erofs: support reading chunk-based uncompressed files
Add runtime support for chunk-based uncompressed files
described in the previous patch.
Link: https://lore.kernel.org/r/20210820100019.208490-2-hsiangkao@linux.alibaba.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>
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 09c46fbdb..9db8297 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
*/
#include "internal.h"
#include <linux/prefetch.h>
@@ -36,13 +37,6 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
lastblk = nblocks - tailendpacking;
- if (offset >= inode->i_size) {
- /* leave out-of-bound access unmapped */
- map->m_flags = 0;
- map->m_plen = 0;
- goto out;
- }
-
/* there is no hole in flatmode */
map->m_flags = EROFS_MAP_MAPPED;
@@ -77,14 +71,90 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
goto err_out;
}
-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)
{
@@ -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;
