- Feb 09, 2019
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Coly Li authored
This patch export dc->backing_dev_name to sysfs file /sys/block/bcache<?>/bcache/backing_dev_name, then people or user space tools may know the backing device name of this bcache device. Of cause it can be done by parsing sysfs links, but this method can be much simpler to find the link between bcache device and backing device. Signed-off-by:
Coly Li <colyli@suse.de> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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Coly Li authored
In stats.c:bch_cache_accounting_clear(), a hard coded number '7' is used in memset(). It is because in struct cache_stats, there are 7 atomic_t type members. This is not good when new members added into struct stats, the hard coded number will only clear part of memory. This patch replaces 'sizeof(unsigned long) * 7' by more generic 'sizeof(struct cache_stats))', to avoid potential error if new member added into struct cache_stats. Signed-off-by:
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Daniel Axtens authored
Some users see panics like the following when performing fstrim on a bcached volume: [ 529.803060] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 530.183928] #PF error: [normal kernel read fault] [ 530.412392] PGD 8000001f42163067 P4D 8000001f42163067 PUD 1f42168067 PMD 0 [ 530.750887] Oops: 0000 [#1] SMP PTI [ 530.920869] CPU: 10 PID: 4167 Comm: fstrim Kdump: loaded Not tainted 5.0.0-rc1+ #3 [ 531.290204] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015 [ 531.693137] RIP: 0010:blk_queue_split+0x148/0x620 [ 531.922205] Code: 60 38 89 55 a0 45 31 db 45 31 f6 45 31 c9 31 ff 89 4d 98 85 db 0f 84 7f 04 00 00 44 8b 6d 98 4c 89 ee 48 c1 e6 04 49 03 70 78 <8b> 46 08 44 8b 56 0c 48 8b 16 44 29 e0 39 d8 48 89 55 a8 0f 47 c3 [ 532.838634] RSP: 0018:ffffb9b708df39b0 EFLAGS: 00010246 [ 533.093571] RAX: 00000000ffffffff RBX: 0000000000046000 RCX: 0000000000000000 [ 533.441865] RDX: 0000000000000200 RSI: 0000000000000000 RDI: 0000000000000000 [ 533.789922] RBP: ffffb9b708df3a48 R08: ffff940d3b3fdd20 R09: 0000000000000000 [ 534.137512] R10: ffffb9b708df3958 R11: 0000000000000000 R12: 0000000000000000 [ 534.485329] R13: 0000000000000000 R14: 0000000000000000 R15: ffff940d39212020 [ 534.833319] FS: 00007efec26e3840(0000) GS:ffff940d1f480000(0000) knlGS:0000000000000000 [ 535.224098] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 535.504318] CR2: 0000000000000008 CR3: 0000001f4e256004 CR4: 00000000001606e0 [ 535.851759] Call Trace: [ 535.970308] ? mempool_alloc_slab+0x15/0x20 [ 536.174152] ? bch_data_insert+0x42/0xd0 [bcache] [ 536.403399] blk_mq_make_request+0x97/0x4f0 [ 536.607036] generic_make_request+0x1e2/0x410 [ 536.819164] submit_bio+0x73/0x150 [ 536.980168] ? submit_bio+0x73/0x150 [ 537.149731] ? bio_associate_blkg_from_css+0x3b/0x60 [ 537.391595] ? _cond_resched+0x1a/0x50 [ 537.573774] submit_bio_wait+0x59/0x90 [ 537.756105] blkdev_issue_discard+0x80/0xd0 [ 537.959590] ext4_trim_fs+0x4a9/0x9e0 [ 538.137636] ? ext4_trim_fs+0x4a9/0x9e0 [ 538.324087] ext4_ioctl+0xea4/0x1530 [ 538.497712] ? _copy_to_user+0x2a/0x40 [ 538.679632] do_vfs_ioctl+0xa6/0x600 [ 538.853127] ? __do_sys_newfstat+0x44/0x70 [ 539.051951] ksys_ioctl+0x6d/0x80 [ 539.212785] __x64_sys_ioctl+0x1a/0x20 [ 539.394918] do_syscall_64+0x5a/0x110 [ 539.568674] entry_SYSCALL_64_after_hwframe+0x44/0xa9 We have observed it where both: 1) LVM/devmapper is involved (bcache backing device is LVM volume) and 2) writeback cache is involved (bcache cache_mode is writeback) On one machine, we can reliably reproduce it with: # echo writeback > /sys/block/bcache0/bcache/cache_mode (not sure whether above line is required) # mount /dev/bcache0 /test # for i in {0..10}; do file="$(mktemp /test/zero.XXX)" dd if=/dev/zero of="$file" bs=1M count=256 sync rm $file done # fstrim -v /test Observing this with tracepoints on, we see the following writes: fstrim-18019 [022] .... 91107.302026: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 4260112 + 196352 hit 0 bypass 1 fstrim-18019 [022] .... 91107.302050: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 4456464 + 262144 hit 0 bypass 1 fstrim-18019 [022] .... 91107.302075: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 4718608 + 81920 hit 0 bypass 1 fstrim-18019 [022] .... 91107.302094: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 5324816 + 180224 hit 0 bypass 1 fstrim-18019 [022] .... 91107.302121: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 5505040 + 262144 hit 0 bypass 1 fstrim-18019 [022] .... 91107.302145: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 5767184 + 81920 hit 0 bypass 1 fstrim-18019 [022] .... 91107.308777: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0 DS 6373392 + 180224 hit 1 bypass 0 <crash> Note the final one has different hit/bypass flags. This is because in should_writeback(), we were hitting a case where the partial stripe condition was returning true and so should_writeback() was returning true early. If that hadn't been the case, it would have hit the would_skip test, and as would_skip == s->iop.bypass == true, should_writeback() would have returned false. Looking at the git history from 'commit 72c27061 ("bcache: Write out full stripes")', it looks like the idea was to optimise for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data To fix this issue, make sure that should_writeback() on a discard op never returns true. More details of debugging: https://www.spinics.net/lists/linux-bcache/msg06996.html Previous reports: - https://bugzilla.kernel.org/show_bug.cgi?id=201051 - https://bugzilla.kernel.org/show_bug.cgi?id=196103 - https://www.spinics.net/lists/linux-bcache/msg06885.html (Coly Li: minor modification to follow maximum 75 chars per line rule) Cc: Kent Overstreet <koverstreet@google.com> Cc: stable@vger.kernel.org Fixes: 72c27061 ("bcache: Write out full stripes") Signed-off-by:Daniel Axtens <dja@axtens.net> Signed-off-by:
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- Dec 13, 2018
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Guoju Fang authored
Sometimes flush journal may be very frequent, so it's useful to dump number of keys every time write journal. Signed-off-by:
Guoju Fang <fangguoju@gmail.com> Signed-off-by:
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Coly Li authored
Because CUTOFF_WRITEBACK is defined as 40, so before the changes of dynamic cutoff writeback values, writeback_percent is limited to [0, CUTOFF_WRITEBACK]. Any value larger than CUTOFF_WRITEBACK will be fixed up to 40. Now cutof writeback limit is a dynamic value bch_cutoff_writeback, so the range of writeback_percent can be a more flexible range as [0, bch_cutoff_writeback]. The flexibility is, it can be expended to a larger or smaller range than [0, 40], depends on how value bch_cutoff_writeback is specified. The default value is still strongly recommended to most of users for most of workloads. But for people who want to do research on bcache writeback perforamnce tuning, they may have chance to specify more flexible writeback_percent in range [0, 70]. Signed-off-by:
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Coly Li authored
Currently the cutoff writeback and cutoff writeback sync thresholds are defined by CUTOFF_WRITEBACK (40) and CUTOFF_WRITEBACK_SYNC (70) as static values. Most of time these they work fine, but when people want to do research on bcache writeback mode performance tuning, there is no chance to modify the soft and hard cutoff writeback values. This patch introduces two module parameters bch_cutoff_writeback_sync and bch_cutoff_writeback which permit people to tune the values when loading bcache.ko. If they are not specified by module loading, current values CUTOFF_WRITEBACK_SYNC and CUTOFF_WRITEBACK will be used as default and nothing changes. When people want to tune this two values, - cutoff_writeback can be set in range [1, 70] - cutoff_writeback_sync can be set in range [1, 90] - cutoff_writeback always <= cutoff_writeback_sync The default values are strongly recommended to most of users for most of workloads. Anyway, if people wants to take their own risk to do research on new writeback cutoff tuning for their own workload, now they can make it. Signed-off-by:
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Coly Li authored
This patch moves MODULE_AUTHOR and MODULE_LICENSE to end of super.c, and add MODULE_DESCRIPTION("Bcache: a Linux block layer cache"). This is preparation for adding module parameters. Signed-off-by: -
Coly Li authored
The option gc_after_writeback is disabled by default, because garbage collection will discard SSD data which drops cached data. Echo 1 into /sys/fs/bcache/<UUID>/internal/gc_after_writeback will enable this option, which wakes up gc thread when writeback accomplished and all cached data is clean. This option is helpful for people who cares writing performance more. In heavy writing workload, all cached data can be clean only happens when writeback thread cleans all cached data in I/O idle time. In such situation a following gc running may help to shrink bcache B+ tree and discard more clean data, which may be helpful for future writing requests. If you are not sure whether this is helpful for your own workload, please leave it as disabled by default. Signed-off-by:
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Coly Li authored
Garbage collection thread starts to work when c->sectors_to_gc is negative value, otherwise nothing will happen even the gc thread is woken up by wake_up_gc(). force_wake_up_gc() sets c->sectors_to_gc to -1 before calling wake_up_gc(), then gc thread may have chance to run if no one else sets c->sectors_to_gc to a positive value before gc_should_run(). This routine can be called where the gc thread is woken up and required to run in force. Signed-off-by:
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Shenghui Wang authored
"echo 1 > writeback_running" marks writeback_running even if no writeback kthread created as "d_strtoul(writeback_running)" will simply set dc-> writeback_running without checking the existence of dc->writeback_thread. Add check for setting writeback_running via sysfs: if no writeback kthread available, reject setting to 1. v2 -> v3: * Make message on wrong assignment more clear. * Print name of bcache device instead of name of backing device. Signed-off-by:
Shenghui Wang <shhuiw@foxmail.com> Signed-off-by:
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Shenghui Wang authored
A fresh backing device is not attached to any cache_set, and has no writeback kthread created until first attached to some cache_set. But bch_cached_dev_writeback_init run " dc->writeback_running = true; WARN_ON(test_and_clear_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)); " for any newly formatted backing devices. For a fresh standalone backing device, we can get something like following even if no writeback kthread created: ------------------------ /sys/block/bcache0/bcache# cat writeback_running 1 /sys/block/bcache0/bcache# cat writeback_rate_debug rate: 512.0k/sec dirty: 0.0k target: 0.0k proportional: 0.0k integral: 0.0k change: 0.0k/sec next io: -15427384ms The none ZERO fields are misleading as no alive writeback kthread yet. Set dc->writeback_running false as no writeback thread created in bch_cached_dev_writeback_init(). We have writeback thread created and woken up in bch_cached_dev_writeback _start(). Set dc->writeback_running true before bch_writeback_queue() called, as a writeback thread will check if dc->writeback_running is true before writing back dirty data, and hung if false detected. After the change, we can get the following output for a fresh standalone backing device: ----------------------- /sys/block/bcache0/bcache$ cat writeback_running 0 /sys/block/bcache0/bcache# cat writeback_rate_debug rate: 0.0k/sec dirty: 0.0k target: 0.0k proportional: 0.0k integral: 0.0k change: 0.0k/sec next io: 0ms v1 -> v2: Set dc->writeback_running before bch_writeback_queue() called, Signed-off-by:
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Shenghui Wang authored
We have struct cached_dev allocated by kzalloc in register_bcache(), which initializes all the fields of cached_dev with 0s. And commit ce4c3e19 ("bcache: Replace bch_read_string_list() by __sysfs_match_string()") has remove the string "default". Update the comment. Signed-off-by:
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Shenghui Wang authored
commit 220bb38c ("bcache: Break up struct search") introduced changes to struct search and s->iop. bypass/bio are fields of struct data_insert_op now. Update the comment. Signed-off-by:
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Shenghui Wang authored
debugfs_remove and debugfs_remove_recursive will check if the dentry pointer is NULL or ERR, and will do nothing in that case. Remove the check in cache_set_free and bch_debug_init. Signed-off-by:
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Shenghui Wang authored
We have the following define for btree iterator: struct btree_iter { size_t size, used; #ifdef CONFIG_BCACHE_DEBUG struct btree_keys *b; #endif struct btree_iter_set { struct bkey *k, *end; } data[MAX_BSETS]; }; We can see that the length of data[] field is static MAX_BSETS, which is defined as 4 currently. But a btree node on disk could have too many bsets for an iterator to fit on the stack - maybe far more that MAX_BSETS. Have to dynamically allocate space to host more btree_iter_sets. bch_cache_set_alloc() will make sure the pool cache_set->fill_iter can allocate an iterator equipped with enough room that can host (sb.bucket_size / sb.block_size) btree_iter_sets, which is more than static MAX_BSETS. bch_btree_node_read_done() will use that pool to allocate one iterator, to host many bsets in one btree node. Add more comment around cache_set->fill_iter to make code less confusing. Signed-off-by:
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- Oct 08, 2018
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Dongbo Cao authored
when the nbuckets of cache device is smaller than 1024, making cache device will trigger BUG_ON in kernel, add a condition to avoid this. Reported-by:
nitroxis <n@nxs.re> Signed-off-by:
Dongbo Cao <cdbdyx@163.com> Signed-off-by:
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Dongbo Cao authored
Split the combined '||' statements in if() check, to make the code easier for debug. Signed-off-by:
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Shenghui Wang authored
Current cache_set has MAX_CACHES_PER_SET caches most, and the macro is used for " struct cache *cache_by_alloc[MAX_CACHES_PER_SET]; " in the define of struct cache_set. Use MAX_CACHES_PER_SET instead of magic number 8 in __bch_bucket_alloc_set. Signed-off-by:
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Coly Li authored
In extents.c:bch_extent_bad(), number 96 is used as parameter to call btree_bug_on(). The purpose is to check whether stale gen value exceeds BUCKET_GC_GEN_MAX, so it is better to use macro BUCKET_GC_GEN_MAX to make the code more understandable. Signed-off-by:
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Dongbo Cao authored
Parameter "struct kobject *kobj" in bch_debug_init() is useless, remove it in this patch. Signed-off-by:
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Shenghui Wang authored
struct kmem_cache *bch_passthrough_cache is not used in bcache code. Remove it. Signed-off-by:
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Shenghui Wang authored
Recal cached_dev_sectors on cached_dev detached, as recal done on cached_dev attached. Update the cached_dev_sectors before bcache_device_detach called as bcache_device_detach will set bcache_device->c to NULL. Signed-off-by:
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Tang Junhui authored
refill->end record the last key of writeback, for example, at the first time, keys (1,128K) to (1,1024K) are flush to the backend device, but the end key (1,1024K) is not included, since the bellow code: if (bkey_cmp(k, refill->end) >= 0) { ret = MAP_DONE; goto out; } And in the next time when we refill writeback keybuf again, we searched key start from (1,1024K), and got a key bigger than it, so the key (1,1024K) missed. This patch modify the above code, and let the end key to be included to the writeback key buffer. Signed-off-by:Tang Junhui <tang.junhui.linux@gmail.com> Cc: stable@vger.kernel.org Signed-off-by:
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Ben Peddell authored
Forgot to include the maintainers with my first email. Somewhere between Michael Lyle's original "bcache: PI controller for writeback rate V2" patch dated 07 Sep 2017 and 1d316e65 bcache: implement PI controller for writeback rate, the mapping of the writeback_rate_minimum attribute was dropped. Re-add the missing sysfs writeback_rate_minimum attribute mapping to "allow the user to specify a minimum rate at which dirty blocks are retired." Fixes: 1d316e65 ("bcache: implement PI controller for writeback rate") Signed-off-by:
Ben Peddell <klightspeed@killerwolves.net> Signed-off-by:
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Tang Junhui authored
When bcache device is clean, dirty keys may still exist after journal replay, so we need to count these dirty keys even device in clean status, otherwise after writeback, the amount of dirty data would be incorrect. Signed-off-by:
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Coly Li authored
The code comments of closure_return_with_destructor() in closure.h makrs function name as closure_return(). This patch fixes this type with the correct name - closure_return_with_destructor. Signed-off-by:
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Tang Junhui authored
When doing ioctl in flash device, it will call ioctl_dev() in super.c, then we should not to get cached device since flash only device has no backend device. This patch just move the jugement dc->io_disable to cached_dev_ioctl() to make ioctl in flash device correctly. Fixes: 0f0709e6 ("bcache: stop bcache device when backing device is offline") Signed-off-by:
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Coly Li authored
In cached_dev_cache_miss() and check_should_bypass(), REQ_META is used to check whether a bio is for metadata request. REQ_META is used for blktrace, the correct REQ_ flag should be REQ_PRIO. This flag means the bio should be prior to other bio, and frequently be used to indicate metadata io in file system code. This patch replaces REQ_META with correct flag REQ_PRIO. CC Adam Manzanares because he explains to me what REQ_PRIO is for. Signed-off-by:
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Tang Junhui authored
Missed reading IOs are identified by s->cache_missed, not the s->cache_miss, so in trace_bcache_read() using trace_bcache_read to identify whether the IO is missed or not. Signed-off-by:
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Shenghui Wang authored
UUIDs are considered as metadata. __uuid_write should add the number of buckets (in sectors) written to disk to ca->meta_sectors_written. Currently only 1 bucket is used in uuid write. Steps to test: 1) create a fresh backing device and a fresh cache device separately. The backing device didn't attach to any cache set. 2) cd /sys/block/<cache device>/bcache cat metadata_written // record the output value cat bucket_size 3) attach the backing device to cache set 4) cat metadata_written The output value is almost the same as the value in step 2 before the change. After the change, the value is bigger about 1 bucket size. Signed-off-by:
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- Sep 27, 2018
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Guoju Fang authored
After write SSD completed, bcache schedules journal_write work to system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM flag. system_wq is also a bound wq, and there may be no idle kworker on current processor. Creating a new kworker may unfortunately need to reclaim memory first, by shrinking cache and slab used by vfs, which depends on bcache device. That's a deadlock. This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM flag. It's rescuer thread will work to avoid the deadlock. Signed-off-by:
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- Aug 22, 2018
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Shan Hai authored
The writeback thread would exit with a lock held when the cache device is detached via sysfs interface, fix it by releasing the held lock before exiting the while-loop. Fixes: fadd94e0 (bcache: quit dc->writeback_thread when BCACHE_DEV_DETACHING is set) Signed-off-by:
Shan Hai <shan.hai@oracle.com> Signed-off-by:
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Coly Li authored
Now we have crc64 calculation in lib/crc64.c, it is unnecessary for bcache to use its own version. This patch changes bcache code to use crc64 routines in lib/crc64.c. Link: http://lkml.kernel.org/r/20180718165545.1622-3-colyli@suse.de Signed-off-by:
Hannes Reinecke <hare@suse.de> Reviewed-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Michael Lyle <mlyle@lyle.org> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Noah Massey <noah.massey@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- Aug 11, 2018
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Coly Li authored
Checkpatch.pl warns there are 2 locations of smp_mb() and smp_wmb() without code comment. This patch adds the missing code comments for these memory barrier calls. Signed-off-by:
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Coly Li authored
This is warned by checkpatch.pl, this patch removes the extra space. Signed-off-by:
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Coly Li authored
The SPDX header is missing fro closure.c, super.c and util.c, this patch adds SPDX header for GPL-2.0 into these files. Signed-off-by:
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Coly Li authored
This is not a preferred style to place open brace '{' at the end of function definition, checkpatch.pl reports error for such coding style. This patch moves them into the start of the next new line. Signed-off-by: -
Coly Li authored
This patch declares char * array with const prefix in sysfs.c, which is suggested by checkpatch.pl. Signed-off-by:
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Coly Li authored
This patch fixes 3 style issues warned by checkpatch.pl, - Comment lines are not aligned - Comments use "/*" on subsequent lines - Comment lines use a trailing "*/" Signed-off-by:
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Coly Li authored
kmem_cache_destroy() is safe for NULL pointer as input, the NULL pointer checking is unncessary. This patch just removes the NULL pointer checking to make code simpler. Signed-off-by:
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