btrfs: cache max and min order inside btrfs_fs_info

Inside btrfs_fs_info we cache several bits shift like sectorsize_bits.

Apply this to max and min folio orders so that every time mapping order
needs to be applied we can skip the calculation.

Signed-off-by: Qu Wenruo <[email protected]>
Signed-off-by: David Sterba <[email protected]>

Author: adam900710

fs/btrfs/btrfs_inode.h

@@ -532,9 +532,9 @@ static inline void btrfs_set_inode_mapping_order(struct btrfs_inode *inode)
 
 	/* We only allow BITS_PER_LONGS blocks for each bitmap. */
 #ifdef CONFIG_BTRFS_EXPERIMENTAL
-	mapping_set_folio_order_range(inode->vfs_inode.i_mapping, 0,
-			ilog2(((BITS_PER_LONG << inode->root->fs_info->sectorsize_bits)
-				>> PAGE_SHIFT)));
+	mapping_set_folio_order_range(inode->vfs_inode.i_mapping,
+				      inode->root->fs_info->block_min_order,
+				      inode->root->fs_info->block_max_order);
 #endif
 }
 

fs/btrfs/disk-io.c

@@ -3383,6 +3383,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	fs_info->nodesize_bits = ilog2(nodesize);
 	fs_info->sectorsize = sectorsize;
 	fs_info->sectorsize_bits = ilog2(sectorsize);
+	fs_info->block_min_order = ilog2(round_up(sectorsize, PAGE_SIZE) >> PAGE_SHIFT);
+	fs_info->block_max_order = ilog2((BITS_PER_LONG << fs_info->sectorsize_bits) >> PAGE_SHIFT);
 	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
 	fs_info->stripesize = stripesize;
 	fs_info->fs_devices->fs_info = fs_info;

fs/btrfs/fs.h

@@ -825,6 +825,8 @@ struct btrfs_fs_info {
 	u32 sectorsize;
 	/* ilog2 of sectorsize, use to avoid 64bit division */
 	u32 sectorsize_bits;
+	u32 block_min_order;
+	u32 block_max_order;
 	u32 csum_size;
 	u32 csums_per_leaf;
 	u32 stripesize;