linux/fs/erofs/data.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2021, Alibaba Cloud
*/
#include "internal.h"
#include <linux/prefetch.h>
#include <linux/dax.h>
#include <trace/events/erofs.h>
struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
{
struct address_space *const mapping = sb->s_bdev->bd_inode->i_mapping;
struct page *page;
page = read_cache_page_gfp(mapping, blkaddr,
mapping_gfp_constraint(mapping, ~__GFP_FS));
/* should already be PageUptodate */
if (!IS_ERR(page))
lock_page(page);
return page;
}
static int erofs_map_blocks_flatmode(struct inode *inode,
struct erofs_map_blocks *map,
int flags)
{
int err = 0;
erofs_blk_t nblocks, lastblk;
u64 offset = map->m_la;
struct erofs_inode *vi = EROFS_I(inode);
bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
lastblk = nblocks - tailendpacking;
/* there is no hole in flatmode */
map->m_flags = EROFS_MAP_MAPPED;
if (offset < blknr_to_addr(lastblk)) {
map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
map->m_plen = blknr_to_addr(lastblk) - offset;
} else if (tailendpacking) {
/* 2 - inode inline B: inode, [xattrs], inline last blk... */
struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
vi->xattr_isize + erofs_blkoff(map->m_la);
map->m_plen = inode->i_size - offset;
/* inline data should be located in one meta block */
if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
erofs_err(inode->i_sb,
"inline data cross block boundary @ nid %llu",
vi->nid);
DBG_BUGON(1);
err = -EFSCORRUPTED;
goto err_out;
}
map->m_flags |= EROFS_MAP_META;
} else {
erofs_err(inode->i_sb,
"internal error @ nid: %llu (size %llu), m_la 0x%llx",
vi->nid, inode->i_size, map->m_la);
DBG_BUGON(1);
err = -EIO;
goto err_out;
}
map->m_llen = map->m_plen;
err_out:
trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
return err;
}
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 = EROFS_BLOCK_MAP_ENTRY_SIZE; /* block map */
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",
le16_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)
{
int ret;
struct erofs_map_blocks map;
map.m_la = offset;
map.m_llen = length;
ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
if (ret < 0)
return ret;
iomap->bdev = inode->i_sb->s_bdev;
iomap->dax_dev = EROFS_I_SB(inode)->dax_dev;
iomap->offset = map.m_la;
iomap->length = map.m_llen;
iomap->flags = 0;
iomap->private = NULL;
if (!(map.m_flags & EROFS_MAP_MAPPED)) {
iomap->type = IOMAP_HOLE;
iomap->addr = IOMAP_NULL_ADDR;
if (!iomap->length)
iomap->length = length;
return 0;
}
if (map.m_flags & EROFS_MAP_META) {
struct page *ipage;
iomap->type = IOMAP_INLINE;
ipage = erofs_get_meta_page(inode->i_sb,
erofs_blknr(map.m_pa));
if (IS_ERR(ipage))
return PTR_ERR(ipage);
iomap->inline_data = page_address(ipage) +
erofs_blkoff(map.m_pa);
iomap->private = ipage;
} else {
iomap->type = IOMAP_MAPPED;
iomap->addr = map.m_pa;
}
return 0;
}
static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
ssize_t written, unsigned int flags, struct iomap *iomap)
{
struct page *ipage = iomap->private;
if (ipage) {
DBG_BUGON(iomap->type != IOMAP_INLINE);
unlock_page(ipage);
put_page(ipage);
} else {
DBG_BUGON(iomap->type == IOMAP_INLINE);
}
return written;
}
static const struct iomap_ops erofs_iomap_ops = {
.iomap_begin = erofs_iomap_begin,
.iomap_end = erofs_iomap_end,
};
int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
u64 start, u64 len)
{
if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
#ifdef CONFIG_EROFS_FS_ZIP
return iomap_fiemap(inode, fieinfo, start, len,
&z_erofs_iomap_report_ops);
#else
return -EOPNOTSUPP;
#endif
}
return iomap_fiemap(inode, fieinfo, start, len, &erofs_iomap_ops);
}
/*
* since we dont have write or truncate flows, so no inode
* locking needs to be held at the moment.
*/
static int erofs_readpage(struct file *file, struct page *page)
{
return iomap_readpage(page, &erofs_iomap_ops);
}
static void erofs_readahead(struct readahead_control *rac)
{
return iomap_readahead(rac, &erofs_iomap_ops);
}
static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
{
return iomap_bmap(mapping, block, &erofs_iomap_ops);
}
static int erofs_prepare_dio(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
loff_t align = iocb->ki_pos | iov_iter_count(to) |
iov_iter_alignment(to);
struct block_device *bdev = inode->i_sb->s_bdev;
unsigned int blksize_mask;
if (bdev)
blksize_mask = (1 << ilog2(bdev_logical_block_size(bdev))) - 1;
else
blksize_mask = (1 << inode->i_blkbits) - 1;
if (align & blksize_mask)
return -EINVAL;
return 0;
}
static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
/* no need taking (shared) inode lock since it's a ro filesystem */
if (!iov_iter_count(to))
return 0;
#ifdef CONFIG_FS_DAX
if (IS_DAX(iocb->ki_filp->f_mapping->host))
return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
#endif
if (iocb->ki_flags & IOCB_DIRECT) {
int err = erofs_prepare_dio(iocb, to);
if (!err)
return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
NULL, 0);
if (err < 0)
return err;
}
return filemap_read(iocb, to, 0);
}
/* for uncompressed (aligned) files and raw access for other files */
const struct address_space_operations erofs_raw_access_aops = {
.readpage = erofs_readpage,
.readahead = erofs_readahead,
.bmap = erofs_bmap,
.direct_IO = noop_direct_IO,
};
#ifdef CONFIG_FS_DAX
static vm_fault_t erofs_dax_huge_fault(struct vm_fault *vmf,
enum page_entry_size pe_size)
{
return dax_iomap_fault(vmf, pe_size, NULL, NULL, &erofs_iomap_ops);
}
static vm_fault_t erofs_dax_fault(struct vm_fault *vmf)
{
return erofs_dax_huge_fault(vmf, PE_SIZE_PTE);
}
static const struct vm_operations_struct erofs_dax_vm_ops = {
.fault = erofs_dax_fault,
.huge_fault = erofs_dax_huge_fault,
};
static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
if (!IS_DAX(file_inode(file)))
return generic_file_readonly_mmap(file, vma);
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
return -EINVAL;
vma->vm_ops = &erofs_dax_vm_ops;
vma->vm_flags |= VM_HUGEPAGE;
return 0;
}
#else
#define erofs_file_mmap generic_file_readonly_mmap
#endif
const struct file_operations erofs_file_fops = {
.llseek = generic_file_llseek,
.read_iter = erofs_file_read_iter,
.mmap = erofs_file_mmap,
.splice_read = generic_file_splice_read,
};