[PATCH] btrfs-progs: subv del: hide a bogus warning on an unprivileged delete

From: Adam Borowski <kilobyte@angband.pl>
To: linux-btrfs@vger.kernel.org
Cc: Adam Borowski <kilobyte@angband.pl>
Subject: [PATCH] btrfs-progs: subv del: hide a bogus warning on an unprivileged delete
Date: Mon, 24 Jan 2022 14:36:32 +0100	[thread overview]
Message-ID: <20220124133632.62597-1-kilobyte@angband.pl> (raw)

Checking the default subvolume uses TREE_SEARCH which is a CAP_SYS_ADMIN
only operation, and thus will fail when unprivileged, even if we have
permissions to actually delete the subvolume.

This produces a warning even if all is ok.  Let's hide it if we're not
root (root but !CAP is odd enough to warn).

Fixes 87804a3f0663a4d1891395bd97b8e81e6f183e66
Ref: https://bugs.debian.org/998840
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
---
 cmds/subvolume.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/cmds/subvolume.c b/cmds/subvolume.c
index 6aac7dd1..e767e20d 100644
--- a/cmds/subvolume.c
+++ b/cmds/subvolume.c
@@ -376,7 +376,8 @@ again:
 
 	err = btrfs_util_get_default_subvolume_fd(fd, &default_subvol_id);
 	if (err) {
-		warning("cannot read default subvolume id: %m");
+		if (!geteuid())
+			warning("cannot read default subvolume id: %m");
 		default_subvol_id = 0;
 	}
 
-- 
2.34.1

