Btrfs: Add a clear_cache mount option

Commit Message

Josef Bacik Sept. 21, 2010, 6:23 p.m. UTC

None

Patch

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 1ecd8f6..470f06c 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1226,6 +1226,7 @@  struct btrfs_root {
 #define BTRFS_MOUNT_NOSSD		(1 << 9)
 #define BTRFS_MOUNT_DISCARD		(1 << 10)
 #define BTRFS_MOUNT_FORCE_COMPRESS      (1 << 11)
+#define BTRFS_MOUNT_CLEAR_CACHE		(1 << 12)
 
 #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/extent-tree.c b/fs/btrfs/extent-tree.c
index c0a9ad3..5343e56 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2836,6 +2836,7 @@  int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 	int err = 0;
 	struct btrfs_path *path;
 	u64 last = 0;
+	u64 features = btrfs_super_incompat_flags(&root->fs_info->super_copy);
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -2885,8 +2886,13 @@  again:
 			continue;
 		}
 
-		if (cache->disk_cache_state == BTRFS_DC_SETUP)
-			cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
+		if (cache->disk_cache_state == BTRFS_DC_SETUP) {
+			if (features & BTRFS_FEATURE_INCOMPAT_SPACE_CACHE)
+				cache->disk_cache_state = BTRFS_DC_NEED_WRITE;
+			else
+				cache->disk_cache_state = BTRFS_DC_WRITTEN;
+		}
+
 		cache->dirty = 0;
 		last = cache->key.objectid + cache->key.offset;
 
@@ -8262,6 +8268,9 @@  int btrfs_read_block_groups(struct btrfs_root *root)
 			free_excluded_extents(root, cache);
 		}
 
+		if (btrfs_test_opt(root, CLEAR_CACHE))
+			cache->disk_cache_state = BTRFS_DC_CLEAR;
+
 		ret = update_space_info(info, cache->flags, found_key.offset,
 					btrfs_block_group_used(&cache->item),
 					&space_info);
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index c1e8b6e..81085b4 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -242,8 +242,6 @@  int load_free_space_cache(struct btrfs_fs_info *fs_info,
 	 */
 	spin_lock(&block_group->lock);
 	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
-		printk(KERN_ERR "not reading block group %llu, dcs is %d\n", block_group->key.objectid,
-		       block_group->disk_cache_state);
 		spin_unlock(&block_group->lock);
 		return 0;
 	}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6a625e9..1b92f57 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -68,7 +68,7 @@  enum {
 	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
 	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
 	Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
-	Opt_discard, Opt_space_cache, Opt_err,
+	Opt_discard, Opt_space_cache, Opt_clear_cache, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -93,6 +93,7 @@  static match_table_t tokens = {
 	{Opt_ratio, "metadata_ratio=%d"},
 	{Opt_discard, "discard"},
 	{Opt_space_cache, "space_cache"},
+	{Opt_clear_cache, "clear_cache"},
 	{Opt_err, NULL},
 };
 
@@ -244,6 +245,9 @@  int btrfs_parse_options(struct btrfs_root *root, char *options)
 			features |= BTRFS_FEATURE_INCOMPAT_SPACE_CACHE;
 			btrfs_set_super_incompat_flags(disk_super, features);
 			break;
+		case Opt_clear_cache:
+			btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
+			break;
 		case Opt_err:
 			printk(KERN_INFO "btrfs: unrecognized mount option "
 			       "'%s'\n", p);