worse than expected compression ratios with -o compress

Commit Message

Chris Mason Jan. 20, 2010, 4:30 p.m. UTC

None

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9f806dd..2aa8ec6 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1161,6 +1161,7 @@  struct btrfs_root {
 #define BTRFS_MOUNT_SSD_SPREAD		(1 << 8)
 #define BTRFS_MOUNT_NOSSD		(1 << 9)
 #define BTRFS_MOUNT_DISCARD		(1 << 10)
+#define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
 
 #define btrfs_clear_opt(o, opt)		((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)		((o) |= BTRFS_MOUNT_##opt)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b330e27..f46c572 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -483,7 +483,8 @@  again:
 		nr_pages_ret = 0;
 
 		/* flag the file so we don't compress in the future */
-		BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
+		if (!btrfs_test_opt(root, FORCE_COMPRESS))
+			BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
 	}
 	if (will_compress) {
 		*num_added += 1;
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 @@  enum {
 	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 @@  static match_table_t tokens = {
 	{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 @@  int btrfs_parse_options(struct btrfs_root *root, char *options)
 			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);