From bf59a5a21604ef79da9105bef1bae817fd053e75 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 20 Aug 2020 11:46:05 -0400 Subject: [PATCH] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW For similar reasons as BTRFS_NESTING_COW, we need BTRFS_NESTING_LEFT/RIGHT_COW. The pattern is this lock leaf -> BTRFS_NESTING_NORMAL cow leaf -> BTRFS_NESTING_COW split leaf lock left -> BTRFS_NESTING_LEFT cow left -> BTRFS_NESTING_LEFT_COW We need this in order to indicate to lockdep that these locks are discrete and are being taken in a safe order. Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/ctree.c | 12 ++++++------ fs/btrfs/locking.h | 8 ++++++++ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 94af1f385ea6..ecf8bf240d73 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1900,7 +1900,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, btrfs_set_lock_blocking_write(left); wret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, - BTRFS_NESTING_COW); + BTRFS_NESTING_LEFT_COW); if (wret) { ret = wret; goto enospc; @@ -1916,7 +1916,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans, btrfs_set_lock_blocking_write(right); wret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, - BTRFS_NESTING_COW); + BTRFS_NESTING_RIGHT_COW); if (wret) { ret = wret; goto enospc; @@ -2085,7 +2085,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, } else { ret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, - BTRFS_NESTING_COW); + BTRFS_NESTING_LEFT_COW); if (ret) wret = 1; else { @@ -2140,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans, } else { ret = btrfs_cow_block(trans, root, right, parent, pslot + 1, - &right, BTRFS_NESTING_COW); + &right, BTRFS_NESTING_RIGHT_COW); if (ret) wret = 1; else { @@ -3815,7 +3815,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root /* cow and double check */ ret = btrfs_cow_block(trans, root, right, upper, - slot + 1, &right, BTRFS_NESTING_COW); + slot + 1, &right, BTRFS_NESTING_RIGHT_COW); if (ret) goto out_unlock; @@ -4057,7 +4057,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root /* cow and double check */ ret = btrfs_cow_block(trans, root, left, path->nodes[1], slot - 1, &left, - BTRFS_NESTING_COW); + BTRFS_NESTING_LEFT_COW); if (ret) { /* we hit -ENOSPC, but it isn't fatal here */ if (ret == -ENOSPC) diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index 5844bc1c8410..16563bc486c7 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -44,6 +44,14 @@ enum btrfs_lock_nesting { BTRFS_NESTING_LEFT, BTRFS_NESTING_RIGHT, + /* + * When splitting we will be holding a lock on the left/right node when + * we need to cow that node, thus we need a new set of subclasses for + * these two operations. + */ + BTRFS_NESTING_LEFT_COW, + BTRFS_NESTING_RIGHT_COW, + /* * We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so * add this in here and add a static_assert to keep us from going over -- GitLab