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Btrfs: avoid unnecessary switch of path locks to blocking mode

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If we need to cow a node, increase the write lock level and retry the
tree search, there's no point of changing the node locks in our path
to blocking mode, as we only waste time and unnecessarily wake up other
tasks waiting on the spinning locks (just to block them again shortly
after) because we release our path before repeating the tree search.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Filipe Manana 2014-07-28 19:37:17 +01:00 committed by Chris Mason
parent 24cdc847d9
commit 160f4089c8
1 changed files with 1 additions and 2 deletions
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3
fs/btrfs/ctree.c
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@ -2792,8 +2792,6 @@ again:
if (!should_cow_block(trans, root, b))
goto cow_done;
btrfs_set_path_blocking(p);
/*
* must have write locks on this node and the
* parent
@ -2807,6 +2805,7 @@ again:
goto again;
}
btrfs_set_path_blocking(p);
err = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
p->slots[level + 1], &b);