packing)\n", au->idx, au->free_clusters);
goto ret_new_cold;
}
/* ALLOC_COLD_ALIGNED */
/* Check if the adjacent AU is clean */
if (old_au && ((old_au->idx + 1) < amap->n_au)) {
au = GET_AU(amap, old_au->idx + 1);
if ((au->free_clusters == amap->clusters_per_au) &&
!IS_AU_HOT(au, amap) &&
!IS_AU_IGNORED(au, amap)) {
MMSG("AMAP: new cold AU(%d) with %d clusters "
"(adjacent)\n", au->idx, au->free_clusters);
amap_remove_cold_au(amap, au);
goto ret_new_cold;
}
}
/* Clean or largest AU */
au = amap_pop_cold_au_largest(amap, 0);
if (!au) {
//ASSERT(amap->total_fclu_hot == (fsi->num_clusters - fsi->used_clusters - 2));
dest = ALLOC_HOT;
goto retry;
}
MMSG("AMAP: New cold AU (%d) with %d clusters\n",
au->idx, au->free_clusters);
ret_new_cold:
SET_AU_WORKING(au);
amap->cur_cold.au = au;
amap->cur_cold.idx = 0;
amap->cur_cold.clu_to_skip = n_clu_to_skip;
}
return &amap->cur_cold;
}
/* Put and update target AU */
void amap_put_target_au(AMAP_T *amap, TARGET_AU_T *cur, unsigned int num_allocated)
{
/* Update AMAP info vars. */
if (num_allocated > 0 &&
(cur->au->free_clusters + num_allocated) == amap->clusters_per_au) {
/* if the target AU was a clean AU before this allocation ... */
amap->n_clean_au--;
}
if (num_allocated > 0 &&
cur->au->free_clusters == 0)
amap->n_full_au++;
if (IS_AU_HOT(cur->au, amap)) {
/* Hot AU */
MMSG("AMAP: hot allocation at AU %d\n", cur->au->idx);
amap->total_fclu_hot -= num_allocated;
/* Intra-AU round-robin */
if (cur->idx >= amap->clusters_per_au)
cur->idx = 0;
/* No more space available */
if (cur->au->free_clusters == 0)
cur->au = NULL;
} else {
/* non-hot AU */
ASSERT(IS_AU_WORKING(cur->au, amap));
if (cur->idx >= amap->clusters_per_au || cur->au->free_clusters == 0) {
/* It should be inserted back to AU MAP */
cur->au->shead.head = NULL; // SET_AU_NOT_WORKING
amap_add_cold_au(amap, cur->au);
// cur->au = NULL; // This value will be used for the next AU selection
cur->idx = amap->clusters_per_au; // AU closing
}
}
}
/* Reposition target->idx for packing (Heuristics):
* Skip (num_to_skip) free clusters in (cur->au)
*/
static inline int amap_skip_cluster(struct super_block *sb, TARGET_AU_T *cur, int num_to_skip)
{
AMAP_T *amap = SDFAT_SB(sb)->fsi.amap;
u32 clu, read_clu;
MMSG_VAR(int num_to_skip_orig = num_to_skip);
if (num_to_skip >= cur->au->free_clusters) {
EMSG("AMAP(%s): skip mis-use. amap_566\n", __func__);
return -EIO;
}
clu = CLU_of_i_AU(amap, cur->au->idx, cur->idx);
while (num_to_skip > 0) {
if (clu >= CLUS_BASE) {
/* Cf.
* If AMAP's integrity is okay,
* we don't need to check if (clu < fsi->num_clusters)
*/
if (fat_ent_get(sb, clu, &read_clu))
return -EIO;
if (IS_CLUS_FREE(read_clu))
num_to_skip--;
}
// Move clu->idx
clu++;
(cur->idx)++;
if (cur->idx >= amap->clusters_per_au) {
/* End of AU (Not supposed) */
EMSG("AMAP: Skip - End of AU?! (amap_596)\n");
cur->idx = 0;
return -EIO;
}
}
MMSG("AMAP: Skip_clusters (%d skipped => %d, among %d free clus)\n",
num_to_skip_orig, cur->idx, cur->au->free_clusters);
return 0;
}
/* AMAP-based allocation function for FAT32 */
s32 amap_fat_alloc_cluster(struct super_block *sb, u32 num_alloc, CHAIN_T *p_chain, s32 dest)
{
AMAP_T *amap = SDFAT_SB(sb)->fsi.amap;
TARGET_AU_T *cur = NULL;
AU_INFO_T *target_au = NULL; /* Allocation target AU */
s32 ret = -ENOSPC;
u32 last_clu = CLUS_EOF, read_clu;
u32 new_clu, total_cnt;
u32 num_allocated = 0, num_allocated_each = 0;
FS_INFO_T *fsi = &(SDFAT_SB(sb)->fsi);
BUG_ON(!amap);
BUG_ON(IS_CLUS_EOF(fsi->used_clusters));
total_cnt = fsi->num_clusters - CLUS_BASE;
if (unlikely(total_cnt < fsi->used_clusters)) {
sdfat_fs_error_ratelimit(sb,
"AMAP(%s): invalid used clusters(t:%u,u:%u)\n",
__func__, total_cnt, fsi->used_clusters);
return -EIO;
}