btrfs: Add datacow mount option.
Add datacow mount option to enable copy-on-write with
remount option.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt
index 79c08f3..bbd1f0f 100644
--- a/Documentation/filesystems/btrfs.txt
+++ b/Documentation/filesystems/btrfs.txt
@@ -154,9 +154,10 @@
(non-battery-backed) write-back cache, nobarrier option will lead to
filesystem corruption on a system crash or power loss.
+ datacow(*)
nodatacow
- Disable data copy-on-write for newly created files. Implies nodatasum,
- and disables all compression.
+ Enable/disable data copy-on-write for newly created files.
+ Nodatacow implies nodatasum, and disables all compression.
nodatasum
Disable data checksumming for newly created files.
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 76eecd1..6567865 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -324,7 +324,7 @@
Opt_check_integrity, Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
- Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl,
+ Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
Opt_err,
};
@@ -335,6 +335,7 @@
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
{Opt_nodatacow, "nodatacow"},
+ {Opt_datacow, "datacow"},
{Opt_nobarrier, "nobarrier"},
{Opt_barrier, "barrier"},
{Opt_max_inline, "max_inline=%s"},
@@ -446,6 +447,11 @@
btrfs_set_opt(info->mount_opt, NODATACOW);
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
+ case Opt_datacow:
+ if (btrfs_test_opt(root, NODATACOW))
+ btrfs_info(root->fs_info, "setting datacow");
+ btrfs_clear_opt(info->mount_opt, NODATACOW);
+ break;
case Opt_compress_force:
case Opt_compress_force_type:
compress_force = true;