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| author | Josef Bacik <josef@toxicpanda.com> | 2020-08-20 18:46:06 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2020-10-07 13:12:16 +0300 |
| commit | 4dff97e69005ea90266f3e3dda295264e854c15d (patch) | |
| tree | 6f2cc1bb65ab472f6cec7106c7b3fa2c04277163 | |
| parent | bf59a5a21604ef79da9105bef1bae817fd053e75 (diff) | |
| download | linux-4dff97e69005ea90266f3e3dda295264e854c15d.tar.xz | |
btrfs: introduce BTRFS_NESTING_SPLIT for split blocks
If we are splitting a leaf/node, we could do something like the
following
lock(leaf) BTRFS_NESTING_NORMAL
lock(left) BTRFS_NESTING_LEFT + BTRFS_NESTING_COW
push from leaf -> left
reset path to point to left
split left
allocate new block, lock block BTRFS_NESTING_SPLIT
at the new block point we need to have a different nesting level,
because we have already used either BTRFS_NESTING_LEFT or
BTRFS_NESTING_RIGHT when pushing items from the original leaf into the
adjacent leaves.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/ctree.c | 4 | ||||
| -rw-r--r-- | fs/btrfs/locking.h | 9 |
2 files changed, 11 insertions, 2 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index ecf8bf240d73..884c8b5a0e62 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -3537,7 +3537,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans, btrfs_node_key(c, &disk_key, mid); split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level, - c->start, 0, BTRFS_NESTING_NORMAL); + c->start, 0, BTRFS_NESTING_SPLIT); if (IS_ERR(split)) return PTR_ERR(split); @@ -4324,7 +4324,7 @@ again: btrfs_item_key(l, &disk_key, mid); right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0, - l->start, 0, BTRFS_NESTING_NORMAL); + l->start, 0, BTRFS_NESTING_SPLIT); if (IS_ERR(right)) return PTR_ERR(right); diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h index 16563bc486c7..a6b59808e046 100644 --- a/fs/btrfs/locking.h +++ b/fs/btrfs/locking.h @@ -53,6 +53,15 @@ enum btrfs_lock_nesting { BTRFS_NESTING_RIGHT_COW, /* + * When splitting we may push nodes to the left or right, but still use + * the subsequent nodes in our path, keeping our locks on those adjacent + * blocks. Thus when we go to allocate a new split block we've already + * used up all of our available subclasses, so this subclass exists to + * handle this case where we need to allocate a new split block. + */ + BTRFS_NESTING_SPLIT, + + /* * 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 * the limit. As of this writing we're limited to 8, and we're |