From 8cef4e160d74920ad1725f58c89fd75ec4c4ac38 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Thu, 12 Nov 2009 09:33:26 +0000 Subject: Btrfs: Avoid superfluous tree-log writeout We allow two log transactions at a time, but use same flag to mark dirty tree-log btree blocks. So we may flush dirty blocks belonging to newer log transaction when committing a log transaction. This patch fixes the issue by using two flags to mark dirty tree-log btree blocks. Signed-off-by: Yan Zheng Signed-off-by: Chris Mason --- fs/btrfs/tree-log.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 741666a7676a..31da0002e78b 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -1977,10 +1977,11 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, { int index1; int index2; + int mark; int ret; struct btrfs_root *log = root->log_root; struct btrfs_root *log_root_tree = root->fs_info->log_root_tree; - u64 log_transid = 0; + unsigned long log_transid = 0; mutex_lock(&root->log_mutex); index1 = root->log_transid % 2; @@ -2014,24 +2015,29 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, goto out; } + log_transid = root->log_transid; + if (log_transid % 2 == 0) + mark = EXTENT_DIRTY; + else + mark = EXTENT_NEW; + /* we start IO on all the marked extents here, but we don't actually * wait for them until later. */ - ret = btrfs_write_marked_extents(log, &log->dirty_log_pages); + ret = btrfs_write_marked_extents(log, &log->dirty_log_pages, mark); BUG_ON(ret); btrfs_set_root_node(&log->root_item, log->node); root->log_batch = 0; - log_transid = root->log_transid; root->log_transid++; log->log_transid = root->log_transid; root->log_start_pid = 0; smp_mb(); /* - * log tree has been flushed to disk, new modifications of - * the log will be written to new positions. so it's safe to - * allow log writers to go in. + * IO has been started, blocks of the log tree have WRITTEN flag set + * in their headers. new modifications of the log will be written to + * new positions. so it's safe to allow log writers to go in. */ mutex_unlock(&root->log_mutex); @@ -2052,7 +2058,7 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, index2 = log_root_tree->log_transid % 2; if (atomic_read(&log_root_tree->log_commit[index2])) { - btrfs_wait_marked_extents(log, &log->dirty_log_pages); + btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark); wait_log_commit(trans, log_root_tree, log_root_tree->log_transid); mutex_unlock(&log_root_tree->log_mutex); @@ -2072,16 +2078,17 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, * check the full commit flag again */ if (root->fs_info->last_trans_log_full_commit == trans->transid) { - btrfs_wait_marked_extents(log, &log->dirty_log_pages); + btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark); mutex_unlock(&log_root_tree->log_mutex); ret = -EAGAIN; goto out_wake_log_root; } ret = btrfs_write_and_wait_marked_extents(log_root_tree, - &log_root_tree->dirty_log_pages); + &log_root_tree->dirty_log_pages, + EXTENT_DIRTY | EXTENT_NEW); BUG_ON(ret); - btrfs_wait_marked_extents(log, &log->dirty_log_pages); + btrfs_wait_marked_extents(log, &log->dirty_log_pages, mark); btrfs_set_super_log_root(&root->fs_info->super_for_commit, log_root_tree->node->start); @@ -2147,12 +2154,12 @@ int btrfs_free_log(struct btrfs_trans_handle *trans, struct btrfs_root *root) while (1) { ret = find_first_extent_bit(&log->dirty_log_pages, - 0, &start, &end, EXTENT_DIRTY); + 0, &start, &end, EXTENT_DIRTY | EXTENT_NEW); if (ret) break; - clear_extent_dirty(&log->dirty_log_pages, - start, end, GFP_NOFS); + clear_extent_bits(&log->dirty_log_pages, start, end, + EXTENT_DIRTY | EXTENT_NEW, GFP_NOFS); } if (log->log_transid > 0) { -- cgit v1.2.3