Btrfs: Add mount -o compress-force
The default btrfs mount -o compress mode will quickly back off
compressing a file if it notices that compression does not reduce the
size of the data being written. This can save considerable CPU because
all future writes to the file go through uncompressed.
But some files are both very large and have mixed data stored in
them. In that case, we want to add the ability to always try
compressing data before writing it.
This commit adds mount -o compress-force. A later commit will add
a new inode flag that does the same thing.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 3f9b457..8a1ea6e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -66,7 +66,8 @@
Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl,
- Opt_compress, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
+ Opt_compress, Opt_compress_force, Opt_notreelog, Opt_ratio,
+ Opt_flushoncommit,
Opt_discard, Opt_err,
};
@@ -82,6 +83,7 @@
{Opt_alloc_start, "alloc_start=%s"},
{Opt_thread_pool, "thread_pool=%d"},
{Opt_compress, "compress"},
+ {Opt_compress_force, "compress-force"},
{Opt_ssd, "ssd"},
{Opt_ssd_spread, "ssd_spread"},
{Opt_nossd, "nossd"},
@@ -173,6 +175,11 @@
printk(KERN_INFO "btrfs: use compression\n");
btrfs_set_opt(info->mount_opt, COMPRESS);
break;
+ case Opt_compress_force:
+ printk(KERN_INFO "btrfs: forcing compression\n");
+ btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ break;
case Opt_ssd:
printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
btrfs_set_opt(info->mount_opt, SSD);