[PATCH 5.14 153/432] f2fs: should put a page beyond EOF when preparing a write

Greg Kroah-Hartman
2021-09-16T17:25:45Z

From: Jaegeuk Kim <jaegeuk@kernel.org>

[ 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>
---
fs/f2fs/data.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f2498e4ad89d..a86f004c0c07 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2153,6 +2153,8 @@ 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--;
}
--
2.30.2