From 244b2c5ca8b14627e4a17755e5922221e121c771 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:15:07 +0000
Subject: [PATCH] change system file
---
kernel/fs/fat/fatent.c | 131 ++++++++++++++++++++++++++++++-------------
1 files changed, 90 insertions(+), 41 deletions(-)
diff --git a/kernel/fs/fat/fatent.c b/kernel/fs/fat/fatent.c
index 4c6c635..3537350 100644
--- a/kernel/fs/fat/fatent.c
+++ b/kernel/fs/fat/fatent.c
@@ -1,6 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2004, OGAWA Hirofumi
- * Released under GPL v2.
*/
#include <linux/blkdev.h>
@@ -93,7 +93,8 @@
err_brelse:
brelse(bhs[0]);
err:
- fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", (llu)blocknr);
+ fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
+ (llu)blocknr);
return -EIO;
}
@@ -106,8 +107,8 @@
fatent->fat_inode = MSDOS_SB(sb)->fat_inode;
fatent->bhs[0] = sb_bread(sb, blocknr);
if (!fatent->bhs[0]) {
- fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
- (llu)blocknr);
+ fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
+ (llu)blocknr);
return -EIO;
}
fatent->nr_bhs = 1;
@@ -290,19 +291,17 @@
mutex_init(&sbi->fat_lock);
- switch (sbi->fat_bits) {
- case 32:
+ if (is_fat32(sbi)) {
sbi->fatent_shift = 2;
sbi->fatent_ops = &fat32_ops;
- break;
- case 16:
+ } else if (is_fat16(sbi)) {
sbi->fatent_shift = 1;
sbi->fatent_ops = &fat16_ops;
- break;
- case 12:
+ } else if (is_fat12(sbi)) {
sbi->fatent_shift = -1;
sbi->fatent_ops = &fat12_ops;
- break;
+ } else {
+ fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits);
}
}
@@ -310,7 +309,7 @@
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
- if (sb_rdonly(sb) || sbi->fat_bits != 32)
+ if (sb_rdonly(sb) || !is_fat32(sbi))
return;
__mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC);
@@ -327,7 +326,7 @@
/* Is this fatent's blocks including this entry? */
if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
return 0;
- if (sbi->fat_bits == 12) {
+ if (is_fat12(sbi)) {
if ((offset + 1) < sb->s_blocksize) {
/* This entry is on bhs[0]. */
if (fatent->nr_bhs == 2) {
@@ -634,20 +633,83 @@
}
EXPORT_SYMBOL_GPL(fat_free_clusters);
-/* 128kb is the whole sectors for FAT12 and FAT16 */
-#define FAT_READA_SIZE (128 * 1024)
+struct fatent_ra {
+ sector_t cur;
+ sector_t limit;
-static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent,
- unsigned long reada_blocks)
+ unsigned int ra_blocks;
+ sector_t ra_advance;
+ sector_t ra_next;
+ sector_t ra_limit;
+};
+
+static void fat_ra_init(struct super_block *sb, struct fatent_ra *ra,
+ struct fat_entry *fatent, int ent_limit)
{
- const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
- sector_t blocknr;
- int i, offset;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ sector_t blocknr, block_end;
+ int offset;
+ /*
+ * This is the sequential read, so ra_pages * 2 (but try to
+ * align the optimal hardware IO size).
+ * [BTW, 128kb covers the whole sectors for FAT12 and FAT16]
+ */
+ unsigned long ra_pages = sb->s_bdi->ra_pages;
+ unsigned int reada_blocks;
+ if (fatent->entry >= ent_limit)
+ return;
+
+ if (ra_pages > sb->s_bdi->io_pages)
+ ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages);
+ reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1);
+
+ /* Initialize the range for sequential read */
ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+ ops->ent_blocknr(sb, ent_limit - 1, &offset, &block_end);
+ ra->cur = 0;
+ ra->limit = (block_end + 1) - blocknr;
- for (i = 0; i < reada_blocks; i++)
- sb_breadahead(sb, blocknr + i);
+ /* Advancing the window at half size */
+ ra->ra_blocks = reada_blocks >> 1;
+ ra->ra_advance = ra->cur;
+ ra->ra_next = ra->cur;
+ ra->ra_limit = ra->cur + min_t(sector_t, reada_blocks, ra->limit);
+}
+
+/* Assuming to be called before reading a new block (increments ->cur). */
+static void fat_ent_reada(struct super_block *sb, struct fatent_ra *ra,
+ struct fat_entry *fatent)
+{
+ if (ra->ra_next >= ra->ra_limit)
+ return;
+
+ if (ra->cur >= ra->ra_advance) {
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ const struct fatent_operations *ops = sbi->fatent_ops;
+ struct blk_plug plug;
+ sector_t blocknr, diff;
+ int offset;
+
+ ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+
+ diff = blocknr - ra->cur;
+ blk_start_plug(&plug);
+ /*
+ * FIXME: we would want to directly use the bio with
+ * pages to reduce the number of segments.
+ */
+ for (; ra->ra_next < ra->ra_limit; ra->ra_next++)
+ sb_breadahead(sb, ra->ra_next + diff);
+ blk_finish_plug(&plug);
+
+ /* Advance the readahead window */
+ ra->ra_advance += ra->ra_blocks;
+ ra->ra_limit += min_t(sector_t,
+ ra->ra_blocks, ra->limit - ra->ra_limit);
+ }
+ ra->cur++;
}
int fat_count_free_clusters(struct super_block *sb)
@@ -655,27 +717,20 @@
struct msdos_sb_info *sbi = MSDOS_SB(sb);
const struct fatent_operations *ops = sbi->fatent_ops;
struct fat_entry fatent;
- unsigned long reada_blocks, reada_mask, cur_block;
+ struct fatent_ra fatent_ra;
int err = 0, free;
lock_fat(sbi);
if (sbi->free_clusters != -1 && sbi->free_clus_valid)
goto out;
- reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
- reada_mask = reada_blocks - 1;
- cur_block = 0;
-
free = 0;
fatent_init(&fatent);
fatent_set_entry(&fatent, FAT_START_ENT);
+ fat_ra_init(sb, &fatent_ra, &fatent, sbi->max_cluster);
while (fatent.entry < sbi->max_cluster) {
/* readahead of fat blocks */
- if ((cur_block & reada_mask) == 0) {
- unsigned long rest = sbi->fat_length - cur_block;
- fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
- }
- cur_block++;
+ fat_ent_reada(sb, &fatent_ra, &fatent);
err = fat_ent_read_block(sb, &fatent);
if (err)
@@ -709,9 +764,9 @@
struct msdos_sb_info *sbi = MSDOS_SB(sb);
const struct fatent_operations *ops = sbi->fatent_ops;
struct fat_entry fatent;
+ struct fatent_ra fatent_ra;
u64 ent_start, ent_end, minlen, trimmed = 0;
u32 free = 0;
- unsigned long reada_blocks, reada_mask, cur_block = 0;
int err = 0;
/*
@@ -729,19 +784,13 @@
if (ent_end >= sbi->max_cluster)
ent_end = sbi->max_cluster - 1;
- reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
- reada_mask = reada_blocks - 1;
-
fatent_init(&fatent);
lock_fat(sbi);
fatent_set_entry(&fatent, ent_start);
+ fat_ra_init(sb, &fatent_ra, &fatent, ent_end + 1);
while (fatent.entry <= ent_end) {
/* readahead of fat blocks */
- if ((cur_block & reada_mask) == 0) {
- unsigned long rest = sbi->fat_length - cur_block;
- fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
- }
- cur_block++;
+ fat_ent_reada(sb, &fatent_ra, &fatent);
err = fat_ent_read_block(sb, &fatent);
if (err)
--
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