btrfs: add cached_state to read_extent_buffer_subpage

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We don't use a cached state here at all, which generally makes sense as
async reads are going to unlock at endio time.  However for blocking
reads we will call wait_extent_bit() for our range.  Since the
lock_extent() stuff will return the cached_state for the start of the
range this is a helpful optimization to have for this case, we'll have
the exact state we want to wait on.  Add a cached state here and simply
throw it away if we're a non-blocking read, otherwise we'll get a small
improvement by eliminating some tree searches.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

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Josef Bacik 2022-09-30 16:45:13 -04:00 • committed by David Sterba

parent 123a7f008c

commit e5e886bad9

1 changed files with 10 additions and 5 deletions

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fs/btrfs/extent_io.c

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