From mboxrd@z Thu Jan 1 00:00:00 1970 From: liubo Subject: Re: [PATCH 1/9] Btrfs: introduce sub transaction stuff Date: Wed, 25 May 2011 22:48:24 -0400 Message-ID: <4DDDBF78.5020600@cn.fujitsu.com> References: <1305792692-10635-1-git-send-email-liubo2009@cn.fujitsu.com> <1305792692-10635-2-git-send-email-liubo2009@cn.fujitsu.com> <1305850961-sup-454@shiny> <1306161195-sup-8189@shiny> <4DDC7E08.4020207@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-btrfs , josef To: Chris Mason Return-path: In-Reply-To: <4DDC7E08.4020207@cn.fujitsu.com> List-ID: On 05/24/2011 11:56 PM, liubo wrote: >> > >> > Second, we use the generation number of the super to read in the log >> > tree root after a crash. This doesn't always match the sub trans id and >> > so it doesn't always match the transid stored in the btree blocks. >> > >> > There are a few solutions to this, we can use some of the reserved >> > fields in the super for the generation numbers of the roots the super >> > points to, and use whichever one is bigger when we read things in. >> > > > All right, I'm going to dig it more. > I've got this resolved via 'log_root_transid' of 'struct btrfs_super_block', and it looks nice on both syntactic and functional side. :) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index ac8d2ac..1006898 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2103,6 +2103,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, if (btrfs_super_log_root(disk_super) != 0 && !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) { u64 bytenr = btrfs_super_log_root(disk_super); + u64 log_root_transid = btrfs_super_log_root_transid(disk_super); if (fs_devices->rw_devices == 0) { printk(KERN_WARNING "Btrfs log replay required " @@ -2125,7 +2126,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, log_tree_root->node = read_tree_block(tree_root, bytenr, blocksize, - generation + 1); + log_root_transid); ret = btrfs_recover_log_trees(log_tree_root); BUG_ON(ret); diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 912397c..b304ec1 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -2089,6 +2089,8 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, log_root_tree->node->start); btrfs_set_super_log_root_level(&root->fs_info->super_for_commit, btrfs_header_level(log_root_tree->node)); + btrfs_set_super_log_root_transid(&root->fs_info->super_for_commit, + trans->transid); log_root_tree->log_batch = 0; log_root_tree->log_transid++; thanks, liubo