314 Commits

Author	SHA1	Message	Date
Sidong Yang	457b0a3d6e	btrfs: qgroup: remove outdated TODO comments ... These comments are old, outdated and not very specific. It seems that it doesn't help to inspire anybody to work on that. So we remove them. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Sidong Yang <realwakka@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-03-14 13:13:50 +01:00
Sidong Yang	a8f6f619e4	btrfs: qgroup: remove duplicated check in adding qgroup relations ... Removes duplicated check when adding qgroup relations. btrfs_add_qgroup_relations function adds relations by calling add_relation_rb(). add_relation_rb() checks that member/parentid exists in current qgroup_tree. But it already checked before calling the function. It seems that we don't need to double check. Add new function __add_relation_rb() that adds relations with qgroup structures and makes old function use the new one. And it makes btrfs_add_qgroup_relation() function work without double checks by calling the new function. Signed-off-by: Sidong Yang <realwakka@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add comments ] Signed-off-by: David Sterba <dsterba@suse.com>	2022-03-14 13:13:50 +01:00
Josef Bacik	ef3eccc19a	btrfs: disable qgroups in extent tree v2 ... Backref lookups are going to be drastically different with extent tree v2, disable qgroups until we do the work to add this support for extent tree v2. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-03-14 13:13:48 +01:00
Nikolay Borisov	db5df25412	btrfs: move QUOTA_ENABLED check to rescan_should_stop from btrfs_qgroup_rescan_worker ... Instead of having 2 places that short circuit the qgroup leaf scan have everything in the qgroup_rescan_leaf function. In addition to that, also ensure that the inconsistent qgroup flag is set when rescan_should_stop returns true. This both retains the old behavior when -EINTR was set in the body of the loop and at the same time also extends this behavior when scanning is interrupted due to remount or unmount operations. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-03-14 13:13:47 +01:00
Sidong Yang	d4aef1e122	btrfs: qgroup: fix deadlock between rescan worker and remove qgroup ... The commit e804861bd4 ("btrfs: fix deadlock between quota disable and qgroup rescan worker") by Kawasaki resolves deadlock between quota disable and qgroup rescan worker. But also there is a deadlock case like it. It's about enabling or disabling quota and creating or removing qgroup. It can be reproduced in simple script below. for i in {1..100} do btrfs quota enable /mnt & btrfs qgroup create 1/0 /mnt & btrfs qgroup destroy 1/0 /mnt & btrfs quota disable /mnt & done Here's why the deadlock happens: 1) The quota rescan task is running. 2) Task A calls btrfs_quota_disable(), locks the qgroup_ioctl_lock mutex, and then calls btrfs_qgroup_wait_for_completion(), to wait for the quota rescan task to complete. 3) Task B calls btrfs_remove_qgroup() and it blocks when trying to lock the qgroup_ioctl_lock mutex, because it's being held by task A. At that point task B is holding a transaction handle for the current transaction. 4) The quota rescan task calls btrfs_commit_transaction(). This results in it waiting for all other tasks to release their handles on the transaction, but task B is blocked on the qgroup_ioctl_lock mutex while holding a handle on the transaction, and that mutex is being held by task A, which is waiting for the quota rescan task to complete, resulting in a deadlock between these 3 tasks. To resolve this issue, the thread disabling quota should unlock qgroup_ioctl_lock before waiting rescan completion. Move btrfs_qgroup_wait_for_completion() after unlock of qgroup_ioctl_lock. Fixes: e804861bd4 ("btrfs: fix deadlock between quota disable and qgroup rescan worker") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Sidong Yang <realwakka@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-03-02 16:53:04 +01:00
Shin'ichiro Kawasaki	e804861bd4	btrfs: fix deadlock between quota disable and qgroup rescan worker ... Quota disable ioctl starts a transaction before waiting for the qgroup rescan worker completes. However, this wait can be infinite and results in deadlock because of circular dependency among the quota disable ioctl, the qgroup rescan worker and the other task with transaction such as block group relocation task. The deadlock happens with the steps following: 1) Task A calls ioctl to disable quota. It starts a transaction and waits for qgroup rescan worker completes. 2) Task B such as block group relocation task starts a transaction and joins to the transaction that task A started. Then task B commits to the transaction. In this commit, task B waits for a commit by task A. 3) Task C as the qgroup rescan worker starts its job and starts a transaction. In this transaction start, task C waits for completion of the transaction that task A started and task B committed. This deadlock was found with fstests test case btrfs/115 and a zoned null_blk device. The test case enables and disables quota, and the block group reclaim was triggered during the quota disable by chance. The deadlock was also observed by running quota enable and disable in parallel with 'btrfs balance' command on regular null_blk devices. An example report of the deadlock: [372.469894] INFO: task kworker/u16:6:103 blocked for more than 122 seconds. [372.479944] Not tainted 5.16.0-rc8 #7 [372.485067] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.493898] task:kworker/u16:6 state:D stack: 0 pid: 103 ppid: 2 flags:0x00004000 [372.503285] Workqueue: btrfs-qgroup-rescan btrfs_work_helper [btrfs] [372.510782] Call Trace: [372.514092] <TASK> [372.521684] __schedule+0xb56/0x4850 [372.530104] ? io_schedule_timeout+0x190/0x190 [372.538842] ? lockdep_hardirqs_on+0x7e/0x100 [372.547092] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.555591] schedule+0xe0/0x270 [372.561894] btrfs_commit_transaction+0x18bb/0x2610 [btrfs] [372.570506] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [372.578875] ? free_unref_page+0x3f2/0x650 [372.585484] ? finish_wait+0x270/0x270 [372.591594] ? release_extent_buffer+0x224/0x420 [btrfs] [372.599264] btrfs_qgroup_rescan_worker+0xc13/0x10c0 [btrfs] [372.607157] ? lock_release+0x3a9/0x6d0 [372.613054] ? btrfs_qgroup_account_extent+0xda0/0xda0 [btrfs] [372.620960] ? do_raw_spin_lock+0x11e/0x250 [372.627137] ? rwlock_bug.part.0+0x90/0x90 [372.633215] ? lock_is_held_type+0xe4/0x140 [372.639404] btrfs_work_helper+0x1ae/0xa90 [btrfs] [372.646268] process_one_work+0x7e9/0x1320 [372.652321] ? lock_release+0x6d0/0x6d0 [372.658081] ? pwq_dec_nr_in_flight+0x230/0x230 [372.664513] ? rwlock_bug.part.0+0x90/0x90 [372.670529] worker_thread+0x59e/0xf90 [372.676172] ? process_one_work+0x1320/0x1320 [372.682440] kthread+0x3b9/0x490 [372.687550] ? _raw_spin_unlock_irq+0x24/0x50 [372.693811] ? set_kthread_struct+0x100/0x100 [372.700052] ret_from_fork+0x22/0x30 [372.705517] </TASK> [372.709747] INFO: task btrfs-transacti:2347 blocked for more than 123 seconds. [372.729827] Not tainted 5.16.0-rc8 #7 [372.745907] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [372.767106] task:btrfs-transacti state:D stack: 0 pid: 2347 ppid: 2 flags:0x00004000 [372.787776] Call Trace: [372.801652] <TASK> [372.812961] __schedule+0xb56/0x4850 [372.830011] ? io_schedule_timeout+0x190/0x190 [372.852547] ? lockdep_hardirqs_on+0x7e/0x100 [372.871761] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [372.886792] schedule+0xe0/0x270 [372.901685] wait_current_trans+0x22c/0x310 [btrfs] [372.919743] ? btrfs_put_transaction+0x3d0/0x3d0 [btrfs] [372.938923] ? finish_wait+0x270/0x270 [372.959085] ? join_transaction+0xc75/0xe30 [btrfs] [372.977706] start_transaction+0x938/0x10a0 [btrfs] [372.997168] transaction_kthread+0x19d/0x3c0 [btrfs] [373.013021] ? btrfs_cleanup_transaction.isra.0+0xfc0/0xfc0 [btrfs] [373.031678] kthread+0x3b9/0x490 [373.047420] ? _raw_spin_unlock_irq+0x24/0x50 [373.064645] ? set_kthread_struct+0x100/0x100 [373.078571] ret_from_fork+0x22/0x30 [373.091197] </TASK> [373.105611] INFO: task btrfs:3145 blocked for more than 123 seconds. [373.114147] Not tainted 5.16.0-rc8 #7 [373.120401] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [373.130393] task:btrfs state:D stack: 0 pid: 3145 ppid: 3141 flags:0x00004000 [373.140998] Call Trace: [373.145501] <TASK> [373.149654] __schedule+0xb56/0x4850 [373.155306] ? io_schedule_timeout+0x190/0x190 [373.161965] ? lockdep_hardirqs_on+0x7e/0x100 [373.168469] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [373.175468] schedule+0xe0/0x270 [373.180814] wait_for_commit+0x104/0x150 [btrfs] [373.187643] ? test_and_set_bit+0x20/0x20 [btrfs] [373.194772] ? kmem_cache_free+0x124/0x550 [373.201191] ? btrfs_put_transaction+0x69/0x3d0 [btrfs] [373.208738] ? finish_wait+0x270/0x270 [373.214704] ? __btrfs_end_transaction+0x347/0x7b0 [btrfs] [373.222342] btrfs_commit_transaction+0x44d/0x2610 [btrfs] [373.230233] ? join_transaction+0x255/0xe30 [btrfs] [373.237334] ? btrfs_record_root_in_trans+0x4d/0x170 [btrfs] [373.245251] ? btrfs_apply_pending_changes+0x50/0x50 [btrfs] [373.253296] relocate_block_group+0x105/0xc20 [btrfs] [373.260533] ? mutex_lock_io_nested+0x1270/0x1270 [373.267516] ? btrfs_wait_nocow_writers+0x85/0x180 [btrfs] [373.275155] ? merge_reloc_roots+0x710/0x710 [btrfs] [373.283602] ? btrfs_wait_ordered_extents+0xd30/0xd30 [btrfs] [373.291934] ? kmem_cache_free+0x124/0x550 [373.298180] btrfs_relocate_block_group+0x35c/0x930 [btrfs] [373.306047] btrfs_relocate_chunk+0x85/0x210 [btrfs] [373.313229] btrfs_balance+0x12f4/0x2d20 [btrfs] [373.320227] ? lock_release+0x3a9/0x6d0 [373.326206] ? btrfs_relocate_chunk+0x210/0x210 [btrfs] [373.333591] ? lock_is_held_type+0xe4/0x140 [373.340031] ? rcu_read_lock_sched_held+0x3f/0x70 [373.346910] btrfs_ioctl_balance+0x548/0x700 [btrfs] [373.354207] btrfs_ioctl+0x7f2/0x71b0 [btrfs] [373.360774] ? lockdep_hardirqs_on_prepare+0x410/0x410 [373.367957] ? lockdep_hardirqs_on_prepare+0x410/0x410 [373.375327] ? btrfs_ioctl_get_supported_features+0x20/0x20 [btrfs] [373.383841] ? find_held_lock+0x2c/0x110 [373.389993] ? lock_release+0x3a9/0x6d0 [373.395828] ? mntput_no_expire+0xf7/0xad0 [373.402083] ? lock_is_held_type+0xe4/0x140 [373.408249] ? vfs_fileattr_set+0x9f0/0x9f0 [373.414486] ? selinux_file_ioctl+0x349/0x4e0 [373.420938] ? trace_raw_output_lock+0xb4/0xe0 [373.427442] ? selinux_inode_getsecctx+0x80/0x80 [373.434224] ? lockdep_hardirqs_on+0x7e/0x100 [373.440660] ? force_qs_rnp+0x2a0/0x6b0 [373.446534] ? lock_is_held_type+0x9b/0x140 [373.452763] ? __blkcg_punt_bio_submit+0x1b0/0x1b0 [373.459732] ? security_file_ioctl+0x50/0x90 [373.466089] __x64_sys_ioctl+0x127/0x190 [373.472022] do_syscall_64+0x3b/0x90 [373.477513] entry_SYSCALL_64_after_hwframe+0x44/0xae [373.484823] RIP: 0033:0x7f8f4af7e2bb [373.490493] RSP: 002b:00007ffcbf936178 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [373.500197] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8f4af7e2bb [373.509451] RDX: 00007ffcbf936220 RSI: 00000000c4009420 RDI: 0000000000000003 [373.518659] RBP: 00007ffcbf93774a R08: 0000000000000013 R09: 00007f8f4b02d4e0 [373.527872] R10: 00007f8f4ae87740 R11: 0000000000000246 R12: 0000000000000001 [373.537222] R13: 00007ffcbf936220 R14: 0000000000000000 R15: 0000000000000002 [373.546506] </TASK> [373.550878] INFO: task btrfs:3146 blocked for more than 123 seconds. [373.559383] Not tainted 5.16.0-rc8 #7 [373.565748] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [373.575748] task:btrfs state:D stack: 0 pid: 3146 ppid: 2168 flags:0x00000000 [373.586314] Call Trace: [373.590846] <TASK> [373.595121] __schedule+0xb56/0x4850 [373.600901] ? __lock_acquire+0x23db/0x5030 [373.607176] ? io_schedule_timeout+0x190/0x190 [373.613954] schedule+0xe0/0x270 [373.619157] schedule_timeout+0x168/0x220 [373.625170] ? usleep_range_state+0x150/0x150 [373.631653] ? mark_held_locks+0x9e/0xe0 [373.637767] ? do_raw_spin_lock+0x11e/0x250 [373.643993] ? lockdep_hardirqs_on_prepare+0x17b/0x410 [373.651267] ? _raw_spin_unlock_irq+0x24/0x50 [373.657677] ? lockdep_hardirqs_on+0x7e/0x100 [373.664103] wait_for_completion+0x163/0x250 [373.670437] ? bit_wait_timeout+0x160/0x160 [373.676585] btrfs_quota_disable+0x176/0x9a0 [btrfs] [373.683979] ? btrfs_quota_enable+0x12f0/0x12f0 [btrfs] [373.691340] ? down_write+0xd0/0x130 [373.696880] ? down_write_killable+0x150/0x150 [373.703352] btrfs_ioctl+0x3945/0x71b0 [btrfs] [373.710061] ? find_held_lock+0x2c/0x110 [373.716192] ? lock_release+0x3a9/0x6d0 [373.722047] ? __handle_mm_fault+0x23cd/0x3050 [373.728486] ? btrfs_ioctl_get_supported_features+0x20/0x20 [btrfs] [373.737032] ? set_pte+0x6a/0x90 [373.742271] ? do_raw_spin_unlock+0x55/0x1f0 [373.748506] ? lock_is_held_type+0xe4/0x140 [373.754792] ? vfs_fileattr_set+0x9f0/0x9f0 [373.761083] ? selinux_file_ioctl+0x349/0x4e0 [373.767521] ? selinux_inode_getsecctx+0x80/0x80 [373.774247] ? __up_read+0x182/0x6e0 [373.780026] ? count_memcg_events.constprop.0+0x46/0x60 [373.787281] ? up_write+0x460/0x460 [373.792932] ? security_file_ioctl+0x50/0x90 [373.799232] __x64_sys_ioctl+0x127/0x190 [373.805237] do_syscall_64+0x3b/0x90 [373.810947] entry_SYSCALL_64_after_hwframe+0x44/0xae [373.818102] RIP: 0033:0x7f1383ea02bb [373.823847] RSP: 002b:00007fffeb4d71f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [373.833641] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1383ea02bb [373.842961] RDX: 00007fffeb4d7210 RSI: 00000000c0109428 RDI: 0000000000000003 [373.852179] RBP: 0000000000000003 R08: 0000000000000003 R09: 0000000000000078 [373.861408] R10: 00007f1383daec78 R11: 0000000000000202 R12: 00007fffeb4d874a [373.870647] R13: 0000000000493099 R14: 0000000000000001 R15: 0000000000000000 [373.879838] </TASK> [373.884018] Showing all locks held in the system: [373.894250] 3 locks held by kworker/4:1/58: [373.900356] 1 lock held by khungtaskd/63: [373.906333] #0: ffffffff8945ff60 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 [373.917307] 3 locks held by kworker/u16:6/103: [373.923938] #0: ffff888127b4f138 ((wq_completion)btrfs-qgroup-rescan){+.+.}-{0:0}, at: process_one_work+0x712/0x1320 [373.936555] #1: ffff88810b817dd8 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x73f/0x1320 [373.951109] #2: ffff888102dd4650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_qgroup_rescan_worker+0x1f6/0x10c0 [btrfs] [373.964027] 2 locks held by less/1803: [373.969982] #0: ffff88813ed56098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 [373.981295] #1: ffffc90000b3b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x9e2/0x1060 [373.992969] 1 lock held by btrfs-transacti/2347: [373.999893] #0: ffff88813d4887a8 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0xe3/0x3c0 [btrfs] [374.015872] 3 locks held by btrfs/3145: [374.022298] #0: ffff888102dd4460 (sb_writers#18){.+.+}-{0:0}, at: btrfs_ioctl_balance+0xc3/0x700 [btrfs] [374.034456] #1: ffff88813d48a0a0 (&fs_info->reclaim_bgs_lock){+.+.}-{3:3}, at: btrfs_balance+0xfe5/0x2d20 [btrfs] [374.047646] #2: ffff88813d488838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x354/0x930 [btrfs] [374.063295] 4 locks held by btrfs/3146: [374.069647] #0: ffff888102dd4460 (sb_writers#18){.+.+}-{0:0}, at: btrfs_ioctl+0x38b1/0x71b0 [btrfs] [374.081601] #1: ffff88813d488bb8 (&fs_info->subvol_sem){+.+.}-{3:3}, at: btrfs_ioctl+0x38fd/0x71b0 [btrfs] [374.094283] #2: ffff888102dd4650 (sb_internal#2){.+.+}-{0:0}, at: btrfs_quota_disable+0xc8/0x9a0 [btrfs] [374.106885] #3: ffff88813d489800 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_disable+0xd5/0x9a0 [btrfs] [374.126780] ============================================= To avoid the deadlock, wait for the qgroup rescan worker to complete before starting the transaction for the quota disable ioctl. Clear BTRFS_FS_QUOTA_ENABLE flag before the wait and the transaction to request the worker to complete. On transaction start failure, set the BTRFS_FS_QUOTA_ENABLE flag again. These BTRFS_FS_QUOTA_ENABLE flag changes can be done safely since the function btrfs_quota_disable is not called concurrently because of fs_info->subvol_sem. Also check the BTRFS_FS_QUOTA_ENABLE flag in qgroup_rescan_init to avoid another qgroup rescan worker to start after the previous qgroup worker completed. CC: stable@vger.kernel.org # 5.4+ Suggested-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-01-31 16:05:44 +01:00
Josef Bacik	29cbcf4017	btrfs: stop accessing ->extent_root directly ... When we start having multiple extent roots we'll need to use a helper to get to the correct extent_root. Rename fs_info->extent_root to _extent_root and convert all of the users of the extent root to using the btrfs_extent_root() helper. This will allow us to easily clean up the remaining direct accesses in the future. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-01-03 15:09:49 +01:00
Filipe Manana	232796df8c	btrfs: fix deadlock between quota enable and other quota operations ... When enabling quotas, we attempt to commit a transaction while holding the mutex fs_info->qgroup_ioctl_lock. This can result on a deadlock with other quota operations such as: - qgroup creation and deletion, ioctl BTRFS_IOC_QGROUP_CREATE; - adding and removing qgroup relations, ioctl BTRFS_IOC_QGROUP_ASSIGN. This is because these operations join a transaction and after that they attempt to lock the mutex fs_info->qgroup_ioctl_lock. Acquiring that mutex after joining or starting a transaction is a pattern followed everywhere in qgroups, so the quota enablement operation is the one at fault here, and should not commit a transaction while holding that mutex. Fix this by making the transaction commit while not holding the mutex. We are safe from two concurrent tasks trying to enable quotas because we are serialized by the rw semaphore fs_info->subvol_sem at btrfs_ioctl_quota_ctl(), which is the only call site for enabling quotas. When this deadlock happens, it produces a trace like the following: INFO: task syz-executor:25604 blocked for more than 143 seconds. Not tainted 5.15.0-rc6 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:24800 pid:25604 ppid: 24873 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 btrfs_commit_transaction+0x994/0x2e90 fs/btrfs/transaction.c:2201 btrfs_quota_enable+0x95c/0x1790 fs/btrfs/qgroup.c:1120 btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:4229 [inline] btrfs_ioctl+0x637e/0x7b70 fs/btrfs/ioctl.c:5010 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f86920b2c4d RSP: 002b:00007f868f61ac58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f86921d90a0 RCX: 00007f86920b2c4d RDX: 0000000020005e40 RSI: 00000000c0109428 RDI: 0000000000000008 RBP: 00007f869212bd80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f86921d90a0 R13: 00007fff6d233e4f R14: 00007fff6d233ff0 R15: 00007f868f61adc0 INFO: task syz-executor:25628 blocked for more than 143 seconds. Not tainted 5.15.0-rc6 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:29080 pid:25628 ppid: 24873 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xcd9/0x2530 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425 __mutex_lock_common kernel/locking/mutex.c:669 [inline] __mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729 btrfs_remove_qgroup+0xb7/0x7d0 fs/btrfs/qgroup.c:1548 btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:4333 [inline] btrfs_ioctl+0x683c/0x7b70 fs/btrfs/ioctl.c:5014 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported-by: Hao Sun <sunhao.th@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CACkBjsZQF19bQ1C6=yetF3BvL10OSORpFUcWXTP6HErshDB4dQ@mail.gmail.com/ Fixes: 340f1aa27f ("btrfs: qgroups: Move transaction management inside btrfs_quota_enable/disable") CC: stable@vger.kernel.org # 4.19 Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2022-01-03 15:09:41 +01:00
Filipe Manana	7a1636089a	btrfs: fix invalid delayed ref after subvolume creation failure ... When creating a subvolume, at ioctl.c:create_subvol(), if we fail to insert the new root's root item into the root tree, we are freeing the metadata extent we reserved for the new root to prevent a metadata extent leak, as we don't abort the transaction at that point (since there is nothing at that point that is irreversible). However we allocated the metadata extent for the new root which we are creating for the new subvolume, so its delayed reference refers to the ID of this new root. But when we free the metadata extent we pass the root of the subvolume where the new subvolume is located to btrfs_free_tree_block() - this is incorrect because this will generate a delayed reference that refers to the ID of the parent subvolume's root, and not to ID of the new root. This results in a failure when running delayed references that leads to a transaction abort and a trace like the following: [3868.738042] RIP: 0010:__btrfs_free_extent+0x709/0x950 [btrfs] [3868.739857] Code: 68 0f 85 e6 fb ff (...) [3868.742963] RSP: 0018:ffffb0e9045cf910 EFLAGS: 00010246 [3868.743908] RAX: 00000000fffffffe RBX: 00000000fffffffe RCX: 0000000000000002 [3868.745312] RDX: 00000000fffffffe RSI: 0000000000000002 RDI: ffff90b0cd793b88 [3868.746643] RBP: 000000000e5d8000 R08: 0000000000000000 R09: ffff90b0cd793b88 [3868.747979] R10: 0000000000000002 R11: 00014ded97944d68 R12: 0000000000000000 [3868.749373] R13: ffff90b09afe4a28 R14: 0000000000000000 R15: ffff90b0cd793b88 [3868.750725] FS: 00007f281c4a8b80(0000) GS:ffff90b3ada00000(0000) knlGS:0000000000000000 [3868.752275] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [3868.753515] CR2: 00007f281c6a5000 CR3: 0000000108a42006 CR4: 0000000000370ee0 [3868.754869] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [3868.756228] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [3868.757803] Call Trace: [3868.758281] <TASK> [3868.758655] ? btrfs_merge_delayed_refs+0x178/0x1c0 [btrfs] [3868.759827] __btrfs_run_delayed_refs+0x2b1/0x1250 [btrfs] [3868.761047] btrfs_run_delayed_refs+0x86/0x210 [btrfs] [3868.762069] ? lock_acquired+0x19f/0x420 [3868.762829] btrfs_commit_transaction+0x69/0xb20 [btrfs] [3868.763860] ? _raw_spin_unlock+0x29/0x40 [3868.764614] ? btrfs_block_rsv_release+0x1c2/0x1e0 [btrfs] [3868.765870] create_subvol+0x1d8/0x9a0 [btrfs] [3868.766766] btrfs_mksubvol+0x447/0x4c0 [btrfs] [3868.767669] ? preempt_count_add+0x49/0xa0 [3868.768444] __btrfs_ioctl_snap_create+0x123/0x190 [btrfs] [3868.769639] ? _copy_from_user+0x66/0xa0 [3868.770391] btrfs_ioctl_snap_create_v2+0xbb/0x140 [btrfs] [3868.771495] btrfs_ioctl+0xd1e/0x35c0 [btrfs] [3868.772364] ? __slab_free+0x10a/0x360 [3868.773198] ? rcu_read_lock_sched_held+0x12/0x60 [3868.774121] ? lock_release+0x223/0x4a0 [3868.774863] ? lock_acquired+0x19f/0x420 [3868.775634] ? rcu_read_lock_sched_held+0x12/0x60 [3868.776530] ? trace_hardirqs_on+0x1b/0xe0 [3868.777373] ? _raw_spin_unlock_irqrestore+0x3e/0x60 [3868.778280] ? kmem_cache_free+0x321/0x3c0 [3868.779011] ? __x64_sys_ioctl+0x83/0xb0 [3868.779718] __x64_sys_ioctl+0x83/0xb0 [3868.780387] do_syscall_64+0x3b/0xc0 [3868.781059] entry_SYSCALL_64_after_hwframe+0x44/0xae [3868.781953] RIP: 0033:0x7f281c59e957 [3868.782585] Code: 3c 1c 48 f7 d8 4c (...) [3868.785867] RSP: 002b:00007ffe1f83e2b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [3868.787198] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281c59e957 [3868.788450] RDX: 00007ffe1f83e2c0 RSI: 0000000050009418 RDI: 0000000000000003 [3868.789748] RBP: 00007ffe1f83f300 R08: 0000000000000000 R09: 00007ffe1f83fe36 [3868.791214] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003 [3868.792468] R13: 0000000000000003 R14: 00007ffe1f83e2c0 R15: 00000000000003cc [3868.793765] </TASK> [3868.794037] irq event stamp: 0 [3868.794548] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [3868.795670] hardirqs last disabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040 [3868.797086] softirqs last enabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040 [3868.798309] softirqs last disabled at (0): [<0000000000000000>] 0x0 [3868.799284] ---[ end trace be24c7002fe27747 ]--- [3868.799928] BTRFS info (device dm-0): leaf 241188864 gen 1268 total ptrs 214 free space 469 owner 2 [3868.801133] BTRFS info (device dm-0): refs 2 lock_owner 225627 current 225627 [3868.802056] item 0 key (237436928 169 0) itemoff 16250 itemsize 33 [3868.802863] extent refs 1 gen 1265 flags 2 [3868.803447] ref#0: tree block backref root 1610 (...) [3869.064354] item 114 key (241008640 169 0) itemoff 12488 itemsize 33 [3869.065421] extent refs 1 gen 1268 flags 2 [3869.066115] ref#0: tree block backref root 1689 (...) [3869.403834] BTRFS error (device dm-0): unable to find ref byte nr 241008640 parent 0 root 1622 owner 0 offset 0 [3869.405641] BTRFS: error (device dm-0) in __btrfs_free_extent:3076: errno=-2 No such entry [3869.407138] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2159: errno=-2 No such entry Fix this by passing the new subvolume's root ID to btrfs_free_tree_block(). This requires changing the root argument of btrfs_free_tree_block() from struct btrfs_root * to a u64, since at this point during the subvolume creation we have not yet created the struct btrfs_root for the new subvolume, and btrfs_free_tree_block() only needs a root ID and nothing else from a struct btrfs_root. This was triggered by test case generic/475 from fstests. Fixes: 67addf2900 ("btrfs: fix metadata extent leak after failure to create subvolume") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-12-15 17:07:33 +01:00
Filipe Manana	c7bcbb2120	btrfs: remove ignore_offset argument from btrfs_find_all_roots() ... Currently all the callers of btrfs_find_all_roots() pass a value of false for its ignore_offset argument. This makes the argument pointless and we can remove it and make btrfs_find_all_roots() always pass false as the ignore_offset argument for btrfs_find_all_roots_safe(). So just do that. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-08-23 13:19:01 +02:00
Filipe Manana	8949b9a114	btrfs: fix lock inversion problem when doing qgroup extent tracing ... At btrfs_qgroup_trace_extent_post() we call btrfs_find_all_roots() with a NULL value as the transaction handle argument, which makes that function take the commit_root_sem semaphore, which is necessary when we don't hold a transaction handle or any other mechanism to prevent a transaction commit from wiping out commit roots. However btrfs_qgroup_trace_extent_post() can be called in a context where we are holding a write lock on an extent buffer from a subvolume tree, namely from btrfs_truncate_inode_items(), called either during truncate or unlink operations. In this case we end up with a lock inversion problem because the commit_root_sem is a higher level lock, always supposed to be acquired before locking any extent buffer. Lockdep detects this lock inversion problem since we switched the extent buffer locks from custom locks to semaphores, and when running btrfs/158 from fstests, it reported the following trace: [ 9057.626435] ====================================================== [ 9057.627541] WARNING: possible circular locking dependency detected [ 9057.628334] 5.14.0-rc2-btrfs-next-93 #1 Not tainted [ 9057.628961] ------------------------------------------------------ [ 9057.629867] kworker/u16:4/30781 is trying to acquire lock: [ 9057.630824] ffff8e2590f58760 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 9057.632542] but task is already holding lock: [ 9057.633551] ffff8e25582d4b70 (&fs_info->commit_root_sem){++++}-{3:3}, at: iterate_extent_inodes+0x10b/0x280 [btrfs] [ 9057.635255] which lock already depends on the new lock. [ 9057.636292] the existing dependency chain (in reverse order) is: [ 9057.637240] -> #1 (&fs_info->commit_root_sem){++++}-{3:3}: [ 9057.638138] down_read+0x46/0x140 [ 9057.638648] btrfs_find_all_roots+0x41/0x80 [btrfs] [ 9057.639398] btrfs_qgroup_trace_extent_post+0x37/0x70 [btrfs] [ 9057.640283] btrfs_add_delayed_data_ref+0x418/0x490 [btrfs] [ 9057.641114] btrfs_free_extent+0x35/0xb0 [btrfs] [ 9057.641819] btrfs_truncate_inode_items+0x424/0xf70 [btrfs] [ 9057.642643] btrfs_evict_inode+0x454/0x4f0 [btrfs] [ 9057.643418] evict+0xcf/0x1d0 [ 9057.643895] do_unlinkat+0x1e9/0x300 [ 9057.644525] do_syscall_64+0x3b/0xc0 [ 9057.645110] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 9057.645835] -> #0 (btrfs-tree-00){++++}-{3:3}: [ 9057.646600] __lock_acquire+0x130e/0x2210 [ 9057.647248] lock_acquire+0xd7/0x310 [ 9057.647773] down_read_nested+0x4b/0x140 [ 9057.648350] __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 9057.649175] btrfs_read_lock_root_node+0x31/0x40 [btrfs] [ 9057.650010] btrfs_search_slot+0x537/0xc00 [btrfs] [ 9057.650849] scrub_print_warning_inode+0x89/0x370 [btrfs] [ 9057.651733] iterate_extent_inodes+0x1e3/0x280 [btrfs] [ 9057.652501] scrub_print_warning+0x15d/0x2f0 [btrfs] [ 9057.653264] scrub_handle_errored_block.isra.0+0x135f/0x1640 [btrfs] [ 9057.654295] scrub_bio_end_io_worker+0x101/0x2e0 [btrfs] [ 9057.655111] btrfs_work_helper+0xf8/0x400 [btrfs] [ 9057.655831] process_one_work+0x247/0x5a0 [ 9057.656425] worker_thread+0x55/0x3c0 [ 9057.656993] kthread+0x155/0x180 [ 9057.657494] ret_from_fork+0x22/0x30 [ 9057.658030] other info that might help us debug this: [ 9057.659064] Possible unsafe locking scenario: [ 9057.659824] CPU0 CPU1 [ 9057.660402] ---- ---- [ 9057.660988] lock(&fs_info->commit_root_sem); [ 9057.661581] lock(btrfs-tree-00); [ 9057.662348] lock(&fs_info->commit_root_sem); [ 9057.663254] lock(btrfs-tree-00); [ 9057.663690] *** DEADLOCK *** [ 9057.664437] 4 locks held by kworker/u16:4/30781: [ 9057.665023] #0: ffff8e25922a1148 ((wq_completion)btrfs-scrub){+.+.}-{0:0}, at: process_one_work+0x1c7/0x5a0 [ 9057.666260] #1: ffffabb3451ffe70 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x1c7/0x5a0 [ 9057.667639] #2: ffff8e25922da198 (&ret->mutex){+.+.}-{3:3}, at: scrub_handle_errored_block.isra.0+0x5d2/0x1640 [btrfs] [ 9057.669017] #3: ffff8e25582d4b70 (&fs_info->commit_root_sem){++++}-{3:3}, at: iterate_extent_inodes+0x10b/0x280 [btrfs] [ 9057.670408] stack backtrace: [ 9057.670976] CPU: 7 PID: 30781 Comm: kworker/u16:4 Not tainted 5.14.0-rc2-btrfs-next-93 #1 [ 9057.672030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 9057.673492] Workqueue: btrfs-scrub btrfs_work_helper [btrfs] [ 9057.674258] Call Trace: [ 9057.674588] dump_stack_lvl+0x57/0x72 [ 9057.675083] check_noncircular+0xf3/0x110 [ 9057.675611] __lock_acquire+0x130e/0x2210 [ 9057.676132] lock_acquire+0xd7/0x310 [ 9057.676605] ? __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 9057.677313] ? lock_is_held_type+0xe8/0x140 [ 9057.677849] down_read_nested+0x4b/0x140 [ 9057.678349] ? __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 9057.679068] __btrfs_tree_read_lock+0x24/0x110 [btrfs] [ 9057.679760] btrfs_read_lock_root_node+0x31/0x40 [btrfs] [ 9057.680458] btrfs_search_slot+0x537/0xc00 [btrfs] [ 9057.681083] ? _raw_spin_unlock+0x29/0x40 [ 9057.681594] ? btrfs_find_all_roots_safe+0x11f/0x140 [btrfs] [ 9057.682336] scrub_print_warning_inode+0x89/0x370 [btrfs] [ 9057.683058] ? btrfs_find_all_roots_safe+0x11f/0x140 [btrfs] [ 9057.683834] ? scrub_write_block_to_dev_replace+0xb0/0xb0 [btrfs] [ 9057.684632] iterate_extent_inodes+0x1e3/0x280 [btrfs] [ 9057.685316] scrub_print_warning+0x15d/0x2f0 [btrfs] [ 9057.685977] ? ___ratelimit+0xa4/0x110 [ 9057.686460] scrub_handle_errored_block.isra.0+0x135f/0x1640 [btrfs] [ 9057.687316] scrub_bio_end_io_worker+0x101/0x2e0 [btrfs] [ 9057.688021] btrfs_work_helper+0xf8/0x400 [btrfs] [ 9057.688649] ? lock_is_held_type+0xe8/0x140 [ 9057.689180] process_one_work+0x247/0x5a0 [ 9057.689696] worker_thread+0x55/0x3c0 [ 9057.690175] ? process_one_work+0x5a0/0x5a0 [ 9057.690731] kthread+0x155/0x180 [ 9057.691158] ? set_kthread_struct+0x40/0x40 [ 9057.691697] ret_from_fork+0x22/0x30 Fix this by making btrfs_find_all_roots() never attempt to lock the commit_root_sem when it is called from btrfs_qgroup_trace_extent_post(). We can't just pass a non-NULL transaction handle to btrfs_find_all_roots() from btrfs_qgroup_trace_extent_post(), because that would make backref lookup not use commit roots and acquire read locks on extent buffers, and therefore could deadlock when btrfs_qgroup_trace_extent_post() is called from the btrfs_truncate_inode_items() code path which has acquired a write lock on an extent buffer of the subvolume btree. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-07-22 15:50:07 +02:00
Filipe Manana	35b22c19af	btrfs: send: fix crash when memory allocations trigger reclaim ... When doing a send we don't expect the task to ever start a transaction after the initial check that verifies if commit roots match the regular roots. This is because after that we set current->journal_info with a stub (special value) that signals we are in send context, so that we take a read lock on an extent buffer when reading it from disk and verifying it is valid (its generation matches the generation stored in the parent). This stub was introduced in 2014 by commit a26e8c9f75 ("Btrfs: don't clear uptodate if the eb is under IO") in order to fix a concurrency issue between send and balance. However there is one particular exception where we end up needing to start a transaction and when this happens it results in a crash with a stack trace like the following: [60015.902283] kernel: WARNING: CPU: 3 PID: 58159 at arch/x86/include/asm/kfence.h:44 kfence_protect_page+0x21/0x80 [60015.902292] kernel: Modules linked in: uinput rfcomm snd_seq_dummy (...) [60015.902384] kernel: CPU: 3 PID: 58159 Comm: btrfs Not tainted 5.12.9-300.fc34.x86_64 #1 [60015.902387] kernel: Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./F2A88XN-WIFI, BIOS F6 12/24/2015 [60015.902389] kernel: RIP: 0010:kfence_protect_page+0x21/0x80 [60015.902393] kernel: Code: ff 0f 1f 84 00 00 00 00 00 55 48 89 fd (...) [60015.902396] kernel: RSP: 0018:ffff9fb583453220 EFLAGS: 00010246 [60015.902399] kernel: RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff9fb583453224 [60015.902401] kernel: RDX: ffff9fb583453224 RSI: 0000000000000000 RDI: 0000000000000000 [60015.902402] kernel: RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [60015.902404] kernel: R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 [60015.902406] kernel: R13: ffff9fb583453348 R14: 0000000000000000 R15: 0000000000000001 [60015.902408] kernel: FS: 00007f158e62d8c0(0000) GS:ffff93bd37580000(0000) knlGS:0000000000000000 [60015.902410] kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [60015.902412] kernel: CR2: 0000000000000039 CR3: 00000001256d2000 CR4: 00000000000506e0 [60015.902414] kernel: Call Trace: [60015.902419] kernel: kfence_unprotect+0x13/0x30 [60015.902423] kernel: page_fault_oops+0x89/0x270 [60015.902427] kernel: ? search_module_extables+0xf/0x40 [60015.902431] kernel: ? search_bpf_extables+0x57/0x70 [60015.902435] kernel: kernelmode_fixup_or_oops+0xd6/0xf0 [60015.902437] kernel: __bad_area_nosemaphore+0x142/0x180 [60015.902440] kernel: exc_page_fault+0x67/0x150 [60015.902445] kernel: asm_exc_page_fault+0x1e/0x30 [60015.902450] kernel: RIP: 0010:start_transaction+0x71/0x580 [60015.902454] kernel: Code: d3 0f 84 92 00 00 00 80 e7 06 0f 85 63 (...) [60015.902456] kernel: RSP: 0018:ffff9fb5834533f8 EFLAGS: 00010246 [60015.902458] kernel: RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000000 [60015.902460] kernel: RDX: 0000000000000801 RSI: 0000000000000000 RDI: 0000000000000039 [60015.902462] kernel: RBP: ffff93bc0a7eb800 R08: 0000000000000001 R09: 0000000000000000 [60015.902463] kernel: R10: 0000000000098a00 R11: 0000000000000001 R12: 0000000000000001 [60015.902464] kernel: R13: 0000000000000000 R14: ffff93bc0c92b000 R15: ffff93bc0c92b000 [60015.902468] kernel: btrfs_commit_inode_delayed_inode+0x5d/0x120 [60015.902473] kernel: btrfs_evict_inode+0x2c5/0x3f0 [60015.902476] kernel: evict+0xd1/0x180 [60015.902480] kernel: inode_lru_isolate+0xe7/0x180 [60015.902483] kernel: __list_lru_walk_one+0x77/0x150 [60015.902487] kernel: ? iput+0x1a0/0x1a0 [60015.902489] kernel: ? iput+0x1a0/0x1a0 [60015.902491] kernel: list_lru_walk_one+0x47/0x70 [60015.902495] kernel: prune_icache_sb+0x39/0x50 [60015.902497] kernel: super_cache_scan+0x161/0x1f0 [60015.902501] kernel: do_shrink_slab+0x142/0x240 [60015.902505] kernel: shrink_slab+0x164/0x280 [60015.902509] kernel: shrink_node+0x2c8/0x6e0 [60015.902512] kernel: do_try_to_free_pages+0xcb/0x4b0 [60015.902514] kernel: try_to_free_pages+0xda/0x190 [60015.902516] kernel: __alloc_pages_slowpath.constprop.0+0x373/0xcc0 [60015.902521] kernel: ? __memcg_kmem_charge_page+0xc2/0x1e0 [60015.902525] kernel: __alloc_pages_nodemask+0x30a/0x340 [60015.902528] kernel: pipe_write+0x30b/0x5c0 [60015.902531] kernel: ? set_next_entity+0xad/0x1e0 [60015.902534] kernel: ? switch_mm_irqs_off+0x58/0x440 [60015.902538] kernel: __kernel_write+0x13a/0x2b0 [60015.902541] kernel: kernel_write+0x73/0x150 [60015.902543] kernel: send_cmd+0x7b/0xd0 [60015.902545] kernel: send_extent_data+0x5a3/0x6b0 [60015.902549] kernel: process_extent+0x19b/0xed0 [60015.902551] kernel: btrfs_ioctl_send+0x1434/0x17e0 [60015.902554] kernel: ? _btrfs_ioctl_send+0xe1/0x100 [60015.902557] kernel: _btrfs_ioctl_send+0xbf/0x100 [60015.902559] kernel: ? enqueue_entity+0x18c/0x7b0 [60015.902562] kernel: btrfs_ioctl+0x185f/0x2f80 [60015.902564] kernel: ? psi_task_change+0x84/0xc0 [60015.902569] kernel: ? _flat_send_IPI_mask+0x21/0x40 [60015.902572] kernel: ? check_preempt_curr+0x2f/0x70 [60015.902576] kernel: ? selinux_file_ioctl+0x137/0x1e0 [60015.902579] kernel: ? expand_files+0x1cb/0x1d0 [60015.902582] kernel: ? __x64_sys_ioctl+0x82/0xb0 [60015.902585] kernel: __x64_sys_ioctl+0x82/0xb0 [60015.902588] kernel: do_syscall_64+0x33/0x40 [60015.902591] kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae [60015.902595] kernel: RIP: 0033:0x7f158e38f0ab [60015.902599] kernel: Code: ff ff ff 85 c0 79 9b (...) [60015.902602] kernel: RSP: 002b:00007ffcb2519bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [60015.902605] kernel: RAX: ffffffffffffffda RBX: 00007ffcb251ae00 RCX: 00007f158e38f0ab [60015.902607] kernel: RDX: 00007ffcb2519cf0 RSI: 0000000040489426 RDI: 0000000000000004 [60015.902608] kernel: RBP: 0000000000000004 R08: 00007f158e297640 R09: 00007f158e297640 [60015.902610] kernel: R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000000 [60015.902612] kernel: R13: 0000000000000002 R14: 00007ffcb251aee0 R15: 0000558c1a83e2a0 [60015.902615] kernel: ---[ end trace 7bbc33e23bb887ae ]--- This happens because when writing to the pipe, by calling kernel_write(), we end up doing page allocations using GFP_HIGHUSER | __GFP_ACCOUNT as the gfp flags, which allow reclaim to happen if there is memory pressure. This allocation happens at fs/pipe.c:pipe_write(). If the reclaim is triggered, inode eviction can be triggered and that in turn can result in starting a transaction if the inode has a link count of 0. The transaction start happens early on during eviction, when we call btrfs_commit_inode_delayed_inode() at btrfs_evict_inode(). This happens if there is currently an open file descriptor for an inode with a link count of 0 and the reclaim task gets a reference on the inode before that descriptor is closed, in which case the reclaim task ends up doing the final iput that triggers the inode eviction. When we have assertions enabled (CONFIG_BTRFS_ASSERT=y), this triggers the following assertion at transaction.c:start_transaction(): /* Send isn't supposed to start transactions. */ ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB); And when assertions are not enabled, it triggers a crash since after that assertion we cast current->journal_info into a transaction handle pointer and then dereference it: if (current->journal_info) { WARN_ON(type & TRANS_EXTWRITERS); h = current->journal_info; refcount_inc(&h->use_count); (...) Which obviously results in a crash due to an invalid memory access. The same type of issue can happen during other memory allocations we do directly in the send code with kmalloc (and friends) as they use GFP_KERNEL and therefore may trigger reclaim too, which started to happen since 2016 after commit e780b0d1c1 ("btrfs: send: use GFP_KERNEL everywhere"). The issue could be solved by setting up a NOFS context for the entire send operation so that reclaim could not be triggered when allocating memory or pages through kernel_write(). However that is not very friendly and we can in fact get rid of the send stub because: 1) The stub was introduced way back in 2014 by commit a26e8c9f75 ("Btrfs: don't clear uptodate if the eb is under IO") to solve an issue exclusive to when send and balance are running in parallel, however there were other problems between balance and send and we do not allow anymore to have balance and send run concurrently since commit 9e967495e0 ("Btrfs: prevent send failures and crashes due to concurrent relocation"). More generically the issues are between send and relocation, and that last commit eliminated only the possibility of having send and balance run concurrently, but shrinking a device also can trigger relocation, and on zoned filesystems we have relocation of partially used block groups triggered automatically as well. The previous patch that has a subject of: "btrfs: ensure relocation never runs while we have send operations running" Addresses all the remaining cases that can trigger relocation. 2) We can actually allow starting and even committing transactions while in a send context if needed because send is not holding any locks that would block the start or the commit of a transaction. So get rid of all the logic added by commit a26e8c9f75 ("Btrfs: don't clear uptodate if the eb is under IO"). We can now always call clear_extent_buffer_uptodate() at verify_parent_transid() since send is the only case that uses commit roots without having a transaction open or without holding the commit_root_sem. Reported-by: Chris Murphy <lists@colorremedies.com> Link: https://lore.kernel.org/linux-btrfs/CAJCQCtRQ57=qXo3kygwpwEBOU_CA_eKvdmjP52sU=eFvuVOEGw@mail.gmail.com/ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-06-22 14:11:58 +02:00
David Sterba	1a9fd4172d	btrfs: fix typos in comments ... Fix typos that have snuck in since the last round. Found by codespell. Signed-off-by: David Sterba <dsterba@suse.com>	2021-06-22 14:11:57 +02:00
Filipe Manana	f9baa501b4	btrfs: fix deadlock when cloning inline extents and using qgroups ... There are a few exceptional cases where cloning an inline extent needs to copy the inline extent data into a page of the destination inode. When this happens, we end up starting a transaction while having a dirty page for the destination inode and while having the range locked in the destination's inode iotree too. Because when reserving metadata space for a transaction we may need to flush existing delalloc in case there is not enough free space, we have a mechanism in place to prevent a deadlock, which was introduced in commit 3d45f221ce ("btrfs: fix deadlock when cloning inline extent and low on free metadata space"). However when using qgroups, a transaction also reserves metadata qgroup space, which can also result in flushing delalloc in case there is not enough available space at the moment. When this happens we deadlock, since flushing delalloc requires locking the file range in the inode's iotree and the range was already locked at the very beginning of the clone operation, before attempting to start the transaction. When this issue happens, stack traces like the following are reported: [72747.556262] task:kworker/u81:9 state:D stack: 0 pid: 225 ppid: 2 flags:0x00004000 [72747.556268] Workqueue: writeback wb_workfn (flush-btrfs-1142) [72747.556271] Call Trace: [72747.556273] __schedule+0x296/0x760 [72747.556277] schedule+0x3c/0xa0 [72747.556279] io_schedule+0x12/0x40 [72747.556284] __lock_page+0x13c/0x280 [72747.556287] ? generic_file_readonly_mmap+0x70/0x70 [72747.556325] extent_write_cache_pages+0x22a/0x440 [btrfs] [72747.556331] ? __set_page_dirty_nobuffers+0xe7/0x160 [72747.556358] ? set_extent_buffer_dirty+0x5e/0x80 [btrfs] [72747.556362] ? update_group_capacity+0x25/0x210 [72747.556366] ? cpumask_next_and+0x1a/0x20 [72747.556391] extent_writepages+0x44/0xa0 [btrfs] [72747.556394] do_writepages+0x41/0xd0 [72747.556398] __writeback_single_inode+0x39/0x2a0 [72747.556403] writeback_sb_inodes+0x1ea/0x440 [72747.556407] __writeback_inodes_wb+0x5f/0xc0 [72747.556410] wb_writeback+0x235/0x2b0 [72747.556414] ? get_nr_inodes+0x35/0x50 [72747.556417] wb_workfn+0x354/0x490 [72747.556420] ? newidle_balance+0x2c5/0x3e0 [72747.556424] process_one_work+0x1aa/0x340 [72747.556426] worker_thread+0x30/0x390 [72747.556429] ? create_worker+0x1a0/0x1a0 [72747.556432] kthread+0x116/0x130 [72747.556435] ? kthread_park+0x80/0x80 [72747.556438] ret_from_fork+0x1f/0x30 [72747.566958] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] [72747.566961] Call Trace: [72747.566964] __schedule+0x296/0x760 [72747.566968] ? finish_wait+0x80/0x80 [72747.566970] schedule+0x3c/0xa0 [72747.566995] wait_extent_bit.constprop.68+0x13b/0x1c0 [btrfs] [72747.566999] ? finish_wait+0x80/0x80 [72747.567024] lock_extent_bits+0x37/0x90 [btrfs] [72747.567047] btrfs_invalidatepage+0x299/0x2c0 [btrfs] [72747.567051] ? find_get_pages_range_tag+0x2cd/0x380 [72747.567076] __extent_writepage+0x203/0x320 [btrfs] [72747.567102] extent_write_cache_pages+0x2bb/0x440 [btrfs] [72747.567106] ? update_load_avg+0x7e/0x5f0 [72747.567109] ? enqueue_entity+0xf4/0x6f0 [72747.567134] extent_writepages+0x44/0xa0 [btrfs] [72747.567137] ? enqueue_task_fair+0x93/0x6f0 [72747.567140] do_writepages+0x41/0xd0 [72747.567144] __filemap_fdatawrite_range+0xc7/0x100 [72747.567167] btrfs_run_delalloc_work+0x17/0x40 [btrfs] [72747.567195] btrfs_work_helper+0xc2/0x300 [btrfs] [72747.567200] process_one_work+0x1aa/0x340 [72747.567202] worker_thread+0x30/0x390 [72747.567205] ? create_worker+0x1a0/0x1a0 [72747.567208] kthread+0x116/0x130 [72747.567211] ? kthread_park+0x80/0x80 [72747.567214] ret_from_fork+0x1f/0x30 [72747.569686] task:fsstress state:D stack: 0 pid:841421 ppid:841417 flags:0x00000000 [72747.569689] Call Trace: [72747.569691] __schedule+0x296/0x760 [72747.569694] schedule+0x3c/0xa0 [72747.569721] try_flush_qgroup+0x95/0x140 [btrfs] [72747.569725] ? finish_wait+0x80/0x80 [72747.569753] btrfs_qgroup_reserve_data+0x34/0x50 [btrfs] [72747.569781] btrfs_check_data_free_space+0x5f/0xa0 [btrfs] [72747.569804] btrfs_buffered_write+0x1f7/0x7f0 [btrfs] [72747.569810] ? path_lookupat.isra.48+0x97/0x140 [72747.569833] btrfs_file_write_iter+0x81/0x410 [btrfs] [72747.569836] ? __kmalloc+0x16a/0x2c0 [72747.569839] do_iter_readv_writev+0x160/0x1c0 [72747.569843] do_iter_write+0x80/0x1b0 [72747.569847] vfs_writev+0x84/0x140 [72747.569869] ? btrfs_file_llseek+0x38/0x270 [btrfs] [72747.569873] do_writev+0x65/0x100 [72747.569876] do_syscall_64+0x33/0x40 [72747.569879] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [72747.569899] task:fsstress state:D stack: 0 pid:841424 ppid:841417 flags:0x00004000 [72747.569903] Call Trace: [72747.569906] __schedule+0x296/0x760 [72747.569909] schedule+0x3c/0xa0 [72747.569936] try_flush_qgroup+0x95/0x140 [btrfs] [72747.569940] ? finish_wait+0x80/0x80 [72747.569967] __btrfs_qgroup_reserve_meta+0x36/0x50 [btrfs] [72747.569989] start_transaction+0x279/0x580 [btrfs] [72747.570014] clone_copy_inline_extent+0x332/0x490 [btrfs] [72747.570041] btrfs_clone+0x5b7/0x7a0 [btrfs] [72747.570068] ? lock_extent_bits+0x64/0x90 [btrfs] [72747.570095] btrfs_clone_files+0xfc/0x150 [btrfs] [72747.570122] btrfs_remap_file_range+0x3d8/0x4a0 [btrfs] [72747.570126] do_clone_file_range+0xed/0x200 [72747.570131] vfs_clone_file_range+0x37/0x110 [72747.570134] ioctl_file_clone+0x7d/0xb0 [72747.570137] do_vfs_ioctl+0x138/0x630 [72747.570140] __x64_sys_ioctl+0x62/0xc0 [72747.570143] do_syscall_64+0x33/0x40 [72747.570146] entry_SYSCALL_64_after_hwframe+0x44/0xa9 So fix this by skipping the flush of delalloc for an inode that is flagged with BTRFS_INODE_NO_DELALLOC_FLUSH, meaning it is currently under such a special case of cloning an inline extent, when flushing delalloc during qgroup metadata reservation. The special cases for cloning inline extents were added in kernel 5.7 by by commit 05a5a7621c ("Btrfs: implement full reflink support for inline extents"), while having qgroup metadata space reservation flushing delalloc when low on space was added in kernel 5.9 by commit c53e965360 ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT"). So use a "Fixes:" tag for the later commit to ease stable kernel backports. Reported-by: Wang Yugui <wangyugui@e16-tech.com> Link: https://lore.kernel.org/linux-btrfs/20210421083137.31E3.409509F4@e16-tech.com/ Fixes: c53e965360 ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT") CC: stable@vger.kernel.org # 5.9+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-04-28 20:09:47 +02:00
Filipe Manana	ffb7c2e923	btrfs: do not consider send context as valid when trying to flush qgroups ... At qgroup.c:try_flush_qgroup() we are asserting that current->journal_info is either NULL or has the value BTRFS_SEND_TRANS_STUB. However allowing for BTRFS_SEND_TRANS_STUB makes no sense because: 1) It is misleading, because send operations are read-only and do not ever need to reserve qgroup space; 2) We already assert that current->journal_info != BTRFS_SEND_TRANS_STUB at transaction.c:start_transaction(); 3) On a kernel without CONFIG_BTRFS_ASSERT=y set, it would result in a crash if try_flush_qgroup() is ever called in a send context, because at transaction.c:start_transaction we cast current->journal_info into a struct btrfs_trans_handle pointer and then dereference it. So just do allow a send context at try_flush_qgroup() and update the comment about it. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-04-28 20:09:42 +02:00
Filipe Manana	f3a84ccd28	btrfs: move the tree mod log code into its own file ... The tree modification log, which records modifications done to btrees, is quite large and currently spread all over ctree.c, which is a huge file already. To make things better organized, move all that code into its own separate source and header files. Functions and definitions that are used outside of the module (mostly by ctree.c) are renamed so that they start with a "btrfs_" prefix. Everything else remains unchanged. This makes it easier to go over the tree modification log code every time I need to go read it to fix a bug. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor comment updates ] Signed-off-by: David Sterba <dsterba@suse.com>	2021-04-19 17:25:16 +02:00
Nikolay Borisov	d6ade6894e	btrfs: don't opencode extent_changeset_free ... Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-04-19 17:25:15 +02:00
Nikolay Borisov	ae396a3b7a	btrfs: simplify commit logic in try_flush_qgroup ... It's no longer expected to call this function with an open transaction so all the workarounds concerning this can be removed. In fact it'll constitute a bug to call this function with a transaction already held so WARN in this case. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-04-19 17:25:14 +02:00
Filipe Manana	0bb7883009	btrfs: fix sleep while in non-sleep context during qgroup removal ... While removing a qgroup's sysfs entry we end up taking the kernfs_mutex, through kobject_del(), while holding the fs_info->qgroup_lock spinlock, producing the following trace: [821.843637] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:281 [821.843641] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 28214, name: podman [821.843644] CPU: 3 PID: 28214 Comm: podman Tainted: G W 5.11.6 #15 [821.843646] Hardware name: Dell Inc. PowerEdge R330/084XW4, BIOS 2.11.0 12/08/2020 [821.843647] Call Trace: [821.843650] dump_stack+0xa1/0xfb [821.843656] ___might_sleep+0x144/0x160 [821.843659] mutex_lock+0x17/0x40 [821.843662] kernfs_remove_by_name_ns+0x1f/0x80 [821.843666] sysfs_remove_group+0x7d/0xe0 [821.843668] sysfs_remove_groups+0x28/0x40 [821.843670] kobject_del+0x2a/0x80 [821.843672] btrfs_sysfs_del_one_qgroup+0x2b/0x40 [btrfs] [821.843685] __del_qgroup_rb+0x12/0x150 [btrfs] [821.843696] btrfs_remove_qgroup+0x288/0x2a0 [btrfs] [821.843707] btrfs_ioctl+0x3129/0x36a0 [btrfs] [821.843717] ? __mod_lruvec_page_state+0x5e/0xb0 [821.843719] ? page_add_new_anon_rmap+0xbc/0x150 [821.843723] ? kfree+0x1b4/0x300 [821.843725] ? mntput_no_expire+0x55/0x330 [821.843728] __x64_sys_ioctl+0x5a/0xa0 [821.843731] do_syscall_64+0x33/0x70 [821.843733] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [821.843736] RIP: 0033:0x4cd3fb [821.843741] RSP: 002b:000000c000906b20 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 [821.843744] RAX: ffffffffffffffda RBX: 000000c000050000 RCX: 00000000004cd3fb [821.843745] RDX: 000000c000906b98 RSI: 000000004010942a RDI: 000000000000000f [821.843747] RBP: 000000c000907cd0 R08: 000000c000622901 R09: 0000000000000000 [821.843748] R10: 000000c000d992c0 R11: 0000000000000206 R12: 000000000000012d [821.843749] R13: 000000000000012c R14: 0000000000000200 R15: 0000000000000049 Fix this by removing the qgroup sysfs entry while not holding the spinlock, since the spinlock is only meant for protection of the qgroup rbtree. Reported-by: Stuart Shelton <srcshelton@gmail.com> Link: https://lore.kernel.org/linux-btrfs/7A5485BB-0628-419D-A4D3-27B1AF47E25A@gmail.com/ Fixes: 49e5fb4621 ("btrfs: qgroup: export qgroups in sysfs") CC: stable@vger.kernel.org # 5.10+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-03-18 16:53:24 +01:00
Nikolay Borisov	80e9baed72	btrfs: export and rename qgroup_reserve_meta ... Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2021-03-02 16:58:30 +01:00
Filipe Manana	cb13eea3b4	btrfs: fix transaction leak and crash after RO remount caused by qgroup rescan ... If we remount a filesystem in RO mode while the qgroup rescan worker is running, we can end up having it still running after the remount is done, and at unmount time we may end up with an open transaction that ends up never getting committed. If that happens we end up with several memory leaks and can crash when hardware acceleration is unavailable for crc32c. Possibly it can lead to other nasty surprises too, due to use-after-free issues. The following steps explain how the problem happens. 1) We have a filesystem mounted in RW mode and the qgroup rescan worker is running; 2) We remount the filesystem in RO mode, and never stop/pause the rescan worker, so after the remount the rescan worker is still running. The important detail here is that the rescan task is still running after the remount operation committed any ongoing transaction through its call to btrfs_commit_super(); 3) The rescan is still running, and after the remount completed, the rescan worker started a transaction, after it finished iterating all leaves of the extent tree, to update the qgroup status item in the quotas tree. It does not commit the transaction, it only releases its handle on the transaction; 4) A filesystem unmount operation starts shortly after; 5) The unmount task, at close_ctree(), stops the transaction kthread, which had not had a chance to commit the open transaction since it was sleeping and the commit interval (default of 30 seconds) has not yet elapsed since the last time it committed a transaction; 6) So after stopping the transaction kthread we still have the transaction used to update the qgroup status item open. At close_ctree(), when the filesystem is in RO mode and no transaction abort happened (or the filesystem is in error mode), we do not expect to have any transaction open, so we do not call btrfs_commit_super(); 7) We then proceed to destroy the work queues, free the roots and block groups, etc. After that we drop the last reference on the btree inode by calling iput() on it. Since there are dirty pages for the btree inode, corresponding to the COWed extent buffer for the quotas btree, btree_write_cache_pages() is invoked to flush those dirty pages. This results in creating a bio and submitting it, which makes us end up at btrfs_submit_metadata_bio(); 8) At btrfs_submit_metadata_bio() we end up at the if-then-else branch that calls btrfs_wq_submit_bio(), because check_async_write() returned a value of 1. This value of 1 is because we did not have hardware acceleration available for crc32c, so BTRFS_FS_CSUM_IMPL_FAST was not set in fs_info->flags; 9) Then at btrfs_wq_submit_bio() we call btrfs_queue_work() against the workqueue at fs_info->workers, which was already freed before by the call to btrfs_stop_all_workers() at close_ctree(). This results in an invalid memory access due to a use-after-free, leading to a crash. When this happens, before the crash there are several warnings triggered, since we have reserved metadata space in a block group, the delayed refs reservation, etc: ------------[ cut here ]------------ WARNING: CPU: 4 PID: 1729896 at fs/btrfs/block-group.c:125 btrfs_put_block_group+0x63/0xa0 [btrfs] Modules linked in: btrfs dm_snapshot dm_thin_pool (...) CPU: 4 PID: 1729896 Comm: umount Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:btrfs_put_block_group+0x63/0xa0 [btrfs] Code: f0 01 00 00 48 39 c2 75 (...) RSP: 0018:ffffb270826bbdd8 EFLAGS: 00010206 RAX: 0000000000000001 RBX: ffff947ed73e4000 RCX: ffff947ebc8b29c8 RDX: 0000000000000001 RSI: ffffffffc0b150a0 RDI: ffff947ebc8b2800 RBP: ffff947ebc8b2800 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff947ed73e4110 R13: ffff947ed73e4160 R14: ffff947ebc8b2988 R15: dead000000000100 FS: 00007f15edfea840(0000) GS:ffff9481ad600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f37e2893320 CR3: 0000000138f68001 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: btrfs_free_block_groups+0x17f/0x2f0 [btrfs] close_ctree+0x2ba/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f15ee221ee7 Code: ff 0b 00 f7 d8 64 89 01 48 (...) RSP: 002b:00007ffe9470f0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f15ee347264 RCX: 00007f15ee221ee7 RDX: ffffffffffffff78 RSI: 0000000000000000 RDI: 000056169701d000 RBP: 0000561697018a30 R08: 0000000000000000 R09: 00007f15ee2e2be0 R10: 000056169701efe0 R11: 0000000000000246 R12: 0000000000000000 R13: 000056169701d000 R14: 0000561697018b40 R15: 0000561697018c60 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last enabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace dd74718fef1ed5c6 ]--- ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1729896 at fs/btrfs/block-rsv.c:459 btrfs_release_global_block_rsv+0x70/0xc0 [btrfs] Modules linked in: btrfs dm_snapshot dm_thin_pool (...) CPU: 2 PID: 1729896 Comm: umount Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:btrfs_release_global_block_rsv+0x70/0xc0 [btrfs] Code: 48 83 bb b0 03 00 00 00 (...) RSP: 0018:ffffb270826bbdd8 EFLAGS: 00010206 RAX: 000000000033c000 RBX: ffff947ed73e4000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffffffffc0b0d8c1 RDI: 00000000ffffffff RBP: ffff947ebc8b7000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff947ed73e4110 R13: ffff947ed73e5278 R14: dead000000000122 R15: dead000000000100 FS: 00007f15edfea840(0000) GS:ffff9481aca00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000561a79f76e20 CR3: 0000000138f68006 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: btrfs_free_block_groups+0x24c/0x2f0 [btrfs] close_ctree+0x2ba/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f15ee221ee7 Code: ff 0b 00 f7 d8 64 89 01 (...) RSP: 002b:00007ffe9470f0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f15ee347264 RCX: 00007f15ee221ee7 RDX: ffffffffffffff78 RSI: 0000000000000000 RDI: 000056169701d000 RBP: 0000561697018a30 R08: 0000000000000000 R09: 00007f15ee2e2be0 R10: 000056169701efe0 R11: 0000000000000246 R12: 0000000000000000 R13: 000056169701d000 R14: 0000561697018b40 R15: 0000561697018c60 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last enabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace dd74718fef1ed5c7 ]--- ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1729896 at fs/btrfs/block-group.c:3377 btrfs_free_block_groups+0x25d/0x2f0 [btrfs] Modules linked in: btrfs dm_snapshot dm_thin_pool (...) CPU: 5 PID: 1729896 Comm: umount Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:btrfs_free_block_groups+0x25d/0x2f0 [btrfs] Code: ad de 49 be 22 01 00 (...) RSP: 0018:ffffb270826bbde8 EFLAGS: 00010206 RAX: ffff947ebeae1d08 RBX: ffff947ed73e4000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff947e9d823ae8 RDI: 0000000000000246 RBP: ffff947ebeae1d08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: ffff947ebeae1c00 R13: ffff947ed73e5278 R14: dead000000000122 R15: dead000000000100 FS: 00007f15edfea840(0000) GS:ffff9481ad200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1475d98ea8 CR3: 0000000138f68005 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: close_ctree+0x2ba/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f15ee221ee7 Code: ff 0b 00 f7 d8 64 89 (...) RSP: 002b:00007ffe9470f0f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f15ee347264 RCX: 00007f15ee221ee7 RDX: ffffffffffffff78 RSI: 0000000000000000 RDI: 000056169701d000 RBP: 0000561697018a30 R08: 0000000000000000 R09: 00007f15ee2e2be0 R10: 000056169701efe0 R11: 0000000000000246 R12: 0000000000000000 R13: 000056169701d000 R14: 0000561697018b40 R15: 0000561697018c60 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last enabled at (0): [<ffffffff8bcae560>] copy_process+0x8a0/0x1d70 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace dd74718fef1ed5c8 ]--- BTRFS info (device sdc): space_info 4 has 268238848 free, is not full BTRFS info (device sdc): space_info total=268435456, used=114688, pinned=0, reserved=16384, may_use=0, readonly=65536 BTRFS info (device sdc): global_block_rsv: size 0 reserved 0 BTRFS info (device sdc): trans_block_rsv: size 0 reserved 0 BTRFS info (device sdc): chunk_block_rsv: size 0 reserved 0 BTRFS info (device sdc): delayed_block_rsv: size 0 reserved 0 BTRFS info (device sdc): delayed_refs_rsv: size 524288 reserved 0 And the crash, which only happens when we do not have crc32c hardware acceleration, produces the following trace immediately after those warnings: stack segment: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI CPU: 2 PID: 1749129 Comm: umount Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:btrfs_queue_work+0x36/0x190 [btrfs] Code: 54 55 53 48 89 f3 (...) RSP: 0018:ffffb27082443ae8 EFLAGS: 00010282 RAX: 0000000000000004 RBX: ffff94810ee9ad90 RCX: 0000000000000000 RDX: 0000000000000001 RSI: ffff94810ee9ad90 RDI: ffff947ed8ee75a0 RBP: a56b6b6b6b6b6b6b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000001 R12: ffff947fa9b435a8 R13: ffff94810ee9ad90 R14: 0000000000000000 R15: ffff947e93dc0000 FS: 00007f3cfe974840(0000) GS:ffff9481ac600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1b42995a70 CR3: 0000000127638003 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: btrfs_wq_submit_bio+0xb3/0xd0 [btrfs] btrfs_submit_metadata_bio+0x44/0xc0 [btrfs] submit_one_bio+0x61/0x70 [btrfs] btree_write_cache_pages+0x414/0x450 [btrfs] ? kobject_put+0x9a/0x1d0 ? trace_hardirqs_on+0x1b/0xf0 ? _raw_spin_unlock_irqrestore+0x3c/0x60 ? free_debug_processing+0x1e1/0x2b0 do_writepages+0x43/0xe0 ? lock_acquired+0x199/0x490 __writeback_single_inode+0x59/0x650 writeback_single_inode+0xaf/0x120 write_inode_now+0x94/0xd0 iput+0x187/0x2b0 close_ctree+0x2c6/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f3cfebabee7 Code: ff 0b 00 f7 d8 64 89 01 (...) RSP: 002b:00007ffc9c9a05f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f3cfecd1264 RCX: 00007f3cfebabee7 RDX: ffffffffffffff78 RSI: 0000000000000000 RDI: 0000562b6b478000 RBP: 0000562b6b473a30 R08: 0000000000000000 R09: 00007f3cfec6cbe0 R10: 0000562b6b479fe0 R11: 0000000000000246 R12: 0000000000000000 R13: 0000562b6b478000 R14: 0000562b6b473b40 R15: 0000562b6b473c60 Modules linked in: btrfs dm_snapshot dm_thin_pool (...) ---[ end trace dd74718fef1ed5cc ]--- Finally when we remove the btrfs module (rmmod btrfs), there are several warnings about objects that were allocated from our slabs but were never freed, consequence of the transaction that was never committed and got leaked: ============================================================================= BUG btrfs_delayed_ref_head (Tainted: G B W ): Objects remaining in btrfs_delayed_ref_head on __kmem_cache_shutdown() ----------------------------------------------------------------------------- INFO: Slab 0x0000000094c2ae56 objects=24 used=2 fp=0x000000002bfa2521 flags=0x17fffc000010200 CPU: 5 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 slab_err+0xb7/0xdc ? lock_acquired+0x199/0x490 __kmem_cache_shutdown+0x1ac/0x3c0 ? lock_release+0x20e/0x4c0 kmem_cache_destroy+0x55/0x120 btrfs_delayed_ref_exit+0x11/0x35 [btrfs] exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 f5 (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 INFO: Object 0x0000000050cbdd61 @offset=12104 INFO: Allocated in btrfs_add_delayed_tree_ref+0xbb/0x480 [btrfs] age=1894 cpu=6 pid=1729873 __slab_alloc.isra.0+0x109/0x1c0 kmem_cache_alloc+0x7bb/0x830 btrfs_add_delayed_tree_ref+0xbb/0x480 [btrfs] btrfs_free_tree_block+0x128/0x360 [btrfs] __btrfs_cow_block+0x489/0x5f0 [btrfs] btrfs_cow_block+0xf7/0x220 [btrfs] btrfs_search_slot+0x62a/0xc40 [btrfs] btrfs_del_orphan_item+0x65/0xd0 [btrfs] btrfs_find_orphan_roots+0x1bf/0x200 [btrfs] open_ctree+0x125a/0x18a0 [btrfs] btrfs_mount_root.cold+0x13/0xed [btrfs] legacy_get_tree+0x30/0x60 vfs_get_tree+0x28/0xe0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] INFO: Freed in __btrfs_run_delayed_refs+0x1117/0x1290 [btrfs] age=4292 cpu=2 pid=1729526 kmem_cache_free+0x34c/0x3c0 __btrfs_run_delayed_refs+0x1117/0x1290 [btrfs] btrfs_run_delayed_refs+0x81/0x210 [btrfs] commit_cowonly_roots+0xfb/0x300 [btrfs] btrfs_commit_transaction+0x367/0xc40 [btrfs] sync_filesystem+0x74/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 INFO: Object 0x0000000086e9b0ff @offset=12776 INFO: Allocated in btrfs_add_delayed_tree_ref+0xbb/0x480 [btrfs] age=1900 cpu=6 pid=1729873 __slab_alloc.isra.0+0x109/0x1c0 kmem_cache_alloc+0x7bb/0x830 btrfs_add_delayed_tree_ref+0xbb/0x480 [btrfs] btrfs_alloc_tree_block+0x2bf/0x360 [btrfs] alloc_tree_block_no_bg_flush+0x4f/0x60 [btrfs] __btrfs_cow_block+0x12d/0x5f0 [btrfs] btrfs_cow_block+0xf7/0x220 [btrfs] btrfs_search_slot+0x62a/0xc40 [btrfs] btrfs_del_orphan_item+0x65/0xd0 [btrfs] btrfs_find_orphan_roots+0x1bf/0x200 [btrfs] open_ctree+0x125a/0x18a0 [btrfs] btrfs_mount_root.cold+0x13/0xed [btrfs] legacy_get_tree+0x30/0x60 vfs_get_tree+0x28/0xe0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 INFO: Freed in __btrfs_run_delayed_refs+0x1117/0x1290 [btrfs] age=3141 cpu=6 pid=1729803 kmem_cache_free+0x34c/0x3c0 __btrfs_run_delayed_refs+0x1117/0x1290 [btrfs] btrfs_run_delayed_refs+0x81/0x210 [btrfs] btrfs_write_dirty_block_groups+0x17d/0x3d0 [btrfs] commit_cowonly_roots+0x248/0x300 [btrfs] btrfs_commit_transaction+0x367/0xc40 [btrfs] close_ctree+0x113/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kmem_cache_destroy btrfs_delayed_ref_head: Slab cache still has objects CPU: 5 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 kmem_cache_destroy+0x119/0x120 btrfs_delayed_ref_exit+0x11/0x35 [btrfs] exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 f5 0b (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 ============================================================================= BUG btrfs_delayed_tree_ref (Tainted: G B W ): Objects remaining in btrfs_delayed_tree_ref on __kmem_cache_shutdown() ----------------------------------------------------------------------------- INFO: Slab 0x0000000011f78dc0 objects=37 used=2 fp=0x0000000032d55d91 flags=0x17fffc000010200 CPU: 3 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 slab_err+0xb7/0xdc ? lock_acquired+0x199/0x490 __kmem_cache_shutdown+0x1ac/0x3c0 ? lock_release+0x20e/0x4c0 kmem_cache_destroy+0x55/0x120 btrfs_delayed_ref_exit+0x1d/0x35 [btrfs] exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 f5 (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 INFO: Object 0x000000001a340018 @offset=4408 INFO: Allocated in btrfs_add_delayed_tree_ref+0x9e/0x480 [btrfs] age=1917 cpu=6 pid=1729873 __slab_alloc.isra.0+0x109/0x1c0 kmem_cache_alloc+0x7bb/0x830 btrfs_add_delayed_tree_ref+0x9e/0x480 [btrfs] btrfs_free_tree_block+0x128/0x360 [btrfs] __btrfs_cow_block+0x489/0x5f0 [btrfs] btrfs_cow_block+0xf7/0x220 [btrfs] btrfs_search_slot+0x62a/0xc40 [btrfs] btrfs_del_orphan_item+0x65/0xd0 [btrfs] btrfs_find_orphan_roots+0x1bf/0x200 [btrfs] open_ctree+0x125a/0x18a0 [btrfs] btrfs_mount_root.cold+0x13/0xed [btrfs] legacy_get_tree+0x30/0x60 vfs_get_tree+0x28/0xe0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] INFO: Freed in __btrfs_run_delayed_refs+0x63d/0x1290 [btrfs] age=4167 cpu=4 pid=1729795 kmem_cache_free+0x34c/0x3c0 __btrfs_run_delayed_refs+0x63d/0x1290 [btrfs] btrfs_run_delayed_refs+0x81/0x210 [btrfs] btrfs_commit_transaction+0x60/0xc40 [btrfs] create_subvol+0x56a/0x990 [btrfs] btrfs_mksubvol+0x3fb/0x4a0 [btrfs] __btrfs_ioctl_snap_create+0x119/0x1a0 [btrfs] btrfs_ioctl_snap_create+0x58/0x80 [btrfs] btrfs_ioctl+0x1a92/0x36f0 [btrfs] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 INFO: Object 0x000000002b46292a @offset=13648 INFO: Allocated in btrfs_add_delayed_tree_ref+0x9e/0x480 [btrfs] age=1923 cpu=6 pid=1729873 __slab_alloc.isra.0+0x109/0x1c0 kmem_cache_alloc+0x7bb/0x830 btrfs_add_delayed_tree_ref+0x9e/0x480 [btrfs] btrfs_alloc_tree_block+0x2bf/0x360 [btrfs] alloc_tree_block_no_bg_flush+0x4f/0x60 [btrfs] __btrfs_cow_block+0x12d/0x5f0 [btrfs] btrfs_cow_block+0xf7/0x220 [btrfs] btrfs_search_slot+0x62a/0xc40 [btrfs] btrfs_del_orphan_item+0x65/0xd0 [btrfs] btrfs_find_orphan_roots+0x1bf/0x200 [btrfs] open_ctree+0x125a/0x18a0 [btrfs] btrfs_mount_root.cold+0x13/0xed [btrfs] legacy_get_tree+0x30/0x60 vfs_get_tree+0x28/0xe0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 INFO: Freed in __btrfs_run_delayed_refs+0x63d/0x1290 [btrfs] age=3164 cpu=6 pid=1729803 kmem_cache_free+0x34c/0x3c0 __btrfs_run_delayed_refs+0x63d/0x1290 [btrfs] btrfs_run_delayed_refs+0x81/0x210 [btrfs] commit_cowonly_roots+0xfb/0x300 [btrfs] btrfs_commit_transaction+0x367/0xc40 [btrfs] close_ctree+0x113/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kmem_cache_destroy btrfs_delayed_tree_ref: Slab cache still has objects CPU: 5 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 kmem_cache_destroy+0x119/0x120 btrfs_delayed_ref_exit+0x1d/0x35 [btrfs] exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 f5 (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 ============================================================================= BUG btrfs_delayed_extent_op (Tainted: G B W ): Objects remaining in btrfs_delayed_extent_op on __kmem_cache_shutdown() ----------------------------------------------------------------------------- INFO: Slab 0x00000000f145ce2f objects=22 used=1 fp=0x00000000af0f92cf flags=0x17fffc000010200 CPU: 5 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 slab_err+0xb7/0xdc ? lock_acquired+0x199/0x490 __kmem_cache_shutdown+0x1ac/0x3c0 ? __mutex_unlock_slowpath+0x45/0x2a0 kmem_cache_destroy+0x55/0x120 exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 f5 (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 INFO: Object 0x000000004cf95ea8 @offset=6264 INFO: Allocated in btrfs_alloc_tree_block+0x1e0/0x360 [btrfs] age=1931 cpu=6 pid=1729873 __slab_alloc.isra.0+0x109/0x1c0 kmem_cache_alloc+0x7bb/0x830 btrfs_alloc_tree_block+0x1e0/0x360 [btrfs] alloc_tree_block_no_bg_flush+0x4f/0x60 [btrfs] __btrfs_cow_block+0x12d/0x5f0 [btrfs] btrfs_cow_block+0xf7/0x220 [btrfs] btrfs_search_slot+0x62a/0xc40 [btrfs] btrfs_del_orphan_item+0x65/0xd0 [btrfs] btrfs_find_orphan_roots+0x1bf/0x200 [btrfs] open_ctree+0x125a/0x18a0 [btrfs] btrfs_mount_root.cold+0x13/0xed [btrfs] legacy_get_tree+0x30/0x60 vfs_get_tree+0x28/0xe0 fc_mount+0xe/0x40 vfs_kern_mount.part.0+0x71/0x90 btrfs_mount+0x13b/0x3e0 [btrfs] INFO: Freed in __btrfs_run_delayed_refs+0xabd/0x1290 [btrfs] age=3173 cpu=6 pid=1729803 kmem_cache_free+0x34c/0x3c0 __btrfs_run_delayed_refs+0xabd/0x1290 [btrfs] btrfs_run_delayed_refs+0x81/0x210 [btrfs] commit_cowonly_roots+0xfb/0x300 [btrfs] btrfs_commit_transaction+0x367/0xc40 [btrfs] close_ctree+0x113/0x2fa [btrfs] generic_shutdown_super+0x6c/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x68/0xb0 exit_to_user_mode_prepare+0x1bb/0x1c0 syscall_exit_to_user_mode+0x4b/0x260 entry_SYSCALL_64_after_hwframe+0x44/0xa9 kmem_cache_destroy btrfs_delayed_extent_op: Slab cache still has objects CPU: 3 PID: 1729921 Comm: rmmod Tainted: G B W 5.10.0-rc4-btrfs-next-73 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8d/0xb5 kmem_cache_destroy+0x119/0x120 exit_btrfs_fs+0xa/0x59 [btrfs] __x64_sys_delete_module+0x194/0x260 ? fpregs_assert_state_consistent+0x1e/0x40 ? exit_to_user_mode_prepare+0x55/0x1c0 ? trace_hardirqs_on+0x1b/0xf0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f693e305897 Code: 73 01 c3 48 8b 0d f9 (...) RSP: 002b:00007ffcf73eb508 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559df504f760 RCX: 00007f693e305897 RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559df504f7c8 RBP: 00007ffcf73eb568 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f693e378ac0 R11: 0000000000000206 R12: 00007ffcf73eb740 R13: 00007ffcf73ec5a6 R14: 0000559df504f2a0 R15: 0000559df504f760 BTRFS: state leak: start 30408704 end 30425087 state 1 in tree 1 refs 1 Fix this issue by having the remount path stop the qgroup rescan worker when we are remounting RO and teach the rescan worker to stop when a remount is in progress. If later a remount in RW mode happens, we are already resuming the qgroup rescan worker through the call to btrfs_qgroup_rescan_resume(), so we do not need to worry about that. Tested-by: Fabian Vogt <fvogt@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-18 14:59:57 +01:00
Qu Wenruo	ae5e070eac	btrfs: qgroup: don't try to wait flushing if we're already holding a transaction ... There is a chance of racing for qgroup flushing which may lead to deadlock: Thread A | Thread B (not holding trans handle) | (holding a trans handle) --------------------------------+-------------------------------- __btrfs_qgroup_reserve_meta() | __btrfs_qgroup_reserve_meta() |- try_flush_qgroup() | |- try_flush_qgroup() |- QGROUP_FLUSHING bit set | | | | |- test_and_set_bit() | | |- wait_event() |- btrfs_join_transaction() | |- btrfs_commit_transaction()| !!! DEAD LOCK !!! Since thread A wants to commit transaction, but thread B is holding a transaction handle, blocking the commit. At the same time, thread B is waiting for thread A to finish its commit. This is just a hot fix, and would lead to more EDQUOT when we're near the qgroup limit. The proper fix would be to make all metadata/data reservations happen without holding a transaction handle. CC: stable@vger.kernel.org # 5.9+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-18 14:50:07 +01:00
Josef Bacik	1b7ec85ef4	btrfs: pass root owner to read_tree_block ... In order to properly set the lockdep class of a newly allocated block we need to know the owner of the block. For non-refcounted trees this is straightforward, we always know in advance what tree we're reading from. For refcounted trees we don't necessarily know, however all refcounted trees share the same lockdep class name, tree-<level>. Fix all the callers of read_tree_block() to pass in the root objectid we're using. In places like relocation and backref we could probably unconditionally use 0, but just in case use the root when we have it, otherwise use 0 in the cases we don't have the root as it's going to be a refcounted tree anyway. This is a preparation patch for further changes. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:07 +01:00
Josef Bacik	182c79fcb8	btrfs: use btrfs_read_node_slot in btrfs_qgroup_trace_subtree ... We're open-coding btrfs_read_node_slot() here, replace with the helper. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:07 +01:00
Josef Bacik	3acfbd6a99	btrfs: use btrfs_read_node_slot in qgroup_trace_new_subtree_blocks ... We're open-coding btrfs_read_node_slot() here, replace with the helper. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:07 +01:00
Josef Bacik	6b2cb7cb95	btrfs: use btrfs_read_node_slot in qgroup_trace_extent_swap ... We're open-coding btrfs_read_node_slot() here, replace with the helper. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:06 +01:00
Josef Bacik	b9729ce014	btrfs: locking: rip out path->leave_spinning ... We no longer distinguish between blocking and spinning, so rip out all this code. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:02 +01:00
Josef Bacik	ac5887c8e0	btrfs: locking: remove all the blocking helpers ... Now that we're using a rw_semaphore we no longer need to indicate if a lock is blocking or not, nor do we need to flip the entire path from blocking to spinning. Remove these helpers and all the places they are called. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-12-08 15:54:01 +01:00
Filipe Manana	a855fbe692	btrfs: fix lockdep splat when enabling and disabling qgroups ... When running test case btrfs/017 from fstests, lockdep reported the following splat: [ 1297.067385] ====================================================== [ 1297.067708] WARNING: possible circular locking dependency detected [ 1297.068022] 5.10.0-rc4-btrfs-next-73 #1 Not tainted [ 1297.068322] ------------------------------------------------------ [ 1297.068629] btrfs/189080 is trying to acquire lock: [ 1297.068929] ffff9f2725731690 (sb_internal#2){.+.+}-{0:0}, at: btrfs_quota_enable+0xaf/0xa70 [btrfs] [ 1297.069274] but task is already holding lock: [ 1297.069868] ffff9f2702b61a08 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_enable+0x3b/0xa70 [btrfs] [ 1297.070219] which lock already depends on the new lock. [ 1297.071131] the existing dependency chain (in reverse order) is: [ 1297.071721] -> #1 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}: [ 1297.072375] lock_acquire+0xd8/0x490 [ 1297.072710] __mutex_lock+0xa3/0xb30 [ 1297.073061] btrfs_qgroup_inherit+0x59/0x6a0 [btrfs] [ 1297.073421] create_subvol+0x194/0x990 [btrfs] [ 1297.073780] btrfs_mksubvol+0x3fb/0x4a0 [btrfs] [ 1297.074133] __btrfs_ioctl_snap_create+0x119/0x1a0 [btrfs] [ 1297.074498] btrfs_ioctl_snap_create+0x58/0x80 [btrfs] [ 1297.074872] btrfs_ioctl+0x1a90/0x36f0 [btrfs] [ 1297.075245] __x64_sys_ioctl+0x83/0xb0 [ 1297.075617] do_syscall_64+0x33/0x80 [ 1297.075993] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1297.076380] -> #0 (sb_internal#2){.+.+}-{0:0}: [ 1297.077166] check_prev_add+0x91/0xc60 [ 1297.077572] __lock_acquire+0x1740/0x3110 [ 1297.077984] lock_acquire+0xd8/0x490 [ 1297.078411] start_transaction+0x3c5/0x760 [btrfs] [ 1297.078853] btrfs_quota_enable+0xaf/0xa70 [btrfs] [ 1297.079323] btrfs_ioctl+0x2c60/0x36f0 [btrfs] [ 1297.079789] __x64_sys_ioctl+0x83/0xb0 [ 1297.080232] do_syscall_64+0x33/0x80 [ 1297.080680] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1297.081139] other info that might help us debug this: [ 1297.082536] Possible unsafe locking scenario: [ 1297.083510] CPU0 CPU1 [ 1297.084005] ---- ---- [ 1297.084500] lock(&fs_info->qgroup_ioctl_lock); [ 1297.084994] lock(sb_internal#2); [ 1297.085485] lock(&fs_info->qgroup_ioctl_lock); [ 1297.085974] lock(sb_internal#2); [ 1297.086454] *** DEADLOCK *** [ 1297.087880] 3 locks held by btrfs/189080: [ 1297.088324] #0: ffff9f2725731470 (sb_writers#14){.+.+}-{0:0}, at: btrfs_ioctl+0xa73/0x36f0 [btrfs] [ 1297.088799] #1: ffff9f2702b60cc0 (&fs_info->subvol_sem){++++}-{3:3}, at: btrfs_ioctl+0x1f4d/0x36f0 [btrfs] [ 1297.089284] #2: ffff9f2702b61a08 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_enable+0x3b/0xa70 [btrfs] [ 1297.089771] stack backtrace: [ 1297.090662] CPU: 5 PID: 189080 Comm: btrfs Not tainted 5.10.0-rc4-btrfs-next-73 #1 [ 1297.091132] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 1297.092123] Call Trace: [ 1297.092629] dump_stack+0x8d/0xb5 [ 1297.093115] check_noncircular+0xff/0x110 [ 1297.093596] check_prev_add+0x91/0xc60 [ 1297.094076] ? kvm_clock_read+0x14/0x30 [ 1297.094553] ? kvm_sched_clock_read+0x5/0x10 [ 1297.095029] __lock_acquire+0x1740/0x3110 [ 1297.095510] lock_acquire+0xd8/0x490 [ 1297.095993] ? btrfs_quota_enable+0xaf/0xa70 [btrfs] [ 1297.096476] start_transaction+0x3c5/0x760 [btrfs] [ 1297.096962] ? btrfs_quota_enable+0xaf/0xa70 [btrfs] [ 1297.097451] btrfs_quota_enable+0xaf/0xa70 [btrfs] [ 1297.097941] ? btrfs_ioctl+0x1f4d/0x36f0 [btrfs] [ 1297.098429] btrfs_ioctl+0x2c60/0x36f0 [btrfs] [ 1297.098904] ? do_user_addr_fault+0x20c/0x430 [ 1297.099382] ? kvm_clock_read+0x14/0x30 [ 1297.099854] ? kvm_sched_clock_read+0x5/0x10 [ 1297.100328] ? sched_clock+0x5/0x10 [ 1297.100801] ? sched_clock_cpu+0x12/0x180 [ 1297.101272] ? __x64_sys_ioctl+0x83/0xb0 [ 1297.101739] __x64_sys_ioctl+0x83/0xb0 [ 1297.102207] do_syscall_64+0x33/0x80 [ 1297.102673] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1297.103148] RIP: 0033:0x7f773ff65d87 This is because during the quota enable ioctl we lock first the mutex qgroup_ioctl_lock and then start a transaction, and starting a transaction acquires a fs freeze semaphore (at the VFS level). However, every other code path, except for the quota disable ioctl path, we do the opposite: we start a transaction and then lock the mutex. So fix this by making the quota enable and disable paths to start the transaction without having the mutex locked, and then, after starting the transaction, lock the mutex and check if some other task already enabled or disabled the quotas, bailing with success if that was the case. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-11-23 21:16:43 +01:00
Filipe Manana	7aa6d35984	btrfs: do nofs allocations when adding and removing qgroup relations ... When adding or removing a qgroup relation we are doing a GFP_KERNEL allocation which is not safe because we are holding a transaction handle open and that can make us deadlock if the allocator needs to recurse into the filesystem. So just surround those calls with a nofs context. Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-11-23 21:16:40 +01:00
Filipe Manana	3d05cad3c3	btrfs: fix lockdep splat when reading qgroup config on mount ... Lockdep reported the following splat when running test btrfs/190 from fstests: [ 9482.126098] ====================================================== [ 9482.126184] WARNING: possible circular locking dependency detected [ 9482.126281] 5.10.0-rc4-btrfs-next-73 #1 Not tainted [ 9482.126365] ------------------------------------------------------ [ 9482.126456] mount/24187 is trying to acquire lock: [ 9482.126534] ffffa0c869a7dac0 (&fs_info->qgroup_rescan_lock){+.+.}-{3:3}, at: qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.126647] but task is already holding lock: [ 9482.126777] ffffa0c892ebd3a0 (btrfs-quota-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x120 [btrfs] [ 9482.126886] which lock already depends on the new lock. [ 9482.127078] the existing dependency chain (in reverse order) is: [ 9482.127213] -> #1 (btrfs-quota-00){++++}-{3:3}: [ 9482.127366] lock_acquire+0xd8/0x490 [ 9482.127436] down_read_nested+0x45/0x220 [ 9482.127528] __btrfs_tree_read_lock+0x27/0x120 [btrfs] [ 9482.127613] btrfs_read_lock_root_node+0x41/0x130 [btrfs] [ 9482.127702] btrfs_search_slot+0x514/0xc30 [btrfs] [ 9482.127788] update_qgroup_status_item+0x72/0x140 [btrfs] [ 9482.127877] btrfs_qgroup_rescan_worker+0xde/0x680 [btrfs] [ 9482.127964] btrfs_work_helper+0xf1/0x600 [btrfs] [ 9482.128039] process_one_work+0x24e/0x5e0 [ 9482.128110] worker_thread+0x50/0x3b0 [ 9482.128181] kthread+0x153/0x170 [ 9482.128256] ret_from_fork+0x22/0x30 [ 9482.128327] -> #0 (&fs_info->qgroup_rescan_lock){+.+.}-{3:3}: [ 9482.128464] check_prev_add+0x91/0xc60 [ 9482.128551] __lock_acquire+0x1740/0x3110 [ 9482.128623] lock_acquire+0xd8/0x490 [ 9482.130029] __mutex_lock+0xa3/0xb30 [ 9482.130590] qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.131577] btrfs_read_qgroup_config+0x43a/0x550 [btrfs] [ 9482.132175] open_ctree+0x1228/0x18a0 [btrfs] [ 9482.132756] btrfs_mount_root.cold+0x13/0xed [btrfs] [ 9482.133325] legacy_get_tree+0x30/0x60 [ 9482.133866] vfs_get_tree+0x28/0xe0 [ 9482.134392] fc_mount+0xe/0x40 [ 9482.134908] vfs_kern_mount.part.0+0x71/0x90 [ 9482.135428] btrfs_mount+0x13b/0x3e0 [btrfs] [ 9482.135942] legacy_get_tree+0x30/0x60 [ 9482.136444] vfs_get_tree+0x28/0xe0 [ 9482.136949] path_mount+0x2d7/0xa70 [ 9482.137438] do_mount+0x75/0x90 [ 9482.137923] __x64_sys_mount+0x8e/0xd0 [ 9482.138400] do_syscall_64+0x33/0x80 [ 9482.138873] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 9482.139346] other info that might help us debug this: [ 9482.140735] Possible unsafe locking scenario: [ 9482.141594] CPU0 CPU1 [ 9482.142011] ---- ---- [ 9482.142411] lock(btrfs-quota-00); [ 9482.142806] lock(&fs_info->qgroup_rescan_lock); [ 9482.143216] lock(btrfs-quota-00); [ 9482.143629] lock(&fs_info->qgroup_rescan_lock); [ 9482.144056] *** DEADLOCK *** [ 9482.145242] 2 locks held by mount/24187: [ 9482.145637] #0: ffffa0c8411c40e8 (&type->s_umount_key#44/1){+.+.}-{3:3}, at: alloc_super+0xb9/0x400 [ 9482.146061] #1: ffffa0c892ebd3a0 (btrfs-quota-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x120 [btrfs] [ 9482.146509] stack backtrace: [ 9482.147350] CPU: 1 PID: 24187 Comm: mount Not tainted 5.10.0-rc4-btrfs-next-73 #1 [ 9482.147788] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 9482.148709] Call Trace: [ 9482.149169] dump_stack+0x8d/0xb5 [ 9482.149628] check_noncircular+0xff/0x110 [ 9482.150090] check_prev_add+0x91/0xc60 [ 9482.150561] ? kvm_clock_read+0x14/0x30 [ 9482.151017] ? kvm_sched_clock_read+0x5/0x10 [ 9482.151470] __lock_acquire+0x1740/0x3110 [ 9482.151941] ? __btrfs_tree_read_lock+0x27/0x120 [btrfs] [ 9482.152402] lock_acquire+0xd8/0x490 [ 9482.152887] ? qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.153354] __mutex_lock+0xa3/0xb30 [ 9482.153826] ? qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.154301] ? qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.154768] ? qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.155226] qgroup_rescan_init+0x43/0xf0 [btrfs] [ 9482.155690] btrfs_read_qgroup_config+0x43a/0x550 [btrfs] [ 9482.156160] open_ctree+0x1228/0x18a0 [btrfs] [ 9482.156643] btrfs_mount_root.cold+0x13/0xed [btrfs] [ 9482.157108] ? rcu_read_lock_sched_held+0x5d/0x90 [ 9482.157567] ? kfree+0x31f/0x3e0 [ 9482.158030] legacy_get_tree+0x30/0x60 [ 9482.158489] vfs_get_tree+0x28/0xe0 [ 9482.158947] fc_mount+0xe/0x40 [ 9482.159403] vfs_kern_mount.part.0+0x71/0x90 [ 9482.159875] btrfs_mount+0x13b/0x3e0 [btrfs] [ 9482.160335] ? rcu_read_lock_sched_held+0x5d/0x90 [ 9482.160805] ? kfree+0x31f/0x3e0 [ 9482.161260] ? legacy_get_tree+0x30/0x60 [ 9482.161714] legacy_get_tree+0x30/0x60 [ 9482.162166] vfs_get_tree+0x28/0xe0 [ 9482.162616] path_mount+0x2d7/0xa70 [ 9482.163070] do_mount+0x75/0x90 [ 9482.163525] __x64_sys_mount+0x8e/0xd0 [ 9482.163986] do_syscall_64+0x33/0x80 [ 9482.164437] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 9482.164902] RIP: 0033:0x7f51e907caaa This happens because at btrfs_read_qgroup_config() we can call qgroup_rescan_init() while holding a read lock on a quota btree leaf, acquired by the previous call to btrfs_search_slot_for_read(), and qgroup_rescan_init() acquires the mutex qgroup_rescan_lock. A qgroup rescan worker does the opposite: it acquires the mutex qgroup_rescan_lock, at btrfs_qgroup_rescan_worker(), and then tries to update the qgroup status item in the quota btree through the call to update_qgroup_status_item(). This inversion of locking order between the qgroup_rescan_lock mutex and quota btree locks causes the splat. Fix this simply by releasing and freeing the path before calling qgroup_rescan_init() at btrfs_read_qgroup_config(). CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-11-23 21:16:30 +01:00
Qu Wenruo	6f23277a49	btrfs: qgroup: don't commit transaction when we already hold the handle ... [BUG] When running the following script, btrfs will trigger an ASSERT(): #/bin/bash mkfs.btrfs -f $dev mount $dev $mnt xfs_io -f -c "pwrite 0 1G" $mnt/file sync btrfs quota enable $mnt btrfs quota rescan -w $mnt # Manually set the limit below current usage btrfs qgroup limit 512M $mnt $mnt # Crash happens touch $mnt/file The dmesg looks like this: assertion failed: refcount_read(&trans->use_count) == 1, in fs/btrfs/transaction.c:2022 ------------[ cut here ]------------ kernel BUG at fs/btrfs/ctree.h:3230! invalid opcode: 0000 [#1] SMP PTI RIP: 0010:assertfail.constprop.0+0x18/0x1a [btrfs] btrfs_commit_transaction.cold+0x11/0x5d [btrfs] try_flush_qgroup+0x67/0x100 [btrfs] __btrfs_qgroup_reserve_meta+0x3a/0x60 [btrfs] btrfs_delayed_update_inode+0xaa/0x350 [btrfs] btrfs_update_inode+0x9d/0x110 [btrfs] btrfs_dirty_inode+0x5d/0xd0 [btrfs] touch_atime+0xb5/0x100 iterate_dir+0xf1/0x1b0 __x64_sys_getdents64+0x78/0x110 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fb5afe588db [CAUSE] In try_flush_qgroup(), we assume we don't hold a transaction handle at all. This is true for data reservation and mostly true for metadata. Since data space reservation always happens before we start a transaction, and for most metadata operation we reserve space in start_transaction(). But there is an exception, btrfs_delayed_inode_reserve_metadata(). It holds a transaction handle, while still trying to reserve extra metadata space. When we hit EDQUOT inside btrfs_delayed_inode_reserve_metadata(), we will join current transaction and commit, while we still have transaction handle from qgroup code. [FIX] Let's check current->journal before we join the transaction. If current->journal is unset or BTRFS_SEND_TRANS_STUB, it means we are not holding a transaction, thus are able to join and then commit transaction. If current->journal is a valid transaction handle, we avoid committing transaction and just end it This is less effective than committing current transaction, as it won't free metadata reserved space, but we may still free some data space before new data writes. Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1178634 Fixes: c53e965360 ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT") Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-11-13 22:17:57 +01:00
Dan Carpenter	f07728d541	btrfs: clean up NULL checks in qgroup_unreserve_range() ... Smatch complains that this code dereferences "entry" before checking whether it's NULL on the next line. Fortunately, rb_entry() will never return NULL so it doesn't cause a problem. We can clean up the NULL checking a bit to silence the warning and make the code more clear. Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-11-05 13:02:20 +01:00
Josef Bacik	5223cc60b4	btrfs: drop the path before adding qgroup items when enabling qgroups ... When enabling qgroups we walk the tree_root and then add a qgroup item for every root that we have. This creates a lock dependency on the tree_root and qgroup_root, which results in the following lockdep splat (with tree locks using rwsem), eg. in tests btrfs/017 or btrfs/022: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-default+ #1299 Not tainted ------------------------------------------------------ btrfs/24552 is trying to acquire lock: ffff9142dfc5f630 (btrfs-quota-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] but task is already holding lock: ffff9142dfc5d0b0 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-root-00){++++}-{3:3}: __lock_acquire+0x3fb/0x730 lock_acquire.part.0+0x6a/0x130 down_read_nested+0x46/0x130 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] __btrfs_read_lock_root_node+0x3a/0x50 [btrfs] btrfs_search_slot_get_root+0x11d/0x290 [btrfs] btrfs_search_slot+0xc3/0x9f0 [btrfs] btrfs_insert_item+0x6e/0x140 [btrfs] btrfs_create_tree+0x1cb/0x240 [btrfs] btrfs_quota_enable+0xcd/0x790 [btrfs] btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs] __x64_sys_ioctl+0x83/0xa0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (btrfs-quota-00){++++}-{3:3}: check_prev_add+0x91/0xc30 validate_chain+0x491/0x750 __lock_acquire+0x3fb/0x730 lock_acquire.part.0+0x6a/0x130 down_read_nested+0x46/0x130 __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] __btrfs_read_lock_root_node+0x3a/0x50 [btrfs] btrfs_search_slot_get_root+0x11d/0x290 [btrfs] btrfs_search_slot+0xc3/0x9f0 [btrfs] btrfs_insert_empty_items+0x58/0xa0 [btrfs] add_qgroup_item.part.0+0x72/0x210 [btrfs] btrfs_quota_enable+0x3bb/0x790 [btrfs] btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs] __x64_sys_ioctl+0x83/0xa0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-root-00); lock(btrfs-quota-00); lock(btrfs-root-00); lock(btrfs-quota-00); *** DEADLOCK *** 5 locks held by btrfs/24552: #0: ffff9142df431478 (sb_writers#10){.+.+}-{0:0}, at: mnt_want_write_file+0x22/0xa0 #1: ffff9142f9b10cc0 (&fs_info->subvol_sem){++++}-{3:3}, at: btrfs_ioctl_quota_ctl+0x7b/0xe0 [btrfs] #2: ffff9142f9b11a08 (&fs_info->qgroup_ioctl_lock){+.+.}-{3:3}, at: btrfs_quota_enable+0x3b/0x790 [btrfs] #3: ffff9142df431698 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x406/0x510 [btrfs] #4: ffff9142dfc5d0b0 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] stack backtrace: CPU: 1 PID: 24552 Comm: btrfs Not tainted 5.9.0-default+ #1299 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 Call Trace: dump_stack+0x77/0x97 check_noncircular+0xf3/0x110 check_prev_add+0x91/0xc30 validate_chain+0x491/0x750 __lock_acquire+0x3fb/0x730 lock_acquire.part.0+0x6a/0x130 ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] ? lock_acquire+0xc4/0x140 ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] down_read_nested+0x46/0x130 ? __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] __btrfs_tree_read_lock+0x35/0x1c0 [btrfs] ? btrfs_root_node+0xd9/0x200 [btrfs] __btrfs_read_lock_root_node+0x3a/0x50 [btrfs] btrfs_search_slot_get_root+0x11d/0x290 [btrfs] btrfs_search_slot+0xc3/0x9f0 [btrfs] btrfs_insert_empty_items+0x58/0xa0 [btrfs] add_qgroup_item.part.0+0x72/0x210 [btrfs] btrfs_quota_enable+0x3bb/0x790 [btrfs] btrfs_ioctl_quota_ctl+0xc9/0xe0 [btrfs] __x64_sys_ioctl+0x83/0xa0 do_syscall_64+0x2d/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by dropping the path whenever we find a root item, add the qgroup item, and then re-lookup the root item we found and continue processing roots. Reported-by: David Sterba <dsterba@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-10-26 15:04:57 +01:00
Randy Dunlap	260db43cd2	btrfs: delete duplicated words + other fixes in comments ... Delete repeated words in fs/btrfs/. {to, the, a, and old} and change "into 2 part" to "into 2 parts". Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-10-07 12:06:50 +02:00
Qu Wenruo	adca4d945c	btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT ... commit a514d63882 ("btrfs: qgroup: Commit transaction in advance to reduce early EDQUOT") tries to reduce the early EDQUOT problems by checking the qgroup free against threshold and tries to wake up commit kthread to free some space. The problem of that mechanism is, it can only free qgroup per-trans metadata space, can't do anything to data, nor prealloc qgroup space. Now since we have the ability to flush qgroup space, and implemented retry-after-EDQUOT behavior, such mechanism can be completely replaced. So this patch will cleanup such mechanism in favor of retry-after-EDQUOT. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:43 +02:00
Qu Wenruo	c53e965360	btrfs: qgroup: try to flush qgroup space when we get -EDQUOT ... [PROBLEM] There are known problem related to how btrfs handles qgroup reserved space. One of the most obvious case is the the test case btrfs/153, which do fallocate, then write into the preallocated range. btrfs/153 1s ... - output mismatch (see xfstests-dev/results//btrfs/153.out.bad) --- tests/btrfs/153.out 2019-10-22 15:18:14.068965341 +0800 +++ xfstests-dev/results//btrfs/153.out.bad 2020-07-01 20:24:40.730000089 +0800 @@ -1,2 +1,5 @@ QA output created by 153 +pwrite: Disk quota exceeded +/mnt/scratch/testfile2: Disk quota exceeded +/mnt/scratch/testfile2: Disk quota exceeded Silence is golden ... (Run 'diff -u xfstests-dev/tests/btrfs/153.out xfstests-dev/results//btrfs/153.out.bad' to see the entire diff) [CAUSE] Since commit c6887cd111 ("Btrfs: don't do nocow check unless we have to"), we always reserve space no matter if it's COW or not. Such behavior change is mostly for performance, and reverting it is not a good idea anyway. For preallcoated extent, we reserve qgroup data space for it already, and since we also reserve data space for qgroup at buffered write time, it needs twice the space for us to write into preallocated space. This leads to the -EDQUOT in buffered write routine. And we can't follow the same solution, unlike data/meta space check, qgroup reserved space is shared between data/metadata. The EDQUOT can happen at the metadata reservation, so doing NODATACOW check after qgroup reservation failure is not a solution. [FIX] To solve the problem, we don't return -EDQUOT directly, but every time we got a -EDQUOT, we try to flush qgroup space: - Flush all inodes of the root NODATACOW writes will free the qgroup reserved at run_dealloc_range(). However we don't have the infrastructure to only flush NODATACOW inodes, here we flush all inodes anyway. - Wait for ordered extents This would convert the preallocated metadata space into per-trans metadata, which can be freed in later transaction commit. - Commit transaction This will free all per-trans metadata space. Also we don't want to trigger flush multiple times, so here we introduce a per-root wait list and a new root status, to ensure only one thread starts the flushing. Fixes: c6887cd111 ("Btrfs: don't do nocow check unless we have to") Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:42 +02:00
Qu Wenruo	263da812e8	btrfs: qgroup: allow to unreserve range without releasing other ranges ... [PROBLEM] Before this patch, when btrfs_qgroup_reserve_data() fails, we free all reserved space of the changeset. For example: ret = btrfs_qgroup_reserve_data(inode, changeset, 0, SZ_1M); ret = btrfs_qgroup_reserve_data(inode, changeset, SZ_1M, SZ_1M); ret = btrfs_qgroup_reserve_data(inode, changeset, SZ_2M, SZ_1M); If the last btrfs_qgroup_reserve_data() failed, it will release the entire [0, 3M) range. This behavior is kind of OK for now, as when we hit -EDQUOT, we normally go error handling and need to release all reserved ranges anyway. But this also means the following call is not possible: ret = btrfs_qgroup_reserve_data(); if (ret == -EDQUOT) { /* Do something to free some qgroup space */ ret = btrfs_qgroup_reserve_data(); } As if the first btrfs_qgroup_reserve_data() fails, it will free all reserved qgroup space. [CAUSE] This is because we release all reserved ranges when btrfs_qgroup_reserve_data() fails. [FIX] This patch will implement a new function, qgroup_unreserve_range(), to iterate through the ulist nodes, to find any nodes in the failure range, and remove the EXTENT_QGROUP_RESERVED bits from the io_tree, and decrease the extent_changeset::bytes_changed, so that we can revert to previous state. This allows later patches to retry btrfs_qgroup_reserve_data() if EDQUOT happens. Suggested-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:42 +02:00
Qu Wenruo	49e5fb4621	btrfs: qgroup: export qgroups in sysfs ... This patch will add the following sysfs interface: /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/referenced /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/exclusive /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/max_referenced /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/max_exclusive /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/limit_flags Which is also available in output of "btrfs qgroup show". /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_data /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_meta_pertrans /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_meta_prealloc The last 3 rsv related members are not visible to users, but can be very useful to debug qgroup limit related bugs. Also, to avoid '/' used in <qgroup_id>, the separator between qgroup level and qgroup id is changed to '_'. The interface is not hidden behind 'debug' as we want this interface to be included into production build and to provide another way to read the qgroup information besides the ioctls. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:37 +02:00
Qu Wenruo	06f67c4707	btrfs: use __u16 for the return value of btrfs_qgroup_level() ... The qgroup level is limited to u16, so no need to use u64 for it. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:37 +02:00
Nikolay Borisov	cfdd459215	btrfs: make btrfs_qgroup_check_reserved_leak take btrfs_inode ... vfs_inode is used only for the inode number everything else requires btrfs_inode. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ use btrfs_ino ] Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:37 +02:00
Nikolay Borisov	7661a3e033	btrfs: make btrfs_qgroup_reserve_data take btrfs_inode ... There's only a single use of vfs_inode in a tracepoint so let's take btrfs_inode directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:35 +02:00
Nikolay Borisov	72b7d15bf1	btrfs: make btrfs_qgroup_release_data take btrfs_inode ... It just forwards its argument to __btrfs_qgroup_release_data. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:32 +02:00
Nikolay Borisov	8b8a979f1f	btrfs: make btrfs_qgroup_free_data take btrfs_inode ... It passes btrfs_inode to its callee so change the interface. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:30 +02:00
Nikolay Borisov	8769af96cf	btrfs: make __btrfs_qgroup_release_data take btrfs_inode ... It uses vfs_inode only for a tracepoint so convert its interface to take btrfs_inode directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:30 +02:00
Nikolay Borisov	df2cfd131f	btrfs: make qgroup_free_reserved_data take btrfs_inode ... It only uses btrfs_inode so can just as easily take it as an argument. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:30 +02:00
Qu Wenruo	5958253cf6	btrfs: qgroup: catch reserved space leaks at unmount time ... Before this patch, qgroup completely relies on per-inode extent io tree to detect reserved data space leak. However previous bug has already shown how release page before btrfs_finish_ordered_io() could lead to leak, and since it's QGROUP_RESERVED bit cleared without triggering qgroup rsv, it can't be detected by per-inode extent io tree. So this patch adds another (and hopefully the final) safety net to catch qgroup data reserved space leak. At least the new safety net catches all the leaks during development, so it should be pretty useful in the real world. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-07-27 12:55:24 +02:00
Qu Wenruo	cbab8ade58	btrfs: qgroup: mark qgroup inconsistent if we're inherting snapshot to a new qgroup ... [BUG] For the following operation, qgroup is guaranteed to be screwed up due to snapshot adding to a new qgroup: # mkfs.btrfs -f $dev # mount $dev $mnt # btrfs qgroup en $mnt # btrfs subv create $mnt/src # xfs_io -f -c "pwrite 0 1m" $mnt/src/file # sync # btrfs qgroup create 1/0 $mnt/src # btrfs subv snapshot -i 1/0 $mnt/src $mnt/snapshot # btrfs qgroup show -prce $mnt/src qgroupid rfer excl max_rfer max_excl parent child -------- ---- ---- -------- -------- ------ ----- 0/5 16.00KiB 16.00KiB none none --- --- 0/257 1.02MiB 16.00KiB none none --- --- 0/258 1.02MiB 16.00KiB none none 1/0 --- 1/0 0.00B 0.00B none none --- 0/258 ^^^^^^^^^^^^^^^^^^^^ [CAUSE] The problem is in btrfs_qgroup_inherit(), we don't have good enough check to determine if the new relation would break the existing accounting. Unlike btrfs_add_qgroup_relation(), which has proper check to determine if we can do quick update without a rescan, in btrfs_qgroup_inherit() we can even assign a snapshot to multiple qgroups. [FIX] Fix it by manually marking qgroup inconsistent for snapshot inheritance. For subvolume creation, since all its extents are exclusively owned, we don't need to rescan. In theory, we should call relation check like quick_update_accounting() when doing qgroup inheritance and inform user about qgroup accounting inconsistency. But we don't have good mechanism to relay that back to the user in the snapshot creation context, thus we can only silently mark the qgroup inconsistent. Anyway, user shouldn't use qgroup inheritance during snapshot creation, and should add qgroup relationship after snapshot creation by 'btrfs qgroup assign', which has a much better UI to inform user about qgroup inconsistent and kick in rescan automatically. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-05-25 11:25:29 +02:00
Josef Bacik	8c38938c7b	btrfs: move the root freeing stuff into btrfs_put_root ... There are a few different ways to free roots, either you allocated them yourself and you just do free_extent_buffer(root->node); free_extent_buffer(root->commit_node); btrfs_put_root(root); Which is the pattern for log roots. Or for snapshots/subvolumes that are being dropped you simply call btrfs_free_fs_root() which does all the cleanup for you. Unify this all into btrfs_put_root(), so that we don't free up things associated with the root until the last reference is dropped. This makes the root freeing code much more significant. The only caveat is at close_ctree() time we have to free the extent buffers for all of our main roots (extent_root, chunk_root, etc) because we have to drop the btree_inode and we'll run into issues if we hold onto those nodes until ->kill_sb() time. This will be addressed in the future when we kill the btree_inode. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-03-23 17:01:59 +01:00
Qu Wenruo	daf475c915	btrfs: qgroup: Remove the unnecesaary spin lock for qgroup_rescan_running ... After the previous patch, qgroup_rescan_running is protected by btrfs_fs_info::qgroup_rescan_lock, thus no need for the extra spinlock. Suggested-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>	2020-03-23 17:01:47 +01:00