linux-dev/drivers/md/bcache/super.c, branch linus/master

bcache: avoid journal no-space deadlock by reserving 1 journal bucket

2022-05-24T12:19:33Z

The journal no-space deadlock was reported time to time. Such deadlock can happen in the following situation. When all journal buckets are fully filled by active jset with heavy write I/O load, the cache set registration (after a reboot) will load all active jsets and inserting them into the btree again (which is called journal replay). If a journaled bkey is inserted into a btree node and results btree node split, new journal request might be triggered. For example, the btree grows one more level after the node split, then the root node record in cache device super block will be upgrade by bch_journal_meta() from bch_btree_set_root(). But there is no space in journal buckets, the journal replay has to wait for new journal bucket to be reclaimed after at least one journal bucket replayed. This is one example that how the journal no-space deadlock happens. The solution to avoid the deadlock is to reserve 1 journal bucket in run time, and only permit the reserved journal bucket to be used during cache set registration procedure for things like journal replay. Then the journal space will never be fully filled, there is no chance for journal no-space deadlock to happen anymore. This patch adds a new member "bool do_reserve" in struct journal, it is inititalized to 0 (false) when struct journal is allocated, and set to 1 (true) by bch_journal_space_reserve() when all initialization done in run_cache_set(). In the run time when journal_reclaim() tries to allocate a new journal bucket, free_journal_buckets() is called to check whether there are enough free journal buckets to use. If there is only 1 free journal bucket and journal->do_reserve is 1 (true), the last bucket is reserved and free_journal_buckets() will return 0 to indicate no free journal bucket. Then journal_reclaim() will give up, and try next time to see whetheer there is free journal bucket to allocate. By this method, there is always 1 jouranl bucket reserved in run time. During the cache set registration, journal->do_reserve is 0 (false), so the reserved journal bucket can be used to avoid the no-space deadlock. Reported-by: Nikhil Kshirsagar Signed-off-by: Coly Li Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220524102336.10684-5-colyli@suse.de Signed-off-by: Jens Axboe

block: remove QUEUE_FLAG_DISCARD

2022-04-18T01:49:59Z

Just use a non-zero max_discard_sectors as an indicator for discard support, similar to what is done for write zeroes. The only places where needs special attention is the RAID5 driver, which must clear discard support for security reasons by default, even if the default stacking rules would allow for it. Signed-off-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Acked-by: Christoph Böhmwalder [drbd] Acked-by: Jan Höppner [s390] Acked-by: Coly Li [bcache] Acked-by: David Sterba [btrfs] Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de Signed-off-by: Jens Axboe

block: pass a block_device and opf to bio_init

2022-02-02T14:49:59Z

Pass the block_device that we plan to use this bio for and the operation to bio_init to optimize the assignment. A NULL block_device can be passed, both for the passthrough case on a raw request_queue and to temporarily avoid refactoring some nasty code. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20220124091107.642561-19-hch@lst.de Signed-off-by: Jens Axboe

block: remove genhd.h

2022-02-02T14:49:59Z

There is no good reason to keep genhd.h separate from the main blkdev.h header that includes it. So fold the contents of genhd.h into blkdev.h and remove genhd.h entirely. Signed-off-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de Signed-off-by: Jens Axboe

bcache: fix NULL pointer reference in cached_dev_detach_finish

2021-12-15T03:32:54Z

Commit 0259d4498ba4 ("bcache: move calc_cached_dev_sectors to proper place on backing device detach") tries to fix calc_cached_dev_sectors when bcache device detaches, but now we have: cached_dev_detach_finish ... bcache_device_detach(&dc->disk); ... closure_put(&d->c->caching); d->c = NULL; [*explicitly set dc->disk.c to NULL*] list_move(&dc->list, &uncached_devices); calc_cached_dev_sectors(dc->disk.c); [*passing a NULL pointer*] ... Upper codeflows shows how bug happens, this patch fix the problem by caching dc->disk.c beforehand, and cache_set won't be freed under us because c->caching closure at least holds a reference count and closure callback __cache_set_unregister only being called by bch_cache_set_stop which using closure_queue(&c->caching), that means c->caching closure callback for destroying cache_set won't be trigger by previous closure_put(&d->c->caching). So at this stage(while cached_dev_detach_finish is calling) it's safe to access cache_set dc->disk.c. Fixes: 0259d4498ba4 ("bcache: move calc_cached_dev_sectors to proper place on backing device detach") Signed-off-by: Lin Feng Signed-off-by: Coly Li Link: https://lore.kernel.org/r/20211112053629.3437-2-colyli@suse.de Signed-off-by: Jens Axboe

Merge tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block

2021-11-09T19:24:08Z

Pull more block driver updates from Jens Axboe: - Last series adding error handling support for add_disk() in drivers. After this one, and once the SCSI side has been merged, we can finally annotate add_disk() as must_check. (Luis) - bcache fixes (Coly) - zram fixes (Ming) - ataflop locking fix (Tetsuo) - nbd fixes (Ye, Yu) - MD merge via Song - Cleanup (Yang) - sysfs fix (Guoqing) - Misc fixes (Geert, Wu, luo) * tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block: (34 commits) bcache: Revert "bcache: use bvec_virt" ataflop: Add missing semicolon to return statement floppy: address add_disk() error handling on probe ataflop: address add_disk() error handling on probe block: update __register_blkdev() probe documentation ataflop: remove ataflop_probe_lock mutex mtd/ubi/block: add error handling support for add_disk() block/sunvdc: add error handling support for add_disk() z2ram: add error handling support for add_disk() nvdimm/pmem: use add_disk() error handling nvdimm/pmem: cleanup the disk if pmem_release_disk() is yet assigned nvdimm/blk: add error handling support for add_disk() nvdimm/blk: avoid calling del_gendisk() on early failures nvdimm/btt: add error handling support for add_disk() nvdimm/btt: use goto error labels on btt_blk_init() loop: Remove duplicate assignments drbd: Fix double free problem in drbd_create_device nvdimm/btt: do not call del_gendisk() if not needed bcache: fix use-after-free problem in bcache_device_free() zram: replace fsync_bdev with sync_blockdev ...

bcache: fix use-after-free problem in bcache_device_free()

2021-11-03T12:00:29Z

In bcache_device_free(), pointer disk is referenced still in ida_simple_remove() after blk_cleanup_disk() gets called on this pointer. This may cause a potential panic by use-after-free on the disk pointer. This patch fixes the problem by calling blk_cleanup_disk() after ida_simple_remove(). Fixes: bc70852fd104 ("bcache: convert to blk_alloc_disk/blk_cleanup_disk") Signed-off-by: Coly Li Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Ulf Hansson Cc: stable@vger.kernel.org # v5.14+ Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20211103064917.67383-1-colyli@suse.de Signed-off-by: Jens Axboe

Merge tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block

2021-11-01T16:50:37Z

Pull bdev size cleanups from Jens Axboe: "Clean up the bdev size handling with new bdev_nr_bytes() helper" * tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block: (34 commits) partitions/ibm: use bdev_nr_sectors instead of open coding it partitions/efi: use bdev_nr_bytes instead of open coding it block/ioctl: use bdev_nr_sectors and bdev_nr_bytes block: cache inode size in bdev udf: use sb_bdev_nr_blocks reiserfs: use sb_bdev_nr_blocks ntfs: use sb_bdev_nr_blocks jfs: use sb_bdev_nr_blocks ext4: use sb_bdev_nr_blocks block: add a sb_bdev_nr_blocks helper block: use bdev_nr_bytes instead of open coding it in blkdev_fallocate squashfs: use bdev_nr_bytes instead of open coding it reiserfs: use bdev_nr_bytes instead of open coding it pstore/blk: use bdev_nr_bytes instead of open coding it ntfs3: use bdev_nr_bytes instead of open coding it nilfs2: use bdev_nr_bytes instead of open coding it nfs/blocklayout: use bdev_nr_bytes instead of open coding it jfs: use bdev_nr_bytes instead of open coding it hfsplus: use bdev_nr_sectors instead of open coding it hfs: use bdev_nr_sectors instead of open coding it ...

bcache: add error handling support for add_disk()

2021-10-21T15:00:56Z

We never checked for errors on add_disk() as this function returned void. Now that this is fixed, use the shiny new error handling. This driver doesn't do any unwinding with blk_cleanup_disk() even on errors after add_disk() and so we follow that tradition. Acked-by: Coly Li Signed-off-by: Luis Chamberlain Link: https://lore.kernel.org/r/20211015233028.2167651-5-mcgrof@kernel.org Signed-off-by: Jens Axboe

bcache: remove the backing_dev_name field from struct cached_dev

2021-10-20T14:40:54Z

Just use the %pg format specifier to print the name directly. Signed-off-by: Christoph Hellwig Signed-off-by: Coly Li Link: https://lore.kernel.org/r/20211020143812.6403-7-colyli@suse.de Signed-off-by: Jens Axboe