linux-kernel - [PATCH 2/5] f2fs: fix to avoid potential deadlock

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Date:   Mon, 24 Feb 2020 19:20:16 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <chao@...nel.org>,
        Chao Yu <yuchao0@...wei.com>
Subject: [PATCH 2/5] f2fs: fix to avoid potential deadlock

Using f2fs_trylock_op() in f2fs_write_compressed_pages() to avoid potential
deadlock like we did in f2fs_write_single_data_page().

Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
 fs/f2fs/compress.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index b1bc057ee266..4ba65a3b0456 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -772,7 +772,6 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 		.encrypted_page = NULL,
 		.compressed_page = NULL,
 		.submitted = false,
-		.need_lock = LOCK_RETRY,
 		.io_type = io_type,
 		.io_wbc = wbc,
 		.encrypted = f2fs_encrypted_file(cc->inode),
@@ -785,9 +784,10 @@ static int f2fs_write_compressed_pages(struct compress_ctx *cc,
 	loff_t psize;
 	int i, err;
 
-	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
+	if (!f2fs_trylock_op(sbi))
+		return -EAGAIN;
 
-	f2fs_lock_op(sbi);
+	set_new_dnode(&dn, cc->inode, NULL, NULL, 0);
 
 	err = f2fs_get_dnode_of_data(&dn, start_idx, LOOKUP_NODE);
 	if (err)
-- 
2.18.0.rc1