Signed-off-by: Sami Kerola <kerolasa@xxxxxx> --- disk-utils/mkswap.8 | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/disk-utils/mkswap.8 b/disk-utils/mkswap.8 index 0a0b715..815c23d 100644 --- a/disk-utils/mkswap.8 +++ b/disk-utils/mkswap.8 @@ -128,9 +128,19 @@ e.g.\& using a command like .RE .fi -Note that a swap file must not contain any holes (so, using +Note that a swap file must not contain any holes. Using .BR cp (1) -to create the file is not acceptable). +to create the file is not acceptable. Neither is use of +.BR fallocate (1) +on file systems that support preallocated files, such as +.BR XFS " or " ext4 , +or on copy-on-write filesystems like +.BR btrfs . +It is recommended to use +.BR dd (1) +and /dev/zero to in these cases. Please read notes from +.BR swapon (8) +before adding a swap file to copy-on-write filesystems. .SH ENVIRONMENT .IP LIBBLKID_DEBUG=all -- 2.4.4 -- To unsubscribe from this list: send the line "unsubscribe util-linux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
