btrfs: simplify the inline extent map creation

With the tree-checker ensuring all inline file extents starts at file
offset 0 and has a length no larger than sectorsize, we can simplify the
calculation to assigned those fixes values directly.

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

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 5fead7a253df8cbc0c9df9f5d5013c672ef2cc8a..bce95f871750931c8744bfbb1620157135966b2e 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -1279,20 +1279,19 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
        struct extent_buffer *leaf = path->nodes[0];
        const int slot = path->slots[0];
        struct btrfs_key key;
-       u64 extent_start, extent_end;
+       u64 extent_start;
        u64 bytenr;
        u8 type = btrfs_file_extent_type(leaf, fi);
        int compress_type = btrfs_file_extent_compression(leaf, fi);
 
        btrfs_item_key_to_cpu(leaf, &key, slot);
        extent_start = key.offset;
-       extent_end = btrfs_file_extent_end(path);
        em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi);
        em->generation = btrfs_file_extent_generation(leaf, fi);
        if (type == BTRFS_FILE_EXTENT_REG ||
            type == BTRFS_FILE_EXTENT_PREALLOC) {
                em->start = extent_start;
-               em->len = extent_end - extent_start;
+               em->len = btrfs_file_extent_end(path) - extent_start;
                em->orig_start = extent_start -
                        btrfs_file_extent_offset(leaf, fi);
                em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi);
@@ -1313,9 +1312,12 @@ void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode,
                                em->flags |= EXTENT_FLAG_PREALLOC;
                }
        } else if (type == BTRFS_FILE_EXTENT_INLINE) {
+               /* Tree-checker has ensured this. */
+               ASSERT(extent_start == 0);
+
                em->block_start = EXTENT_MAP_INLINE;
-               em->start = extent_start;
-               em->len = extent_end - extent_start;
+               em->start = 0;
+               em->len = fs_info->sectorsize;
                /*
                 * Initialize orig_start and block_len with the same values
                 * as in inode.c:btrfs_get_extent().
@@ -1348,12 +1350,10 @@ u64 btrfs_file_extent_end(const struct btrfs_path *path)
        ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
        fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
 
-       if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE) {
-               end = btrfs_file_extent_ram_bytes(leaf, fi);
-               end = ALIGN(key.offset + end, leaf->fs_info->sectorsize);
-       } else {
+       if (btrfs_file_extent_type(leaf, fi) == BTRFS_FILE_EXTENT_INLINE)
+               end = leaf->fs_info->sectorsize;
+       else
                end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
-       }
 
        return end;
 }