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SubjectRe: [PATCH v2 2/2] erofs: support reading chunk-based uncompressed files
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On 2021/8/20 17:12, Gao Xiang wrote:
> Hi Chao,
>
> On Fri, Aug 20, 2021 at 05:04:13PM +0800, Chao Yu wrote:
>> On 2021/8/19 14:33, Gao Xiang wrote:
>
> ...
>
>>> }
>>> +static int erofs_map_blocks(struct inode *inode,
>>> + struct erofs_map_blocks *map, int flags)
>>> +{
>>> + struct super_block *sb = inode->i_sb;
>>> + struct erofs_inode *vi = EROFS_I(inode);
>>> + struct erofs_inode_chunk_index *idx;
>>> + struct page *page;
>>> + u64 chunknr;
>>> + unsigned int unit;
>>> + erofs_off_t pos;
>>> + int err = 0;
>>> +
>>> + if (map->m_la >= inode->i_size) {
>>> + /* leave out-of-bound access unmapped */
>>> + map->m_flags = 0;
>>> + map->m_plen = 0;
>>> + goto out;
>>> + }
>>> +
>>> + if (vi->datalayout != EROFS_INODE_CHUNK_BASED)
>>> + return erofs_map_blocks_flatmode(inode, map, flags);
>>> +
>>> + if (vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)
>>> + unit = sizeof(*idx); /* chunk index */
>>> + else
>>> + unit = 4; /* block map */
>>
>> You mean sizeof(__le32)?
>
> Yeah, sizeof(__le32) == 4, either way works for me.
>
> If some tendency about this, I will update when applying.

Xiang,

Yeah, I preper:

#define EROFS_BLOCK_MAP_ENTRY_SIZE sizeof(__le32)

unit = EROFS_BLOCK_MAP_ENTRY_SIZE;

to improve readablity, but unit = sizeof(__le32) is fine as well.

Thanks,

>
>>
>> Otherwise it looks good to me.
>>
>> Reviewed-by: Chao Yu <chao@kernel.org>
>>
>
> Thanks for the review!
>
> Thanks,
> Gao Xiang
>
>> Thanks,
>>
>>> +
>>> + chunknr = map->m_la >> vi->chunkbits;
>>> + pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
>>> + vi->xattr_isize, unit) + unit * chunknr;
>>> +
>>> + page = erofs_get_meta_page(inode->i_sb, erofs_blknr(pos));
>>> + if (IS_ERR(page))
>>> + return PTR_ERR(page);
>>> +
>>> + map->m_la = chunknr << vi->chunkbits;
>>> + map->m_plen = min_t(erofs_off_t, 1UL << vi->chunkbits,
>>> + roundup(inode->i_size - map->m_la, EROFS_BLKSIZ));
>>> +
>>> + /* handle block map */
>>> + if (!(vi->chunkformat & EROFS_CHUNK_FORMAT_INDEXES)) {
>>> + __le32 *blkaddr = page_address(page) + erofs_blkoff(pos);
>>> +
>>> + if (le32_to_cpu(*blkaddr) == EROFS_NULL_ADDR) {
>>> + map->m_flags = 0;
>>> + } else {
>>> + map->m_pa = blknr_to_addr(le32_to_cpu(*blkaddr));
>>> + map->m_flags = EROFS_MAP_MAPPED;
>>> + }
>>> + goto out_unlock;
>>> + }
>>> + /* parse chunk indexes */
>>> + idx = page_address(page) + erofs_blkoff(pos);
>>> + switch (le32_to_cpu(idx->blkaddr)) {
>>> + case EROFS_NULL_ADDR:
>>> + map->m_flags = 0;
>>> + break;
>>> + default:
>>> + /* only one device is supported for now */
>>> + if (idx->device_id) {
>>> + erofs_err(sb, "invalid device id %u @ %llu for nid %llu",
>>> + le32_to_cpu(idx->device_id),
>>> + chunknr, vi->nid);
>>> + err = -EFSCORRUPTED;
>>> + goto out_unlock;
>>> + }
>>> + map->m_pa = blknr_to_addr(le32_to_cpu(idx->blkaddr));
>>> + map->m_flags = EROFS_MAP_MAPPED;
>>> + break;
>>> + }
>>> +out_unlock:
>>> + unlock_page(page);
>>> + put_page(page);
>>> +out:
>>> + map->m_llen = map->m_plen;
>>> + return err;
>>> +}
>>> +
>>> static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>>> unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
>>> {
>>> @@ -94,7 +164,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>>> map.m_la = offset;
>>> map.m_llen = length;
>>> - ret = erofs_map_blocks_flatmode(inode, &map, EROFS_GET_BLOCKS_RAW);
>>> + ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
>>> if (ret < 0)
>>> return ret;
>>> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
>>> index d13e0709599c..4408929bd6f5 100644
>>> --- a/fs/erofs/inode.c
>>> +++ b/fs/erofs/inode.c
>>> @@ -2,6 +2,7 @@
>>> /*
>>> * Copyright (C) 2017-2018 HUAWEI, Inc.
>>> * https://www.huawei.com/
>>> + * Copyright (C) 2021, Alibaba Cloud
>>> */
>>> #include "xattr.h"
>>> @@ -122,7 +123,9 @@ static struct page *erofs_read_inode(struct inode *inode,
>>> /* total blocks for compressed files */
>>> if (erofs_inode_is_data_compressed(vi->datalayout))
>>> nblks = le32_to_cpu(die->i_u.compressed_blocks);
>>> -
>>> + else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
>>> + /* fill chunked inode summary info */
>>> + vi->chunkformat = le16_to_cpu(die->i_u.c.format);
>>> kfree(copied);
>>> break;
>>> case EROFS_INODE_LAYOUT_COMPACT:
>>> @@ -160,6 +163,8 @@ static struct page *erofs_read_inode(struct inode *inode,
>>> inode->i_size = le32_to_cpu(dic->i_size);
>>> if (erofs_inode_is_data_compressed(vi->datalayout))
>>> nblks = le32_to_cpu(dic->i_u.compressed_blocks);
>>> + else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
>>> + vi->chunkformat = le16_to_cpu(dic->i_u.c.format);
>>> break;
>>> default:
>>> erofs_err(inode->i_sb,
>>> @@ -169,6 +174,17 @@ static struct page *erofs_read_inode(struct inode *inode,
>>> goto err_out;
>>> }
>>> + if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
>>> + if (!(vi->chunkformat & EROFS_CHUNK_FORMAT_ALL)) {
>>> + erofs_err(inode->i_sb,
>>> + "unsupported chunk format %x of nid %llu",
>>> + vi->chunkformat, vi->nid);
>>> + err = -EOPNOTSUPP;
>>> + goto err_out;
>>> + }
>>> + vi->chunkbits = LOG_BLOCK_SIZE +
>>> + (vi->chunkformat & EROFS_CHUNK_FORMAT_BLKBITS_MASK);
>>> + }
>>> inode->i_mtime.tv_sec = inode->i_ctime.tv_sec;
>>> inode->i_atime.tv_sec = inode->i_ctime.tv_sec;
>>> inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec;
>>> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
>>> index 91089ab8a816..9524e155b38f 100644
>>> --- a/fs/erofs/internal.h
>>> +++ b/fs/erofs/internal.h
>>> @@ -2,6 +2,7 @@
>>> /*
>>> * Copyright (C) 2017-2018 HUAWEI, Inc.
>>> * https://www.huawei.com/
>>> + * Copyright (C) 2021, Alibaba Cloud
>>> */
>>> #ifndef __EROFS_INTERNAL_H
>>> #define __EROFS_INTERNAL_H
>>> @@ -261,6 +262,10 @@ struct erofs_inode {
>>> union {
>>> erofs_blk_t raw_blkaddr;
>>> + struct {
>>> + unsigned short chunkformat;
>>> + unsigned char chunkbits;
>>> + };
>>> #ifdef CONFIG_EROFS_FS_ZIP
>>> struct {
>>> unsigned short z_advise;
>>>

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