btrfs: add an fs_info parameter for compression workspace manager

[BACKGROUND]
Currently btrfs shares workspaces and their managers for all filesystems,
this is mostly fine as all those workspaces are using page size based
buffers, and btrfs only support block size (bs) <= page size (ps).

This means even if bs < ps, we at most waste some buffer space in the
workspace, but everything will still work fine.

The problem here is that is limiting our support for bs > ps cases.

As now a workspace now may need larger buffer to handle bs > ps cases,
but since the pool has no way to distinguish different workspaces, a
regular workspace (which is still using buffer size based on ps) can be
passed to a btrfs whose bs > ps.

In that case the buffer is not large enough, and will cause various
problems.

[ENHANCEMENT]
To prepare for the per-fs workspace migration, add an fs_info parameter
to all workspace related functions.

For now this new fs_info parameter is not yet utilized.

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

1 files changed, 38 insertions, 35 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 839c8c33aa5a..d8ba6d0d4e83 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -702,7 +702,7 @@ static void free_heuristic_ws(struct list_head *ws)
 	kfree(workspace);
 }
 
-static struct list_head *alloc_heuristic_ws(void)
+static struct list_head *alloc_heuristic_ws(struct btrfs_fs_info *fs_info)
 {
 	struct heuristic_ws *ws;
 
@@ -741,13 +741,13 @@ static const struct btrfs_compress_op * const btrfs_compress_op[] = {
 	&btrfs_zstd_compress,
 };
 
-static struct list_head *alloc_workspace(int type, int level)
+static struct list_head *alloc_workspace(struct btrfs_fs_info *fs_info, int type, int level)
 {
 	switch (type) {
-	case BTRFS_COMPRESS_NONE: return alloc_heuristic_ws();
-	case BTRFS_COMPRESS_ZLIB: return zlib_alloc_workspace(level);
-	case BTRFS_COMPRESS_LZO:  return lzo_alloc_workspace();
-	case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(level);
+	case BTRFS_COMPRESS_NONE: return alloc_heuristic_ws(fs_info);
+	case BTRFS_COMPRESS_ZLIB: return zlib_alloc_workspace(fs_info, level);
+	case BTRFS_COMPRESS_LZO:  return lzo_alloc_workspace(fs_info);
+	case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(fs_info, level);
 	default:
 		/*
 		 * This can't happen, the type is validated several times
@@ -773,7 +773,7 @@ static void free_workspace(int type, struct list_head *ws)
 	}
 }
 
-static void btrfs_init_workspace_manager(int type)
+static void btrfs_init_workspace_manager(struct btrfs_fs_info *fs_info, int type)
 {
 	struct workspace_manager *wsm;
 	struct list_head *workspace;
@@ -788,9 +788,9 @@ static void btrfs_init_workspace_manager(int type)
 	 * Preallocate one workspace for each compression type so we can
 	 * guarantee forward progress in the worst case
 	 */
-	workspace = alloc_workspace(type, 0);
+	workspace = alloc_workspace(fs_info, type, 0);
 	if (IS_ERR(workspace)) {
-		btrfs_warn(NULL,
+		btrfs_warn(fs_info,
 			   "cannot preallocate compression workspace, will try later");
 	} else {
 		atomic_set(&wsm->total_ws, 1);
@@ -819,7 +819,7 @@ static void btrfs_cleanup_workspace_manager(int type)
  * Preallocation makes a forward progress guarantees and we do not return
  * errors.
  */
-struct list_head *btrfs_get_workspace(int type, int level)
+struct list_head *btrfs_get_workspace(struct btrfs_fs_info *fs_info, int type, int level)
 {
 	struct workspace_manager *wsm;
 	struct list_head *workspace;
@@ -867,7 +867,7 @@ again:
 	 * context of btrfs_compress_bio/btrfs_compress_pages
 	 */
 	nofs_flag = memalloc_nofs_save();
-	workspace = alloc_workspace(type, level);
+	workspace = alloc_workspace(fs_info, type, level);
 	memalloc_nofs_restore(nofs_flag);
 
 	if (IS_ERR(workspace)) {
@@ -890,7 +890,7 @@ again:
 					/* no burst */ 1);
 
 			if (__ratelimit(&_rs))
-				btrfs_warn(NULL,
+				btrfs_warn(fs_info,
 				"no compression workspaces, low memory, retrying");
 		}
 		goto again;
@@ -898,13 +898,13 @@ again:
 	return workspace;
 }
 
-static struct list_head *get_workspace(int type, int level)
+static struct list_head *get_workspace(struct btrfs_fs_info *fs_info, int type, int level)
 {
 	switch (type) {
-	case BTRFS_COMPRESS_NONE: return btrfs_get_workspace(type, level);
-	case BTRFS_COMPRESS_ZLIB: return zlib_get_workspace(level);
-	case BTRFS_COMPRESS_LZO:  return btrfs_get_workspace(type, level);
-	case BTRFS_COMPRESS_ZSTD: return zstd_get_workspace(level);
+	case BTRFS_COMPRESS_NONE: return btrfs_get_workspace(fs_info, type, level);
+	case BTRFS_COMPRESS_ZLIB: return zlib_get_workspace(fs_info, level);
+	case BTRFS_COMPRESS_LZO:  return btrfs_get_workspace(fs_info, type, level);
+	case BTRFS_COMPRESS_ZSTD: return zstd_get_workspace(fs_info, level);
 	default:
 		/*
 		 * This can't happen, the type is validated several times
@@ -918,7 +918,7 @@ static struct list_head *get_workspace(int type, int level)
  * put a workspace struct back on the list or free it if we have enough
  * idle ones sitting around
  */
-void btrfs_put_workspace(int type, struct list_head *ws)
+void btrfs_put_workspace(struct btrfs_fs_info *fs_info, int type, struct list_head *ws)
 {
 	struct workspace_manager *wsm;
 	struct list_head *idle_ws;
@@ -949,13 +949,13 @@ wake:
 	cond_wake_up(ws_wait);
 }
 
-static void put_workspace(int type, struct list_head *ws)
+static void put_workspace(struct btrfs_fs_info *fs_info, int type, struct list_head *ws)
 {
 	switch (type) {
-	case BTRFS_COMPRESS_NONE: return btrfs_put_workspace(type, ws);
-	case BTRFS_COMPRESS_ZLIB: return btrfs_put_workspace(type, ws);
-	case BTRFS_COMPRESS_LZO:  return btrfs_put_workspace(type, ws);
-	case BTRFS_COMPRESS_ZSTD: return zstd_put_workspace(ws);
+	case BTRFS_COMPRESS_NONE: return btrfs_put_workspace(fs_info, type, ws);
+	case BTRFS_COMPRESS_ZLIB: return btrfs_put_workspace(fs_info, type, ws);
+	case BTRFS_COMPRESS_LZO:  return btrfs_put_workspace(fs_info, type, ws);
+	case BTRFS_COMPRESS_ZSTD: return zstd_put_workspace(fs_info, ws);
 	default:
 		/*
 		 * This can't happen, the type is validated several times
@@ -1038,29 +1038,31 @@ int btrfs_compress_folios(unsigned int type, int level, struct btrfs_inode *inod
 			 u64 start, struct folio **folios, unsigned long *out_folios,
 			 unsigned long *total_in, unsigned long *total_out)
 {
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
 	const unsigned long orig_len = *total_out;
 	struct list_head *workspace;
 	int ret;
 
 	level = btrfs_compress_set_level(type, level);
-	workspace = get_workspace(type, level);
+	workspace = get_workspace(fs_info, type, level);
 	ret = compression_compress_pages(type, workspace, inode, start, folios,
 					 out_folios, total_in, total_out);
 	/* The total read-in bytes should be no larger than the input. */
 	ASSERT(*total_in <= orig_len);
-	put_workspace(type, workspace);
+	put_workspace(fs_info, type, workspace);
 	return ret;
 }
 
 static int btrfs_decompress_bio(struct compressed_bio *cb)
 {
+	struct btrfs_fs_info *fs_info = cb_to_fs_info(cb);
 	struct list_head *workspace;
 	int ret;
 	int type = cb->compress_type;
 
-	workspace = get_workspace(type, 0);
+	workspace = get_workspace(fs_info, type, 0);
 	ret = compression_decompress_bio(workspace, cb);
-	put_workspace(type, workspace);
+	put_workspace(fs_info, type, workspace);
 
 	if (!ret)
 		zero_fill_bio(&cb->orig_bbio->bio);
@@ -1087,10 +1089,10 @@ int btrfs_decompress(int type, const u8 *data_in, struct folio *dest_folio,
 	 */
 	ASSERT(dest_pgoff + destlen <= PAGE_SIZE && destlen <= sectorsize);
 
-	workspace = get_workspace(type, 0);
+	workspace = get_workspace(fs_info, type, 0);
 	ret = compression_decompress(type, workspace, data_in, dest_folio,
 				     dest_pgoff, srclen, destlen);
-	put_workspace(type, workspace);
+	put_workspace(fs_info, type, workspace);
 
 	return ret;
 }
@@ -1106,10 +1108,10 @@ int __init btrfs_init_compress(void)
 	if (!compr_pool.shrinker)
 		return -ENOMEM;
 
-	btrfs_init_workspace_manager(BTRFS_COMPRESS_NONE);
-	btrfs_init_workspace_manager(BTRFS_COMPRESS_ZLIB);
-	btrfs_init_workspace_manager(BTRFS_COMPRESS_LZO);
-	zstd_init_workspace_manager();
+	btrfs_init_workspace_manager(NULL, BTRFS_COMPRESS_NONE);
+	btrfs_init_workspace_manager(NULL, BTRFS_COMPRESS_ZLIB);
+	btrfs_init_workspace_manager(NULL, BTRFS_COMPRESS_LZO);
+	zstd_init_workspace_manager(NULL);
 
 	spin_lock_init(&compr_pool.lock);
 	INIT_LIST_HEAD(&compr_pool.list);
@@ -1543,7 +1545,8 @@ static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end,
  */
 int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end)
 {
-	struct list_head *ws_list = get_workspace(0, 0);
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
+	struct list_head *ws_list = get_workspace(fs_info, 0, 0);
 	struct heuristic_ws *ws;
 	u32 i;
 	u8 byte;
@@ -1612,7 +1615,7 @@ int btrfs_compress_heuristic(struct btrfs_inode *inode, u64 start, u64 end)
 	}
 
 out:
-	put_workspace(0, ws_list);
+	put_workspace(fs_info, 0, ws_list);
 	return ret;
 }