btrfs: change set_level() to bound the level passed in

Currently, the only user of set_level() is zlib which sets an internal
workspace parameter. As level is now plumbed into get_workspace(), this
can be handled there rather than separately.

This repurposes set_level() to bound the level passed in so it can be
used when setting the mounts compression level and as well as verifying
the level before getting a workspace. The other benefit is this divides
the meaning of compress(0) and get_workspace(0). The former means we
want to use the default compression level of the compression type. The
latter means we can use any workspace available.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 17 insertions, 8 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index ccd6bb2061f6..eb8e20b740d6 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -1009,8 +1009,6 @@ int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping,
 	int ret;
 
 	workspace = get_workspace(type, level);
-
-	btrfs_compress_op[type]->set_level(workspace, level);
 	ret = btrfs_compress_op[type]->compress_pages(workspace, mapping,
 						      start, pages,
 						      out_pages,
@@ -1563,14 +1561,25 @@ out:
 	return ret;
 }
 
-unsigned int btrfs_compress_str2level(const char *str)
+/*
+ * Convert the compression suffix (eg. after "zlib" starting with ":") to
+ * level, unrecognized string will set the default level
+ */
+unsigned int btrfs_compress_str2level(unsigned int type, const char *str)
 {
-	if (strncmp(str, "zlib", 4) != 0)
+	unsigned int level = 0;
+	int ret;
+
+	if (!type)
 		return 0;
 
-	/* Accepted form: zlib:1 up to zlib:9 and nothing left after the number */
-	if (str[4] == ':' && '1' <= str[5] && str[5] <= '9' && str[6] == 0)
-		return str[5] - '0';
+	if (str[0] == ':') {
+		ret = kstrtouint(str + 1, 10, &level);
+		if (ret)
+			level = 0;
+	}
+
+	level = btrfs_compress_op[type]->set_level(level);
 
-	return BTRFS_ZLIB_DEFAULT_LEVEL;
+	return level;
 }