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erofs: use meta buffers for super operations

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Get rid of old erofs_get_meta_page() within super operations by
using on-stack meta buffers in order to prepare subpage and folio
features.

Link: https://lore.kernel.org/r/20220102081317.109797-1-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This commit is contained in:
Gao Xiang 2022-01-02 16:13:17 +08:00
parent c521e3ad6c
commit 2b5379f786
1 changed files with 27 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

102
fs/erofs/super.c
View File

@ -2,6 +2,7 @@
/*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2021, Alibaba Cloud
*/
#include <linux/module.h>
#include <linux/buffer_head.h>
@ -124,80 +125,50 @@ static bool check_layout_compatibility(struct super_block *sb,
#ifdef CONFIG_EROFS_FS_ZIP
/* read variable-sized metadata, offset will be aligned by 4-byte */
static void *erofs_read_metadata(struct super_block *sb, struct page **pagep,
static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
erofs_off_t *offset, int *lengthp)
{
struct page *page = *pagep;
u8 *buffer, *ptr;
int len, i, cnt;
erofs_blk_t blk;
*offset = round_up(*offset, 4);
blk = erofs_blknr(*offset);
ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP);
if (IS_ERR(ptr))
return ptr;
if (!page || page->index != blk) {
if (page) {
unlock_page(page);
put_page(page);
}
page = erofs_get_meta_page(sb, blk);
if (IS_ERR(page))
goto err_nullpage;
}
ptr = kmap(page);
len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]);
if (!len)
len = U16_MAX + 1;
buffer = kmalloc(len, GFP_KERNEL);
if (!buffer) {
buffer = ERR_PTR(-ENOMEM);
goto out;
}
if (!buffer)
return ERR_PTR(-ENOMEM);
*offset += sizeof(__le16);
*lengthp = len;
for (i = 0; i < len; i += cnt) {
cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i);
blk = erofs_blknr(*offset);
if (!page || page->index != blk) {
if (page) {
kunmap(page);
unlock_page(page);
put_page(page);
}
page = erofs_get_meta_page(sb, blk);
if (IS_ERR(page)) {
ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset),
EROFS_KMAP);
if (IS_ERR(ptr)) {
kfree(buffer);
goto err_nullpage;
}
ptr = kmap(page);
return ptr;
}
memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt);
*offset += cnt;
}
out:
kunmap(page);
*pagep = page;
return buffer;
err_nullpage:
*pagep = NULL;
return page;
}
static int erofs_load_compr_cfgs(struct super_block *sb,
struct erofs_super_block *dsb)
{
struct erofs_sb_info *sbi;
struct page *page;
struct erofs_sb_info *sbi = EROFS_SB(sb);
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
unsigned int algs, alg;
erofs_off_t offset;
int size, ret;
int size, ret = 0;
sbi = EROFS_SB(sb);
sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
@ -205,20 +176,17 @@ static int erofs_load_compr_cfgs(struct super_block *sb,
}
offset = EROFS_SUPER_OFFSET + sbi->sb_size;
page = NULL;
alg = 0;
ret = 0;
for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
void *data;
if (!(algs & 1))
continue;
data = erofs_read_metadata(sb, &page, &offset, &size);
data = erofs_read_metadata(sb, &buf, &offset, &size);
if (IS_ERR(data)) {
ret = PTR_ERR(data);
goto err;
break;
}
switch (alg) {
@ -234,13 +202,9 @@ static int erofs_load_compr_cfgs(struct super_block *sb,
}
kfree(data);
if (ret)
goto err;
}
err:
if (page) {
unlock_page(page);
put_page(page);
break;
}
erofs_put_metabuf(&buf);
return ret;
}
#else
@ -261,7 +225,7 @@ static int erofs_init_devices(struct super_block *sb,
struct erofs_sb_info *sbi = EROFS_SB(sb);
unsigned int ondisk_extradevs;
erofs_off_t pos;
struct page *page = NULL;
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
struct erofs_device_info *dif;
struct erofs_deviceslot *dis;
void *ptr;
@ -285,22 +249,13 @@ static int erofs_init_devices(struct super_block *sb,
pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
down_read(&sbi->devs->rwsem);
idr_for_each_entry(&sbi->devs->tree, dif, id) {
erofs_blk_t blk = erofs_blknr(pos);
struct block_device *bdev;
if (!page || page->index != blk) {
if (page) {
kunmap(page);
unlock_page(page);
put_page(page);
}
page = erofs_get_meta_page(sb, blk);
if (IS_ERR(page)) {
up_read(&sbi->devs->rwsem);
return PTR_ERR(page);
}
ptr = kmap(page);
ptr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos),
EROFS_KMAP);
if (IS_ERR(ptr)) {
err = PTR_ERR(ptr);
break;
}
dis = ptr + erofs_blkoff(pos);
@ -309,7 +264,7 @@ static int erofs_init_devices(struct super_block *sb,
sb->s_type);
if (IS_ERR(bdev)) {
err = PTR_ERR(bdev);
goto err_out;
break;
}
dif->bdev = bdev;
dif->dax_dev = fs_dax_get_by_bdev(bdev);
@ -318,13 +273,8 @@ static int erofs_init_devices(struct super_block *sb,
sbi->total_blocks += dif->blocks;
pos += EROFS_DEVT_SLOT_SIZE;
}
err_out:
up_read(&sbi->devs->rwsem);
if (page) {
kunmap(page);
unlock_page(page);
put_page(page);
}
erofs_put_metabuf(&buf);
return err;
}