kernel/linux.git/fs/btrfs/delayed-ref.c, branch linux-6.0.y

btrfs: switch btrfs_block_rsv::full to bool

2022-07-25T15:45:40+00:00

Use simple bool type for the block reserve full status, there's short to save space as there used to be int but there's no reason for that. Reviewed-by: Anand Jain Reviewed-by: Johannes Thumshirn Signed-off-by: David Sterba

btrfs: remove btrfs_delayed_extent_op::is_data

2022-05-16T15:17:31+00:00

The value of btrfs_delayed_extent_op::is_data is always false, we can cascade the change and simplify code that depends on it, removing the structure member eventually. Reviewed-by: Johannes Thumshirn Reviewed-by: Nikolay Borisov Signed-off-by: David Sterba

btrfs: reserve extra space for the free space tree

2022-01-07T13:18:25+00:00

Filipe reported a problem where sometimes he'd get an ENOSPC abort when running delayed refs with generic/619 and the free space tree enabled. This is partly because we do not reserve space for modifying the free space tree, nor do we have a block rsv associated with that tree. The delayed_refs_rsv tracks the amount of space required to run delayed refs. This means 1 modification means 1 change to the extent root. With the free space tree this turns into 2 changes, because modifying 1 extent means updating the extent tree and potentially updating the free space tree to either remove that entry or add the free space. Thus if we have the FST enabled, simply double the reservation size for our modification. Reviewed-by: Nikolay Borisov Signed-off-by: Josef Bacik Signed-off-by: David Sterba

btrfs: change root to fs_info for btrfs_reserve_metadata_bytes

2022-01-03T14:09:45+00:00

We used to need the root for btrfs_reserve_metadata_bytes to check the orphan cleanup state, but we no longer need that, we simply need the fs_info. Change btrfs_reserve_metadata_bytes() to use the fs_info, and change both btrfs_block_rsv_refill() and btrfs_block_rsv_add() to do the same as they simply call btrfs_reserve_metadata_bytes() and then manipulate the block_rsv that is being used. Reviewed-by: Nikolay Borisov Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: pull up qgroup checks from delayed-ref core to init time

2021-10-26T17:08:06+00:00

Instead of checking whether qgroup processing for a dealyed ref has to happen in the core of delayed ref, simply pull the check at init time of respective delayed ref structures. This eliminates the final use of real_root in delayed-ref core paving the way to making this member optional. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rely on owning_root field in btrfs_add_delayed_tree_ref to detect CHUNK_ROOT

2021-10-26T17:08:06+00:00

The real_root field is going to be used only by ref-verify tool so limit its use outside of it. Blocks belonging to the chunk root will always have it as an owner so the check is equivalent. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: rename root fields in delayed refs structs

2021-10-26T17:08:06+00:00

Both data and metadata delayed ref structures have fields named root/ref_root respectively. Those are somewhat cryptic and don't really convey the real meaning. In fact those roots are really the original owners of the respective block (i.e in case of a snapshot a data delayed ref will contain the original root that owns the given block). Rename those fields accordingly and adjust comments. Signed-off-by: Nikolay Borisov Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: fix lock inversion problem when doing qgroup extent tracing

2021-07-22T13:50:07+00:00

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 Signed-off-by: Filipe Manana Signed-off-by: David Sterba

btrfs: rip out btrfs_space_info::total_bytes_pinned

2021-06-22T12:55:25+00:00

We used this in may_commit_transaction() in order to determine if we needed to commit the transaction. However we no longer have that logic and thus have no use of this counter anymore, so delete it. Reviewed-by: Nikolay Borisov Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: update debug message when checking seq number of a delayed ref

2021-04-19T15:25:17+00:00

We used to encode two different numbers in the tree mod log counter used for sequence numbers, one in the upper 32 bits and the other one in the lower 32 bits. However that is no longer the case, we stopped doing that since commit fcebe4562dec83 ("Btrfs: rework qgroup accounting"). So update the debug message at btrfs_check_delayed_seq to stop extracting the two 32 bits counters and print instead the 64 bits sequence numbers. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba