just a few quick things for the changelog:
On 09/29/2017 01:43 PM, Josef Bacik wrote:
> Right now we do a lot of weird hoops around outstanding_extents in order
> to keep the extent count consistent. This is because we logically
> transfer the outstanding_extent count from the initial reservation
> through the set_delalloc_bits. This makes it pretty difficult to get a
> handle on how and when we need to mess with outstanding_extents.
>
> Fix this by revamping the rules of how we deal with outstanding_extents.
> Now instead everybody that is holding on to a delalloc extent is
> required to increase the outstanding extents count for itself. This
> means we'll have something like this
>
> btrfs_dealloc_reserve_metadata - outstanding_extents = 1
s/dealloc/delalloc/
> btrfs_set_delalloc - outstanding_extents = 2
should be btrfs_set_extent_delalloc?
> btrfs_release_delalloc_extents - outstanding_extents = 1
>
> for an initial file write. Now take the append write where we extend an
> existing delalloc range but still under the maximum extent size
>
> btrfs_delalloc_reserve_metadata - outstanding_extents = 2
> btrfs_set_delalloc
btrfs_set_extent_delalloc?
> btrfs_set_bit_hook - outstanding_extents = 3
> btrfs_merge_bit_hook - outstanding_extents = 2
should be btrfs_clear_bit_hook? (or btrfs_merge_extent_hook?)
> btrfs_release_delalloc_extents - outstanding_extnets = 1
btrfs_delalloc_release_metadata?
>
> In order to make the ordered extent transition we of course must now
> make ordered extents carry their own outstanding_extent reservation, so
> for cow_file_range we end up with
>
> btrfs_add_ordered_extent - outstanding_extents = 2
> clear_extent_bit - outstanding_extents = 1
> btrfs_remove_ordered_extent - outstanding_extents = 0
>
> This makes all manipulations of outstanding_extents much more explicit.
> Every successful call to btrfs_reserve_delalloc_metadata _must_ now be
^
btrfs_delalloc_reserve_metadata?
Thanks,
Ed
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