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| author | Jan Schmidt <list.btrfs@jan-o-sch.net> | 2012-05-20 15:43:53 +0200 |
|---|---|---|
| committer | Jan Schmidt <list.btrfs@jan-o-sch.net> | 2012-05-30 15:17:36 +0200 |
| commit | 20b297d620cd1bb94127942bbb3702fb7b1030b2 (patch) | |
| tree | 45e1d42c376b168ae55460e2d481f915d6cc8b78 | |
| parent | 19ae4e8133f370d820c4cdd61a4b703235664a5f (diff) | |
| download | linux-20b297d620cd1bb94127942bbb3702fb7b1030b2.tar.bz2 | |
Btrfs: tree mod log sanity checks in join_transaction
When a fresh transaction begins, the tree mod log must be clean. Users of
the tree modification log must ensure they never span across transaction
boundaries.
We reset the sequence to 0 in this safe situation to make absolutely sure
overflow can't happen.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
| -rw-r--r-- | fs/btrfs/transaction.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index eb2bd826bb04..667735fb45e6 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -122,6 +122,24 @@ loop: cur_trans->delayed_refs.flushing = 0; cur_trans->delayed_refs.run_delayed_start = 0; cur_trans->delayed_refs.seq = 1; + + /* + * although the tree mod log is per file system and not per transaction, + * the log must never go across transaction boundaries. + */ + smp_mb(); + if (!list_empty(&fs_info->tree_mod_seq_list)) { + printk(KERN_ERR "btrfs: tree_mod_seq_list not empty when " + "creating a fresh transaction\n"); + WARN_ON(1); + } + if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) { + printk(KERN_ERR "btrfs: tree_mod_log rb tree not empty when " + "creating a fresh transaction\n"); + WARN_ON(1); + } + atomic_set(&fs_info->tree_mod_seq, 0); + init_waitqueue_head(&cur_trans->delayed_refs.seq_wait); spin_lock_init(&cur_trans->commit_lock); spin_lock_init(&cur_trans->delayed_refs.lock); |