Commit 40ab3be1 authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
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btrfs: zoned: extend zoned allocator to use dedicated tree-log block group 



This is the 1/3 patch to enable tree log on zoned filesystems.

The tree-log feature does not work on a zoned filesystem as is. Blocks for
a tree-log tree are allocated mixed with other metadata blocks and btrfs
writes and syncs the tree-log blocks to devices at the time of fsync(),
which has a different timing than a global transaction commit. As a
result, both writing tree-log blocks and writing other metadata blocks
become non-sequential writes that zoned filesystems must avoid.

Introduce a dedicated block group for tree-log blocks, so that tree-log
blocks and other metadata blocks can be separate write streams.  As a
result, each write stream can now be written to devices separately.
"fs_info->treelog_bg" tracks the dedicated block group and assigns
"treelog_bg" on-demand on tree-log block allocation time.

This commit extends the zoned block allocator to use the block group.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 6ab6ebb7

fs/btrfs/block-group.c

+2 −0
Original line number Diff line number Diff line
@@ -901,6 +901,8 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, 
	btrfs_return_cluster_to_free_space(block_group, cluster);

	spin_unlock(&cluster->refill_lock);



	btrfs_clear_treelog_bg(block_group);



	path = btrfs_alloc_path();

	if (!path) {

		ret = -ENOMEM;

fs/btrfs/ctree.h

+2 −0
Original line number Diff line number Diff line
@@ -976,6 +976,8 @@ struct btrfs_fs_info { 
	/* Max size to emit ZONE_APPEND write command */

	u64 max_zone_append_size;

	struct mutex zoned_meta_io_lock;

	spinlock_t treelog_bg_lock;

	u64 treelog_bg;



#ifdef CONFIG_BTRFS_FS_REF_VERIFY

	spinlock_t ref_verify_lock;

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -2787,6 +2787,7 @@ void btrfs_init_fs_info(struct btrfs_fs_info *fs_info) 
	spin_lock_init(&fs_info->super_lock);

	spin_lock_init(&fs_info->buffer_lock);

	spin_lock_init(&fs_info->unused_bgs_lock);

	spin_lock_init(&fs_info->treelog_bg_lock);

	rwlock_init(&fs_info->tree_mod_log_lock);

	mutex_init(&fs_info->unused_bg_unpin_mutex);

	mutex_init(&fs_info->delete_unused_bgs_mutex);

fs/btrfs/extent-tree.c

+71 −4
Original line number Diff line number Diff line
@@ -3497,6 +3497,9 @@ struct find_free_extent_ctl { 
	bool have_caching_bg;

	bool orig_have_caching_bg;



	/* Allocation is called for tree-log */

	bool for_treelog;



	/* RAID index, converted from flags */

	int index;
@@ -3725,6 +3728,22 @@ static int do_allocation_clustered(struct btrfs_block_group *block_group, 
	return find_free_extent_unclustered(block_group, ffe_ctl);

}



/*

 * Tree-log block group locking

 * ============================

 *

 * fs_info::treelog_bg_lock protects the fs_info::treelog_bg which

 * indicates the starting address of a block group, which is reserved only

 * for tree-log metadata.

 *

 * Lock nesting

 * ============

 *

 * space_info::lock

 *   block_group::lock

 *     fs_info::treelog_bg_lock

 */



/*

 * Simple allocator for sequential-only block group. It only allows sequential

 * allocation. No need to play with trees. This function also reserves the
@@ -3734,23 +3753,54 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, 
			       struct find_free_extent_ctl *ffe_ctl,

			       struct btrfs_block_group **bg_ret)

{

	struct btrfs_fs_info *fs_info = block_group->fs_info;

	struct btrfs_space_info *space_info = block_group->space_info;

	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;

	u64 start = block_group->start;

	u64 num_bytes = ffe_ctl->num_bytes;

	u64 avail;

	u64 bytenr = block_group->start;

	u64 log_bytenr;

	int ret = 0;

	bool skip;



	ASSERT(btrfs_is_zoned(block_group->fs_info));



	/*

	 * Do not allow non-tree-log blocks in the dedicated tree-log block

	 * group, and vice versa.

	 */

	spin_lock(&fs_info->treelog_bg_lock);

	log_bytenr = fs_info->treelog_bg;

	skip = log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||

			      (!ffe_ctl->for_treelog && bytenr == log_bytenr));

	spin_unlock(&fs_info->treelog_bg_lock);

	if (skip)

		return 1;



	spin_lock(&space_info->lock);

	spin_lock(&block_group->lock);

	spin_lock(&fs_info->treelog_bg_lock);



	ASSERT(!ffe_ctl->for_treelog ||

	       block_group->start == fs_info->treelog_bg ||

	       fs_info->treelog_bg == 0);



	if (block_group->ro) {

		ret = 1;

		goto out;

	}



	/*

	 * Do not allow currently using block group to be tree-log dedicated

	 * block group.

	 */

	if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&

	    (block_group->used || block_group->reserved)) {

		ret = 1;

		goto out;

	}



	avail = block_group->length - block_group->alloc_offset;

	if (avail < num_bytes) {

		if (ffe_ctl->max_extent_size < avail) {
@@ -3765,6 +3815,9 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, 
		goto out;

	}



	if (ffe_ctl->for_treelog && !fs_info->treelog_bg)

		fs_info->treelog_bg = block_group->start;



	ffe_ctl->found_offset = start + block_group->alloc_offset;

	block_group->alloc_offset += num_bytes;

	spin_lock(&ctl->tree_lock);
@@ -3779,6 +3832,9 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, 
	ffe_ctl->search_start = ffe_ctl->found_offset;



out:

	if (ret && ffe_ctl->for_treelog)

		fs_info->treelog_bg = 0;

	spin_unlock(&fs_info->treelog_bg_lock);

	spin_unlock(&block_group->lock);

	spin_unlock(&space_info->lock);

	return ret;
@@ -4028,7 +4084,12 @@ static int prepare_allocation(struct btrfs_fs_info *fs_info, 
		return prepare_allocation_clustered(fs_info, ffe_ctl,

						    space_info, ins);

	case BTRFS_EXTENT_ALLOC_ZONED:

		/* Nothing to do */

		if (ffe_ctl->for_treelog) {

			spin_lock(&fs_info->treelog_bg_lock);

			if (fs_info->treelog_bg)

				ffe_ctl->hint_byte = fs_info->treelog_bg;

			spin_unlock(&fs_info->treelog_bg_lock);

		}

		return 0;

	default:

		BUG();
@@ -4072,6 +4133,7 @@ static noinline int find_free_extent(struct btrfs_root *root, 
	struct find_free_extent_ctl ffe_ctl = {0};

	struct btrfs_space_info *space_info;

	bool full_search = false;

	bool for_treelog = (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);



	WARN_ON(num_bytes < fs_info->sectorsize);
@@ -4085,6 +4147,7 @@ static noinline int find_free_extent(struct btrfs_root *root, 
	ffe_ctl.orig_have_caching_bg = false;

	ffe_ctl.found_offset = 0;

	ffe_ctl.hint_byte = hint_byte_orig;

	ffe_ctl.for_treelog = for_treelog;

	ffe_ctl.policy = BTRFS_EXTENT_ALLOC_CLUSTERED;



	/* For clustered allocation */
@@ -4159,8 +4222,11 @@ static noinline int find_free_extent(struct btrfs_root *root, 
		struct btrfs_block_group *bg_ret;



		/* If the block group is read-only, we can skip it entirely. */

		if (unlikely(block_group->ro))

		if (unlikely(block_group->ro)) {

			if (for_treelog)

				btrfs_clear_treelog_bg(block_group);

			continue;

		}



		btrfs_grab_block_group(block_group, delalloc);

		ffe_ctl.search_start = block_group->start;
@@ -4346,6 +4412,7 @@ int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, 
	bool final_tried = num_bytes == min_alloc_size;

	u64 flags;

	int ret;

	bool for_treelog = (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);



	flags = get_alloc_profile_by_root(root, is_data);

again:
@@ -4369,8 +4436,8 @@ int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes, 


			sinfo = btrfs_find_space_info(fs_info, flags);

			btrfs_err(fs_info,

				  "allocation failed flags %llu, wanted %llu",

				  flags, num_bytes);

			"allocation failed flags %llu, wanted %llu tree-log %d",

				  flags, num_bytes, for_treelog);

			if (sinfo)

				btrfs_dump_space_info(fs_info, sinfo,

						      num_bytes, 1);

fs/btrfs/zoned.h

+14 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/blkdev.h>

#include "volumes.h"

#include "disk-io.h"

#include "block-group.h"



struct btrfs_zoned_device_info {

	/*
@@ -290,4 +291,17 @@ static inline void btrfs_zoned_meta_io_unlock(struct btrfs_fs_info *fs_info) 
	mutex_unlock(&fs_info->zoned_meta_io_lock);

}



static inline void btrfs_clear_treelog_bg(struct btrfs_block_group *bg)

{

	struct btrfs_fs_info *fs_info = bg->fs_info;



	if (!btrfs_is_zoned(fs_info))

		return;



	spin_lock(&fs_info->treelog_bg_lock);

	if (fs_info->treelog_bg == bg->start)

		fs_info->treelog_bg = 0;

	spin_unlock(&fs_info->treelog_bg_lock);

}



#endif