This patchset can be fetched from my github: https://github.com/Damenly/btrfs-progs/tree/lowmem_repair based on kdave/devel. Thanks to Qu Wenruo's ideas and suggestions first. Any suggestions about names of functions and variables are welcome. Patch[1-3] fix minor problems of lowmem repair. Patch[4-8] introduce two ways to avoid extents overwrite: 1) Traverse trees and exclude all metadata blocks. It's time-inefficient for big filesystems. 2) Mark all existed chunks full, allocate new chunk for CoW. More efficient than method 1. However, it can't not handle situation like no space. Lowmem repair will try method 2 first and method 1 next now. Patch[9-17] remove parameters in lowmem repair functions. They will try to avoid extents overwrite if necessary and start transactions themselves. Those patches are mainly for lowmem repair. Original mode is not influenced. Since btrfs-progs v4.14, lowmem mode changed to check all tree blocks backrefs. There are many bugs about shared backref in lowmem mode now. If lowmem check can not work as expected, lowmem repair are useless. I will fix lowmem check in next. --- Changlog: v1->v2: - Let @err in check_btrfs_root() record err bits but excluded negative values. - Do not delete a line of code to release path after extent item' insertion in repair_extent_data_item(). - Add patch[3]. - Force CoW in new allocated chunk to avoid extents overwrite. - Remove parameters @trans in check_chunks_and_extents_v2() and related callees. - Repair functions for lowmem mode call try_avoid_extents_overwrite() and start transactions. Su Yue (17): btrfs-progs: lowmem check: release path in repair_extent_data_item() btrfs-progs: lowmem check: record returned errors after walk_down_tree_v2() btrfs-progs: lowmem check: assign @parent early in repair_extent_data_item() btrfs-progs: lowmem check: exclude extents of metadata blocks btrfs-progs: lowmem check: introduce modify_block_groups_cache() btrfs-progs: lowmem check: introduce force_cow_in_new_chunk() btrfs-progs: lowmem check: introduce try_avoid_extents_overwrite() btrfs-progs: lowmem check: exclude extents if init-extent-tree in lowmem btrfs-progs: lowmem check: start to remove parameters @trans in lowmem btrfs-progs: lowmem check: remove parameter @trans of delete_extent_item() btrfs-progs: lowmem check: remove parameter @trans of repair_chunk_item() btrfs-progs: lowmem check: remove parameter @trans of repair_extent_item() btrfs-progs: lowmem check: remove parameter @trans of check_leaf_items() btrfs-progs: lowmem check: remove parameter @trans of repair_tree_back_ref() btrfs-progs: lowmem check: remove parameter @trans of check_btrfs_root() btrfs-progs: lowmem check: introduce repair_block_accounting() btrfs-progs: lowmem check: end of removing parameters @trans in lowmem cmds-check.c | 620 +++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 515 insertions(+), 105 deletions(-) -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
