btrfs: replace sb::s_blocksize by fs_info::sectorsize

The block size stored in the super block is used by subsystems outside
of btrfs and it's a copy of fs_info::sectorsize. Unify that to always
use our sectorsize, with the exception of mount where we first need to
use fixed values (4K) until we read the super block and can set the
sectorsize.

Replace all uses, in most cases it's fewer pointer indirections.

Reviewed-by: Josef Bacik <[e-mail]>
Reviewed-by: Anand Jain <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/disk-io.c

···
 	int ret;
 
 	fs_info->sb = sb;
+	/* Temporary fixed values for block size until we read the superblock. */
 	sb->s_blocksize = BTRFS_BDEV_BLOCKSIZE;
 	sb->s_blocksize_bits = blksize_bits(BTRFS_BDEV_BLOCKSIZE);
 
···
 	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
 	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 
+	/* Update the values for the current filesystem. */
 	sb->s_blocksize = sectorsize;
 	sb->s_blocksize_bits = blksize_bits(sectorsize);
 	memcpy(&sb->s_uuid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE);

fs/btrfs/extent_io.c

···
 	int ret = 0;
 	size_t pg_offset = 0;
 	size_t iosize;
-	size_t blocksize = inode->i_sb->s_blocksize;
+	size_t blocksize = fs_info->sectorsize;
 	struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
 
 	ret = set_page_extent_mapped(page);
···
 	struct extent_state *cached_state = NULL;
 	u64 start = folio_pos(folio);
 	u64 end = start + folio_size(folio) - 1;
-	size_t blocksize = folio->mapping->host->i_sb->s_blocksize;
+	size_t blocksize = btrfs_sb(folio->mapping->host->i_sb)->sectorsize;
 
 	/* This function is only called for the btree inode */
 	ASSERT(tree->owner == IO_TREE_BTREE_INODE_IO);

fs/btrfs/inode.c

···
 	u64 delalloc_bytes;
 	u64 inode_bytes;
 	struct inode *inode = d_inode(path->dentry);
-	u32 blocksize = inode->i_sb->s_blocksize;
+	u32 blocksize = btrfs_sb(inode->i_sb)->sectorsize;
 	u32 bi_flags = BTRFS_I(inode)->flags;
 	u32 bi_ro_flags = BTRFS_I(inode)->ro_flags;
 

fs/btrfs/ioctl.c

···
 	 * block group is in the logical address space, which can be any
 	 * sectorsize aligned bytenr in  the range [0, U64_MAX].
 	 */
-	if (range.len < fs_info->sb->s_blocksize)
+	if (range.len < fs_info->sectorsize)
 		return -EINVAL;
 
 	range.minlen = max(range.minlen, minlen);

fs/btrfs/reflink.c

···
 				   struct inode *dst, u64 dst_loff)
 {
 	struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info;
-	const u64 bs = fs_info->sb->s_blocksize;
+	const u64 bs = fs_info->sectorsize;
 	int ret;
 
 	/*
···
 	int ret;
 	int wb_ret;
 	u64 len = olen;
-	u64 bs = fs_info->sb->s_blocksize;
+	u64 bs = fs_info->sectorsize;
 
 	/*
 	 * VFS's generic_remap_file_range_prep() protects us from cloning the
···
 {
 	struct inode *inode_in = file_inode(file_in);
 	struct inode *inode_out = file_inode(file_out);
-	u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize;
+	u64 bs = BTRFS_I(inode_out)->root->fs_info->sectorsize;
 	u64 wb_len;
 	int ret;
 

fs/btrfs/send.c

···
 	int ret = 0;
 	u64 offset = key->offset;
 	u64 end;
-	u64 bs = sctx->send_root->fs_info->sb->s_blocksize;
+	u64 bs = sctx->send_root->fs_info->sectorsize;
 
 	end = min_t(u64, btrfs_file_extent_end(path), sctx->cur_inode_size);
 	if (offset >= end)

fs/btrfs/super.c

···
 		buf->f_bavail = 0;
 
 	buf->f_type = BTRFS_SUPER_MAGIC;
-	buf->f_bsize = dentry->d_sb->s_blocksize;
+	buf->f_bsize = fs_info->sectorsize;
 	buf->f_namelen = BTRFS_NAME_LEN;
 
 	/* We treat it as constant endianness (it doesn't matter _which_)