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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022, Alibaba Cloud
*/
#include <linux/fscache.h>
#include "internal.h"
/*
* Read data from fscache and fill the read data into page cache described by
* @start/len, which shall be both aligned with PAGE_SIZE. @pstart describes
* the start physical address in the cache file.
*/
static int erofs_fscache_read_folios(struct fscache_cookie *cookie,
struct address_space *mapping,
loff_t start, size_t len,
loff_t pstart)
{
enum netfs_io_source source;
struct netfs_io_request rreq = {};
struct netfs_io_subrequest subreq = { .rreq = &rreq, };
struct netfs_cache_resources *cres = &rreq.cache_resources;
struct super_block *sb = mapping->host->i_sb;
struct iov_iter iter;
size_t done = 0;
int ret;
ret = fscache_begin_read_operation(cres, cookie);
if (ret)
return ret;
while (done < len) {
subreq.start = pstart + done;
subreq.len = len - done;
subreq.flags = 1 << NETFS_SREQ_ONDEMAND;
source = cres->ops->prepare_read(&subreq, LLONG_MAX);
if (WARN_ON(subreq.len == 0))
source = NETFS_INVALID_READ;
if (source != NETFS_READ_FROM_CACHE) {
erofs_err(sb, "failed to fscache prepare_read (source %d)",
source);
ret = -EIO;
goto out;
}
iov_iter_xarray(&iter, READ, &mapping->i_pages,
start + done, subreq.len);
ret = fscache_read(cres, subreq.start, &iter,
NETFS_READ_HOLE_FAIL, NULL, NULL);
if (ret) {
erofs_err(sb, "failed to fscache_read (ret %d)", ret);
goto out;
}
done += subreq.len;
}
out:
fscache_end_operation(cres);
return ret;
}
static int erofs_fscache_meta_readpage(struct file *data, struct page *page)
{
int ret;
struct folio *folio = page_folio(page);
struct super_block *sb = folio_mapping(folio)->host->i_sb;
struct erofs_map_dev mdev = {
.m_deviceid = 0,
.m_pa = folio_pos(folio),
};
ret = erofs_map_dev(sb, &mdev);
if (ret)
goto out;
ret = erofs_fscache_read_folios(mdev.m_fscache->cookie,
folio_mapping(folio), folio_pos(folio),
folio_size(folio), mdev.m_pa);
if (!ret)
folio_mark_uptodate(folio);
out:
folio_unlock(folio);
return ret;
}
static int erofs_fscache_readpage(struct file *file, struct page *page)
{
struct folio *folio = page_folio(page);
struct inode *inode = folio_mapping(folio)->host;
struct super_block *sb = inode->i_sb;
struct erofs_map_blocks map;
struct erofs_map_dev mdev;
erofs_off_t pos;
loff_t pstart;
int ret;
DBG_BUGON(folio_size(folio) != EROFS_BLKSIZ);
pos = folio_pos(folio);
map.m_la = pos;
ret = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
if (ret)
goto out_unlock;
if (!(map.m_flags & EROFS_MAP_MAPPED)) {
folio_zero_range(folio, 0, folio_size(folio));
goto out_uptodate;
}
mdev = (struct erofs_map_dev) {
.m_deviceid = map.m_deviceid,
.m_pa = map.m_pa,
};
ret = erofs_map_dev(sb, &mdev);
if (ret)
goto out_unlock;
pstart = mdev.m_pa + (pos - map.m_la);
ret = erofs_fscache_read_folios(mdev.m_fscache->cookie,
folio_mapping(folio), folio_pos(folio),
folio_size(folio), pstart);
out_uptodate:
if (!ret)
folio_mark_uptodate(folio);
out_unlock:
folio_unlock(folio);
return ret;
}
static const struct address_space_operations erofs_fscache_meta_aops = {
.readpage = erofs_fscache_meta_readpage,
};
const struct address_space_operations erofs_fscache_access_aops = {
.readpage = erofs_fscache_readpage,
};
int erofs_fscache_register_cookie(struct super_block *sb,
struct erofs_fscache **fscache,
char *name, bool need_inode)
{
struct fscache_volume *volume = EROFS_SB(sb)->volume;
struct erofs_fscache *ctx;
struct fscache_cookie *cookie;
int ret;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
cookie = fscache_acquire_cookie(volume, FSCACHE_ADV_WANT_CACHE_SIZE,
name, strlen(name), NULL, 0, 0);
if (!cookie) {
erofs_err(sb, "failed to get cookie for %s", name);
ret = -EINVAL;
goto err;
}
fscache_use_cookie(cookie, false);
ctx->cookie = cookie;
if (need_inode) {
struct inode *const inode = new_inode(sb);
if (!inode) {
erofs_err(sb, "failed to get anon inode for %s", name);
ret = -ENOMEM;
goto err_cookie;
}
set_nlink(inode, 1);
inode->i_size = OFFSET_MAX;
inode->i_mapping->a_ops = &erofs_fscache_meta_aops;
mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
ctx->inode = inode;
}
*fscache = ctx;
return 0;
err_cookie:
fscache_unuse_cookie(ctx->cookie, NULL, NULL);
fscache_relinquish_cookie(ctx->cookie, false);
ctx->cookie = NULL;
err:
kfree(ctx);
return ret;
}
void erofs_fscache_unregister_cookie(struct erofs_fscache **fscache)
{
struct erofs_fscache *ctx = *fscache;
if (!ctx)
return;
fscache_unuse_cookie(ctx->cookie, NULL, NULL);
fscache_relinquish_cookie(ctx->cookie, false);
ctx->cookie = NULL;
iput(ctx->inode);
ctx->inode = NULL;
kfree(ctx);
*fscache = NULL;
}
int erofs_fscache_register_fs(struct super_block *sb)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
struct fscache_volume *volume;
char *name;
int ret = 0;
name = kasprintf(GFP_KERNEL, "erofs,%s", sbi->opt.fsid);
if (!name)
return -ENOMEM;
volume = fscache_acquire_volume(name, NULL, NULL, 0);
if (IS_ERR_OR_NULL(volume)) {
erofs_err(sb, "failed to register volume for %s", name);
ret = volume ? PTR_ERR(volume) : -EOPNOTSUPP;
volume = NULL;
}
sbi->volume = volume;
kfree(name);
return ret;
}
void erofs_fscache_unregister_fs(struct super_block *sb)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
fscache_relinquish_volume(sbi->volume, NULL, false);
sbi->volume = NULL;
}
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