From 56c2d2904f018e08131bc0ef0c90b6c69b762268 Mon Sep 17 00:00:00 2001 From: Karel Zak Date: Tue, 22 Jan 2019 10:13:54 +0100 Subject: swapon: be more explicit about BTRFS It seems nocow and nodatasum attributes are required. See btrfs_swap_activate() in https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ed46ff3d423780fa5173b38a844bf0fdb210a2a7 Addresses: https://github.com/karelzak/util-linux/issues/633 Signed-off-by: Karel Zak --- sys-utils/swapon.8 | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'sys-utils/swapon.8') diff --git a/sys-utils/swapon.8 b/sys-utils/swapon.8 index 60e4d4feb..d645850bb 100644 --- a/sys-utils/swapon.8 +++ b/sys-utils/swapon.8 @@ -207,9 +207,10 @@ The most portable solution to create a swap file is to use .BR dd (1) and /dev/zero in these cases. .SS Btrfs -The swap files on btrfs are supported since Linux 5.0. The previous versions use -copy-on-write semantic for the swap files, it means that the file location is may not be static -and corruption can result. +The swap files on btrfs are supported since Linux 5.0 on files with nocow and +nodatasum attributes and without compression. The previous versions may use +copy-on-write semantic for the swap files, it means that the file location is +may not be static and corruption can result. .sp One possible workaround is to map the swap file to a loopback device. This will allow the filesystem to determine the mapping properly but may come with a performance impact. -- cgit v1.2.3-55-g7522