diff options
Diffstat (limited to 'fs/btrfs/extent_map.c')
| -rw-r--r-- | fs/btrfs/extent_map.c | 79 |
1 files changed, 75 insertions, 4 deletions
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index a9d60d1eade9..0242f354e1af 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -229,6 +229,61 @@ static bool mergeable_maps(const struct extent_map *prev, const struct extent_ma return next->block_start == prev->block_start; } +/* + * Handle the on-disk data extents merge for @prev and @next. + * + * Only touches disk_bytenr/disk_num_bytes/offset/ram_bytes. + * For now only uncompressed regular extent can be merged. + * + * @prev and @next will be both updated to point to the new merged range. + * Thus one of them should be removed by the caller. + */ +static void merge_ondisk_extents(struct extent_map *prev, struct extent_map *next) +{ + u64 new_disk_bytenr; + u64 new_disk_num_bytes; + u64 new_offset; + + /* @prev and @next should not be compressed. */ + ASSERT(!extent_map_is_compressed(prev)); + ASSERT(!extent_map_is_compressed(next)); + + /* + * There are two different cases where @prev and @next can be merged. + * + * 1) They are referring to the same data extent: + * + * |<----- data extent A ----->| + * |<- prev ->|<- next ->| + * + * 2) They are referring to different data extents but still adjacent: + * + * |<-- data extent A -->|<-- data extent B -->| + * |<- prev ->|<- next ->| + * + * The calculation here always merges the data extents first, then updates + * @offset using the new data extents. + * + * For case 1), the merged data extent would be the same. + * For case 2), we just merge the two data extents into one. + */ + new_disk_bytenr = min(prev->disk_bytenr, next->disk_bytenr); + new_disk_num_bytes = max(prev->disk_bytenr + prev->disk_num_bytes, + next->disk_bytenr + next->disk_num_bytes) - + new_disk_bytenr; + new_offset = prev->disk_bytenr + prev->offset - new_disk_bytenr; + + prev->disk_bytenr = new_disk_bytenr; + prev->disk_num_bytes = new_disk_num_bytes; + prev->ram_bytes = new_disk_num_bytes; + prev->offset = new_offset; + + next->disk_bytenr = new_disk_bytenr; + next->disk_num_bytes = new_disk_num_bytes; + next->ram_bytes = new_disk_num_bytes; + next->offset = new_offset; +} + static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) { struct extent_map_tree *tree = &inode->extent_tree; @@ -260,6 +315,9 @@ static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) em->block_len += merge->block_len; em->block_start = merge->block_start; em->generation = max(em->generation, merge->generation); + + if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) + merge_ondisk_extents(merge, em); em->flags |= EXTENT_FLAG_MERGED; rb_erase(&merge->rb_node, &tree->root); @@ -275,6 +333,8 @@ static void try_merge_map(struct btrfs_inode *inode, struct extent_map *em) if (rb && can_merge_extent_map(merge) && mergeable_maps(em, merge)) { em->len += merge->len; em->block_len += merge->block_len; + if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) + merge_ondisk_extents(em, merge); rb_erase(&merge->rb_node, &tree->root); RB_CLEAR_NODE(&merge->rb_node); em->generation = max(em->generation, merge->generation); @@ -562,6 +622,7 @@ static noinline int merge_extent_mapping(struct btrfs_inode *inode, !extent_map_is_compressed(em)) { em->block_start += start_diff; em->block_len = em->len; + em->offset += start_diff; } return add_extent_mapping(inode, em, 0); } @@ -785,14 +846,18 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end, split->block_len = em->block_len; else split->block_len = split->len; + split->disk_bytenr = em->disk_bytenr; split->disk_num_bytes = max(split->block_len, em->disk_num_bytes); + split->offset = em->offset; split->ram_bytes = em->ram_bytes; } else { split->orig_start = split->start; split->block_len = 0; split->block_start = em->block_start; + split->disk_bytenr = em->disk_bytenr; split->disk_num_bytes = 0; + split->offset = 0; split->ram_bytes = split->len; } @@ -813,13 +878,14 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end, split->start = end; split->len = em_end - end; split->block_start = em->block_start; + split->disk_bytenr = em->disk_bytenr; split->flags = flags; split->generation = gen; if (em->block_start < EXTENT_MAP_LAST_BYTE) { split->disk_num_bytes = max(em->block_len, em->disk_num_bytes); - + split->offset = em->offset + end - em->start; split->ram_bytes = em->ram_bytes; if (compressed) { split->block_len = em->block_len; @@ -832,10 +898,11 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, u64 start, u64 end, split->orig_start = em->orig_start; } } else { + split->disk_num_bytes = 0; + split->offset = 0; split->ram_bytes = split->len; split->orig_start = split->start; split->block_len = 0; - split->disk_num_bytes = 0; } if (extent_map_in_tree(em)) { @@ -989,10 +1056,12 @@ int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, /* First, replace the em with a new extent_map starting from * em->start */ split_pre->start = em->start; split_pre->len = pre; + split_pre->disk_bytenr = new_logical; + split_pre->disk_num_bytes = split_pre->len; + split_pre->offset = 0; split_pre->orig_start = split_pre->start; split_pre->block_start = new_logical; split_pre->block_len = split_pre->len; - split_pre->disk_num_bytes = split_pre->block_len; split_pre->ram_bytes = split_pre->len; split_pre->flags = flags; split_pre->generation = em->generation; @@ -1007,10 +1076,12 @@ int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, /* Insert the middle extent_map. */ split_mid->start = em->start + pre; split_mid->len = em->len - pre; + split_mid->disk_bytenr = em->block_start + pre; + split_mid->disk_num_bytes = split_mid->len; + split_mid->offset = 0; split_mid->orig_start = split_mid->start; split_mid->block_start = em->block_start + pre; split_mid->block_len = split_mid->len; - split_mid->disk_num_bytes = split_mid->block_len; split_mid->ram_bytes = split_mid->len; split_mid->flags = flags; split_mid->generation = em->generation; |