Commit e38e2ed7 authored by Filipe Manana's avatar Filipe Manana Committed by Chris Mason
Browse files

Btrfs: make find_first_extent_bit be able to cache any state 



Right now the only caller of find_first_extent_bit() that is interested
in caching extent states (transaction or log commit), never gets an extent
state cached. This is because find_first_extent_bit() only caches states
that have at least one of the flags EXTENT_IOBITS or EXTENT_BOUNDARY, and
the transaction/log commit caller always passes a tree that doesn't have
ever extent states with any of those flags (they can only have one of the
following flags: EXTENT_DIRTY, EXTENT_NEW or EXTENT_NEED_WAIT).

This change together with the following one in the patch series (titled
"Btrfs: avoid returning -ENOMEM in convert_extent_bit() too early") will
help reduce significantly the chances of calls to convert_extent_bit()
fail with -ENOMEM when called from the transaction/log commit code.

Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 663dfbb0

fs/btrfs/extent_io.c

+12 −4
Original line number Original line Diff line number Diff line
@@ -796,17 +796,25 @@ static void set_state_bits(struct extent_io_tree *tree, 
	state->state |= bits_to_set;

	state->state |= bits_to_set;

}

}





static void cache_state(struct extent_state *state,

static void cache_state_if_flags(struct extent_state *state,

			struct extent_state **cached_ptr)

				 struct extent_state **cached_ptr,

				 const u64 flags)

{

{

	if (cached_ptr && !(*cached_ptr)) {

	if (cached_ptr && !(*cached_ptr)) {

		if (state->state & (EXTENT_IOBITS | EXTENT_BOUNDARY)) {

		if (!flags || (state->state & flags)) {

			*cached_ptr = state;

			*cached_ptr = state;

			atomic_inc(&state->refs);

			atomic_inc(&state->refs);

		}

		}

	}

	}

}

}





static void cache_state(struct extent_state *state,

			struct extent_state **cached_ptr)

{

	return cache_state_if_flags(state, cached_ptr,

				    EXTENT_IOBITS | EXTENT_BOUNDARY);

}



/*

/*

 * set some bits on a range in the tree.  This may require allocations or

 * set some bits on a range in the tree.  This may require allocations or

 * sleeping, so the gfp mask is used to indicate what is allowed.

 * sleeping, so the gfp mask is used to indicate what is allowed.
@@ -1482,7 +1490,7 @@ int find_first_extent_bit(struct extent_io_tree *tree, u64 start, 
	state = find_first_extent_bit_state(tree, start, bits);

	state = find_first_extent_bit_state(tree, start, bits);

got_it:

got_it:

	if (state) {

	if (state) {

		cache_state(state, cached_state);

		cache_state_if_flags(state, cached_state, 0);

		*start_ret = state->start;

		*start_ret = state->start;

		*end_ret = state->end;

		*end_ret = state->end;

		ret = 0;

		ret = 0;

fs/btrfs/transaction.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -883,6 +883,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root, 
			werr = err;

			werr = err;

		else if (wait_writeback)

		else if (wait_writeback)

			werr = filemap_fdatawait_range(mapping, start, end);

			werr = filemap_fdatawait_range(mapping, start, end);

		free_extent_state(cached_state);

		cached_state = NULL;

		cached_state = NULL;

		cond_resched();

		cond_resched();

		start = end + 1;

		start = end + 1;
@@ -927,6 +928,8 @@ int btrfs_wait_marked_extents(struct btrfs_root *root, 
			err = filemap_fdatawait_range(mapping, start, end);

			err = filemap_fdatawait_range(mapping, start, end);

		if (err)

		if (err)

			werr = err;

			werr = err;

		free_extent_state(cached_state);

		cached_state = NULL;

		cond_resched();

		cond_resched();

		start = end + 1;

		start = end + 1;

	}

	}

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