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2021-02-21Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+1
Pull core block updates from Jens Axboe: "Another nice round of removing more code than what is added, mostly due to Christoph's relentless pursuit of tech debt removal/cleanups. This pull request contains: - Two series of BFQ improvements (Paolo, Jan, Jia) - Block iov_iter improvements (Pavel) - bsg error path fix (Pan) - blk-mq scheduler improvements (Jan) - -EBUSY discard fix (Jan) - bvec allocation improvements (Ming, Christoph) - bio allocation and init improvements (Christoph) - Store bdev pointer in bio instead of gendisk + partno (Christoph) - Block trace point cleanups (Christoph) - hard read-only vs read-only split (Christoph) - Block based swap cleanups (Christoph) - Zoned write granularity support (Damien) - Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)" * tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits) mm: simplify swapdev_block sd_zbc: clear zone resources for non-zoned case block: introduce blk_queue_clear_zone_settings() zonefs: use zone write granularity as block size block: introduce zone_write_granularity limit block: use blk_queue_set_zoned in add_partition() nullb: use blk_queue_set_zoned() to setup zoned devices nvme: cleanup zone information initialization block: document zone_append_max_bytes attribute block: use bi_max_vecs to find the bvec pool md/raid10: remove dead code in reshape_request block: mark the bio as cloned in bio_iov_bvec_set block: set BIO_NO_PAGE_REF in bio_iov_bvec_set block: remove a layer of indentation in bio_iov_iter_get_pages block: turn the nr_iovecs argument to bio_alloc* into an unsigned short block: remove the 1 and 4 vec bvec_slabs entries block: streamline bvec_alloc block: factor out a bvec_alloc_gfp helper block: move struct biovec_slab to bio.c block: reuse BIO_INLINE_VECS for integrity bvecs ...
2021-02-09btrfs: zoned: relocate block group to repair IO failure in zoned filesystemsNaohiro Aota1-0/+72
When a bad checksum is found and if the filesystem has a mirror of the damaged data, we read the correct data from the mirror and writes it to damaged blocks. This however, violates the sequential write constraints of a zoned block device. We can consider three methods to repair an IO failure in zoned filesystems: (1) Reset and rewrite the damaged zone (2) Allocate new device extent and replace the damaged device extent to the new extent (3) Relocate the corresponding block group Method (1) is most similar to a behavior done with regular devices. However, it also wipes non-damaged data in the same device extent, and so it unnecessary degrades non-damaged data. Method (2) is much like device replacing but done in the same device. It is safe because it keeps the device extent until the replacing finish. However, extending device replacing is non-trivial. It assumes "src_dev->physical == dst_dev->physical". Also, the extent mapping replacing function should be extended to support replacing device extent position in one device. Method (3) invokes relocation of the damaged block group and is straightforward to implement. It relocates all the mirrored device extents, so it potentially is a more costly operation than method (1) or (2). But it relocates only used extents which reduce the total IO size. Let's apply method (3) for now. In the future, we can extend device-replace and apply method (2). For protecting a block group gets relocated multiple time with multiple IO errors, this commit introduces "relocating_repair" bit to show it's now relocating to repair IO failures. Also it uses a new kthread "btrfs-relocating-repair", not to block IO path with relocating process. This commit also supports repairing in the scrub process. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: implement copying for zoned device-replaceNaohiro Aota1-1/+1
This is 3/4 patch to implement device-replace on zoned filesystems. This commit implements copying. To do this, it tracks the write pointer during the device replace process. As device-replace's copy process is smart enough to only copy used extents on the source device, we have to fill the gap to honor the sequential write requirement in the target device. The device-replace process on zoned filesystems must copy or clone all the extents in the source device exactly once. So, we need to ensure allocations started just before the dev-replace process to have their corresponding extent information in the B-trees. finish_extent_writes_for_zoned() implements that functionality, which basically is the removed code in the commit 042528f8d840 ("Btrfs: fix block group remaining RO forever after error during device replace"). Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: implement cloning for zoned device-replaceNaohiro Aota1-2/+29
This is 2/4 patch to implement device replace for zoned filesystems. In zoned mode, a block group must be either copied (from the source device to the target device) or cloned (to both devices). Implement the cloning part. If a block group targeted by an IO is marked to copy, we should not clone the IO to the destination device, because the block group is eventually copied by the replace process. This commit also handles cloning of device reset. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: use ZONE_APPEND write for zoned modeNaohiro Aota1-0/+14
Enable zone append writing for zoned mode. When using zone append, a bio is issued to the start of a target zone and the device decides to place it inside the zone. Upon completion the device reports the actual written position back to the host. Three parts are necessary to enable zone append mode. First, modify the bio to use REQ_OP_ZONE_APPEND in btrfs_submit_bio_hook() and adjust the bi_sector to point the beginning of the zone. Second, record the returned physical address (and disk/partno) to the ordered extent in end_bio_extent_writepage() after the bio has been completed. We cannot resolve the physical address to the logical address because we can neither take locks nor allocate a buffer in this end_bio context. So, we need to record the physical address to resolve it later in btrfs_finish_ordered_io(). And finally, rewrite the logical addresses of the extent mapping and checksum data according to the physical address using btrfs_rmap_block. If the returned address matches the originally allocated address, we can skip this rewriting process. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: handle REQ_OP_ZONE_APPEND as writingNaohiro Aota1-4/+4
Zoned filesystems use REQ_OP_ZONE_APPEND bios for writing to actual devices. Let btrfs_end_bio() and btrfs_op be aware of it, by mapping REQ_OP_ZONE_APPEND to BTRFS_MAP_WRITE and using btrfs_op() instead of bio_op(). Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: verify device extent is aligned to zoneNaohiro Aota1-0/+14
Add a check in verify_one_dev_extent() to ensure that a device extent on a zoned block device is aligned to the respective zone boundary. If it isn't, mark the filesystem as unclean. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: implement zoned chunk allocatorNaohiro Aota1-17/+154
Implement a zoned chunk and device extent allocator. One device zone becomes a device extent so that a zone reset affects only this device extent and does not change the state of blocks in the neighbor device extents. To implement the allocator, we need to extend the following functions for a zoned filesystem. - init_alloc_chunk_ctl - dev_extent_search_start - dev_extent_hole_check - decide_stripe_size init_alloc_chunk_ctl_zoned() is mostly the same as regular one. It always set the stripe_size to the zone size and aligns the parameters to the zone size. dev_extent_search_start() only aligns the start offset to zone boundaries. We don't care about the first 1MB like in regular filesystem because we anyway reserve the first two zones for superblock logging. dev_extent_hole_check_zoned() checks if zones in given hole are either conventional or empty sequential zones. Also, it skips zones reserved for superblock logging. With the change to the hole, the new hole may now contain pending extents. So, in this case, loop again to check that. Finally, decide_stripe_size_zoned() should shrink the number of devices instead of stripe size because we need to honor stripe_size == zone_size. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-09btrfs: zoned: defer loading zone info after opening treesNaohiro Aota1-4/+0
This is a preparation patch to implement zone emulation on a regular device. To emulate a zoned filesystem on a regular (non-zoned) device, we need to decide an emulated zone size. Instead of making it a compile-time static value, we'll make it configurable at mkfs time. Since we have one zone == one device extent restriction, we can determine the emulated zone size from the size of a device extent. We can extend btrfs_get_dev_zone_info() to show a regular device filled with conventional zones once the zone size is decided. The current call site of btrfs_get_dev_zone_info() during the mount process is earlier than loading the file system trees so that we don't know the size of a device extent at this point. Thus we can't slice a regular device to conventional zones. This patch introduces btrfs_get_dev_zone_info_all_devices to load the zone info for all the devices. And, it places this function in open_ctree() after loading the trees. Reviewed-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08btrfs: let callers of btrfs_get_io_geometry pass the emMichal Rostecki1-25/+18
Before this change, the btrfs_get_io_geometry() function was calling btrfs_get_chunk_map() to get the extent mapping, necessary for calculating the I/O geometry. It was using that extent mapping only internally and freeing the pointer after its execution. That resulted in calling btrfs_get_chunk_map() de facto twice by the __btrfs_map_block() function. It was calling btrfs_get_io_geometry() first and then calling btrfs_get_chunk_map() directly to get the extent mapping, used by the rest of the function. Change that to passing the extent mapping to the btrfs_get_io_geometry() function as an argument. This could improve performance in some cases. For very large filesystems, i.e. several thousands of allocated chunks, not only this avoids searching two times the rbtree, saving time, it may also help reducing contention on the lock that protects the tree - thinking of writeback starting for multiple inodes, other tasks allocating or removing chunks, and anything else that requires access to the rbtree. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Michal Rostecki <mrostecki@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add Filipe's analysis ] Signed-off-by: David Sterba <dsterba@suse.com>
2021-02-08btrfs: consolidate btrfs_previous_item ret val handling in btrfs_shrink_deviceNikolay Borisov1-4/+3
Instead of having three 'if' to handle non-NULL return value consolidate this in one 'if (ret)'. That way the code is more obvious: - Always drop delete_unused_bgs_mutex if ret is not NULL - If ret is negative -> goto done - If it's 1 -> reset ret to 0, release the path and finish the loop. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-29Merge tag 'for-5.11-rc5-tag' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "A few more fixes for a late rc: - fix lockdep complaint on 32bit arches and also remove an unsafe memory use due to device vs filesystem lifetime - two fixes for free space tree: * race during log replay and cache rebuild, now more likely to happen due to changes in this dev cycle * possible free space tree corruption with online conversion during initial tree population" * tag 'for-5.11-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: fix log replay failure due to race with space cache rebuild btrfs: fix lockdep warning due to seqcount_mutex on 32bit arch btrfs: fix possible free space tree corruption with online conversion
2021-01-27btrfs: use bio_kmalloc in __alloc_deviceChristoph Hellwig1-1/+1
Use bio_kmalloc instead of open coding it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Acked-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-01-25btrfs: fix lockdep warning due to seqcount_mutex on 32bit archSu Yue1-1/+1
This effectively reverts commit d5c8238849e7 ("btrfs: convert data_seqcount to seqcount_mutex_t"). While running fstests on 32 bits test box, many tests failed because of warnings in dmesg. One of those warnings (btrfs/003): [66.441317] WARNING: CPU: 6 PID: 9251 at include/linux/seqlock.h:279 btrfs_remove_chunk+0x58b/0x7b0 [btrfs] [66.441446] CPU: 6 PID: 9251 Comm: btrfs Tainted: G O 5.11.0-rc4-custom+ #5 [66.441449] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.14.0-1 04/01/2014 [66.441451] EIP: btrfs_remove_chunk+0x58b/0x7b0 [btrfs] [66.441472] EAX: 00000000 EBX: 00000001 ECX: c576070c EDX: c6b15803 [66.441475] ESI: 10000000 EDI: 00000000 EBP: c56fbcfc ESP: c56fbc70 [66.441477] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00010246 [66.441481] CR0: 80050033 CR2: 05c8da20 CR3: 04b20000 CR4: 00350ed0 [66.441485] Call Trace: [66.441510] btrfs_relocate_chunk+0xb1/0x100 [btrfs] [66.441529] ? btrfs_lookup_block_group+0x17/0x20 [btrfs] [66.441562] btrfs_balance+0x8ed/0x13b0 [btrfs] [66.441586] ? btrfs_ioctl_balance+0x333/0x3c0 [btrfs] [66.441619] ? __this_cpu_preempt_check+0xf/0x11 [66.441643] btrfs_ioctl_balance+0x333/0x3c0 [btrfs] [66.441664] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [66.441683] btrfs_ioctl+0x414/0x2ae0 [btrfs] [66.441700] ? __lock_acquire+0x35f/0x2650 [66.441717] ? lockdep_hardirqs_on+0x87/0x120 [66.441720] ? lockdep_hardirqs_on_prepare+0xd0/0x1e0 [66.441724] ? call_rcu+0x2d3/0x530 [66.441731] ? __might_fault+0x41/0x90 [66.441736] ? kvm_sched_clock_read+0x15/0x50 [66.441740] ? sched_clock+0x8/0x10 [66.441745] ? sched_clock_cpu+0x13/0x180 [66.441750] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [66.441750] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [66.441768] __ia32_sys_ioctl+0x165/0x8a0 [66.441773] ? __this_cpu_preempt_check+0xf/0x11 [66.441785] ? __might_fault+0x89/0x90 [66.441791] __do_fast_syscall_32+0x54/0x80 [66.441796] do_fast_syscall_32+0x32/0x70 [66.441801] do_SYSENTER_32+0x15/0x20 [66.441805] entry_SYSENTER_32+0x9f/0xf2 [66.441808] EIP: 0xab7b5549 [66.441814] EAX: ffffffda EBX: 00000003 ECX: c4009420 EDX: bfa91f5c [66.441816] ESI: 00000003 EDI: 00000001 EBP: 00000000 ESP: bfa91e98 [66.441818] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00000292 [66.441833] irq event stamp: 42579 [66.441835] hardirqs last enabled at (42585): [<c60eb065>] console_unlock+0x495/0x590 [66.441838] hardirqs last disabled at (42590): [<c60eafd5>] console_unlock+0x405/0x590 [66.441840] softirqs last enabled at (41698): [<c601b76c>] call_on_stack+0x1c/0x60 [66.441843] softirqs last disabled at (41681): [<c601b76c>] call_on_stack+0x1c/0x60 ======================================================================== btrfs_remove_chunk+0x58b/0x7b0: __seqprop_mutex_assert at linux/./include/linux/seqlock.h:279 (inlined by) btrfs_device_set_bytes_used at linux/fs/btrfs/volumes.h:212 (inlined by) btrfs_remove_chunk at linux/fs/btrfs/volumes.c:2994 ======================================================================== The warning is produced by lockdep_assert_held() in __seqprop_mutex_assert() if CONFIG_LOCKDEP is enabled. And "olumes.c:2994 is btrfs_device_set_bytes_used() with mutex lock fs_info->chunk_mutex held already. After adding some debug prints, the cause was found that many __alloc_device() are called with NULL @fs_info (during scanning ioctl). Inside the function, btrfs_device_data_ordered_init() is expanded to seqcount_mutex_init(). In this scenario, its second parameter info->chunk_mutex is &NULL->chunk_mutex which equals to offsetof(struct btrfs_fs_info, chunk_mutex) unexpectedly. Thus, seqcount_mutex_init() is called in wrong way. And later btrfs_device_get/set helpers trigger lockdep warnings. The device and filesystem object lifetimes are different and we'd have to synchronize initialization of the btrfs_device::data_seqcount with the fs_info, possibly using some additional synchronization. It would still not prevent concurrent access to the seqcount lock when it's used for read and initialization. Commit d5c8238849e7 ("btrfs: convert data_seqcount to seqcount_mutex_t") does not mention a particular problem being fixed so revert should not cause any harm and we'll get the lockdep warning fixed. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=210139 Reported-by: Erhard F <erhard_f@mailbox.org> Fixes: d5c8238849e7 ("btrfs: convert data_seqcount to seqcount_mutex_t") CC: stable@vger.kernel.org # 5.10 CC: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Su Yue <l@damenly.su> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-20Merge tag 'for-5.11-rc4-tag' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "A few more one line fixes for various bugs, stable material. - fix send when emitting clone operation from the same file and root - fix double free on error when cleaning backrefs - lockdep fix during relocation - handle potential error during reloc when starting transaction - skip running delayed refs during commit (leftover from code removal in this dev cycle)" * tag 'for-5.11-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: don't clear ret in btrfs_start_dirty_block_groups btrfs: fix lockdep splat in btrfs_recover_relocation btrfs: do not double free backref nodes on error btrfs: don't get an EINTR during drop_snapshot for reloc btrfs: send: fix invalid clone operations when cloning from the same file and root btrfs: no need to run delayed refs after commit_fs_roots during commit
2021-01-18btrfs: fix lockdep splat in btrfs_recover_relocationJosef Bacik1-0/+2
While testing the error paths of relocation I hit the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.10.0-rc6+ #217 Not tainted ------------------------------------------------------ mount/779 is trying to acquire lock: ffffa0e676945418 (&fs_info->balance_mutex){+.+.}-{3:3}, at: btrfs_recover_balance+0x2f0/0x340 but task is already holding lock: ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-root-00){++++}-{3:3}: down_read_nested+0x43/0x130 __btrfs_tree_read_lock+0x27/0x100 btrfs_read_lock_root_node+0x31/0x40 btrfs_search_slot+0x462/0x8f0 btrfs_update_root+0x55/0x2b0 btrfs_drop_snapshot+0x398/0x750 clean_dirty_subvols+0xdf/0x120 btrfs_recover_relocation+0x534/0x5a0 btrfs_start_pre_rw_mount+0xcb/0x170 open_ctree+0x151f/0x1726 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (sb_internal#2){.+.+}-{0:0}: start_transaction+0x444/0x700 insert_balance_item.isra.0+0x37/0x320 btrfs_balance+0x354/0xf40 btrfs_ioctl_balance+0x2cf/0x380 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_info->balance_mutex){+.+.}-{3:3}: __lock_acquire+0x1120/0x1e10 lock_acquire+0x116/0x370 __mutex_lock+0x7e/0x7b0 btrfs_recover_balance+0x2f0/0x340 open_ctree+0x1095/0x1726 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &fs_info->balance_mutex --> sb_internal#2 --> btrfs-root-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-root-00); lock(sb_internal#2); lock(btrfs-root-00); lock(&fs_info->balance_mutex); *** DEADLOCK *** 2 locks held by mount/779: #0: ffffa0e60dc040e0 (&type->s_umount_key#47/1){+.+.}-{3:3}, at: alloc_super+0xb5/0x380 #1: ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100 stack backtrace: CPU: 0 PID: 779 Comm: mount Not tainted 5.10.0-rc6+ #217 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb0 check_noncircular+0xcf/0xf0 ? trace_call_bpf+0x139/0x260 __lock_acquire+0x1120/0x1e10 lock_acquire+0x116/0x370 ? btrfs_recover_balance+0x2f0/0x340 __mutex_lock+0x7e/0x7b0 ? btrfs_recover_balance+0x2f0/0x340 ? btrfs_recover_balance+0x2f0/0x340 ? rcu_read_lock_sched_held+0x3f/0x80 ? kmem_cache_alloc_trace+0x2c4/0x2f0 ? btrfs_get_64+0x5e/0x100 btrfs_recover_balance+0x2f0/0x340 open_ctree+0x1095/0x1726 btrfs_mount_root.cold+0x12/0xea ? rcu_read_lock_sched_held+0x3f/0x80 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 ? __kmalloc_track_caller+0x2f2/0x320 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 ? capable+0x3a/0x60 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is straightforward to fix, simply release the path before we setup the balance_ctl. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2021-01-06Merge tag 'for-5.11-rc2-tag' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "A few more fixes that arrived before the end of the year: - a bunch of fixes related to transaction handle lifetime wrt various operations (umount, remount, qgroup scan, orphan cleanup) - async discard scheduling fixes - fix item size calculation when item keys collide for extend refs (hardlinks) - fix qgroup flushing from running transaction - fix send, wrong file path when there is an inode with a pending rmdir - fix deadlock when cloning inline extent and low on free metadata space" * tag 'for-5.11-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: run delayed iputs when remounting RO to avoid leaking them btrfs: add assertion for empty list of transactions at late stage of umount btrfs: fix race between RO remount and the cleaner task btrfs: fix transaction leak and crash after cleaning up orphans on RO mount btrfs: fix transaction leak and crash after RO remount caused by qgroup rescan btrfs: merge critical sections of discard lock in workfn btrfs: fix racy access to discard_ctl data btrfs: fix async discard stall btrfs: tests: initialize test inodes location btrfs: send: fix wrong file path when there is an inode with a pending rmdir btrfs: qgroup: don't try to wait flushing if we're already holding a transaction btrfs: correctly calculate item size used when item key collision happens btrfs: fix deadlock when cloning inline extent and low on free metadata space
2020-12-18btrfs: fix race between RO remount and the cleaner taskFilipe Manana1-2/+2
When we are remounting a filesystem in RO mode we can race with the cleaner task and result in leaking a transaction if the filesystem is unmounted shortly after, before the transaction kthread had a chance to commit that transaction. That also results in a crash during unmount, due to a use-after-free, if hardware acceleration is not available for crc32c. The following sequence of steps explains how the race happens. 1) The filesystem is mounted in RW mode and the cleaner task is running. This means that currently BTRFS_FS_CLEANER_RUNNING is set at fs_info->flags; 2) The cleaner task is currently running delayed iputs for example; 3) A filesystem RO remount operation starts; 4) The RO remount task calls btrfs_commit_super(), which commits any currently open transaction, and it finishes; 5) At this point the cleaner task is still running and it creates a new transaction by doing one of the following things: * When running the delayed iput() for an inode with a 0 link count, in which case at btrfs_evict_inode() we start a transaction through the call to evict_refill_and_join(), use it and then release its handle through btrfs_end_transaction(); * When deleting a dead root through btrfs_clean_one_deleted_snapshot(), a transaction is started at btrfs_drop_snapshot() and then its handle is released through a call to btrfs_end_transaction_throttle(); * When the remount task was still running, and before the remount task called btrfs_delete_unused_bgs(), the cleaner task also called btrfs_delete_unused_bgs() and it picked and removed one block group from the list of unused block groups. Before the cleaner task started a transaction, through btrfs_start_trans_remove_block_group() at btrfs_delete_unused_bgs(), the remount task had already called btrfs_commit_super(); 6) So at this point the filesystem is in RO mode and we have an open transaction that was started by the cleaner task; 7) Shortly after a filesystem unmount operation starts. At close_ctree() we stop the transaction kthread before it had a chance to commit the transaction, since less than 30 seconds (the default commit interval) have elapsed since the last transaction was committed; 8) We end up calling iput() against the btree inode at close_ctree() while there is an open transaction, and since that transaction was used to update btrees by the cleaner, we have dirty pages in the btree inode due to COW operations on metadata extents, and therefore writeback is triggered for the btree inode. So btree_write_cache_pages() is invoked to flush those dirty pages during the final iput() on the btree inode. This results in creating a bio and submitting it, which makes us end up at btrfs_submit_metadata_bio(); 9) 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; 10) 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 So fix this by making the remount path to wait for the cleaner task before calling btrfs_commit_super(). The remount path now waits for the bit BTRFS_FS_CLEANER_RUNNING to be cleared from fs_info->flags before calling btrfs_commit_super() and this ensures the cleaner can not start a transaction after that, because it sleeps when the filesystem is in RO mode and we have already flagged the filesystem as RO before waiting for BTRFS_FS_CLEANER_RUNNING to be cleared. This also introduces a new flag BTRFS_FS_STATE_RO to be used for fs_info->fs_state when the filesystem is in RO mode. This is because we were doing the RO check using the flags of the superblock and setting the RO mode simply by ORing into the superblock's flags - those operations are not atomic and could result in the cleaner not seeing the update from the remount task after it clears BTRFS_FS_CLEANER_RUNNING. 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>
2020-12-16Merge tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-blockLinus Torvalds1-7/+6
Pull block updates from Jens Axboe: "Another series of killing more code than what is being added, again thanks to Christoph's relentless cleanups and tech debt tackling. This contains: - blk-iocost improvements (Baolin Wang) - part0 iostat fix (Jeffle Xu) - Disable iopoll for split bios (Jeffle Xu) - block tracepoint cleanups (Christoph Hellwig) - Merging of struct block_device and hd_struct (Christoph Hellwig) - Rework/cleanup of how block device sizes are updated (Christoph Hellwig) - Simplification of gendisk lookup and removal of block device aliasing (Christoph Hellwig) - Block device ioctl cleanups (Christoph Hellwig) - Removal of bdget()/blkdev_get() as exported API (Christoph Hellwig) - Disk change rework, avoid ->revalidate_disk() (Christoph Hellwig) - sbitmap improvements (Pavel Begunkov) - Hybrid polling fix (Pavel Begunkov) - bvec iteration improvements (Pavel Begunkov) - Zone revalidation fixes (Damien Le Moal) - blk-throttle limit fix (Yu Kuai) - Various little fixes" * tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block: (126 commits) blk-mq: fix msec comment from micro to milli seconds blk-mq: update arg in comment of blk_mq_map_queue blk-mq: add helper allocating tagset->tags Revert "block: Fix a lockdep complaint triggered by request queue flushing" nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class blk-mq: add new API of blk_mq_hctx_set_fq_lock_class block: disable iopoll for split bio block: Improve blk_revalidate_disk_zones() checks sbitmap: simplify wrap check sbitmap: replace CAS with atomic and sbitmap: remove swap_lock sbitmap: optimise sbitmap_deferred_clear() blk-mq: skip hybrid polling if iopoll doesn't spin blk-iocost: Factor out the base vrate change into a separate function blk-iocost: Factor out the active iocgs' state check into a separate function blk-iocost: Move the usage ratio calculation to the correct place blk-iocost: Remove unnecessary advance declaration blk-iocost: Fix some typos in comments blktrace: fix up a kerneldoc comment block: remove the request_queue to argument request based tracepoints ...
2020-12-09btrfs: drop casts of bio bi_sectorDavid Sterba1-2/+2
Since commit 72deb455b5ec ("block: remove CONFIG_LBDAF") (5.2) the sector_t type is u64 on all arches and configs so we don't need to typecast it. It used to be unsigned long and the result of sector size shifts were not guaranteed to fit in the type. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: implement log-structured superblock for ZONED modeNaohiro Aota1-5/+15
Superblock (and its copies) is the only data structure in btrfs which has a fixed location on a device. Since we cannot overwrite in a sequential write required zone, we cannot place superblock in the zone. One easy solution is limiting superblock and copies to be placed only in conventional zones. However, this method has two downsides: one is reduced number of superblock copies. The location of the second copy of superblock is 256GB, which is in a sequential write required zone on typical devices in the market today. So, the number of superblock and copies is limited to be two. Second downside is that we cannot support devices which have no conventional zones at all. To solve these two problems, we employ superblock log writing. It uses two adjacent zones as a circular buffer to write updated superblocks. Once the first zone is filled up, start writing into the second one. Then, when both zones are filled up and before starting to write to the first zone again, it reset the first zone. We can determine the position of the latest superblock by reading write pointer information from a device. One corner case is when both zones are full. For this situation, we read out the last superblock of each zone, and compare them to determine which zone is older. The following zones are reserved as the circular buffer on ZONED btrfs. - The primary superblock: zones 0 and 1 - The first copy: zones 16 and 17 - The second copy: zones 1024 or zone at 256GB which is minimum, and next to it If these reserved zones are conventional, superblock is written fixed at the start of the zone without logging. Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: check and enable ZONED modeNaohiro Aota1-0/+5
Introduce function btrfs_check_zoned_mode() to check if ZONED flag is enabled on the file system and if the file system consists of zoned devices with equal zone size. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-09btrfs: get zone information of zoned block devicesNaohiro Aota1-3/+17
If a zoned block device is found, get its zone information (number of zones and zone size). To avoid costly run-time zone report commands to test the device zones type during block allocation, attach the seq_zones bitmap to the device structure to indicate if a zone is sequential or accept random writes. Also it attaches the empty_zones bitmap to indicate if a zone is empty or not. This patch also introduces the helper function btrfs_dev_is_sequential() to test if the zone storing a block is a sequential write required zone and btrfs_dev_is_empty_zone() to test if the zone is a empty zone. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: remove unused argument seed from btrfs_find_deviceAnand Jain1-12/+10
Commit 343694eee8d8 ("btrfs: switch seed device to list api"), missed to check if the parameter seed is true in the function btrfs_find_device(). This tells it whether to traverse the seed device list or not. After this commit, the argument is unused and can be removed. In device_list_add() it's not necessary because fs_devices always points to the device's fs_devices. So with the devid+uuid matching, it will find the right device and return, thus not needing to traverse seed devices. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: drop never met disk total bytes check in verify_one_dev_extentAnand Jain1-15/+10
Drop the condition in verify_one_dev_extent, btrfs_device::disk_total_bytes is set even for a seed device. The comment is wrong, the size is properly set when cloning the device. Commit 1b3922a8bc74 ("btrfs: Use real device structure to verify dev extent") introduced it but it's unclear why the total_disk_bytes was 0. Theoretically, all devices (including missing and seed) marked with the BTRFS_DEV_STATE_IN_FS_METADATA flag gets the total_disk_bytes updated at fill_device_from_item(): open_ctree() btrfs_read_chunk_tree() read_one_dev() open_seed_device() fill_device_from_item() Even if verify_one_dev_extent() reports total_disk_bytes == 0, then its a bug to be fixed somewhere else and not in verify_one_dev_extent() as it's just a messenger. It is never expected that a total_disk_bytes shall be zero. The function fill_device_from_item() does the job of reading it from the item and updating btrfs_device::disk_total_bytes. So both the missing device and the seed devices do have their disk_total_bytes updated. btrfs_find_device can also return a device from fs_info->seed_list because it searches it as well. Furthermore, while removing the device if there is a power loss, we could have a device with its total_bytes = 0, that's still valid. Instead, introduce a check against maximum block device size in read_one_dev(). Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: drop unused argument step from btrfs_free_extra_devidsAnand Jain1-4/+4
Commit cf89af146b7e ("btrfs: dev-replace: fail mount if we don't have replace item with target device") dropped the multi stage operation of btrfs_free_extra_devids() that does not need to check replace target anymore and we can remove the 'step' argument. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: set the lockdep class for extent buffers on creationJosef Bacik1-1/+0
Both Filipe and Fedora QA recently hit the following lockdep splat: WARNING: possible recursive locking detected 5.10.0-0.rc1.20201028gited8780e3f2ec.57.fc34.x86_64 #1 Not tainted -------------------------------------------- rsync/2610 is trying to acquire lock: ffff89617ed48f20 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 but task is already holding lock: ffff8961757b1130 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&eb->lock); lock(&eb->lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by rsync/2610: #0: ffff896107212b90 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: walk_component+0x10c/0x190 #1: ffff8961757b1130 (&eb->lock){++++}-{2:2}, at: btrfs_tree_read_lock_atomic+0x34/0x140 stack backtrace: CPU: 1 PID: 2610 Comm: rsync Not tainted 5.10.0-0.rc1.20201028gited8780e3f2ec.57.fc34.x86_64 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack+0x8b/0xb0 __lock_acquire.cold+0x12d/0x2a4 ? kvm_sched_clock_read+0x14/0x30 ? sched_clock+0x5/0x10 lock_acquire+0xc8/0x400 ? btrfs_tree_read_lock_atomic+0x34/0x140 ? read_block_for_search.isra.0+0xdd/0x320 _raw_read_lock+0x3d/0xa0 ? btrfs_tree_read_lock_atomic+0x34/0x140 btrfs_tree_read_lock_atomic+0x34/0x140 btrfs_search_slot+0x616/0x9a0 btrfs_lookup_dir_item+0x6c/0xb0 btrfs_lookup_dentry+0xa8/0x520 ? lockdep_init_map_waits+0x4c/0x210 btrfs_lookup+0xe/0x30 __lookup_slow+0x10f/0x1e0 walk_component+0x11b/0x190 path_lookupat+0x72/0x1c0 filename_lookup+0x97/0x180 ? strncpy_from_user+0x96/0x1e0 ? getname_flags.part.0+0x45/0x1a0 vfs_statx+0x64/0x100 ? lockdep_hardirqs_on_prepare+0xff/0x180 ? _raw_spin_unlock_irqrestore+0x41/0x50 __do_sys_newlstat+0x26/0x40 ? lockdep_hardirqs_on_prepare+0xff/0x180 ? syscall_enter_from_user_mode+0x27/0x80 ? syscall_enter_from_user_mode+0x27/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 I have also seen a report of lockdep complaining about the lock class that was looked up being the same as the lock class on the lock we were using, but I can't find the report. These are problems that occur because we do not have the lockdep class set on the extent buffer until _after_ we read the eb in properly. This is problematic for concurrent readers, because we will create the extent buffer, lock it, and then attempt to read the extent buffer. If a second thread comes in and tries to do a search down the same path they'll get the above lockdep splat because the class isn't set properly on the extent buffer. There was a good reason for this, we generally didn't know the real owner of the eb until we read it, specifically in refcounted roots. However now all refcounted roots have the same class name, so we no longer need to worry about this. For non-refcounted trees we know which root we're on based on the parent. Fix this by setting the lockdep class on the eb at creation time instead of read time. This will fix the splat and the weirdness where the class changes in the middle of locking the block. 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>
2020-12-08btrfs: pass the owner_root and level to alloc_extent_bufferJosef Bacik1-1/+2
Now that we've plumbed all of the callers to have the owner root and the level, plumb it down into alloc_extent_buffer(). 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>
2020-12-08btrfs: cleanup extent buffer readaheadJosef Bacik1-6/+2
We're going to pass around more information when we allocate extent buffers, in order to make that cleaner how we do readahead. Most of the callers have the parent node that we're getting our blockptr from, with the sole exception of relocation which simply has the bytenr it wants to read. Add a helper that takes the current arguments that we need (bytenr and gen), and add another helper for simply reading the slot out of a node. In followup patches the helper that takes all the extra arguments will be expanded, and the simpler helper won't need to have it's arguments adjusted. 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>
2020-12-08btrfs: create read policy frameworkAnand Jain1-1/+13
As of now, we use the pid method to read striped mirrored data, which means process id determines the stripe id to read. This type of routing typically helps in a system with many small independent processes tying to read random data. On the other hand, the pid based read IO policy is inefficient because if there is a single process trying to read a large file, the overall disk bandwidth remains underutilized. So this patch introduces a read policy framework so that we could add more read policies, such as IO routing based on the device's wait-queue or manual when we have a read-preferred device or a policy based on the target storage caching. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-08btrfs: introduce mount option rescue=ignorebadrootsJosef Bacik1-0/+13
In the face of extent root corruption, or any other core fs wide root corruption we will fail to mount the file system. This makes recovery kind of a pain, because you need to fall back to userspace tools to scrape off data. Instead provide a mechanism to gracefully handle bad roots, so we can at least mount read-only and possibly recover data from the file system. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-12-01block: remove i_bdevChristoph Hellwig1-7/+6
Switch the block device lookup interfaces to directly work with a dev_t so that struct block_device references are only acquired by the blkdev_get variants (and the blk-cgroup special case). This means that we now don't need an extra reference in the inode and can generally simplify handling of struct block_device to keep the lookups contained in the core block layer code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Hannes Reinecke <hare@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Coly Li <colyli@suse.de> [bcache] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-11-23btrfs: don't access possibly stale fs_info data for printing duplicate deviceJohannes Thumshirn1-1/+7
Syzbot reported a possible use-after-free when printing a duplicate device warning device_list_add(). At this point it can happen that a btrfs_device::fs_info is not correctly setup yet, so we're accessing stale data, when printing the warning message using the btrfs_printk() wrappers. ================================================================== BUG: KASAN: use-after-free in btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245 Read of size 8 at addr ffff8880878e06a8 by task syz-executor225/7068 CPU: 1 PID: 7068 Comm: syz-executor225 Not tainted 5.9.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245 device_list_add+0x1a88/0x1d60 fs/btrfs/volumes.c:943 btrfs_scan_one_device+0x196/0x490 fs/btrfs/volumes.c:1359 btrfs_mount_root+0x48f/0xb60 fs/btrfs/super.c:1634 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x44840a RSP: 002b:00007ffedfffd608 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ffedfffd670 RCX: 000000000044840a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffedfffd630 RBP: 00007ffedfffd630 R08: 00007ffedfffd670 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000001a R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003 Allocated by task 6945: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 kmalloc_node include/linux/slab.h:577 [inline] kvmalloc_node+0x81/0x110 mm/util.c:574 kvmalloc include/linux/mm.h:757 [inline] kvzalloc include/linux/mm.h:765 [inline] btrfs_mount_root+0xd0/0xb60 fs/btrfs/super.c:1613 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6945: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x113/0x200 mm/slab.c:3756 deactivate_locked_super+0xa7/0xf0 fs/super.c:335 btrfs_mount_root+0x72b/0xb60 fs/btrfs/super.c:1678 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880878e0000 which belongs to the cache kmalloc-16k of size 16384 The buggy address is located 1704 bytes inside of 16384-byte region [ffff8880878e0000, ffff8880878e4000) The buggy address belongs to the page: page:0000000060704f30 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x878e0 head:0000000060704f30 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00028e9a08 ffffea00021e3608 ffff8880aa440b00 raw: 0000000000000000 ffff8880878e0000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880878e0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880878e0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880878e0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880878e0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880878e0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== The syzkaller reproducer for this use-after-free crafts a filesystem image and loop mounts it twice in a loop. The mount will fail as the crafted image has an invalid chunk tree. When this happens btrfs_mount_root() will call deactivate_locked_super(), which then cleans up fs_info and fs_info::sb. If a second thread now adds the same block-device to the filesystem, it will get detected as a duplicate device and device_list_add() will reject the duplicate and print a warning. But as the fs_info pointer passed in is non-NULL this will result in a use-after-free. Instead of printing possibly uninitialized or already freed memory in btrfs_printk(), explicitly pass in a NULL fs_info so the printing of the device name will be skipped altogether. There was a slightly different approach discussed in https://lore.kernel.org/linux-btrfs/20200114060920.4527-1-anand.jain@oracle.com/t/#u Link: https://lore.kernel.org/linux-btrfs/000000000000c9e14b05afcc41ba@google.com Reported-by: syzbot+582e66e5edf36a22c7b0@syzkaller.appspotmail.com CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-11-05btrfs: dev-replace: fail mount if we don't have replace item with target deviceAnand Jain1-19/+7
If there is a device BTRFS_DEV_REPLACE_DEVID without the device replace item, then it means the filesystem is inconsistent state. This is either corruption or a crafted image. Fail the mount as this needs a closer look what is actually wrong. As of now if BTRFS_DEV_REPLACE_DEVID is present without the replace item, in __btrfs_free_extra_devids() we determine that there is an extra device, and free those extra devices but continue to mount the device. However, we were wrong in keeping tack of the rw_devices so the syzbot testcase failed: WARNING: CPU: 1 PID: 3612 at fs/btrfs/volumes.c:1166 close_fs_devices.part.0+0x607/0x800 fs/btrfs/volumes.c:1166 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 3612 Comm: syz-executor.2 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 panic+0x347/0x7c0 kernel/panic.c:231 __warn.cold+0x20/0x46 kernel/panic.c:600 report_bug+0x1bd/0x210 lib/bug.c:198 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 RIP: 0010:close_fs_devices.part.0+0x607/0x800 fs/btrfs/volumes.c:1166 RSP: 0018:ffffc900091777e0 EFLAGS: 00010246 RAX: 0000000000040000 RBX: ffffffffffffffff RCX: ffffc9000c8b7000 RDX: 0000000000040000 RSI: ffffffff83097f47 RDI: 0000000000000007 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff8880988a187f R10: 0000000000000000 R11: 0000000000000001 R12: ffff88809593a130 R13: ffff88809593a1ec R14: ffff8880988a1908 R15: ffff88809593a050 close_fs_devices fs/btrfs/volumes.c:1193 [inline] btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179 open_ctree+0x4984/0x4a2d fs/btrfs/disk-io.c:3434 btrfs_fill_super fs/btrfs/super.c:1316 [inline] btrfs_mount_root.cold+0x14/0x165 fs/btrfs/super.c:1672 The fix here is, when we determine that there isn't a replace item then fail the mount if there is a replace target device (devid 0). CC: stable@vger.kernel.org # 4.19+ Reported-by: syzbot+4cfe71a4da060be47502@syzkaller.appspotmail.com Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-27btrfs: convert data_seqcount to seqcount_mutex_tDavidlohr Bueso1-1/+1
By doing so we can associate the sequence counter to the chunk_mutex for lockdep purposes (compiled-out otherwise), the mutex is otherwise used on the write side. Also avoid explicitly disabling preemption around the write region as it will now be done automatically by the seqcount machinery based on the lock type. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-26btrfs: fix readahead hang and use-after-free after removing a deviceFilipe Manana1-0/+3
Very sporadically I had test case btrfs/069 from fstests hanging (for years, it is not a recent regression), with the following traces in dmesg/syslog: [162301.160628] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg started [162301.181196] BTRFS info (device sdc): scrub: finished on devid 4 with status: 0 [162301.287162] BTRFS info (device sdc): dev_replace from /dev/sdd (devid 2) to /dev/sdg finished [162513.513792] INFO: task btrfs-transacti:1356167 blocked for more than 120 seconds. [162513.514318] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.514522] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.514747] task:btrfs-transacti state:D stack: 0 pid:1356167 ppid: 2 flags:0x00004000 [162513.514751] Call Trace: [162513.514761] __schedule+0x5ce/0xd00 [162513.514765] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.514771] schedule+0x46/0xf0 [162513.514844] wait_current_trans+0xde/0x140 [btrfs] [162513.514850] ? finish_wait+0x90/0x90 [162513.514864] start_transaction+0x37c/0x5f0 [btrfs] [162513.514879] transaction_kthread+0xa4/0x170 [btrfs] [162513.514891] ? btrfs_cleanup_transaction+0x660/0x660 [btrfs] [162513.514894] kthread+0x153/0x170 [162513.514897] ? kthread_stop+0x2c0/0x2c0 [162513.514902] ret_from_fork+0x22/0x30 [162513.514916] INFO: task fsstress:1356184 blocked for more than 120 seconds. [162513.515192] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.515431] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.515680] task:fsstress state:D stack: 0 pid:1356184 ppid:1356177 flags:0x00004000 [162513.515682] Call Trace: [162513.515688] __schedule+0x5ce/0xd00 [162513.515691] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.515697] schedule+0x46/0xf0 [162513.515712] wait_current_trans+0xde/0x140 [btrfs] [162513.515716] ? finish_wait+0x90/0x90 [162513.515729] start_transaction+0x37c/0x5f0 [btrfs] [162513.515743] btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs] [162513.515753] btrfs_sync_fs+0x61/0x1c0 [btrfs] [162513.515758] ? __ia32_sys_fdatasync+0x20/0x20 [162513.515761] iterate_supers+0x87/0xf0 [162513.515765] ksys_sync+0x60/0xb0 [162513.515768] __do_sys_sync+0xa/0x10 [162513.515771] do_syscall_64+0x33/0x80 [162513.515774] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [162513.515781] RIP: 0033:0x7f5238f50bd7 [162513.515782] Code: Bad RIP value. [162513.515784] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2 [162513.515786] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7 [162513.515788] RDX: 00000000ffffffff RSI: 000000000daf0e74 RDI: 000000000000003a [162513.515789] RBP: 0000000000000032 R08: 000000000000000a R09: 00007f5239019be0 [162513.515791] R10: fffffffffffff24f R11: 0000000000000206 R12: 000000000000003a [162513.515792] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340 [162513.515804] INFO: task fsstress:1356185 blocked for more than 120 seconds. [162513.516064] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.516329] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.516617] task:fsstress state:D stack: 0 pid:1356185 ppid:1356177 flags:0x00000000 [162513.516620] Call Trace: [162513.516625] __schedule+0x5ce/0xd00 [162513.516628] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.516634] schedule+0x46/0xf0 [162513.516647] wait_current_trans+0xde/0x140 [btrfs] [162513.516650] ? finish_wait+0x90/0x90 [162513.516662] start_transaction+0x4d7/0x5f0 [btrfs] [162513.516679] btrfs_setxattr_trans+0x3c/0x100 [btrfs] [162513.516686] __vfs_setxattr+0x66/0x80 [162513.516691] __vfs_setxattr_noperm+0x70/0x200 [162513.516697] vfs_setxattr+0x6b/0x120 [162513.516703] setxattr+0x125/0x240 [162513.516709] ? lock_acquire+0xb1/0x480 [162513.516712] ? mnt_want_write+0x20/0x50 [162513.516721] ? rcu_read_lock_any_held+0x8e/0xb0 [162513.516723] ? preempt_count_add+0x49/0xa0 [162513.516725] ? __sb_start_write+0x19b/0x290 [162513.516727] ? preempt_count_add+0x49/0xa0 [162513.516732] path_setxattr+0xba/0xd0 [162513.516739] __x64_sys_setxattr+0x27/0x30 [162513.516741] do_syscall_64+0x33/0x80 [162513.516743] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [162513.516745] RIP: 0033:0x7f5238f56d5a [162513.516746] Code: Bad RIP value. [162513.516748] RSP: 002b:00007fff67b97868 EFLAGS: 00000202 ORIG_RAX: 00000000000000bc [162513.516750] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f5238f56d5a [162513.516751] RDX: 000055b1fbb0d5a0 RSI: 00007fff67b978a0 RDI: 000055b1fbb0d470 [162513.516753] RBP: 000055b1fbb0d5a0 R08: 0000000000000001 R09: 00007fff67b97700 [162513.516754] R10: 0000000000000004 R11: 0000000000000202 R12: 0000000000000004 [162513.516756] R13: 0000000000000024 R14: 0000000000000001 R15: 00007fff67b978a0 [162513.516767] INFO: task fsstress:1356196 blocked for more than 120 seconds. [162513.517064] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.517365] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.517763] task:fsstress state:D stack: 0 pid:1356196 ppid:1356177 flags:0x00004000 [162513.517780] Call Trace: [162513.517786] __schedule+0x5ce/0xd00 [162513.517789] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.517796] schedule+0x46/0xf0 [162513.517810] wait_current_trans+0xde/0x140 [btrfs] [162513.517814] ? finish_wait+0x90/0x90 [162513.517829] start_transaction+0x37c/0x5f0 [btrfs] [162513.517845] btrfs_attach_transaction_barrier+0x1f/0x50 [btrfs] [162513.517857] btrfs_sync_fs+0x61/0x1c0 [btrfs] [162513.517862] ? __ia32_sys_fdatasync+0x20/0x20 [162513.517865] iterate_supers+0x87/0xf0 [162513.517869] ksys_sync+0x60/0xb0 [162513.517872] __do_sys_sync+0xa/0x10 [162513.517875] do_syscall_64+0x33/0x80 [162513.517878] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [162513.517881] RIP: 0033:0x7f5238f50bd7 [162513.517883] Code: Bad RIP value. [162513.517885] RSP: 002b:00007fff67b978e8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a2 [162513.517887] RAX: ffffffffffffffda RBX: 000055b1fad2c560 RCX: 00007f5238f50bd7 [162513.517889] RDX: 0000000000000000 RSI: 000000007660add2 RDI: 0000000000000053 [162513.517891] RBP: 0000000000000032 R08: 0000000000000067 R09: 00007f5239019be0 [162513.517893] R10: fffffffffffff24f R11: 0000000000000206 R12: 0000000000000053 [162513.517895] R13: 00007fff67b97950 R14: 00007fff67b97906 R15: 000055b1fad1a340 [162513.517908] INFO: task fsstress:1356197 blocked for more than 120 seconds. [162513.518298] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.518672] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.519157] task:fsstress state:D stack: 0 pid:1356197 ppid:1356177 flags:0x00000000 [162513.519160] Call Trace: [162513.519165] __schedule+0x5ce/0xd00 [162513.519168] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.519174] schedule+0x46/0xf0 [162513.519190] wait_current_trans+0xde/0x140 [btrfs] [162513.519193] ? finish_wait+0x90/0x90 [162513.519206] start_transaction+0x4d7/0x5f0 [btrfs] [162513.519222] btrfs_create+0x57/0x200 [btrfs] [162513.519230] lookup_open+0x522/0x650 [162513.519246] path_openat+0x2b8/0xa50 [162513.519270] do_filp_open+0x91/0x100 [162513.519275] ? find_held_lock+0x32/0x90 [162513.519280] ? lock_acquired+0x33b/0x470 [162513.519285] ? do_raw_spin_unlock+0x4b/0xc0 [162513.519287] ? _raw_spin_unlock+0x29/0x40 [162513.519295] do_sys_openat2+0x20d/0x2d0 [162513.519300] do_sys_open+0x44/0x80 [162513.519304] do_syscall_64+0x33/0x80 [162513.519307] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [162513.519309] RIP: 0033:0x7f5238f4a903 [162513.519310] Code: Bad RIP value. [162513.519312] RSP: 002b:00007fff67b97758 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 [162513.519314] RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f5238f4a903 [162513.519316] RDX: 0000000000000000 RSI: 00000000000001b6 RDI: 000055b1fbb0d470 [162513.519317] RBP: 00007fff67b978c0 R08: 0000000000000001 R09: 0000000000000002 [162513.519319] R10: 00007fff67b974f7 R11: 0000000000000246 R12: 0000000000000013 [162513.519320] R13: 00000000000001b6 R14: 00007fff67b97906 R15: 000055b1fad1c620 [162513.519332] INFO: task btrfs:1356211 blocked for more than 120 seconds. [162513.519727] Not tainted 5.9.0-rc6-btrfs-next-69 #1 [162513.520115] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [162513.520508] task:btrfs state:D stack: 0 pid:1356211 ppid:1356178 flags:0x00004002 [162513.520511] Call Trace: [162513.520516] __schedule+0x5ce/0xd00 [162513.520519] ? _raw_spin_unlock_irqrestore+0x3c/0x60 [162513.520525] schedule+0x46/0xf0 [162513.520544] btrfs_scrub_pause+0x11f/0x180 [btrfs] [162513.520548] ? finish_wait+0x90/0x90 [162513.520562] btrfs_commit_transaction+0x45a/0xc30 [btrfs] [162513.520574] ? start_transaction+0xe0/0x5f0 [btrfs] [162513.520596] btrfs_dev_replace_finishing+0x6d8/0x711 [btrfs] [162513.520619] btrfs_dev_replace_by_ioctl.cold+0x1cc/0x1fd [btrfs] [162513.520639] btrfs_ioctl+0x2a25/0x36f0 [btrfs] [162513.520643] ? do_sigaction+0xf3/0x240 [162513.520645] ? find_held_lock+0x32/0x90 [162513.520648] ? do_sigaction+0xf3/0x240 [162513.520651] ? lock_acquired+0x33b/0x470 [162513.520655] ? _raw_spin_unlock_irq+0x24/0x50 [162513.520657] ? lockdep_hardirqs_on+0x7d/0x100 [162513.520660] ? _raw_spin_unlock_irq+0x35/0x50 [162513.520662] ? do_sigaction+0xf3/0x240 [162513.520671] ? __x64_sys_ioctl+0x83/0xb0 [162513.520672] __x64_sys_ioctl+0x83/0xb0 [162513.520677] do_syscall_64+0x33/0x80 [162513.520679] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [162513.520681] RIP: 0033:0x7fc3cd307d87 [162513.520682] Code: Bad RIP value. [162513.520684] RSP: 002b:00007ffe30a56bb8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [162513.520686] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fc3cd307d87 [162513.520687] RDX: 00007ffe30a57a30 RSI: 00000000ca289435 RDI: 0000000000000003 [162513.520689] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [162513.520690] R10: 0000000000000008 R11: 0000000000000202 R12: 0000000000000003 [162513.520692] R13: 0000557323a212e0 R14: 00007ffe30a5a520 R15: 0000000000000001 [162513.520703] Showing all locks held in the system: [162513.520712] 1 lock held by khungtaskd/54: [162513.520713] #0: ffffffffb40a91a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x197 [162513.520728] 1 lock held by in:imklog/596: [162513.520729] #0: ffff8f3f0d781400 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x4d/0x60 [162513.520782] 1 lock held by btrfs-transacti/1356167: [162513.520784] #0: ffff8f3d810cc848 (&fs_info->transaction_kthread_mutex){+.+.}-{3:3}, at: transaction_kthread+0x4a/0x170 [btrfs] [162513.520798] 1 lock held by btrfs/1356190: [162513.520800] #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write_file+0x22/0x60 [162513.520805] 1 lock held by fsstress/1356184: [162513.520806] #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0 [162513.520811] 3 locks held by fsstress/1356185: [162513.520812] #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50 [162513.520815] #1: ffff8f3d80a650b8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: vfs_setxattr+0x50/0x120 [162513.520820] #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs] [162513.520833] 1 lock held by fsstress/1356196: [162513.520834] #0: ffff8f3d576440e8 (&type->s_umount_key#62){++++}-{3:3}, at: iterate_supers+0x6f/0xf0 [162513.520838] 3 locks held by fsstress/1356197: [162513.520839] #0: ffff8f3d57644470 (sb_writers#15){.+.+}-{0:0}, at: mnt_want_write+0x20/0x50 [162513.520843] #1: ffff8f3d506465e8 (&type->i_mutex_dir_key#10){++++}-{3:3}, at: path_openat+0x2a7/0xa50 [162513.520846] #2: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs] [162513.520858] 2 locks held by btrfs/1356211: [162513.520859] #0: ffff8f3d810cde30 (&fs_info->dev_replace.lock_finishing_cancel_unmount){+.+.}-{3:3}, at: btrfs_dev_replace_finishing+0x52/0x711 [btrfs] [162513.520877] #1: ffff8f3d57644690 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40e/0x5f0 [btrfs] This was weird because the stack traces show that a transaction commit, triggered by a device replace operation, is blocking trying to pause any running scrubs but there are no stack traces of blocked tasks doing a scrub. After poking around with drgn, I noticed there was a scrub task that was constantly running and blocking for shorts periods of time: >>> t = find_task(prog, 1356190) >>> prog.stack_trace(t) #0 __schedule+0x5ce/0xcfc #1 schedule+0x46/0xe4 #2 schedule_timeout+0x1df/0x475 #3 btrfs_reada_wait+0xda/0x132 #4 scrub_stripe+0x2a8/0x112f #5 scrub_chunk+0xcd/0x134 #6 scrub_enumerate_chunks+0x29e/0x5ee #7 btrfs_scrub_dev+0x2d5/0x91b #8 btrfs_ioctl+0x7f5/0x36e7 #9 __x64_sys_ioctl+0x83/0xb0 #10 do_syscall_64+0x33/0x77 #11 entry_SYSCALL_64+0x7c/0x156 Which corresponds to: int btrfs_reada_wait(void *handle) { struct reada_control *rc = handle; struct btrfs_fs_info *fs_info = rc->fs_info; while (atomic_read(&rc->elems)) { if (!atomic_read(&fs_info->reada_works_cnt)) reada_start_machine(fs_info); wait_event_timeout(rc->wait, atomic_read(&rc->elems) == 0, (HZ + 9) / 10); } (...) So the counter "rc->elems" was set to 1 and never decreased to 0, causing the scrub task to loop forever in that function. Then I used the following script for drgn to check the readahead requests: $ cat dump_reada.py import sys import drgn from drgn import NULL, Object, cast, container_of, execscript, \ reinterpret, sizeof from drgn.helpers.linux import * mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1" mnt = None for mnt in for_each_mount(prog, dst = mnt_path): pass if mnt is None: sys.stderr.write(f'Error: mount point {mnt_path} not found\n') sys.exit(1) fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info) def dump_re(re): nzones = re.nzones.value_() print(f're at {hex(re.value_())}') print(f'\t logical {re.logical.value_()}') print(f'\t refcnt {re.refcnt.value_()}') print(f'\t nzones {nzones}') for i in range(nzones): dev = re.zones[i].device name = dev.name.str.string_() print(f'\t\t dev id {dev.devid.value_()} name {name}') print() for _, e in radix_tree_for_each(fs_info.reada_tree): re = cast('struct reada_extent *', e) dump_re(re) $ drgn dump_reada.py re at 0xffff8f3da9d25ad8 logical 38928384 refcnt 1 nzones 1 dev id 0 name b'/dev/sdd' $ So there was one readahead extent with a single zone corresponding to the source device of that last device replace operation logged in dmesg/syslog. Also the ID of that zone's device was 0 which is a special value set in the source device of a device replace operation when the operation finishes (constant BTRFS_DEV_REPLACE_DEVID set at btrfs_dev_replace_finishing()), confirming again that device /dev/sdd was the source of a device replace operation. Normally there should be as many zones in the readahead extent as there are devices, and I wasn't expecting the extent to be in a block group with a 'single' profile, so I went and confirmed with the following drgn script that there weren't any single profile block groups: $ cat dump_block_groups.py import sys import drgn from drgn import NULL, Object, cast, container_of, execscript, \ reinterpret, sizeof from drgn.helpers.linux import * mnt_path = b"/home/fdmanana/btrfs-tests/scratch_1" mnt = None for mnt in for_each_mount(prog, dst = mnt_path): pass if mnt is None: sys.stderr.write(f'Error: mount point {mnt_path} not found\n') sys.exit(1) fs_info = cast('struct btrfs_fs_info *', mnt.mnt.mnt_sb.s_fs_info) BTRFS_BLOCK_GROUP_DATA = (1 << 0) BTRFS_BLOCK_GROUP_SYSTEM = (1 << 1) BTRFS_BLOCK_GROUP_METADATA = (1 << 2) BTRFS_BLOCK_GROUP_RAID0 = (1 << 3) BTRFS_BLOCK_GROUP_RAID1 = (1 << 4) BTRFS_BLOCK_GROUP_DUP = (1 << 5) BTRFS_BLOCK_GROUP_RAID10 = (1 << 6) BTRFS_BLOCK_GROUP_RAID5 = (1 << 7) BTRFS_BLOCK_GROUP_RAID6 = (1 << 8) BTRFS_BLOCK_GROUP_RAID1C3 = (1 << 9) BTRFS_BLOCK_GROUP_RAID1C4 = (1 << 10) def bg_flags_string(bg): flags = bg.flags.value_() ret = '' if flags & BTRFS_BLOCK_GROUP_DATA: ret = 'data' if flags & BTRFS_BLOCK_GROUP_METADATA: if len(ret) > 0: ret += '|' ret += 'meta' if flags & BTRFS_BLOCK_GROUP_SYSTEM: if len(ret) > 0: ret += '|' ret += 'system' if flags & BTRFS_BLOCK_GROUP_RAID0: ret += ' raid0' elif flags & BTRFS_BLOCK_GROUP_RAID1: ret += ' raid1' elif flags & BTRFS_BLOCK_GROUP_DUP: ret += ' dup' elif flags & BTRFS_BLOCK_GROUP_RAID10: ret += ' raid10' elif flags & BTRFS_BLOCK_GROUP_RAID5: ret += ' raid5' elif flags & BTRFS_BLOCK_GROUP_RAID6: ret += ' raid6' elif flags & BTRFS_BLOCK_GROUP_RAID1C3: ret += ' raid1c3' elif flags & BTRFS_BLOCK_GROUP_RAID1C4: ret += ' raid1c4' else: ret += ' single' return ret def dump_bg(bg): print() print(f'block group at {hex(bg.value_())}') print(f'\t start {bg.start.value_()} length {bg.length.value_()}') print(f'\t flags {bg.flags.value_()} - {bg_flags_string(bg)}') bg_root = fs_info.block_group_cache_tree.address_of_() for bg in rbtree_inorder_for_each_entry('struct btrfs_block_group', bg_root, 'cache_node'): dump_bg(bg) $ drgn dump_block_groups.py block group at 0xffff8f3d673b0400 start 22020096 length 16777216 flags 258 - system raid6 block group at 0xffff8f3d53ddb400 start 38797312 length 536870912 flags 260 - meta raid6 block group at 0xffff8f3d5f4d9c00 start 575668224 length 2147483648 flags 257 - data raid6 block group at 0xffff8f3d08189000 start 2723151872 length 67108864 flags 258 - system raid6 block group at 0xffff8f3db70ff000 start 2790260736 length 1073741824 flags 260 - meta raid6 block group at 0xffff8f3d5f4dd800 start 3864002560 length 67108864 flags 258 - system raid6 block group at 0xffff8f3d67037000 start 3931111424 length 2147483648 flags 257 - data raid6 $ So there were only 2 reasons left for having a readahead extent with a single zone: reada_find_zone(), called when creating a readahead extent, returned NULL either because we failed to find the corresponding block group or because a memory allocation failed. With some additional and custom tracing I figured out that on every further ocurrence of the problem the block group had just been deleted when we were looping to create the zones for the readahead extent (at reada_find_extent()), so we ended up with only one zone in the readahead extent, corresponding to a device that ends up getting replaced. So after figuring that out it became obvious why the hang happens: 1) Task A starts a scrub on any device of the filesystem, except for device /dev/sdd; 2) Task B starts a device replace with /dev/sdd as the source device; 3) Task A calls btrfs_reada_add() from scrub_stripe() and it is currently starting to scrub a stripe from block group X. This call to btrfs_reada_add() is the one for the extent tree. When btrfs_reada_add() calls reada_add_block(), it passes the logical address of the extent tree's root node as its 'logical' argument - a value of 38928384; 4) Task A then enters reada_find_extent(), called from reada_add_block(). It finds there isn't any existing readahead extent for the logical address 38928384, so it proceeds to the path of creating a new one. It calls btrfs_map_block() to find out which stripes exist for the block group X. On the first iteration of the for loop that iterates over the stripes, it finds the stripe for device /dev/sdd, so it creates one zone for that device and adds it to the readahead extent. Before getting into the second iteration of the loop, the cleanup kthread deletes block group X because it was empty. So in the iterations for the remaining stripes it does not add more zones to the readahead extent, because the calls to reada_find_zone() returned NULL because they couldn't find block group X anymore. As a result the new readahead extent has a single zone, corresponding to the device /dev/sdd; 4) Before task A returns to btrfs_reada_add() and queues the readahead job for the readahead work queue, task B finishes the device replace and at btrfs_dev_replace_finishing() swaps the device /dev/sdd with the new device /dev/sdg; 5) Task A returns to reada_add_block(), which increments the counter "->elems" of the reada_control structure allocated at btrfs_reada_add(). Then it returns back to btrfs_reada_add() and calls reada_start_machine(). This queues a job in the readahead work queue to run the function reada_start_machine_worker(), which calls __reada_start_machine(). At __reada_start_machine() we take the device list mutex and for each device found in the current device list, we call reada_start_machine_dev() to start the readahead work. However at this point the device /dev/sdd was already freed and is not in the device list anymore. This means the corresponding readahead for the extent at 38928384 is never started, and therefore the "->elems" counter of the reada_control structure allocated at btrfs_reada_add() never goes down to 0, causing the call to btrfs_reada_wait(), done by the scrub task, to wait forever. Note that the readahead request can be made either after the device replace started or before it started, however in pratice it is very unlikely that a device replace is able to start after a readahead request is made and is able to complete before the readahead request completes - maybe only on a very small and nearly empty filesystem. This hang however is not the only problem we can have with readahead and device removals. When the readahead extent has other zones other than the one corresponding to the device that is being removed (either by a device replace or a device remove operation), we risk having a use-after-free on the device when dropping the last reference of the readahead extent. For example if we create a readahead extent with two zones, one for the device /dev/sdd and one for the device /dev/sde: 1) Before the readahead worker starts, the device /dev/sdd is removed, and the corresponding btrfs_device structure is freed. However the readahead extent still has the zone pointing to the device structure; 2) When the readahead worker starts, it only finds device /dev/sde in the current device list of the filesystem; 3) It starts the readahead work, at reada_start_machine_dev(), using the device /dev/sde; 4) Then when it finishes reading the extent from device /dev/sde, it calls __readahead_hook() which ends up dropping the last reference on the readahead extent through the last call to reada_extent_put(); 5) At reada_extent_put() it iterates over each zone of the readahead extent and attempts to delete an element from the device's 'reada_extents' radix tree, resulting in a use-after-free, as the device pointer of the zone for /dev/sdd is now stale. We can also access the device after dropping the last reference of a zone, through reada_zone_release(), also called by reada_extent_put(). And a device remove suffers the same problem, however since it shrinks the device size down to zero before removing the device, it is very unlikely to still have readahead requests not completed by the time we free the device, the only possibility is if the device has a very little space allocated. While the hang problem is exclusive to scrub, since it is currently the only user of btrfs_reada_add() and btrfs_reada_wait(), the use-after-free problem affects any path that triggers readhead, which includes btree_readahead_hook() and __readahead_hook() (a readahead worker can trigger readahed for the children of a node) for example - any path that ends up calling reada_add_block() can trigger the use-after-free after a device is removed. So fix this by waiting for any readahead requests for a device to complete before removing a device, ensuring that while waiting for existing ones no new ones can be made. This problem has been around for a very long time - the readahead code was added in 2011, device remove exists since 2008 and device replace was introduced in 2013, hard to pick a specific commit for a git Fixes tag. CC: stable@vger.kernel.org # 4.4+ 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>
2020-10-07btrfs: skip devices without magic signature when mountingAnand Jain1-6/+12
Many things can happen after the device is scanned and before the device is mounted. One such thing is losing the BTRFS_MAGIC on the device. If it happens we still won't free that device from the memory and cause the userland confusion. For example: As the BTRFS_IOC_DEV_INFO still carries the device path which does not have the BTRFS_MAGIC, 'btrfs fi show' still lists device which does not belong to the filesystem anymore: $ mkfs.btrfs -fq -draid1 -mraid1 /dev/sda /dev/sdb $ wipefs -a /dev/sdb # /dev/sdb does not contain magic signature $ mount -o degraded /dev/sda /btrfs $ btrfs fi show -m Label: none uuid: 470ec6fb-646b-4464-b3cb-df1b26c527bd Total devices 2 FS bytes used 128.00KiB devid 1 size 3.00GiB used 571.19MiB path /dev/sda devid 2 size 3.00GiB used 571.19MiB path /dev/sdb We need to distinguish the missing signature and invalid superblock, so add a specific error code ENODATA for that. This also fixes failure of fstest btrfs/198. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: return error if we're unable to read device statsJosef Bacik1-8/+18
I noticed when fixing device stats for seed devices that we simply threw away the return value from btrfs_search_slot(). This is because we may not have stat items, but we could very well get an error, and thus miss reporting the error up the chain. Fix this by returning ret if it's an actual error, and then stop trying to init the rest of the devices stats and return the error up the chain. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: init device stats for seed devicesJosef Bacik1-41/+46
We recently started recording device stats across the fleet, and noticed a large increase in messages such as this BTRFS warning (device dm-0): get dev_stats failed, not yet valid on our tiers that use seed devices for their root devices. This is because we do not initialize the device stats for any seed devices if we have a sprout device and mount using that sprout device. The basic steps for reproducing are: $ mkfs seed device $ mount seed device # fill seed device $ umount seed device $ btrfstune -S 1 seed device $ mount seed device $ btrfs device add -f sprout device /mnt/wherever $ umount /mnt/wherever $ mount sprout device /mnt/wherever $ btrfs device stats /mnt/wherever This will fail with the above message in dmesg. Fix this by iterating over the fs_devices->seed if they exist in btrfs_init_dev_stats. This fixed the problem and properly reports the stats for both devices. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ rename to btrfs_device_init_dev_stats ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: simplify gotos in open_seed_deviceAnand Jain1-5/+3
The function does not have a common exit block and returns immediatelly so there's no point having the goto. Remove the two cases. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove unnecessary tmp variable in btrfs_assign_next_active_device()Anand Jain1-6/+3
We can check the argument value directly, no need for the temporary variable. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: use sprout device_list_mutex in btrfs_init_devices_lateAnand Jain1-3/+1
On a mounted sprout filesystem, all threads now are using the sprout::device_list_mutex, and this is the only code using the seed::device_list_mutex. This patch converts to use the sprouts fs_info->fs_devices->device_list_mutex. The same reasoning holds true here, that device delete is holding the sprout::device_list_mutex. Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: split and refactor btrfs_sysfs_remove_devices_dirAnand Jain1-4/+4
Similar to btrfs_sysfs_add_devices_dir()'s refactoring, split btrfs_sysfs_remove_devices_dir() so that we don't have to use the device argument to indicate whether to free all devices or just one device. Export btrfs_sysfs_remove_device() as device operations outside of sysfs.c now calls this instead of btrfs_sysfs_remove_devices_dir(). btrfs_sysfs_remove_devices_dir() is renamed to btrfs_sysfs_remove_fs_devices() to suite its new role. Now, no one outside of sysfs.c calls btrfs_sysfs_remove_fs_devices() so it is redeclared s static. And the same function had to be moved before its first caller. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: simplify parameters of btrfs_sysfs_add_devices_dirAnand Jain1-1/+1
When we add a device we need to add it to sysfs, so instead of using the btrfs_sysfs_add_devices_dir() fs_devices argument to specify whether to add a device or all of fs_devices, call the helper function directly btrfs_sysfs_add_device() and thus make it non-static. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: improve device scanning messagesAnand Jain1-6/+8
Systems booting without the initramfs seems to scan an unusual kind of device path (/dev/root). And at a later time, the device is updated to the correct path. We generally print the process name and PID of the process scanning the device but we don't capture the same information if the device path is rescanned with a different pathname. The current message is too long, so drop the unnecessary UUID and add process name and PID. While at this also update the duplicate device warning to include the process name and PID so the messages are consistent CC: stable@vger.kernel.org # 4.19+ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=89721 Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: enumerate the type of exclusive operation in progressGoldwyn Rodrigues1-10/+10
Instead of using a flag bit for exclusive operation, use a variable to store which exclusive operation is being performed. Introduce an API to start and finish an exclusive operation. This would enable another way for tools to check which operation is running on why starting an exclusive operation failed. The followup patch adds a sysfs_notify() to alert userspace when the state changes, so userspace can perform select() on it to get notified of the change. This would enable us to enqueue a command which will wait for current exclusive operation to complete before issuing the next exclusive operation. This has been done synchronously as opposed to a background process, or else error collection (if any) will become difficult. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update comments ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: sysfs: init devices outside of the chunk_mutexJosef Bacik1-3/+4
While running btrfs/061, btrfs/073, btrfs/078, or btrfs/178 we hit the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc3+ #4 Not tainted ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff96ecc22ef4a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc+0x37/0x270 alloc_inode+0x82/0xb0 iget_locked+0x10d/0x2c0 kernfs_get_inode+0x1b/0x130 kernfs_get_tree+0x136/0x240 sysfs_get_tree+0x16/0x40 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (kernfs_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 kernfs_add_one+0x23/0x150 kernfs_create_link+0x63/0xa0 sysfs_do_create_link_sd+0x5e/0xd0 btrfs_sysfs_add_devices_dir+0x81/0x130 btrfs_init_new_device+0x67f/0x1250 btrfs_ioctl+0x1ef/0x2e20 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_insert_empty_items+0x64/0xb0 btrfs_insert_delayed_items+0x90/0x4f0 btrfs_commit_inode_delayed_items+0x93/0x140 btrfs_log_inode+0x5de/0x2020 btrfs_log_inode_parent+0x429/0xc90 btrfs_log_new_name+0x95/0x9b btrfs_rename2+0xbb9/0x1800 vfs_rename+0x64f/0x9f0 do_renameat2+0x320/0x4e0 __x64_sys_rename+0x1f/0x30 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> kernfs_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(kernfs_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff8dd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff96ed2ade30e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 0 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb8 check_noncircular+0x12d/0x150 __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa7/0x3d0 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x41/0x50 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This happens because we are holding the chunk_mutex at the time of adding in a new device. However we only need to hold the device_list_mutex, as we're going to iterate over the fs_devices devices. Move the sysfs init stuff outside of the chunk_mutex to get rid of this lockdep splat. CC: stable@vger.kernel.org # 4.4.x: f3cd2c58110dad14e: btrfs: sysfs, rename device_link add/remove functions CC: stable@vger.kernel.org # 4.4.x Reported-by: David Sterba <dsterba@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>
2020-10-07btrfs: don't opencode sync_blockdev in btrfs_init_new_deviceNikolay Borisov1-1/+1
Instead of opencoding filemap_write_and_wait simply call syncblockdev as it makes it abundantly clear what's going on and why this is used. No semantics changes. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: remove redundant code from btrfs_free_stale_devicesNikolay Borisov1-2/+0
Following the refactor of btrfs_free_stale_devices in 7bcb8164ad94 ("btrfs: use device_list_mutex when removing stale devices") fs_devices are freed after they have been iterated by the inner list_for_each so the use-after-free fixed by introducing the break in fd649f10c3d2 ("btrfs: Fix use-after-free when cleaning up fs_devs with a single stale device") is no longer necessary. Just remove it altogether. No functional changes. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07btrfs: refactor locked condition in btrfs_init_new_deviceNikolay Borisov1-3/+4
Invert unlocked to locked and exploit the fact it can only ever be modified if we are adding a new device to a seed filesystem. This allows to simplify the check in error: label. No semantics changes. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>