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2014-04-11Merge tag 'md/3.15' of git://neil.brown.name/mdLinus Torvalds
Pull md updates from Neil Brown: "Just a few md patches for the 3.15 merge window. Not much happening in md/raid at the moment. Just a few bug fixes (one for -stable) and a couple of performance tweaks" * tag 'md/3.15' of git://neil.brown.name/md: raid5: get_active_stripe avoids device_lock raid5: make_request does less prepare wait md: avoid oops on unload if some process is in poll or select. md/raid1: r1buf_pool_alloc: free allocate pages when subsequent allocation fails. md/bitmap: don't abuse i_writecount for bitmap files.
2014-04-09raid5: get_active_stripe avoids device_lockShaohua Li
For sequential workload (or request size big workload), get_active_stripe can find cached stripe. In this case, we always hold device_lock, which exposes a lot of lock contention for such workload. If stripe count isn't 0, we don't need hold the lock actually, since we just increase its count. And this is the hot code path for such workload. Unfortunately we must delete the BUG_ON. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-09raid5: make_request does less prepare waitShaohua Li
In NUMA machine, prepare_to_wait/finish_wait in make_request exposes a lot of contention for sequential workload (or big request size workload). For such workload, each bio includes several stripes. So we can just do prepare_to_wait/finish_wait once for the whold bio instead of every stripe. This reduces the lock contention completely for such workload. Random workload might have the similar lock contention too, but I didn't see it yet, maybe because my stroage is still not fast enough. Signed-off-by: Shaohua Li <shli@fusionio.com> Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-09md: avoid oops on unload if some process is in poll or select.NeilBrown
If md-mod is unloaded while some process is in poll() or select(), then that process maintains a pointer to md_event_waiters, and when the try to unlink from that list, they will oops. The procfs infrastructure ensures that ->poll won't be called after remove_proc_entry, but doesn't provide a wait_queue_head for us to use, and the waitqueue code doesn't provide a way to remove all listeners from a waitqueue. So we need to: 1/ make sure no further references to md_event_waiters are taken (by setting md_unloading) 2/ wake up all processes currently waiting, and 3/ wait until all those processes have disconnected from our wait_queue_head. Reported-by: "majianpeng" <majianpeng@gmail.com> Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-09md/raid1: r1buf_pool_alloc: free allocate pages when subsequent allocation ↵NeilBrown
fails. When performing a user-request check/repair (MD_RECOVERY_REQUEST is set) on a raid1, we allocate multiple bios each with their own set of pages. If the page allocations for one bio fails, we currently do *not* free the pages allocated for the previous bios, nor do we free the bio itself. This patch frees all the already-allocate pages, and makes sure that all the bios are freed as well. This bug can cause a memory leak which can ultimately OOM a machine. It was introduced in 3.10-rc1. Fixes: a07876064a0b73ab5ef1ebcf14b1cf0231c07858 Cc: Kent Overstreet <koverstreet@google.com> Cc: stable@vger.kernel.org (3.10+) Reported-by: Russell King - ARM Linux <linux@arm.linux.org.uk> Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-09md/bitmap: don't abuse i_writecount for bitmap files.NeilBrown
md bitmap code currently tries to use i_writecount to stop any other process from writing to out bitmap file. But that is really an abuse and has bit-rotted so locking is all wrong. So discard that - root should be allowed to shoot self in foot. Still use it in a much less intrusive way to stop the same file being used as bitmap on two different array, and apply other checks to ensure the file is at least vaguely usable for bitmap storage (is regular, is open for write. Support for ->bmap is already checked elsewhere). Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: NeilBrown <neilb@suse.de>
2014-04-05Merge tag 'dm-3.15-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper changes from Mike Snitzer: - Fix dm-cache corruption caused by discard_block_size > cache_block_size - Fix a lock-inversion detected by LOCKDEP in dm-cache - Fix a dangling bio bug in the dm-thinp target's process_deferred_bios error path - Fix corruption due to non-atomic transaction commit which allowed a metadata superblock to be written before all other metadata was successfully written -- this is common to all targets that use the persistent-data library's transaction manager (dm-thinp, dm-cache and dm-era). - Various small cleanups in the DM core - Add the dm-era target which is useful for keeping track of which blocks were written within a user defined period of time called an 'era'. Use cases include tracking changed blocks for backup software, and partially invalidating the contents of a cache to restore cache coherency after rolling back a vendor snapshot. - Improve the on-disk layout of multithreaded writes to the dm-thin-pool by splitting the pool's deferred bio list to be a per-thin device list and then sorting that list using an rb_tree. The subsequent read throughput of the data written via multiple threads improved by ~70%. - Simplify the multipath target's handling of queuing IO by pushing requests back to the request queue rather than queueing the IO internally. * tag 'dm-3.15-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (24 commits) dm cache: fix a lock-inversion dm thin: sort the per thin deferred bios using an rb_tree dm thin: use per thin device deferred bio lists dm thin: simplify pool_is_congested dm thin: fix dangling bio in process_deferred_bios error path dm mpath: print more useful warnings in multipath_message() dm-mpath: do not activate failed paths dm mpath: remove extra nesting in map function dm mpath: remove map_io() dm mpath: reduce memory pressure when requeuing dm mpath: remove process_queued_ios() dm mpath: push back requests instead of queueing dm table: add dm_table_run_md_queue_async dm mpath: do not call pg_init when it is already running dm: use RCU_INIT_POINTER instead of rcu_assign_pointer in __unbind dm: stop using bi_private dm: remove dm_get_mapinfo dm: make dm_table_alloc_md_mempools static dm: take care to copy the space map roots before locking the superblock dm transaction manager: fix corruption due to non-atomic transaction commit ...
2014-04-04dm cache: fix a lock-inversionJoe Thornber
When suspending a cache the policy is walked and the individual policy hints written to the metadata via sync_metadata(). This led to this lock order: policy->lock cache_metadata->root_lock When loading the cache target the policy is populated while the metadata lock is held: cache_metadata->root_lock policy->lock Fix this potential lock-inversion (ABBA) deadlock in sync_metadata() by ensuring the cache_metadata root_lock is held whilst all the hints are written, rather than being repeatedly locked while policy->lock is held (as was the case with each callout that policy_walk_mappings() made to the old save_hint() method). Found by turning on the CONFIG_PROVE_LOCKING ("Lock debugging: prove locking correctness") build option. However, it is not clear how the LOCKDEP reported paths can lead to a deadlock since the two paths, suspending a target and loading a target, never occur at the same time. But that doesn't mean the same lock-inversion couldn't have occurred elsewhere. Reported-by: Marian Csontos <mcsontos@redhat.com> Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-04-04dm thin: sort the per thin deferred bios using an rb_treeMike Snitzer
A thin-pool will allocate blocks using FIFO order for all thin devices which share the thin-pool. Because of this simplistic allocation the thin-pool's space can become fragmented quite easily; especially when multiple threads are requesting blocks in parallel. Sort each thin device's deferred_bio_list based on logical sector to help reduce fragmentation of the thin-pool's ondisk layout. The following tables illustrate the realized gains/potential offered by sorting each thin device's deferred_bio_list. An "io size"-sized random read of the device would result in "seeks/io" fragments being read, with an average "distance/seek" between each fragment. Data was written to a single thin device using multiple threads via iozone (8 threads, 64K for both the block_size and io_size). unsorted: io size seeks/io distance/seek -------------------------------------- 4k 0.000 0b 16k 0.013 11m 64k 0.065 11m 256k 0.274 10m 1m 1.109 10m 4m 4.411 10m 16m 17.097 11m 64m 60.055 13m 256m 148.798 25m 1g 809.929 21m sorted: io size seeks/io distance/seek -------------------------------------- 4k 0.000 0b 16k 0.000 1g 64k 0.001 1g 256k 0.003 1g 1m 0.011 1g 4m 0.045 1g 16m 0.181 1g 64m 0.747 1011m 256m 3.299 1g 1g 14.373 1g Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-04-01Merge branch 'for-3.15/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block driver update from Jens Axboe: "On top of the core pull request, here's the pull request for the driver related changes for 3.15. It contains: - Improvements for msi-x registration for block drivers (mtip32xx, skd, cciss, nvme) from Alexander Gordeev. - A round of cleanups and improvements for drbd from Andreas Gruenbacher and Rashika Kheria. - A round of clanups and improvements for bcache from Kent. - Removal of sleep_on() and friends in DAC960, ataflop, swim3 from Arnd Bergmann. - Bug fix for a bug in the mtip32xx async completion code from Sam Bradshaw. - Bug fix for accidentally bouncing IO on 32-bit platforms with mtip32xx from Felipe Franciosi" * 'for-3.15/drivers' of git://git.kernel.dk/linux-block: (103 commits) bcache: remove nested function usage bcache: Kill bucket->gc_gen bcache: Kill unused freelist bcache: Rework btree cache reserve handling bcache: Kill btree_io_wq bcache: btree locking rework bcache: Fix a race when freeing btree nodes bcache: Add a real GC_MARK_RECLAIMABLE bcache: Add bch_keylist_init_single() bcache: Improve priority_stats bcache: Better alloc tracepoints bcache: Kill dead cgroup code bcache: stop moving_gc marking buckets that can't be moved. bcache: Fix moving_pred() bcache: Fix moving_gc deadlocking with a foreground write bcache: Fix discard granularity bcache: Fix another bug recovering from unclean shutdown bcache: Fix a bug recovering from unclean shutdown bcache: Fix a journalling reclaim after recovery bug bcache: Fix a null ptr deref in journal replay ...
2014-04-01Merge tag 'char-misc-3.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver patches from Greg KH: "Here's the big char/misc driver updates for 3.15-rc1. Lots of various things here, including the new mcb driver subsystem. All of these have been in linux-next for a while" * tag 'char-misc-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (118 commits) extcon: Move OF helper function to extcon core and change function name extcon: of: Remove unnecessary function call by using the name of device_node extcon: gpio: Use SIMPLE_DEV_PM_OPS macro extcon: palmas: Use SIMPLE_DEV_PM_OPS macro mei: don't use deprecated DEFINE_PCI_DEVICE_TABLE macro mei: amthif: fix checkpatch error mei: client.h fix checkpatch errors mei: use cl_dbg where appropriate mei: fix Unnecessary space after function pointer name mei: report consistently copy_from/to_user failures mei: drop pr_fmt macros mei: make me hw headers private to me hw. mei: fix memory leak of pending write cb objects mei: me: do not reset when less than expected data is received drivers: mcb: Fix build error discovered by 0-day bot cs5535-mfgpt: Simplify dependencies spmi: pm: drop bus-level PM suspend/resume routines spmi: pmic_arb: make selectable on ARCH_QCOM Drivers: hv: vmbus: Increase the limit on the number of pfns we can handle pch_phub: Report error writing MAC back to user ...
2014-03-31dm thin: use per thin device deferred bio listsMike Snitzer
The thin-pool previously only had a single deferred_bios list that would collect bios for all thin devices in the pool. Split this per-pool deferred_bios list out to per-thin deferred_bios_list -- doing so enables increased parallelism when processing deferred bios. And now that each thin device has it's own deferred_bios_list we can sort all bios in the list using logical sector. The requeue code in error handling path is also cleaner as a side-effect. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-03-31dm thin: simplify pool_is_congestedMike Snitzer
The pool is congested if the pool is in PM_OUT_OF_DATA_SPACE mode. This is more explicit/clear/efficient than inferring whether or not the pool is congested by checking if retry_on_resume_list is empty. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
2014-03-28dm thin: fix dangling bio in process_deferred_bios error pathMike Snitzer
If unable to ensure_next_mapping() we must add the current bio, which was removed from the @bios list via bio_list_pop, back to the deferred_bios list before all the remaining @bios. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Cc: stable@vger.kernel.org
2014-03-27dm mpath: print more useful warnings in multipath_message()Jose Castillo
The warning message "Unrecognised multipath message received" is displayed in two different situations in multipath_message(): when the number of arguments passed is invalid and when the string passed in argv[0] is not recognized. Make it easier to identify where the problem is by making these warnings more specific with additional context for each case. Signed-off-by: Jose Castillo <jcastillo@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm-mpath: do not activate failed pathsHannes Reinecke
activate_path() is run without a lock, so the path might be set to failed before activate_path() had a chance to run. This patch add a check for ->active in activate_path() to avoid unnecessary overhead by calling functions which are known to be failing. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm mpath: remove extra nesting in map functionMike Snitzer
Return early for case when no path exists, and when the pathgroup isn't ready. This eliminates the need for extra nesting for the the common case. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de>
2014-03-27dm mpath: remove map_io()Hannes Reinecke
multipath_map() is now just a wrapper around map_io(), so we can rename map_io() to multipath_map(). Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm mpath: reduce memory pressure when requeuingHannes Reinecke
When multipath needs to requeue I/O in the block layer the per-request context shouldn't be allocated, as it will be freed immediately afterwards anyway. Avoiding this memory allocation will reduce memory pressure during requeuing. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm mpath: remove process_queued_ios()Hannes Reinecke
process_queued_ios() has served 3 functions: 1) select pg and pgpath if none is selected 2) start pg_init if requested 3) dispatch queued IOs when pg is ready Basically, a call to queue_work(process_queued_ios) can be replaced by dm_table_run_md_queue_async(), which runs request queue and ends up calling map_io(), which does 1), 2) and 3). Exception is when !pg_ready() (which means either pg_init is running or requested), then multipath_busy() prevents map_io() being called from request_fn. If pg_init is running, it should be ok as long as pg_init_done() does the right thing when pg_init is completed, I.e.: restart pg_init if !pg_ready() or call dm_table_run_md_queue_async() to kick map_io(). If pg_init is requested, we have to make sure the request is detected and pg_init will be started. pg_init is requested in 3 places: a) __choose_pgpath() in map_io() b) __choose_pgpath() in multipath_ioctl() c) pg_init retry in pg_init_done() a) is ok because map_io() calls __pg_init_all_paths(), which does 2). b) needs a call to __pg_init_all_paths(), which does 2). c) needs a call to __pg_init_all_paths(), which does 2). So this patch removes process_queued_ios() and ensures that __pg_init_all_paths() is called at the appropriate locations. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm mpath: push back requests instead of queueingHannes Reinecke
There is no reason why multipath needs to queue requests internally for queue_if_no_path or pg_init; we should rather push them back onto the request queue. And while we're at it we can simplify the conditional statement in map_io() to make it easier to read. Since mpath no longer does internal queuing of I/O the table info no longer emits the internal queue_size. Instead it displays 1 if queuing is being used or 0 if it is not. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm table: add dm_table_run_md_queue_asyncMike Snitzer
Introduce dm_table_run_md_queue_async() to run the request_queue of the mapped_device associated with a request-based DM table. Also add dm_md_get_queue() wrapper to extract the request_queue from a mapped_device. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm mpath: do not call pg_init when it is already runningHannes Reinecke
This patch moves condition checks as a preparation of following patches and has no effect on behaviour. process_queued_ios() is the only caller of __pg_init_all_paths() and 2 condition checks are moved from outside to inside without side effects. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
2014-03-27dm: use RCU_INIT_POINTER instead of rcu_assign_pointer in __unbindMonam Agarwal
Replace rcu_assign_pointer(p, NULL) with RCU_INIT_POINTER(p, NULL). The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL). Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm: stop using bi_privateMikulas Patocka
Device mapper uses the bio structure's bi_private field as a pointer to dm_target_io or dm_rq_clone_bio_info. But a bio structure is embedded in the dm_target_io and dm_rq_clone_bio_info structures, so the pointer to the structure that contains the bio can be found with the container_of() macro. Remove the use of bi_private and use container_of() instead. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm: remove dm_get_mapinfoMikulas Patocka
Remove dm_get_mapinfo() because no target uses it. Targets can allocate per-bio data using ti->per_bio_data_size, this is much more flexible than union map_info. Leave union map_info only for the request-based multipath target's use. Also delete the unused "unsigned long long ll" field of union map_info. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm: make dm_table_alloc_md_mempools staticMikulas Patocka
Make the function dm_table_alloc_md_mempools static because it is not called from another file. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm: take care to copy the space map roots before locking the superblockJoe Thornber
In theory copying the space map root can fail, but in practice it never does because we're careful to check what size buffer is needed. But make certain we're able to copy the space map roots before locking the superblock. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org # drop dm-era and dm-cache changes as needed
2014-03-27dm transaction manager: fix corruption due to non-atomic transaction commitJoe Thornber
The persistent-data library used by dm-thin, dm-cache, etc is transactional. If anything goes wrong, such as an io error when writing new metadata or a power failure, then we roll back to the last transaction. Atomicity when committing a transaction is achieved by: a) Never overwriting data from the previous transaction. b) Writing the superblock last, after all other metadata has hit the disk. This commit and the following commit ("dm: take care to copy the space map roots before locking the superblock") fix a bug associated with (b). When committing it was possible for the superblock to still be written in spite of an io error occurring during the preceeding metadata flush. With these commits we're careful not to take the write lock out on the superblock until after the metadata flush has completed. Change the transaction manager's semantics for dm_tm_commit() to assume all data has been flushed _before_ the single superblock that is passed in. As a prerequisite, split the block manager's block unlocking and flushing by simplifying dm_bm_flush_and_unlock() to dm_bm_flush(). Now the unlocking must be done separately. This issue was discovered by forcing io errors at the crucial time using dm-flakey. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
2014-03-27dm cache: remove remainder of distinct discard block sizeHeinz Mauelshagen
Discard block size not being equal to cache block size causes data corruption by erroneously avoiding migrations in issue_copy() because the discard state is being cleared for a group of cache blocks when it should not. Completely remove all code that enabled a distinction between the cache block size and discard block size. Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm cache: prevent corruption caused by discard_block_size > cache_block_sizeMike Snitzer
If the discard block size is larger than the cache block size we will not properly quiesce IO to a region that is about to be discarded. This results in a race between a cache migration where no copy is needed, and a write to an adjacent cache block that's within the same large discard block. Workaround this by limiting the discard_block_size to cache_block_size. Also limit the max_discard_sectors to cache_block_size. A more comprehensive fix that introduces range locking support in the bio_prison and proper quiescing of a discard range that spans multiple cache blocks is already in development. Reported-by: Morgan Mears <Morgan.Mears@netapp.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com> Acked-by: Heinz Mauelshagen <heinzm@redhat.com> Cc: stable@vger.kernel.org
2014-03-27dm bitset: only flush the current word if it has been dirtiedJoe Thornber
This change offers a big performance boost for dm-era. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-27dm: add era targetJoe Thornber
dm-era is a target that behaves similar to the linear target. In addition it keeps track of which blocks were written within a user defined period of time called an 'era'. Each era target instance maintains the current era as a monotonically increasing 32-bit counter. Use cases include tracking changed blocks for backup software, and partially invalidating the contents of a cache to restore cache coherency after rolling back a vendor snapshot. dm-era is primarily expected to be paired with the dm-cache target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2014-03-18bcache: remove nested function usageJohn Sheu
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 <john.sheu@gmail.com>
2014-03-18bcache: Kill bucket->gc_genKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Kill unused freelistKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Rework btree cache reserve handlingKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Kill btree_io_wqKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: btree locking reworkKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Fix a race when freeing btree nodesKent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Add a real GC_MARK_RECLAIMABLEKent Overstreet
This means the garbage collection code can better check for data and metadata pointers to the same buckets. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Add bch_keylist_init_single()Kent Overstreet
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 <kmo@daterainc.com>
2014-03-18bcache: Improve priority_statsKent Overstreet
Break down data into clean data/dirty data/metadata. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Better alloc tracepointsKent Overstreet
Change the invalidate tracepoint to indicate how much data we're invalidating, and change the alloc tracepoints to indicate what offset they're for. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Kill dead cgroup codeKent Overstreet
This hasn't been used or even enabled in ages. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: stop moving_gc marking buckets that can't be moved.Nicholas Swenson
Signed-off-by: Nicholas Swenson <nks@daterainc.com>
2014-03-18bcache: Fix moving_pred()Kent Overstreet
Avoid a potential null pointer deref (e.g. from check keys for cache misses) Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Fix moving_gc deadlocking with a foreground writeNicholas Swenson
Deadlock happened because a foreground write slept, waiting for a bucket to be allocated. Normally the gc would mark buckets available for invalidation. But the moving_gc was stuck waiting for outstanding writes to complete. These writes used the bcache_wq, the same queue foreground writes used. This fix gives moving_gc its own work queue, so it was still finish moving even if foreground writes are stuck waiting for allocation. It also makes work queue a parameter to the data_insert path, so moving_gc can use its workqueue for writes. Signed-off-by: Nicholas Swenson <nks@daterainc.com> Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Fix discard granularityKent Overstreet
blk_stack_limits() doesn't like a discard granularity of 0. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-03-18bcache: Fix another bug recovering from unclean shutdownKent Overstreet
The on disk bucket gens are allowed to be out of date, when we reuse buckets that didn't have any live data in them. To deal with this, the initial gc has to update the bucket gen when we find a pointer gen newer than the bucket's gen. Unfortunately we weren't doing this for pointers in the journal that we're about to replay. Signed-off-by: Kent Overstreet <kmo@daterainc.com>