From 95a4ba7fde10b90904d9fbb277ce2a4ac926ee24 Mon Sep 17 00:00:00 2001 From: Chunhai Guo Date: Mon, 10 Jul 2023 12:25:31 +0800 Subject: [PATCH] erofs: avoid useless loops in z_erofs_pcluster_readmore() when reading beyond EOF [ Upstream commit 936aa701d82d397c2d1afcd18ce2c739471d978d ] z_erofs_pcluster_readmore() may take a long time to loop when the page offset is large enough, which is unnecessary should be prevented. For example, when the following case is encountered, it will loop 4691368 times, taking about 27 seconds: - offset = 19217289215 - inode_size = 1442672 Signed-off-by: Chunhai Guo Fixes: 386292919c25 ("erofs: introduce readmore decompression strategy") Reviewed-by: Gao Xiang Reviewed-by: Yue Hu Reviewed-by: Chao Yu Link: https://lore.kernel.org/r/20230710042531.28761-1-guochunhai@vivo.com Signed-off-by: Gao Xiang Signed-off-by: Sasha Levin --- fs/erofs/zdata.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 502893e3da01..bedfff5d45fa 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1807,7 +1807,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f, } cur = map->m_la + map->m_llen - 1; - while (cur >= end) { + while ((cur >= end) && (cur < i_size_read(inode))) { pgoff_t index = cur >> PAGE_SHIFT; struct page *page;