kernel/linux.git/drivers/md/bcache, branch v3.15.2

bcache: remove nested function usage

2014-03-18T19:39:28+00:00

Uninlined nested functions can cause crashes when using ftrace, as they don't follow the normal calling convention and confuse the ftrace function graph tracer as it examines the stack. Also, nested functions are supported as a gcc extension, but may fail on other compilers (e.g. llvm). Signed-off-by: John Sheu

bcache: Kill bucket->gc_gen

2014-03-18T19:24:54+00:00

gc_gen was a temporary used to recalculate last_gc, but since we only need bucket->last_gc when gc isn't running (gc_mark_valid = 1), we can just update last_gc directly. Signed-off-by: Kent Overstreet

bcache: Kill unused freelist

2014-03-18T19:23:36+00:00

This was originally added as at optimization that for various reasons isn't needed anymore, but it does add a lot of nasty corner cases (and it was responsible for some recently fixed bugs). Just get rid of it now. Signed-off-by: Kent Overstreet

bcache: Rework btree cache reserve handling

2014-03-18T19:23:35+00:00

This changes the bucket allocation reserves to use _real_ reserves - separate freelists - instead of watermarks, which if nothing else makes the current code saner to reason about and is going to be important in the future when we add support for multiple btrees. It also adds btree_check_reserve(), which checks (and locks) the reserves for both bucket allocation and memory allocation for btree nodes; the old code just kinda sorta assumed that since (e.g. for btree node splits) it had the root locked and that meant no other threads could try to make use of the same reserve; this technically should have been ok for memory allocation (we should always have a reserve for memory allocation (the btree node cache is used as a reserve and we preallocate it)), but multiple btrees will mean that locking the root won't be sufficient anymore, and for the bucket allocation reserve it was technically possible for the old code to deadlock. Signed-off-by: Kent Overstreet

bcache: Kill btree_io_wq

2014-03-18T19:23:35+00:00

With the locking rework in the last patch, this shouldn't be needed anymore - btree_node_write_work() only takes b->write_lock which is never held for very long. Signed-off-by: Kent Overstreet

bcache: btree locking rework

2014-03-18T19:23:35+00:00

Add a new lock, b->write_lock, which is required to actually modify - or write - a btree node; this lock is only held for short durations. This means we can write out a btree node without taking b->lock, which _is_ held for long durations - solving a deadlock when btree_flush_write() (from the journalling code) is called with a btree node locked. Right now just occurs in bch_btree_set_root(), but with an upcoming journalling rework is going to happen a lot more. This also turns b->lock is now more of a read/intent lock instead of a read/write lock - but not completely, since it still blocks readers. May turn it into a real intent lock at some point in the future. Signed-off-by: Kent Overstreet

bcache: Fix a race when freeing btree nodes

2014-03-18T19:23:34+00:00

This isn't a bulletproof fix; btree_node_free() -> bch_bucket_free() puts the bucket on the unused freelist, where it can be reused right away without any ordering requirements. It would be better to wait on at least a journal write to go down before reusing the bucket. bch_btree_set_root() does this, and inserting into non leaf nodes is completely synchronous so we should be ok, but future patches are just going to get rid of the unused freelist - it was needed in the past for various reasons but shouldn't be anymore. Signed-off-by: Kent Overstreet

bcache: Add a real GC_MARK_RECLAIMABLE

2014-03-18T19:22:36+00:00

This means the garbage collection code can better check for data and metadata pointers to the same buckets. Signed-off-by: Kent Overstreet

bcache: Add bch_keylist_init_single()

2014-03-18T19:22:36+00:00

This will potentially save us an allocation when we've got inode/dirent bkeys that don't fit in the keylist's inline keys. Signed-off-by: Kent Overstreet

bcache: Improve priority_stats

2014-03-18T19:22:35+00:00

Break down data into clean data/dirty data/metadata. Signed-off-by: Kent Overstreet