From: Chuck Lever <chuck.lever@oracle.com>
Date: Mon, 6 Mar 2023 10:43:47 -0500
Subject: [PATCH] NFSD: Protect against filesystem freezing
References: bsc#1012628
Patch-mainline: 6.2.7
Git-commit: fd9a2e1d513823e840960cb3bc26d8b7749d4ac2

[ Upstream commit fd9a2e1d513823e840960cb3bc26d8b7749d4ac2 ]

Flole observes this WARNING on occasion:

[1210423.486503] WARNING: CPU: 8 PID: 1524732 at fs/ext4/ext4_jbd2.c:75 ext4_journal_check_start+0x68/0xb0

Reported-by: <flole@flole.de>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217123
Fixes: 73da852e3831 ("nfsd: use vfs_iter_read/write")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 fs/nfsd/vfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 4c3a0d84..bb1e8558 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1100,7 +1100,9 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
 	since = READ_ONCE(file->f_wb_err);
 	if (verf)
 		nfsd_copy_write_verifier(verf, nn);
+	file_start_write(file);
 	host_err = vfs_iter_write(file, &iter, &pos, flags);
+	file_end_write(file);
 	if (host_err < 0) {
 		nfsd_reset_write_verifier(nn);
 		trace_nfsd_writeverf_reset(nn, rqstp, host_err);
-- 
2.35.3