btrfs: add workspace manager initialization for zstd

This involves:

- Add zstd_alloc_workspace_manager() and zstd_free_workspace_manager()
  Those two functions will accept an fs_info pointer, and alloc/free
  fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] pointer.

- Add btrfs_alloc_compress_wsm() and btrfs_free_compress_wsm()
  Those are helpers allocating the workspace managers for all
  algorithms.
  For now only zstd is supported, and the timing is a little unusual,
  the btrfs_alloc_compress_wsm() should only be called after the
  sectorsize being initialized.

  Meanwhile btrfs_free_fs_info_compress() is called in
  btrfs_free_fs_info().

- Move the definition of btrfs_compression_type to "fs.h"
  The reason is that "compression.h" has already included "fs.h", thus
  we can not just include "compression.h" to get the definition of
  BTRFS_NR_COMPRESS_TYPES to define fs_info::compr_wsm[].

For now the per-fs zstd workspace manager won't really have any effect,
and all compression is still going through the global workspace manager.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -1097,6 +1097,24 @@ int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
 	return ret;
 }
 
+int btrfs_alloc_compress_wsm(struct btrfs_fs_info *fs_info)
+{
+	int ret;
+
+	ret = zstd_alloc_workspace_manager(fs_info);
+	if (ret < 0)
+		goto error;
+	return 0;
+error:
+	btrfs_free_compress_wsm(fs_info);
+	return ret;
+}
+
+void btrfs_free_compress_wsm(struct btrfs_fs_info *fs_info)
+{
+	zstd_free_workspace_manager(fs_info);
+}
+
 int __init btrfs_init_compress(void)
 {
 	if (bioset_init(&btrfs_compressed_bioset, BIO_POOL_SIZE,

fs/btrfs/compression.h

@@ -89,6 +89,9 @@ static inline u32 btrfs_calc_input_length(struct folio *folio, u64 range_end, u6
 	return min(range_end, folio_end(folio)) - cur;
 }
 
+int btrfs_alloc_compress_wsm(struct btrfs_fs_info *fs_info);
+void btrfs_free_compress_wsm(struct btrfs_fs_info *fs_info);
+
 int __init btrfs_init_compress(void);
 void __cold btrfs_exit_compress(void);
 
@@ -112,16 +115,6 @@ int btrfs_compress_str2level(unsigned int type, const char *str, int *level_ret)
 struct folio *btrfs_alloc_compr_folio(void);
 void btrfs_free_compr_folio(struct folio *folio);
 
-enum btrfs_compression_type {
-	BTRFS_COMPRESS_NONE  = 0,
-	BTRFS_COMPRESS_ZLIB  = 1,
-	BTRFS_COMPRESS_LZO   = 2,
-	BTRFS_COMPRESS_ZSTD  = 3,
-	BTRFS_NR_COMPRESS_TYPES = 4,
-
-	BTRFS_DEFRAG_DONT_COMPRESS,
-};
-
 struct workspace_manager {
 	struct list_head idle_ws;
 	spinlock_t ws_lock;
@@ -188,6 +181,8 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb);
 int zstd_decompress(struct list_head *ws, const u8 *data_in,
 		struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
 		size_t destlen);
+int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info);
+void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info);
 void zstd_init_workspace_manager(struct btrfs_fs_info *fs_info);
 void zstd_cleanup_workspace_manager(void);
 struct list_head *zstd_alloc_workspace(struct btrfs_fs_info *fs_info, int level);

fs/btrfs/disk-io.c

@@ -1248,6 +1248,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 
 	if (fs_info->fs_devices)
 		btrfs_close_devices(fs_info->fs_devices);
+	btrfs_free_compress_wsm(fs_info);
 	percpu_counter_destroy(&fs_info->stats_read_blocks);
 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
 	percpu_counter_destroy(&fs_info->delalloc_bytes);
@@ -3407,6 +3408,9 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	 */
 	fs_info->max_inline = min_t(u64, fs_info->max_inline, fs_info->sectorsize);
 
+	ret = btrfs_alloc_compress_wsm(fs_info);
+	if (ret)
+		goto fail_sb_buffer;
 	ret = btrfs_init_workqueues(fs_info);
 	if (ret)
 		goto fail_sb_buffer;

fs/btrfs/fs.h

@@ -306,6 +306,16 @@ enum {
 #define BTRFS_WARNING_COMMIT_INTERVAL	(300)
 #define BTRFS_DEFAULT_MAX_INLINE	(2048)
 
+enum btrfs_compression_type {
+	BTRFS_COMPRESS_NONE  = 0,
+	BTRFS_COMPRESS_ZLIB  = 1,
+	BTRFS_COMPRESS_LZO   = 2,
+	BTRFS_COMPRESS_ZSTD  = 3,
+	BTRFS_NR_COMPRESS_TYPES = 4,
+
+	BTRFS_DEFRAG_DONT_COMPRESS,
+};
+
 struct btrfs_dev_replace {
 	/* See #define above */
 	u64 replace_state;
@@ -508,6 +518,9 @@ struct btrfs_fs_info {
 	u64 last_trans_log_full_commit;
 	unsigned long long mount_opt;
 
+	/* Compress related structures. */
+	void *compr_wsm[BTRFS_NR_COMPRESS_TYPES];
+
 	int compress_type;
 	int compress_level;
 	u32 commit_interval;

fs/btrfs/zstd.c

@@ -182,6 +182,36 @@ static void zstd_calc_ws_mem_sizes(void)
 	}
 }
 
+int zstd_alloc_workspace_manager(struct btrfs_fs_info *fs_info)
+{
+	struct zstd_workspace_manager *zwsm;
+	struct list_head *ws;
+
+	ASSERT(fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] == NULL);
+	zwsm = kzalloc(sizeof(*zwsm), GFP_KERNEL);
+	if (!zwsm)
+		return -ENOMEM;
+	zstd_calc_ws_mem_sizes();
+	zwsm->ops = &btrfs_zstd_compress;
+	spin_lock_init(&zwsm->lock);
+	init_waitqueue_head(&zwsm->wait);
+	timer_setup(&zwsm->timer, zstd_reclaim_timer_fn, 0);
+
+	INIT_LIST_HEAD(&zwsm->lru_list);
+	for (int i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++)
+		INIT_LIST_HEAD(&zwsm->idle_ws[i]);
+	fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] = zwsm;
+
+	ws = zstd_alloc_workspace(fs_info, ZSTD_BTRFS_MAX_LEVEL);
+	if (IS_ERR(ws)) {
+		btrfs_warn(NULL, "cannot preallocate zstd compression workspace");
+	} else {
+		set_bit(ZSTD_BTRFS_MAX_LEVEL - 1, &zwsm->active_map);
+		list_add(ws, &zwsm->idle_ws[ZSTD_BTRFS_MAX_LEVEL - 1]);
+	}
+	return 0;
+}
+
 void zstd_init_workspace_manager(struct btrfs_fs_info *fs_info)
 {
 	struct list_head *ws;
@@ -207,6 +237,29 @@ void zstd_init_workspace_manager(struct btrfs_fs_info *fs_info)
 	}
 }
 
+void zstd_free_workspace_manager(struct btrfs_fs_info *fs_info)
+{
+	struct zstd_workspace_manager *zwsm = fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD];
+	struct workspace *workspace;
+
+	if (!zwsm)
+		return;
+	fs_info->compr_wsm[BTRFS_COMPRESS_ZSTD] = NULL;
+	spin_lock_bh(&zwsm->lock);
+	for (int i = 0; i < ZSTD_BTRFS_MAX_LEVEL; i++) {
+		while (!list_empty(&zwsm->idle_ws[i])) {
+			workspace = container_of(zwsm->idle_ws[i].next,
+						 struct workspace, list);
+			list_del(&workspace->list);
+			list_del(&workspace->lru_list);
+			zstd_free_workspace(&workspace->list);
+		}
+	}
+	spin_unlock_bh(&zwsm->lock);
+	timer_delete_sync(&zwsm->timer);
+	kfree(zwsm);
+}
+
 void zstd_cleanup_workspace_manager(void)
 {
 	struct workspace *workspace;