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![Gao Xiang](/assets/img/avatar_default.png)
VLE was an old informal name of fixed-sized output compression which came from published ATC'19 paper [1]. Drop those old annotations since erofs can handle all encoded clusters in block-aligned basis, which is wider than fixed-sized output compression after larger clustersize feature is fully implemented. Unaligned encoding won't be considered in EROFS since it's not friendly to inplace I/O and perhaps decompression inplace. a) Fixed-sized output compression with 16KB pcluster: ___________________________________ |xxxxxxxx|xxxxxxxx|xxxxxxxx|xxxxxxxx| |___ 0___|___ 1___|___ 2___|___ 3___| physical blocks b) Block-aligned fixed-sized input compression with 16KB pcluster: ___________________________________ |xxxxxxxx|xxxxxxxx|xxxxxxxx|xxx00000| |___ 0___|___ 1___|___ 2___|___ 3___| physical blocks c) Block-unaligned fixed-sized input compression with 16KB compression unit: ____________________________________________ |..xxxxxx|xxxxxxxx|xxxxxxxx|xxxxxxxx|x.......| |___ 0___|___ 1___|___ 2___|___ 3___|___ 4___| physical blocks Refine better names for those as well. [1] https://www.usenix.org/conference/atc19/presentation/gao Link: https://lore.kernel.org/r/20191108033733.63919-1-gaoxiang25@huawei.com Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
471 lines
12 KiB
C
471 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2018-2019 HUAWEI, Inc.
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* http://www.huawei.com/
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* Created by Gao Xiang <gaoxiang25@huawei.com>
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*/
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#include "internal.h"
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#include <asm/unaligned.h>
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#include <trace/events/erofs.h>
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int z_erofs_fill_inode(struct inode *inode)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
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vi->z_advise = 0;
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vi->z_algorithmtype[0] = 0;
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vi->z_algorithmtype[1] = 0;
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vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
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vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
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vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
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set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
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}
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inode->i_mapping->a_ops = &z_erofs_aops;
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return 0;
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}
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static int z_erofs_fill_inode_lazy(struct inode *inode)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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struct super_block *const sb = inode->i_sb;
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int err;
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erofs_off_t pos;
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struct page *page;
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void *kaddr;
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struct z_erofs_map_header *h;
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if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
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return 0;
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if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
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return -ERESTARTSYS;
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err = 0;
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if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
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goto out_unlock;
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DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
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pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
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vi->xattr_isize, 8);
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page = erofs_get_meta_page(sb, erofs_blknr(pos));
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if (IS_ERR(page)) {
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err = PTR_ERR(page);
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goto out_unlock;
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}
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kaddr = kmap_atomic(page);
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h = kaddr + erofs_blkoff(pos);
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vi->z_advise = le16_to_cpu(h->h_advise);
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vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
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vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
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if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
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erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
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vi->z_algorithmtype[0], vi->nid);
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err = -EOPNOTSUPP;
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goto unmap_done;
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}
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vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
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vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits +
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((h->h_clusterbits >> 3) & 3);
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if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
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erofs_err(sb, "unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
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vi->z_physical_clusterbits[0], vi->nid);
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err = -EOPNOTSUPP;
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goto unmap_done;
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}
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vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
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((h->h_clusterbits >> 5) & 7);
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set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
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unmap_done:
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kunmap_atomic(kaddr);
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unlock_page(page);
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put_page(page);
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out_unlock:
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clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
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return err;
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}
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struct z_erofs_maprecorder {
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struct inode *inode;
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struct erofs_map_blocks *map;
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void *kaddr;
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unsigned long lcn;
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/* compression extent information gathered */
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u8 type;
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u16 clusterofs;
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u16 delta[2];
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erofs_blk_t pblk;
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};
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static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
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erofs_blk_t eblk)
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{
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struct super_block *const sb = m->inode->i_sb;
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struct erofs_map_blocks *const map = m->map;
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struct page *mpage = map->mpage;
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if (mpage) {
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if (mpage->index == eblk) {
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if (!m->kaddr)
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m->kaddr = kmap_atomic(mpage);
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return 0;
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}
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if (m->kaddr) {
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kunmap_atomic(m->kaddr);
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m->kaddr = NULL;
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}
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put_page(mpage);
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}
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mpage = erofs_get_meta_page(sb, eblk);
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if (IS_ERR(mpage)) {
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map->mpage = NULL;
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return PTR_ERR(mpage);
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}
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m->kaddr = kmap_atomic(mpage);
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unlock_page(mpage);
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map->mpage = mpage;
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return 0;
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}
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static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
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unsigned long lcn)
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{
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struct inode *const inode = m->inode;
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struct erofs_inode *const vi = EROFS_I(inode);
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const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
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const erofs_off_t pos =
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Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
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vi->xattr_isize) +
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lcn * sizeof(struct z_erofs_vle_decompressed_index);
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struct z_erofs_vle_decompressed_index *di;
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unsigned int advise, type;
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int err;
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err = z_erofs_reload_indexes(m, erofs_blknr(pos));
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if (err)
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return err;
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m->lcn = lcn;
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di = m->kaddr + erofs_blkoff(pos);
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advise = le16_to_cpu(di->di_advise);
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type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
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((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
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switch (type) {
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case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
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m->clusterofs = 1 << vi->z_logical_clusterbits;
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m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
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m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
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break;
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case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
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case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
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m->clusterofs = le16_to_cpu(di->di_clusterofs);
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m->pblk = le32_to_cpu(di->di_u.blkaddr);
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break;
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default:
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DBG_BUGON(1);
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return -EOPNOTSUPP;
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}
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m->type = type;
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return 0;
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}
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static unsigned int decode_compactedbits(unsigned int lobits,
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unsigned int lomask,
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u8 *in, unsigned int pos, u8 *type)
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{
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const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
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const unsigned int lo = v & lomask;
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*type = (v >> lobits) & 3;
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return lo;
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}
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static int unpack_compacted_index(struct z_erofs_maprecorder *m,
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unsigned int amortizedshift,
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unsigned int eofs)
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{
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struct erofs_inode *const vi = EROFS_I(m->inode);
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const unsigned int lclusterbits = vi->z_logical_clusterbits;
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const unsigned int lomask = (1 << lclusterbits) - 1;
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unsigned int vcnt, base, lo, encodebits, nblk;
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int i;
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u8 *in, type;
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if (1 << amortizedshift == 4)
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vcnt = 2;
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else if (1 << amortizedshift == 2 && lclusterbits == 12)
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vcnt = 16;
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else
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return -EOPNOTSUPP;
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encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
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base = round_down(eofs, vcnt << amortizedshift);
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in = m->kaddr + base;
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i = (eofs - base) >> amortizedshift;
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lo = decode_compactedbits(lclusterbits, lomask,
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in, encodebits * i, &type);
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m->type = type;
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if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
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m->clusterofs = 1 << lclusterbits;
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if (i + 1 != vcnt) {
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m->delta[0] = lo;
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return 0;
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}
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/*
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* since the last lcluster in the pack is special,
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* of which lo saves delta[1] rather than delta[0].
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* Hence, get delta[0] by the previous lcluster indirectly.
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*/
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lo = decode_compactedbits(lclusterbits, lomask,
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in, encodebits * (i - 1), &type);
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if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
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lo = 0;
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m->delta[0] = lo + 1;
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return 0;
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}
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m->clusterofs = lo;
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m->delta[0] = 0;
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/* figout out blkaddr (pblk) for HEAD lclusters */
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nblk = 1;
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while (i > 0) {
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--i;
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lo = decode_compactedbits(lclusterbits, lomask,
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in, encodebits * i, &type);
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if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
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i -= lo;
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if (i >= 0)
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++nblk;
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}
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in += (vcnt << amortizedshift) - sizeof(__le32);
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m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
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return 0;
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}
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static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
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unsigned long lcn)
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{
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struct inode *const inode = m->inode;
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struct erofs_inode *const vi = EROFS_I(inode);
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const unsigned int lclusterbits = vi->z_logical_clusterbits;
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const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
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vi->inode_isize + vi->xattr_isize, 8) +
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sizeof(struct z_erofs_map_header);
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const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
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unsigned int compacted_4b_initial, compacted_2b;
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unsigned int amortizedshift;
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erofs_off_t pos;
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int err;
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if (lclusterbits != 12)
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return -EOPNOTSUPP;
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if (lcn >= totalidx)
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return -EINVAL;
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m->lcn = lcn;
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/* used to align to 32-byte (compacted_2b) alignment */
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compacted_4b_initial = (32 - ebase % 32) / 4;
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if (compacted_4b_initial == 32 / 4)
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compacted_4b_initial = 0;
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if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
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compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
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else
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compacted_2b = 0;
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pos = ebase;
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if (lcn < compacted_4b_initial) {
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amortizedshift = 2;
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goto out;
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}
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pos += compacted_4b_initial * 4;
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lcn -= compacted_4b_initial;
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if (lcn < compacted_2b) {
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amortizedshift = 1;
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goto out;
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}
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pos += compacted_2b * 2;
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lcn -= compacted_2b;
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amortizedshift = 2;
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out:
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pos += lcn * (1 << amortizedshift);
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err = z_erofs_reload_indexes(m, erofs_blknr(pos));
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if (err)
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return err;
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return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos));
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}
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static int z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
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unsigned int lcn)
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{
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const unsigned int datamode = EROFS_I(m->inode)->datalayout;
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if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
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return legacy_load_cluster_from_disk(m, lcn);
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if (datamode == EROFS_INODE_FLAT_COMPRESSION)
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return compacted_load_cluster_from_disk(m, lcn);
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return -EINVAL;
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}
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static int z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
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unsigned int lookback_distance)
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{
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struct erofs_inode *const vi = EROFS_I(m->inode);
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struct erofs_map_blocks *const map = m->map;
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const unsigned int lclusterbits = vi->z_logical_clusterbits;
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unsigned long lcn = m->lcn;
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int err;
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if (lcn < lookback_distance) {
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erofs_err(m->inode->i_sb,
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"bogus lookback distance @ nid %llu", vi->nid);
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DBG_BUGON(1);
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return -EFSCORRUPTED;
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}
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/* load extent head logical cluster if needed */
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lcn -= lookback_distance;
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err = z_erofs_load_cluster_from_disk(m, lcn);
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if (err)
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return err;
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switch (m->type) {
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case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
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if (!m->delta[0]) {
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erofs_err(m->inode->i_sb,
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"invalid lookback distance 0 @ nid %llu",
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vi->nid);
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DBG_BUGON(1);
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return -EFSCORRUPTED;
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}
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return z_erofs_extent_lookback(m, m->delta[0]);
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case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
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map->m_flags &= ~EROFS_MAP_ZIPPED;
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/* fallthrough */
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case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
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map->m_la = (lcn << lclusterbits) | m->clusterofs;
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break;
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default:
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erofs_err(m->inode->i_sb,
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"unknown type %u @ lcn %lu of nid %llu",
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m->type, lcn, vi->nid);
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DBG_BUGON(1);
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return -EOPNOTSUPP;
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}
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return 0;
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}
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int z_erofs_map_blocks_iter(struct inode *inode,
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struct erofs_map_blocks *map,
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int flags)
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{
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struct erofs_inode *const vi = EROFS_I(inode);
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struct z_erofs_maprecorder m = {
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.inode = inode,
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.map = map,
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};
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int err = 0;
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unsigned int lclusterbits, endoff;
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unsigned long long ofs, end;
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trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
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/* when trying to read beyond EOF, leave it unmapped */
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if (map->m_la >= inode->i_size) {
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map->m_llen = map->m_la + 1 - inode->i_size;
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map->m_la = inode->i_size;
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map->m_flags = 0;
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goto out;
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}
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err = z_erofs_fill_inode_lazy(inode);
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if (err)
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goto out;
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lclusterbits = vi->z_logical_clusterbits;
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ofs = map->m_la;
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m.lcn = ofs >> lclusterbits;
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endoff = ofs & ((1 << lclusterbits) - 1);
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err = z_erofs_load_cluster_from_disk(&m, m.lcn);
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if (err)
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goto unmap_out;
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map->m_flags = EROFS_MAP_ZIPPED; /* by default, compressed */
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end = (m.lcn + 1ULL) << lclusterbits;
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switch (m.type) {
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case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
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if (endoff >= m.clusterofs)
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map->m_flags &= ~EROFS_MAP_ZIPPED;
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/* fallthrough */
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case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
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if (endoff >= m.clusterofs) {
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map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
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break;
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}
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/* m.lcn should be >= 1 if endoff < m.clusterofs */
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if (!m.lcn) {
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erofs_err(inode->i_sb,
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"invalid logical cluster 0 at nid %llu",
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vi->nid);
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err = -EFSCORRUPTED;
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goto unmap_out;
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}
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end = (m.lcn << lclusterbits) | m.clusterofs;
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map->m_flags |= EROFS_MAP_FULL_MAPPED;
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m.delta[0] = 1;
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/* fallthrough */
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case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
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/* get the correspoinding first chunk */
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err = z_erofs_extent_lookback(&m, m.delta[0]);
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if (err)
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goto unmap_out;
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break;
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default:
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erofs_err(inode->i_sb,
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"unknown type %u @ offset %llu of nid %llu",
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m.type, ofs, vi->nid);
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err = -EOPNOTSUPP;
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goto unmap_out;
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}
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map->m_llen = end - map->m_la;
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map->m_plen = 1 << lclusterbits;
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|
map->m_pa = blknr_to_addr(m.pblk);
|
|
map->m_flags |= EROFS_MAP_MAPPED;
|
|
|
|
unmap_out:
|
|
if (m.kaddr)
|
|
kunmap_atomic(m.kaddr);
|
|
|
|
out:
|
|
erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
|
|
__func__, map->m_la, map->m_pa,
|
|
map->m_llen, map->m_plen, map->m_flags);
|
|
|
|
trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
|
|
|
|
/* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
|
|
DBG_BUGON(err < 0 && err != -ENOMEM);
|
|
return err;
|
|
}
|
|
|