From 73a7217912d61e55932617b794910229293ca456 Mon Sep 17 00:00:00 2001 From: Shawn Zhong Date: Wed, 22 Jun 2022 19:34:44 -0500 Subject: [PATCH] Update docs to reflect mount option changes --- Documentation/filesystems/nova.txt | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/Documentation/filesystems/nova.txt b/Documentation/filesystems/nova.txt index af90da1c3fb1..20832a1d157b 100644 --- a/Documentation/filesystems/nova.txt +++ b/Documentation/filesystems/nova.txt @@ -71,7 +71,7 @@ After the OS has booted, you can initialize a NOVA instance with the following c The above commands create a NOVA instance on `/dev/pmem0` and mounts it on `/mnt/ramdisk`. -Nova support several module command line options: +Nova supports several module command line options: * metadata_csum: Enable metadata replication and checksums (default 0) @@ -79,18 +79,18 @@ Nova support several module command line options: * data_parity: Compute parity for file data. (default: 0) - * inplace_data_updates: Update data in place rather than with COW (default: 0) +Nova also supports the following mount options: + + * data_cow: Update data with COW rather than in place. * wprotect: Make PMEM unwritable and then use CR0.WP to enable writes as - needed (default: 0). You must also install the nd_pmem module as with - wprotect =1 (e.g., modprobe nd_pmem readonly=1). + needed. You must also install the nd_pmem module as with wprotect = 1 + (e.g., modprobe nd_pmem readonly=1). For instance to enable all Nova's data protection features: -# modprobe nova metadata_csum=1\ - data_csum=1\ - data_parity=1\ - wprotect=1 +# modprobe nova metadata_csum=1 data_csum=1 data_parity=1 +# mount -t NOVA -o init -o data_cow -o wprotect /dev/pmem0 /mnt/ramdisk Currently, remounting file systems with different combinations of options may not work. @@ -547,9 +547,9 @@ and 'data_checksum=0'). Without parity, Nova can detect but not recover from data corruption. Without checksums, Nova will still detect and recover from media errors, but not scribbles. -Nova also supports in-place file updates (option: inplace_data_updates=1). -This breaks atomicity for writes, but improve performance, especially for -sub-page writes, since these require a full page COW in the default mode. +Nova uses in-place file updates by default. This breaks atomicity for writes, +but improve performance, especially for sub-page writes, since these require a +full page COW. CoW can be enabled with the mount option 'data_cow'. Metadata --------