Currently 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.
We can use log_root_transid to record the log_root_tree's generation
so that when we recover from crash, we can match log_root_tree's btree blocks.
Signed-off-by: Liu Bo <liubo2009@xxxxxxxxxxxxxx>
---
fs/btrfs/disk-io.c | 14 ++++++++++++--
fs/btrfs/tree-log.c | 2 ++
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7572b2e..c2b8351 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2039,7 +2039,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
/* do not make disk changes in broken FS */
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 bytenr;
+ u64 log_root_transid;
if (fs_devices->rw_devices == 0) {
printk(KERN_WARNING "Btrfs log replay required "
@@ -2060,9 +2061,18 @@ struct btrfs_root *open_ctree(struct super_block *sb,
__setup_root(nodesize, leafsize, sectorsize, stripesize,
log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
+ bytenr = btrfs_super_log_root(disk_super);
+
+ /* for old btrfs, we need to do something compatible. */
+ if (btrfs_super_log_root_transid(disk_super))
+ log_root_transid =
+ btrfs_super_log_root_transid(disk_super);
+ else
+ log_root_transid = generation + 1;
+
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 e02b8d3..b96bb5c 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2111,6 +2111,8 @@ 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++;
--
1.6.5.2
--
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