53 Commits

Author SHA1 Message Date
Kent Overstreet
b32f9a577b bcachefs: Run check_extents_to_backpointers() in multiple passes
Similer to the previous patch for check_backpointers_to_extents(), if
the alloc + backpointers btrees do not fit in ram we need to run into
multiple passes.

The counting of btree nodes that fit in memory is different here,
because we have to walk the alloc and backpointers btrees at the same
time, since a backpointer could reside in either of them and we don't
know which without checking both.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:51 -04:00
Kent Overstreet
23792a712d bcachefs: Run bch2_check_backpointers_to_extents() in multiple passes if necessary
When the extents + reflink btrees don't fit into memory this fsck pass
becomes _much_ slower, since we're doing random lookups.

This patch changes this pass to check how much of the relevant btrees
will fit into memory, and run in multiple passes if needed.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:51 -04:00
Kent Overstreet
a8c752bb1d bcachefs: New on disk format: Backpointers
This patch adds backpointers: we now have a reverse index from device
and offset on that device (specifically, offset within a bucket) back to
btree nodes and (non cached) data extents.

The first 40 backpointers within a bucket are stored in the alloc key;
after that backpointers spill over to the next backpointers btree. This
is to help avoid performance regressions from additional btree updates
on large streaming workloads.

This patch adds all the code for creating, checking and repairing
backpointers. The next patch in the series is going to use backpointers
for copygc - finally getting rid of the need to scan all extents to do
copygc.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:50 -04:00