From f47f816a5b1deabc1d501332a1a30af205d22515 Mon Sep 17 00:00:00 2001
From: Bobi Jam <bobijam@whamcloud.com>
Date: Wed, 10 May 2023 13:11:47 +0800
Subject: [PATCH] LU-16808 lfs: lfs find --printf won't hang on special files

Add O_NONBLOCK flag on opening special files lest it hang.

Since '--printf' requires gather_all, and in check_projid case and
gather_all case, it open the special file and try to get project id
from it, we shouldn't error out on only gather_all case.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: Ic2afff7bbccf73ff94c64c62799f9b37b18d10a1
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50905
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Thomas Bertschinger <bertschinger@lanl.gov>
---
 lustre/tests/sanity.sh      | 16 ++++++++++++++++
 lustre/utils/liblustreapi.c | 20 +++++++++++---------
 2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index 4235273..44a38b9 100755
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -7184,6 +7184,22 @@ test_56rc() {
 }
 run_test 56rc "check lfs find --mdt-count/--mdt-hash works"
 
+test_56rd() {
+	local dir=$DIR/$tdir
+
+	test_mkdir $dir
+
+	mkfifo $dir/fifo || error "failed to create fifo file"
+	found=$($LFS find $dir -t p --printf "%y")
+	[[ "p" = $found ]] || error "found $found, expect p"
+
+	mknod $dir/chardev c 1 5 ||
+		error "failed to create character device file"
+	found=$($LFS find $dir -t c --printf "%y")
+	[[ "c" = $found ]] || error "found $found, expect c"
+}
+run_test 56rd "check lfs find --printf special files"
+
 test_56s() { # LU-611 #LU-9369
 	[[ $OSTCOUNT -lt 2 ]] && skip_env "need at least 2 OSTs"
 
diff --git a/lustre/utils/liblustreapi.c b/lustre/utils/liblustreapi.c
index b9a2f8e..a48313d 100644
--- a/lustre/utils/liblustreapi.c
+++ b/lustre/utils/liblustreapi.c
@@ -5499,20 +5499,22 @@ obd_matches:
 		int projid = 0;
 
 		if (fd == -2)
-			fd = open(path, O_RDONLY);
+			fd = open(path, O_RDONLY | O_NONBLOCK);
 
 		if (fd > 0)
 			ret = fget_projid(fd, &projid);
 		else
 			ret = -errno;
-		if (ret)
-			goto out;
-		if (projid == param->fp_projid) {
-			if (param->fp_exclude_projid)
-				goto decided;
-		} else {
-			if (!param->fp_exclude_projid)
-				goto decided;
+		if (param->fp_check_projid) {
+			if (ret)
+				goto out;
+			if (projid == param->fp_projid) {
+				if (param->fp_exclude_projid)
+					goto decided;
+			} else {
+				if (!param->fp_exclude_projid)
+					goto decided;
+			}
 		}
 	}
 
-- 
1.8.3.1