btrfs: explicitly protect ->last_byte_to_unpin in unpin_extent_range

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Currently unpin_extent_range happens in the transaction commit context,
so we are protected from ->last_byte_to_unpin changing while we're
unpinning, because any new transactions would have to wait for us to
complete before modifying ->last_byte_to_unpin.

However in the future we may want to change how this works, for instance
with async unpinning or other such TODO items.  To prepare for that
future explicitly protect ->last_byte_to_unpin with the commit_root_sem
so we are sure it won't change while we're doing our work.

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 2020-10-23 09:58:06 -04:00 • committed by David Sterba

parent 27d56e62e4

commit 2ca08c56e8

1 changed files with 2 additions and 0 deletions

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fs/btrfs/extent-tree.c

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