From b15b2e307c3a1970d92da77a3ef57ee53d119d8e Mon Sep 17 00:00:00 2001 From: Yue Hu Date: Fri, 23 Sep 2022 10:11:22 +0800 Subject: erofs: support on-disk compressed fragments data Introduce on-disk compressed fragments data feature. This approach adds a new field called `h_fragmentoff' in the per-file compression header to indicate the fragment offset of each tail pcluster or the whole file in the special packed inode. Similar to ztailpacking, it will also find and record the 'headlcn' of the tail pcluster when initializing per-inode zmap for making follow-on requests more easy. Signed-off-by: Yue Hu Reviewed-by: Gao Xiang Link: https://lore.kernel.org/r/YzHKxcFTlHGgXeH9@B-P7TQMD6M-0146.local Signed-off-by: Gao Xiang --- fs/erofs/zdata.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) (limited to 'fs/erofs/zdata.c') diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 5792ca9e0d5e..c92a72f5bca6 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -650,6 +650,35 @@ static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe, la < fe->headoffset; } +static int z_erofs_read_fragment(struct inode *inode, erofs_off_t pos, + struct page *page, unsigned int pageofs, + unsigned int len) +{ + struct inode *packed_inode = EROFS_I_SB(inode)->packed_inode; + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; + u8 *src, *dst; + unsigned int i, cnt; + + pos += EROFS_I(inode)->z_fragmentoff; + for (i = 0; i < len; i += cnt) { + cnt = min_t(unsigned int, len - i, + EROFS_BLKSIZ - erofs_blkoff(pos)); + src = erofs_bread(&buf, packed_inode, + erofs_blknr(pos), EROFS_KMAP); + if (IS_ERR(src)) { + erofs_put_metabuf(&buf); + return PTR_ERR(src); + } + + dst = kmap_local_page(page); + memcpy(dst + pageofs + i, src + erofs_blkoff(pos), cnt); + kunmap_local(dst); + pos += cnt; + } + erofs_put_metabuf(&buf); + return 0; +} + static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, struct page *page, struct page **pagepool) { @@ -688,7 +717,8 @@ repeat: /* didn't get a valid pcluster previously (very rare) */ } - if (!(map->m_flags & EROFS_MAP_MAPPED)) + if (!(map->m_flags & EROFS_MAP_MAPPED) || + map->m_flags & EROFS_MAP_FRAGMENT) goto hitted; err = z_erofs_collector_begin(fe); @@ -735,6 +765,24 @@ hitted: zero_user_segment(page, cur, end); goto next_part; } + if (map->m_flags & EROFS_MAP_FRAGMENT) { + unsigned int pageofs, skip, len; + + if (offset > map->m_la) { + pageofs = 0; + skip = offset - map->m_la; + } else { + pageofs = map->m_la & ~PAGE_MASK; + skip = 0; + } + len = min_t(unsigned int, map->m_llen - skip, end - cur); + err = z_erofs_read_fragment(inode, skip, page, pageofs, len); + if (err) + goto out; + ++spiltted; + tight = false; + goto next_part; + } exclusive = (!cur && (!spiltted || tight)); if (cur) -- cgit