user/sven/linux.git, branch v5.4.141

Linux 5.4.141

2021-08-15T11:08:06Z

Link: https://lore.kernel.org/r/20210813150523.364549385@linuxfoundation.org Tested-by: Shuah Khan Tested-by: Sudip Mukherjee Tested-by: Linux Kernel Functional Testing Tested-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

btrfs: don't flush from btrfs_delayed_inode_reserve_metadata

2021-08-15T11:08:06Z

commit 4d14c5cde5c268a2bc26addecf09489cb953ef64 upstream Calling btrfs_qgroup_reserve_meta_prealloc from btrfs_delayed_inode_reserve_metadata can result in flushing delalloc while holding a transaction and delayed node locks. This is deadlock prone. In the past multiple commits: * ae5e070eaca9 ("btrfs: qgroup: don't try to wait flushing if we're already holding a transaction") * 6f23277a49e6 ("btrfs: qgroup: don't commit transaction when we already hold the handle") Tried to solve various aspects of this but this was always a whack-a-mole game. Unfortunately those 2 fixes don't solve a deadlock scenario involving btrfs_delayed_node::mutex. Namely, one thread can call btrfs_dirty_inode as a result of reading a file and modifying its atime: PID: 6963 TASK: ffff8c7f3f94c000 CPU: 2 COMMAND: "test" #0 __schedule at ffffffffa529e07d #1 schedule at ffffffffa529e4ff #2 schedule_timeout at ffffffffa52a1bdd #3 wait_for_completion at ffffffffa529eeea <-- sleeps with delayed node mutex held #4 start_delalloc_inodes at ffffffffc0380db5 #5 btrfs_start_delalloc_snapshot at ffffffffc0393836 #6 try_flush_qgroup at ffffffffc03f04b2 #7 __btrfs_qgroup_reserve_meta at ffffffffc03f5bb6 <-- tries to reserve space and starts delalloc inodes. #8 btrfs_delayed_update_inode at ffffffffc03e31aa <-- acquires delayed node mutex #9 btrfs_update_inode at ffffffffc0385ba8 #10 btrfs_dirty_inode at ffffffffc038627b <-- TRANSACTIION OPENED #11 touch_atime at ffffffffa4cf0000 #12 generic_file_read_iter at ffffffffa4c1f123 #13 new_sync_read at ffffffffa4ccdc8a #14 vfs_read at ffffffffa4cd0849 #15 ksys_read at ffffffffa4cd0bd1 #16 do_syscall_64 at ffffffffa4a052eb #17 entry_SYSCALL_64_after_hwframe at ffffffffa540008c This will cause an asynchronous work to flush the delalloc inodes to happen which can try to acquire the same delayed_node mutex: PID: 455 TASK: ffff8c8085fa4000 CPU: 5 COMMAND: "kworker/u16:30" #0 __schedule at ffffffffa529e07d #1 schedule at ffffffffa529e4ff #2 schedule_preempt_disabled at ffffffffa529e80a #3 __mutex_lock at ffffffffa529fdcb <-- goes to sleep, never wakes up. #4 btrfs_delayed_update_inode at ffffffffc03e3143 <-- tries to acquire the mutex #5 btrfs_update_inode at ffffffffc0385ba8 <-- this is the same inode that pid 6963 is holding #6 cow_file_range_inline.constprop.78 at ffffffffc0386be7 #7 cow_file_range at ffffffffc03879c1 #8 btrfs_run_delalloc_range at ffffffffc038894c #9 writepage_delalloc at ffffffffc03a3c8f #10 __extent_writepage at ffffffffc03a4c01 #11 extent_write_cache_pages at ffffffffc03a500b #12 extent_writepages at ffffffffc03a6de2 #13 do_writepages at ffffffffa4c277eb #14 __filemap_fdatawrite_range at ffffffffa4c1e5bb #15 btrfs_run_delalloc_work at ffffffffc0380987 <-- starts running delayed nodes #16 normal_work_helper at ffffffffc03b706c #17 process_one_work at ffffffffa4aba4e4 #18 worker_thread at ffffffffa4aba6fd #19 kthread at ffffffffa4ac0a3d #20 ret_from_fork at ffffffffa54001ff To fully address those cases the complete fix is to never issue any flushing while holding the transaction or the delayed node lock. This patch achieves it by calling qgroup_reserve_meta directly which will either succeed without flushing or will fail and return -EDQUOT. In the latter case that return value is going to be propagated to btrfs_dirty_inode which will fallback to start a new transaction. That's fine as the majority of time we expect the inode will have BTRFS_DELAYED_NODE_INODE_DIRTY flag set which will result in directly copying the in-memory state. Fixes: c53e9653605d ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT") CC: stable@vger.kernel.org # 5.10+ Reviewed-by: Qu Wenruo Signed-off-by: Nikolay Borisov Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

btrfs: export and rename qgroup_reserve_meta

2021-08-15T11:08:06Z

commit 80e9baed722c853056e0c5374f51524593cb1031 upstream Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

btrfs: qgroup: don't commit transaction when we already hold the handle

2021-08-15T11:08:05Z

commit 6f23277a49e68f8a9355385c846939ad0b1261e7 upstream [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: c53e9653605d ("btrfs: qgroup: try to flush qgroup space when we get -EDQUOT") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

net: xilinx_emaclite: Do not print real IOMEM pointer

2021-08-15T11:08:05Z

commit d0d62baa7f505bd4c59cd169692ff07ec49dde37 upstream. Printing kernel pointers is discouraged because they might leak kernel memory layout. This fixes smatch warning: drivers/net/ethernet/xilinx/xilinx_emaclite.c:1191 xemaclite_of_probe() warn: argument 4 to %08lX specifier is cast from pointer Signed-off-by: YueHaibing Signed-off-by: David S. Miller Signed-off-by: Pavel Machek (CIP) Signed-off-by: Greg Kroah-Hartman

btrfs: fix lockdep splat when enabling and disabling qgroups

2021-08-15T11:08:05Z

commit a855fbe69229078cd8aecd8974fb996a5ca651e6 upstream 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 Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Conflicts: fs/btrfs/qgroup.c Signed-off-by: Greg Kroah-Hartman

btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT

2021-08-15T11:08:05Z

commit adca4d945c8dca28a85df45c5b117e6dac2e77f1 upstream commit a514d63882c3 ("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 Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

btrfs: transaction: Cleanup unused TRANS_STATE_BLOCKED

2021-08-15T11:08:05Z

commit 3296bf562443a8ca35aaad959a76a49e9b412760 upstream The state was introduced in commit 4a9d8bdee368 ("Btrfs: make the state of the transaction more readable"), then in commit 302167c50b32 ("btrfs: don't end the transaction for delayed refs in throttle") the state is completely removed. So we can just clean up the state since it's only compared but never set. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

btrfs: qgroup: try to flush qgroup space when we get -EDQUOT

2021-08-15T11:08:05Z

commit c53e9653605dbf708f5be02902de51831be4b009 upstream [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 c6887cd11149 ("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: c6887cd11149 ("Btrfs: don't do nocow check unless we have to") Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman

btrfs: qgroup: allow to unreserve range without releasing other ranges

2021-08-15T11:08:05Z

commit 263da812e87bac4098a4778efaa32c54275641db upstream [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 Reviewed-by: Josef Bacik Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman