lwn.git/fs/bcachefs/bcachefs_format.h, branch docs-mw

Remove bcachefs core code

2025-09-29T20:43:52+00:00

bcachefs was marked 'externally maintained' in 6.17 but the code remained to make the transition smoother. It's now a DKMS module, making the in-kernel code stale, so remove it to avoid any version confusion. Link: https://lore.kernel.org/linux-bcachefs/yokpt2d2g2lluyomtqrdvmkl3amv3kgnipmenobkpgx537kay7@xgcgjviv3n7x/T/ Signed-off-by: Linus Torvalds

bcachefs: BCH_INODE_has_case_insensitive

2025-05-22T00:15:10+00:00

Add a flag for tracking whether a directory has case-insensitive descendents - so that overlayfs can disallow mounting, even though the filesystem supports case insensitivity. This is a new on disk format version, with a (cheap) upgrade to ensure the flag is correctly set on existing inodes. Create, rename and fssetxattr are all plumbed to ensure the new flag is set, and we've got new fsck code that hooks into check_inode(0. Signed-off-by: Kent Overstreet

bcachefs: bch_sb_field_recovery_passes

2025-05-22T00:14:53+00:00

New superblock section for statistics on recovery passes - last time ran (successfully), last runtime. This will be used by self healing code to determine when to kick off potentially expensive recovery passes. Signed-off-by: Kent Overstreet

bcachefs: recovery_passes_types.h -> recovery_passes_format.h

2025-05-22T00:14:52+00:00

Signed-off-by: Kent Overstreet

bcachefs: bcachefs_metadata_version_fast_device_removal

2025-05-22T00:14:49+00:00

Fast device removal, that uses backpointers to find pointers to the device being removed instead of a full metadata scan. This requires BCH_SB_MEMBER_DELETED_UUID, which is an incompatible change - hence the version number bump. We don't fully trust backpointers, so we don't want to reuse device indexes until after a fsck has verified that there aren't any pointers to removed devices. Signed-off-by: Kent Overstreet

bcachefs: opts.rebalance_on_ac_only

2025-05-22T00:14:48+00:00

Add an option for setting rebalance to only run when connected to mains power. Signed-off-by: Kent Overstreet

bcachefs: bcachefs_metadata_version_snapshot_deletion_v2

2025-05-22T00:14:45+00:00

We're going to be speeding up snapshot deletion, by only having it process the extents/dirents/xattrs btrees if an inode of a given snapshot ID was present. This raises the possibility of 'bkey_in_missing_snapshot' errors popping up, if we ever accidentally don't do the corresponding inode update, or if the new algorithm has bugs. So instead of deleting snapshot IDs, add a new deleted flag, so that 'key in missing snapshot' errors can more definitively tell what happened and automatically repair. Signed-off-by: Kent Overstreet

bcachefs: BCH_FEATURE_small_image

2025-05-22T00:14:20+00:00

We can't go RW if it's an image file that hasn't been resized. Signed-off-by: Kent Overstreet

bcachefs: BCH_FEATURE_no_alloc_info

2025-05-22T00:14:20+00:00

If a filesystem is going to only be used read-only, and will be a deployable image, we can strip out alloc info for a substantial reduction in metadata size - around half, due to backpointers. Alloc info will be regenerated on first read-write mount. Remounting RW is disallowed for now, since we don't yet have check_allocations running in RW mode. Signed-off-by: Kent Overstreet

bcachefs: Single device mode

2025-05-22T00:14:15+00:00

Single device filesystems are now identified by the block device name, not the UUID - and single device filesystems with the same UUID can be mounted simultaneously, without any special options. This allocates a new bit in the superblock, BCH_SB_MULTI_DEVICE, which indicates whether a filesystem has ever been multi device. Signed-off-by: Kent Overstreet