From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Mon, 30 Aug 2021 20:30:45 +0000 (-0700)
Subject: f2fs: should put a page beyond EOF when preparing a write
X-Git-Tag: v5.13.19~245
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2ab0481fe3231456945cf12cc8c0d1fc52464518;p=thirdparty%2Fkernel%2Fstable.git

f2fs: should put a page beyond EOF when preparing a write

[ Upstream commit 9605f75cf36e0bcc0f4ada07b5be712d30107607 ]

The prepare_compress_overwrite() gets/locks a page to prepare a read, and calls
f2fs_read_multi_pages() which checks EOF first. If there's any page beyond EOF,
we unlock the page and set cc->rpages[i] = NULL, which we can't put the page
anymore. This makes page leak, so let's fix by putting that page.

Fixes: a949dc5f2c5c ("f2fs: compress: fix race condition of overwrite vs truncate")
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 3cd509b085f2e..198e5ad7c98b5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2151,6 +2151,8 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
 			continue;
 		}
 		unlock_page(page);
+		if (for_write)
+			put_page(page);
 		cc->rpages[i] = NULL;
 		cc->nr_rpages--;
 	}