11435 Commits

Author SHA1 Message Date
Anand Jain
8a6539ea36 btrfs: scan device in non-exclusive mode
commit 50d281fc434cb8e2497f5e70a309ccca6b1a09f0 upstream.

This fixes mkfs/mount/check failures due to race with systemd-udevd
scan.

During the device scan initiated by systemd-udevd, other user space
EXCL operations such as mkfs, mount, or check may get blocked and result
in a "Device or resource busy" error. This is because the device
scan process opens the device with the EXCL flag in the kernel.

Two reports were received:

 - btrfs/179 test case, where the fsck command failed with the -EBUSY
   error

 - LTP pwritev03 test case, where mkfs.vfs failed with
   the -EBUSY error, when mkfs.vfs tried to overwrite old btrfs filesystem
   on the device.

In both cases, fsck and mkfs (respectively) were racing with a
systemd-udevd device scan, and systemd-udevd won, resulting in the
-EBUSY error for fsck and mkfs.

Reproducing the problem has been difficult because there is a very
small window during which these userspace threads can race to
acquire the exclusive device open. Even on the system where the problem
was observed, the problem occurrences were anywhere between 10 to 400
iterations and chances of reproducing decreases with debug printk()s.

However, an exclusive device open is unnecessary for the scan process,
as there are no write operations on the device during scan. Furthermore,
during the mount process, the superblock is re-read in the below
function call chain:

  btrfs_mount_root
   btrfs_open_devices
    open_fs_devices
     btrfs_open_one_device
       btrfs_get_bdev_and_sb

So, to fix this issue, removes the FMODE_EXCL flag from the scan
operation, and add a comment.

The case where mkfs may still write to the device and a scan is running,
the btrfs signature is not written at that time so scan will not
recognize such device.

Reported-by: Sherry Yang <sherry.yang@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202303170839.fdf23068-oliver.sang@intel.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Filipe Manana
a38ff20248 btrfs: fix race between quota disable and quota assign ioctls
commit 2f1a6be12ab6c8470d5776e68644726c94257c54 upstream.

The quota assign ioctl can currently run in parallel with a quota disable
ioctl call. The assign ioctl uses the quota root, while the disable ioctl
frees that root, and therefore we can have a use-after-free triggered in
the assign ioctl, leading to a trace like the following when KASAN is
enabled:

  [672.723][T736] BUG: KASAN: slab-use-after-free in btrfs_search_slot+0x2962/0x2db0
  [672.723][T736] Read of size 8 at addr ffff888022ec0208 by task btrfs_search_sl/27736
  [672.724][T736]
  [672.725][T736] CPU: 1 PID: 27736 Comm: btrfs_search_sl Not tainted 6.3.0-rc3 #37
  [672.723][T736] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
  [672.727][T736] Call Trace:
  [672.728][T736]  <TASK>
  [672.728][T736]  dump_stack_lvl+0xd9/0x150
  [672.725][T736]  print_report+0xc1/0x5e0
  [672.720][T736]  ? __virt_addr_valid+0x61/0x2e0
  [672.727][T736]  ? __phys_addr+0xc9/0x150
  [672.725][T736]  ? btrfs_search_slot+0x2962/0x2db0
  [672.722][T736]  kasan_report+0xc0/0xf0
  [672.729][T736]  ? btrfs_search_slot+0x2962/0x2db0
  [672.724][T736]  btrfs_search_slot+0x2962/0x2db0
  [672.723][T736]  ? fs_reclaim_acquire+0xba/0x160
  [672.722][T736]  ? split_leaf+0x13d0/0x13d0
  [672.726][T736]  ? rcu_is_watching+0x12/0xb0
  [672.723][T736]  ? kmem_cache_alloc+0x338/0x3c0
  [672.722][T736]  update_qgroup_status_item+0xf7/0x320
  [672.724][T736]  ? add_qgroup_rb+0x3d0/0x3d0
  [672.739][T736]  ? do_raw_spin_lock+0x12d/0x2b0
  [672.730][T736]  ? spin_bug+0x1d0/0x1d0
  [672.737][T736]  btrfs_run_qgroups+0x5de/0x840
  [672.730][T736]  ? btrfs_qgroup_rescan_worker+0xa70/0xa70
  [672.738][T736]  ? __del_qgroup_relation+0x4ba/0xe00
  [672.738][T736]  btrfs_ioctl+0x3d58/0x5d80
  [672.735][T736]  ? tomoyo_path_number_perm+0x16a/0x550
  [672.737][T736]  ? tomoyo_execute_permission+0x4a0/0x4a0
  [672.731][T736]  ? btrfs_ioctl_get_supported_features+0x50/0x50
  [672.737][T736]  ? __sanitizer_cov_trace_switch+0x54/0x90
  [672.734][T736]  ? do_vfs_ioctl+0x132/0x1660
  [672.730][T736]  ? vfs_fileattr_set+0xc40/0xc40
  [672.730][T736]  ? _raw_spin_unlock_irq+0x2e/0x50
  [672.732][T736]  ? sigprocmask+0xf2/0x340
  [672.737][T736]  ? __fget_files+0x26a/0x480
  [672.732][T736]  ? bpf_lsm_file_ioctl+0x9/0x10
  [672.738][T736]  ? btrfs_ioctl_get_supported_features+0x50/0x50
  [672.736][T736]  __x64_sys_ioctl+0x198/0x210
  [672.736][T736]  do_syscall_64+0x39/0xb0
  [672.731][T736]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [672.739][T736] RIP: 0033:0x4556ad
  [672.742][T736]  </TASK>
  [672.743][T736]
  [672.748][T736] Allocated by task 27677:
  [672.743][T736]  kasan_save_stack+0x22/0x40
  [672.741][T736]  kasan_set_track+0x25/0x30
  [672.741][T736]  __kasan_kmalloc+0xa4/0xb0
  [672.749][T736]  btrfs_alloc_root+0x48/0x90
  [672.746][T736]  btrfs_create_tree+0x146/0xa20
  [672.744][T736]  btrfs_quota_enable+0x461/0x1d20
  [672.743][T736]  btrfs_ioctl+0x4a1c/0x5d80
  [672.747][T736]  __x64_sys_ioctl+0x198/0x210
  [672.749][T736]  do_syscall_64+0x39/0xb0
  [672.744][T736]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [672.756][T736]
  [672.757][T736] Freed by task 27677:
  [672.759][T736]  kasan_save_stack+0x22/0x40
  [672.759][T736]  kasan_set_track+0x25/0x30
  [672.756][T736]  kasan_save_free_info+0x2e/0x50
  [672.751][T736]  ____kasan_slab_free+0x162/0x1c0
  [672.758][T736]  slab_free_freelist_hook+0x89/0x1c0
  [672.752][T736]  __kmem_cache_free+0xaf/0x2e0
  [672.752][T736]  btrfs_put_root+0x1ff/0x2b0
  [672.759][T736]  btrfs_quota_disable+0x80a/0xbc0
  [672.752][T736]  btrfs_ioctl+0x3e5f/0x5d80
  [672.756][T736]  __x64_sys_ioctl+0x198/0x210
  [672.753][T736]  do_syscall_64+0x39/0xb0
  [672.765][T736]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [672.769][T736]
  [672.768][T736] The buggy address belongs to the object at ffff888022ec0000
  [672.768][T736]  which belongs to the cache kmalloc-4k of size 4096
  [672.769][T736] The buggy address is located 520 bytes inside of
  [672.769][T736]  freed 4096-byte region [ffff888022ec0000, ffff888022ec1000)
  [672.760][T736]
  [672.764][T736] The buggy address belongs to the physical page:
  [672.761][T736] page:ffffea00008bb000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x22ec0
  [672.766][T736] head:ffffea00008bb000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
  [672.779][T736] flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
  [672.770][T736] raw: 00fff00000010200 ffff888012842140 ffffea000054ba00 dead000000000002
  [672.770][T736] raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
  [672.771][T736] page dumped because: kasan: bad access detected
  [672.778][T736] page_owner tracks the page as allocated
  [672.777][T736] page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 88
  [672.779][T736]  get_page_from_freelist+0x119c/0x2d50
  [672.779][T736]  __alloc_pages+0x1cb/0x4a0
  [672.776][T736]  alloc_pages+0x1aa/0x270
  [672.773][T736]  allocate_slab+0x260/0x390
  [672.771][T736]  ___slab_alloc+0xa9a/0x13e0
  [672.778][T736]  __slab_alloc.constprop.0+0x56/0xb0
  [672.771][T736]  __kmem_cache_alloc_node+0x136/0x320
  [672.789][T736]  __kmalloc+0x4e/0x1a0
  [672.783][T736]  tomoyo_realpath_from_path+0xc3/0x600
  [672.781][T736]  tomoyo_path_perm+0x22f/0x420
  [672.782][T736]  tomoyo_path_unlink+0x92/0xd0
  [672.780][T736]  security_path_unlink+0xdb/0x150
  [672.788][T736]  do_unlinkat+0x377/0x680
  [672.788][T736]  __x64_sys_unlink+0xca/0x110
  [672.789][T736]  do_syscall_64+0x39/0xb0
  [672.783][T736]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [672.784][T736] page last free stack trace:
  [672.787][T736]  free_pcp_prepare+0x4e5/0x920
  [672.787][T736]  free_unref_page+0x1d/0x4e0
  [672.784][T736]  __unfreeze_partials+0x17c/0x1a0
  [672.797][T736]  qlist_free_all+0x6a/0x180
  [672.796][T736]  kasan_quarantine_reduce+0x189/0x1d0
  [672.797][T736]  __kasan_slab_alloc+0x64/0x90
  [672.793][T736]  kmem_cache_alloc+0x17c/0x3c0
  [672.799][T736]  getname_flags.part.0+0x50/0x4e0
  [672.799][T736]  getname_flags+0x9e/0xe0
  [672.792][T736]  vfs_fstatat+0x77/0xb0
  [672.791][T736]  __do_sys_newlstat+0x84/0x100
  [672.798][T736]  do_syscall_64+0x39/0xb0
  [672.796][T736]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [672.790][T736]
  [672.791][T736] Memory state around the buggy address:
  [672.799][T736]  ffff888022ec0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  [672.805][T736]  ffff888022ec0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  [672.802][T736] >ffff888022ec0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  [672.809][T736]                       ^
  [672.809][T736]  ffff888022ec0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  [672.809][T736]  ffff888022ec0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Fix this by having the qgroup assign ioctl take the qgroup ioctl mutex
before calling btrfs_run_qgroups(), which is what all qgroup ioctls should
call.

Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAFcO6XN3VD8ogmHwqRk4kbiwtpUSNySu2VAxN8waEPciCHJvMA@mail.gmail.com/
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Filipe Manana
6134a4bb6b btrfs: fix deadlock when aborting transaction during relocation with scrub
commit 2d82a40aa7d6fcae0250ec68b8566cdee7bfd44c upstream.

Before relocating a block group we pause scrub, then do the relocation and
then unpause scrub. The relocation process requires starting and committing
a transaction, and if we have a failure in the critical section of the
transaction commit path (transaction state >= TRANS_STATE_COMMIT_START),
we will deadlock if there is a paused scrub.

That results in stack traces like the following:

  [42.479] BTRFS info (device sdc): relocating block group 53876686848 flags metadata|raid6
  [42.936] BTRFS warning (device sdc): Skipping commit of aborted transaction.
  [42.936] ------------[ cut here ]------------
  [42.936] BTRFS: Transaction aborted (error -28)
  [42.936] WARNING: CPU: 11 PID: 346822 at fs/btrfs/transaction.c:1977 btrfs_commit_transaction+0xcc8/0xeb0 [btrfs]
  [42.936] Modules linked in: dm_flakey dm_mod loop btrfs (...)
  [42.936] CPU: 11 PID: 346822 Comm: btrfs Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [42.936] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [42.936] RIP: 0010:btrfs_commit_transaction+0xcc8/0xeb0 [btrfs]
  [42.936] Code: ff ff 45 8b (...)
  [42.936] RSP: 0018:ffffb58649633b48 EFLAGS: 00010282
  [42.936] RAX: 0000000000000000 RBX: ffff8be6ef4d5bd8 RCX: 0000000000000000
  [42.936] RDX: 0000000000000002 RSI: ffffffffb35e7782 RDI: 00000000ffffffff
  [42.936] RBP: ffff8be6ef4d5c98 R08: 0000000000000000 R09: ffffb586496339e8
  [42.936] R10: 0000000000000001 R11: 0000000000000001 R12: ffff8be6d38c7c00
  [42.936] R13: 00000000ffffffe4 R14: ffff8be6c268c000 R15: ffff8be6ef4d5cf0
  [42.936] FS:  00007f381a82b340(0000) GS:ffff8beddfcc0000(0000) knlGS:0000000000000000
  [42.936] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [42.936] CR2: 00007f1e35fb7638 CR3: 0000000117680006 CR4: 0000000000370ee0
  [42.936] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [42.936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [42.936] Call Trace:
  [42.936]  <TASK>
  [42.936]  ? start_transaction+0xcb/0x610 [btrfs]
  [42.936]  prepare_to_relocate+0x111/0x1a0 [btrfs]
  [42.936]  relocate_block_group+0x57/0x5d0 [btrfs]
  [42.936]  ? btrfs_wait_nocow_writers+0x25/0xb0 [btrfs]
  [42.936]  btrfs_relocate_block_group+0x248/0x3c0 [btrfs]
  [42.936]  ? __pfx_autoremove_wake_function+0x10/0x10
  [42.936]  btrfs_relocate_chunk+0x3b/0x150 [btrfs]
  [42.936]  btrfs_balance+0x8ff/0x11d0 [btrfs]
  [42.936]  ? __kmem_cache_alloc_node+0x14a/0x410
  [42.936]  btrfs_ioctl+0x2334/0x32c0 [btrfs]
  [42.937]  ? mod_objcg_state+0xd2/0x360
  [42.937]  ? refill_obj_stock+0xb0/0x160
  [42.937]  ? seq_release+0x25/0x30
  [42.937]  ? __rseq_handle_notify_resume+0x3b5/0x4b0
  [42.937]  ? percpu_counter_add_batch+0x2e/0xa0
  [42.937]  ? __x64_sys_ioctl+0x88/0xc0
  [42.937]  __x64_sys_ioctl+0x88/0xc0
  [42.937]  do_syscall_64+0x38/0x90
  [42.937]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [42.937] RIP: 0033:0x7f381a6ffe9b
  [42.937] Code: 00 48 89 44 24 (...)
  [42.937] RSP: 002b:00007ffd45ecf060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [42.937] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f381a6ffe9b
  [42.937] RDX: 00007ffd45ecf150 RSI: 00000000c4009420 RDI: 0000000000000003
  [42.937] RBP: 0000000000000003 R08: 0000000000000013 R09: 0000000000000000
  [42.937] R10: 00007f381a60c878 R11: 0000000000000246 R12: 00007ffd45ed0423
  [42.937] R13: 00007ffd45ecf150 R14: 0000000000000000 R15: 00007ffd45ecf148
  [42.937]  </TASK>
  [42.937] ---[ end trace 0000000000000000 ]---
  [42.937] BTRFS: error (device sdc: state A) in cleanup_transaction:1977: errno=-28 No space left
  [59.196] INFO: task btrfs:346772 blocked for more than 120 seconds.
  [59.196]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.196] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.196] task:btrfs           state:D stack:0     pid:346772 ppid:1      flags:0x00004002
  [59.196] Call Trace:
  [59.196]  <TASK>
  [59.196]  __schedule+0x392/0xa70
  [59.196]  ? __pv_queued_spin_lock_slowpath+0x165/0x370
  [59.196]  schedule+0x5d/0xd0
  [59.196]  __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
  [59.197]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.197]  scrub_pause_off+0x21/0x50 [btrfs]
  [59.197]  scrub_simple_mirror+0x1c7/0x950 [btrfs]
  [59.197]  ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
  [59.198]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.198]  scrub_stripe+0x20d/0x740 [btrfs]
  [59.198]  scrub_chunk+0xc4/0x130 [btrfs]
  [59.198]  scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
  [59.198]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.198]  btrfs_scrub_dev+0x236/0x6a0 [btrfs]
  [59.199]  ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
  [59.199]  ? _copy_from_user+0x7b/0x80
  [59.199]  btrfs_ioctl+0xde1/0x32c0 [btrfs]
  [59.199]  ? refill_stock+0x33/0x50
  [59.199]  ? should_failslab+0xa/0x20
  [59.199]  ? kmem_cache_alloc_node+0x151/0x460
  [59.199]  ? alloc_io_context+0x1b/0x80
  [59.199]  ? preempt_count_add+0x70/0xa0
  [59.199]  ? __x64_sys_ioctl+0x88/0xc0
  [59.199]  __x64_sys_ioctl+0x88/0xc0
  [59.199]  do_syscall_64+0x38/0x90
  [59.199]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.199] RIP: 0033:0x7f82ffaffe9b
  [59.199] RSP: 002b:00007f82ff9fcc50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.199] RAX: ffffffffffffffda RBX: 000055b191e36310 RCX: 00007f82ffaffe9b
  [59.199] RDX: 000055b191e36310 RSI: 00000000c400941b RDI: 0000000000000003
  [59.199] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
  [59.199] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82ff9fd640
  [59.199] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
  [59.199]  </TASK>
  [59.199] INFO: task btrfs:346773 blocked for more than 120 seconds.
  [59.200]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.200] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.201] task:btrfs           state:D stack:0     pid:346773 ppid:1      flags:0x00004002
  [59.201] Call Trace:
  [59.201]  <TASK>
  [59.201]  __schedule+0x392/0xa70
  [59.201]  ? __pv_queued_spin_lock_slowpath+0x165/0x370
  [59.201]  schedule+0x5d/0xd0
  [59.201]  __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
  [59.201]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.201]  scrub_pause_off+0x21/0x50 [btrfs]
  [59.202]  scrub_simple_mirror+0x1c7/0x950 [btrfs]
  [59.202]  ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
  [59.202]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.202]  scrub_stripe+0x20d/0x740 [btrfs]
  [59.202]  scrub_chunk+0xc4/0x130 [btrfs]
  [59.203]  scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
  [59.203]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.203]  btrfs_scrub_dev+0x236/0x6a0 [btrfs]
  [59.203]  ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
  [59.203]  ? _copy_from_user+0x7b/0x80
  [59.203]  btrfs_ioctl+0xde1/0x32c0 [btrfs]
  [59.204]  ? should_failslab+0xa/0x20
  [59.204]  ? kmem_cache_alloc_node+0x151/0x460
  [59.204]  ? alloc_io_context+0x1b/0x80
  [59.204]  ? preempt_count_add+0x70/0xa0
  [59.204]  ? __x64_sys_ioctl+0x88/0xc0
  [59.204]  __x64_sys_ioctl+0x88/0xc0
  [59.204]  do_syscall_64+0x38/0x90
  [59.204]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.204] RIP: 0033:0x7f82ffaffe9b
  [59.204] RSP: 002b:00007f82ff1fbc50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.204] RAX: ffffffffffffffda RBX: 000055b191e36790 RCX: 00007f82ffaffe9b
  [59.204] RDX: 000055b191e36790 RSI: 00000000c400941b RDI: 0000000000000003
  [59.204] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
  [59.204] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82ff1fc640
  [59.204] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
  [59.204]  </TASK>
  [59.204] INFO: task btrfs:346774 blocked for more than 120 seconds.
  [59.205]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.205] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.206] task:btrfs           state:D stack:0     pid:346774 ppid:1      flags:0x00004002
  [59.206] Call Trace:
  [59.206]  <TASK>
  [59.206]  __schedule+0x392/0xa70
  [59.206]  schedule+0x5d/0xd0
  [59.206]  __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
  [59.206]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.206]  scrub_pause_off+0x21/0x50 [btrfs]
  [59.207]  scrub_simple_mirror+0x1c7/0x950 [btrfs]
  [59.207]  ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
  [59.207]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.207]  scrub_stripe+0x20d/0x740 [btrfs]
  [59.208]  scrub_chunk+0xc4/0x130 [btrfs]
  [59.208]  scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
  [59.208]  ? __mutex_unlock_slowpath.isra.0+0x9a/0x120
  [59.208]  btrfs_scrub_dev+0x236/0x6a0 [btrfs]
  [59.208]  ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
  [59.209]  ? _copy_from_user+0x7b/0x80
  [59.209]  btrfs_ioctl+0xde1/0x32c0 [btrfs]
  [59.209]  ? should_failslab+0xa/0x20
  [59.209]  ? kmem_cache_alloc_node+0x151/0x460
  [59.209]  ? alloc_io_context+0x1b/0x80
  [59.209]  ? preempt_count_add+0x70/0xa0
  [59.209]  ? __x64_sys_ioctl+0x88/0xc0
  [59.209]  __x64_sys_ioctl+0x88/0xc0
  [59.209]  do_syscall_64+0x38/0x90
  [59.209]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.209] RIP: 0033:0x7f82ffaffe9b
  [59.209] RSP: 002b:00007f82fe9fac50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.209] RAX: ffffffffffffffda RBX: 000055b191e36c10 RCX: 00007f82ffaffe9b
  [59.209] RDX: 000055b191e36c10 RSI: 00000000c400941b RDI: 0000000000000003
  [59.209] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
  [59.209] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fe9fb640
  [59.209] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
  [59.209]  </TASK>
  [59.209] INFO: task btrfs:346775 blocked for more than 120 seconds.
  [59.210]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.210] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.211] task:btrfs           state:D stack:0     pid:346775 ppid:1      flags:0x00004002
  [59.211] Call Trace:
  [59.211]  <TASK>
  [59.211]  __schedule+0x392/0xa70
  [59.211]  schedule+0x5d/0xd0
  [59.211]  __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
  [59.211]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.211]  scrub_pause_off+0x21/0x50 [btrfs]
  [59.212]  scrub_simple_mirror+0x1c7/0x950 [btrfs]
  [59.212]  ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
  [59.212]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.212]  scrub_stripe+0x20d/0x740 [btrfs]
  [59.213]  scrub_chunk+0xc4/0x130 [btrfs]
  [59.213]  scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
  [59.213]  ? __mutex_unlock_slowpath.isra.0+0x9a/0x120
  [59.213]  btrfs_scrub_dev+0x236/0x6a0 [btrfs]
  [59.213]  ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
  [59.214]  ? _copy_from_user+0x7b/0x80
  [59.214]  btrfs_ioctl+0xde1/0x32c0 [btrfs]
  [59.214]  ? should_failslab+0xa/0x20
  [59.214]  ? kmem_cache_alloc_node+0x151/0x460
  [59.214]  ? alloc_io_context+0x1b/0x80
  [59.214]  ? preempt_count_add+0x70/0xa0
  [59.214]  ? __x64_sys_ioctl+0x88/0xc0
  [59.214]  __x64_sys_ioctl+0x88/0xc0
  [59.214]  do_syscall_64+0x38/0x90
  [59.214]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.214] RIP: 0033:0x7f82ffaffe9b
  [59.214] RSP: 002b:00007f82fe1f9c50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.214] RAX: ffffffffffffffda RBX: 000055b191e37090 RCX: 00007f82ffaffe9b
  [59.214] RDX: 000055b191e37090 RSI: 00000000c400941b RDI: 0000000000000003
  [59.214] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
  [59.214] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fe1fa640
  [59.214] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
  [59.214]  </TASK>
  [59.214] INFO: task btrfs:346776 blocked for more than 120 seconds.
  [59.215]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.216] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.217] task:btrfs           state:D stack:0     pid:346776 ppid:1      flags:0x00004002
  [59.217] Call Trace:
  [59.217]  <TASK>
  [59.217]  __schedule+0x392/0xa70
  [59.217]  ? __pv_queued_spin_lock_slowpath+0x165/0x370
  [59.217]  schedule+0x5d/0xd0
  [59.217]  __scrub_blocked_if_needed+0x74/0xc0 [btrfs]
  [59.217]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.217]  scrub_pause_off+0x21/0x50 [btrfs]
  [59.217]  scrub_simple_mirror+0x1c7/0x950 [btrfs]
  [59.217]  ? scrub_parity_put+0x1a5/0x1d0 [btrfs]
  [59.218]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.218]  scrub_stripe+0x20d/0x740 [btrfs]
  [59.218]  scrub_chunk+0xc4/0x130 [btrfs]
  [59.218]  scrub_enumerate_chunks+0x3e4/0x7a0 [btrfs]
  [59.219]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.219]  btrfs_scrub_dev+0x236/0x6a0 [btrfs]
  [59.219]  ? btrfs_ioctl+0xd97/0x32c0 [btrfs]
  [59.219]  ? _copy_from_user+0x7b/0x80
  [59.219]  btrfs_ioctl+0xde1/0x32c0 [btrfs]
  [59.219]  ? should_failslab+0xa/0x20
  [59.219]  ? kmem_cache_alloc_node+0x151/0x460
  [59.219]  ? alloc_io_context+0x1b/0x80
  [59.219]  ? preempt_count_add+0x70/0xa0
  [59.219]  ? __x64_sys_ioctl+0x88/0xc0
  [59.219]  __x64_sys_ioctl+0x88/0xc0
  [59.219]  do_syscall_64+0x38/0x90
  [59.219]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.219] RIP: 0033:0x7f82ffaffe9b
  [59.219] RSP: 002b:00007f82fd9f8c50 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.219] RAX: ffffffffffffffda RBX: 000055b191e37510 RCX: 00007f82ffaffe9b
  [59.219] RDX: 000055b191e37510 RSI: 00000000c400941b RDI: 0000000000000003
  [59.219] RBP: 0000000000000000 R08: 00007fff1575016f R09: 0000000000000000
  [59.219] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f82fd9f9640
  [59.219] R13: 000000000000006b R14: 00007f82ffa87580 R15: 0000000000000000
  [59.219]  </TASK>
  [59.219] INFO: task btrfs:346822 blocked for more than 120 seconds.
  [59.220]       Tainted: G        W          6.3.0-rc2-btrfs-next-127+ #1
  [59.221] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [59.222] task:btrfs           state:D stack:0     pid:346822 ppid:1      flags:0x00004002
  [59.222] Call Trace:
  [59.222]  <TASK>
  [59.222]  __schedule+0x392/0xa70
  [59.222]  schedule+0x5d/0xd0
  [59.222]  btrfs_scrub_cancel+0x91/0x100 [btrfs]
  [59.222]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.222]  btrfs_commit_transaction+0x572/0xeb0 [btrfs]
  [59.223]  ? start_transaction+0xcb/0x610 [btrfs]
  [59.223]  prepare_to_relocate+0x111/0x1a0 [btrfs]
  [59.223]  relocate_block_group+0x57/0x5d0 [btrfs]
  [59.223]  ? btrfs_wait_nocow_writers+0x25/0xb0 [btrfs]
  [59.223]  btrfs_relocate_block_group+0x248/0x3c0 [btrfs]
  [59.224]  ? __pfx_autoremove_wake_function+0x10/0x10
  [59.224]  btrfs_relocate_chunk+0x3b/0x150 [btrfs]
  [59.224]  btrfs_balance+0x8ff/0x11d0 [btrfs]
  [59.224]  ? __kmem_cache_alloc_node+0x14a/0x410
  [59.224]  btrfs_ioctl+0x2334/0x32c0 [btrfs]
  [59.225]  ? mod_objcg_state+0xd2/0x360
  [59.225]  ? refill_obj_stock+0xb0/0x160
  [59.225]  ? seq_release+0x25/0x30
  [59.225]  ? __rseq_handle_notify_resume+0x3b5/0x4b0
  [59.225]  ? percpu_counter_add_batch+0x2e/0xa0
  [59.225]  ? __x64_sys_ioctl+0x88/0xc0
  [59.225]  __x64_sys_ioctl+0x88/0xc0
  [59.225]  do_syscall_64+0x38/0x90
  [59.225]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [59.225] RIP: 0033:0x7f381a6ffe9b
  [59.225] RSP: 002b:00007ffd45ecf060 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [59.225] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f381a6ffe9b
  [59.225] RDX: 00007ffd45ecf150 RSI: 00000000c4009420 RDI: 0000000000000003
  [59.225] RBP: 0000000000000003 R08: 0000000000000013 R09: 0000000000000000
  [59.225] R10: 00007f381a60c878 R11: 0000000000000246 R12: 00007ffd45ed0423
  [59.225] R13: 00007ffd45ecf150 R14: 0000000000000000 R15: 00007ffd45ecf148
  [59.225]  </TASK>

What happens is the following:

1) A scrub is running, so fs_info->scrubs_running is 1;

2) Task A starts block group relocation, and at btrfs_relocate_chunk() it
   pauses scrub by calling btrfs_scrub_pause(). That increments
   fs_info->scrub_pause_req from 0 to 1 and waits for the scrub task to
   pause (for fs_info->scrubs_paused to be == to fs_info->scrubs_running);

3) The scrub task pauses at scrub_pause_off(), waiting for
   fs_info->scrub_pause_req to decrease to 0;

4) Task A then enters btrfs_relocate_block_group(), and down that call
   chain we start a transaction and then attempt to commit it;

5) When task A calls btrfs_commit_transaction(), it either will do the
   commit itself or wait for some other task that already started the
   commit of the transaction - it doesn't matter which case;

6) The transaction commit enters state TRANS_STATE_COMMIT_START;

7) An error happens during the transaction commit, like -ENOSPC when
   running delayed refs or delayed items for example;

8) This results in calling transaction.c:cleanup_transaction(), where
   we call btrfs_scrub_cancel(), incrementing fs_info->scrub_cancel_req
   from 0 to 1, and blocking this task waiting for fs_info->scrubs_running
   to decrease to 0;

9) From this point on, both the transaction commit and the scrub task
   hang forever:

   1) The transaction commit is waiting for fs_info->scrubs_running to
      be decreased to 0;

   2) The scrub task is at scrub_pause_off() waiting for
      fs_info->scrub_pause_req to decrease to 0 - so it can not proceed
      to stop the scrub and decrement fs_info->scrubs_running from 0 to 1.

   Therefore resulting in a deadlock.

Fix this by having cleanup_transaction(), called if a transaction commit
fails, not call btrfs_scrub_cancel() if relocation is in progress, and
having btrfs_relocate_block_group() call btrfs_scrub_cancel() instead if
the relocation failed and a transaction abort happened.

This was triggered with btrfs/061 from fstests.

Fixes: 55e3a601c81c ("btrfs: Fix data checksum error cause by replace with io-load.")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-06 12:10:51 +02:00
Josef Bacik
f5527b3b4d btrfs: use temporary variable for space_info in btrfs_update_block_group
[ Upstream commit df384da5a49cace5c5e3100803dfd563fd982f93 ]

We do

  cache->space_info->counter += num_bytes;

everywhere in here.  This is makes the lines longer than they need to
be, and will be especially noticeable when we add the active tracking in,
so add a temp variable for the space_info so this is cleaner.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06 12:10:42 +02:00
Josef Bacik
bd265f2061 btrfs: fix uninitialized variable warning in btrfs_update_block_group
[ Upstream commit efbf35a102b20246cfe4409c6ae92e72ecb67ab8 ]

reclaim isn't set in the alloc case, however we only care about
reclaim in the !alloc case.  This isn't an actual problem, however
-Wmaybe-uninitialized will complain, so initialize reclaim to quiet the
compiler.

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>
Stable-dep-of: df384da5a49c ("btrfs: use temporary variable for space_info in btrfs_update_block_group")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06 12:10:42 +02:00
Naohiro Aota
64621e4607 btrfs: zoned: count fresh BG region as zone unusable
[ Upstream commit fa2068d7e922b434eba5bfb0131e6d39febfdb48 ]

The naming of space_info->active_total_bytes is misleading. It counts
not only active block groups but also full ones which are previously
active but now inactive. That confusion results in a bug not counting
the full BGs into active_total_bytes on mount time.

For a background, there are three kinds of block groups in terms of
activation.

  1. Block groups never activated
  2. Block groups currently active
  3. Block groups previously active and currently inactive (due to fully
     written or zone finish)

What we really wanted to exclude from "total_bytes" is the total size of
BGs #1. They seem empty and allocatable but since they are not activated,
we cannot rely on them to do the space reservation.

And, since BGs #1 never get activated, they should have no "used",
"reserved" and "pinned" bytes.

OTOH, BGs #3 can be counted in the "total", since they are already full
we cannot allocate from them anyway. For them, "total_bytes == used +
reserved + pinned + zone_unusable" should hold.

Tracking #2 and #3 as "active_total_bytes" (current implementation) is
confusing. And, tracking #1 and subtract that properly from "total_bytes"
every time you need space reservation is cumbersome.

Instead, we can count the whole region of a newly allocated block group as
zone_unusable. Then, once that block group is activated, release
[0 ..  zone_capacity] from the zone_unusable counters. With this, we can
eliminate the confusing ->active_total_bytes and the code will be common
among regular and the zoned mode. Also, no additional counter is needed
with this approach.

Fixes: 6a921de58992 ("btrfs: zoned: introduce space_info->active_total_bytes")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06 12:10:35 +02:00
Josef Bacik
ea34b8bcc7 btrfs: rename BTRFS_FS_NO_OVERCOMMIT to BTRFS_FS_ACTIVE_ZONE_TRACKING
[ Upstream commit bf1f1fec2724a33b67ec12032402ea75f2a83622 ]

This flag only gets set when we're doing active zone tracking, and we're
going to need to use this flag for things related to this behavior.
Rename the flag to represent what it actually means for the file system
so it can be used in other ways and still make sense.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-04-06 12:10:35 +02:00
Naohiro Aota
00331677c0 btrfs: zoned: fix btrfs_can_activate_zone() to support DUP profile
commit 9e1cdf0c354e46e428c0e0cab008abbe81b6013d upstream.

btrfs_can_activate_zone() returns true if at least one device has one zone
available for activation. This is OK for the single profile, but not OK for
DUP profile. We need two zones to create a DUP block group. Fix it by
properly handling the case with the profile flags.

Fixes: 265f7237dd25 ("btrfs: zoned: allow DUP on meta-data block groups")
CC: stable@vger.kernel.org # 6.1+
Reviewed-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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-30 12:49:22 +02:00
Filipe Manana
6a9379eba1 btrfs: fix extent map logging bit not cleared for split maps after dropping range
[ Upstream commit e4cc1483f35940c9288c332dd275f6fad485f8d2 ]

At btrfs_drop_extent_map_range() we are clearing the EXTENT_FLAG_LOGGING
bit on a 'flags' variable that was not initialized. This makes static
checkers complain about it, so initialize the 'flags' variable before
clearing the bit.

In practice this has no consequences, because EXTENT_FLAG_LOGGING should
not be set when btrfs_drop_extent_map_range() is called, as an fsync locks
the inode in exclusive mode, locks the inode's mmap semaphore in exclusive
mode too and it always flushes all delalloc.

Also add a comment about why we clear EXTENT_FLAG_LOGGING on a copy of the
flags of the split extent map.

Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/Y%2FyipSVozUDEZKow@kili/
Fixes: db21370bffbc ("btrfs: drop extent map range more efficiently")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17 08:50:26 +01:00
Johannes Thumshirn
fceed91ea1 btrfs: fix percent calculation for bg reclaim message
commit 95cd356ca23c3807b5f3503687161e216b1c520d upstream.

We have a report, that the info message for block-group reclaim is
crossing the 100% used mark.

This is happening as we were truncating the divisor for the division
(the block_group->length) to a 32bit value.

Fix this by using div64_u64() to not truncate the divisor.

In the worst case, it can lead to a div by zero error and should be
possible to trigger on 4 disks RAID0, and each device is large enough:

  $ mkfs.btrfs  -f /dev/test/scratch[1234] -m raid1 -d raid0
  btrfs-progs v6.1
  [...]
  Filesystem size:    40.00GiB
  Block group profiles:
    Data:             RAID0             4.00GiB <<<
    Metadata:         RAID1           256.00MiB
    System:           RAID1             8.00MiB

Reported-by: Forza <forza@tnonline.net>
Link: https://lore.kernel.org/linux-btrfs/e99483.c11a58d.1863591ca52@tnonline.net/
Fixes: 5f93e776c673 ("btrfs: zoned: print unusable percentage when reclaiming block groups")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add Qu's note ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17 08:50:14 +01:00
Naohiro Aota
99d232798c btrfs: fix unnecessary increment of read error stat on write error
commit 98e8d36a26c2ed22f78316df7d4bf33e554b9f9f upstream.

Current btrfs_log_dev_io_error() increases the read error count even if the
erroneous IO is a WRITE request. This is because it forget to use "else
if", and all the error WRITE requests counts as READ error as there is (of
course) no REQ_RAHEAD bit set.

Fixes: c3a62baf21ad ("btrfs: use chained bios when cloning")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17 08:50:14 +01:00
Boris Burkov
9b59fb27d4 btrfs: hold block group refcount during async discard
commit 2b5463fcbdfb24e898916bcae2b1359042d26963 upstream.

Async discard does not acquire the block group reference count while it
holds a reference on the discard list. This is generally OK, as the
paths which destroy block groups tend to try to synchronize on
cancelling async discard work. However, relying on cancelling work
requires careful analysis to be sure it is safe from races with
unpinning scheduling more work.

While I am unable to find a race with unpinning in the current code for
either the unused bgs or relocation paths, I believe we have one in an
older version of auto relocation in a Meta internal build. This suggests
that this is in fact an error prone model, and could be fragile to
future changes to these bg deletion paths.

To make this ownership more clear, add a refcount for async discard. If
work is queued for a block group, its refcount should be incremented,
and when work is completed or canceled, it should be decremented.

CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-10 09:34:06 +01:00
Qu Wenruo
063c7d86ee btrfs: scrub: improve tree block error reporting
[ Upstream commit 28232909ba43561887508a6ef46d7f33a648f375 ]

[BUG]
When debugging a scrub related metadata error, it turns out that our
metadata error reporting is not ideal.

The only 3 error messages are:

- BTRFS error (device dm-2): bdev /dev/mapper/test-scratch1 errs: wr 0, rd 0, flush 0, corrupt 0, gen 1
  Showing we have metadata generation mismatch errors.

- BTRFS error (device dm-2): unable to fixup (regular) error at logical 7110656 on dev /dev/mapper/test-scratch1
  Showing which tree blocks are corrupted.

- BTRFS warning (device dm-2): checksum/header error at logical 24772608 on dev /dev/mapper/test-scratch2, physical 3801088: metadata node (level 1) in tree 5
  Showing which physical range the corrupted metadata is at.

We have to combine the above 3 to know we have a corrupted metadata with
generation mismatch.

And this is already the better case, if we have other problems, like
fsid mismatch, we can not even know the cause.

[CAUSE]
The problem is caused by the fact that, scrub_checksum_tree_block()
never outputs any error message.

It just return two bits for scrub: sblock->header_error, and
sblock->generation_error.

And later we report error in scrub_print_warning(), but unfortunately we
only have two bits, there is not really much thing we can done to print
any detailed errors.

[FIX]
This patch will do the following to enhance the error reporting of
metadata scrub:

- Add extra warning (ratelimited) for every error we hit
  This can help us to distinguish the different types of errors.
  Some errors can help us to know what's going wrong immediately,
  like bytenr mismatch.

- Re-order the checks
  Currently we check bytenr first, then immediately generation.
  This can lead to false generation mismatch reports, while the fsid
  mismatches.

Here is the new output for the bug I'm debugging (we forgot to
writeback tree blocks for commit roots):

 BTRFS warning (device dm-2): tree block 24117248 mirror 1 has bad fsid, has b77cd862-f150-4c71-90ec-7baf0544d83f want 17df6abf-23cd-445f-b350-5b3e40bfd2fc
 BTRFS warning (device dm-2): tree block 24117248 mirror 0 has bad fsid, has b77cd862-f150-4c71-90ec-7baf0544d83f want 17df6abf-23cd-445f-b350-5b3e40bfd2fc

Now we can immediately know it's some tree blocks didn't even get written
back, other than the original confusing generation mismatch.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-10 09:33:46 +01:00
David Sterba
07c5877e14 btrfs: send: limit number of clones and allocated memory size
[ Upstream commit 33e17b3f5ab74af12aca58c515bc8424ff69a343 ]

The arg->clone_sources_count is u64 and can trigger a warning when a
huge value is passed from user space and a huge array is allocated.
Limit the allocated memory to 8MiB (can be increased if needed), which
in turn limits the number of clone sources to 8M / sizeof(struct
clone_root) = 8M / 40 = 209715.  Real world number of clones is from
tens to hundreds, so this is future proof.

Reported-by: syzbot+4376a9a073770c173269@syzkaller.appspotmail.com
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-03 11:52:21 +01:00
Filipe Manana
d8c594da79 btrfs: lock the inode in shared mode before starting fiemap
[ Upstream commit 519b7e13b5ae8dd38da1e52275705343be6bb508 ]

Currently fiemap does not take the inode's lock (VFS lock), it only locks
a file range in the inode's io tree. This however can lead to a deadlock
if we have a concurrent fsync on the file and fiemap code triggers a fault
when accessing the user space buffer with fiemap_fill_next_extent(). The
deadlock happens on the inode's i_mmap_lock semaphore, which is taken both
by fsync and btrfs_page_mkwrite(). This deadlock was recently reported by
syzbot and triggers a trace like the following:

   task:syz-executor361 state:D stack:20264 pid:5668  ppid:5119   flags:0x00004004
   Call Trace:
    <TASK>
    context_switch kernel/sched/core.c:5293 [inline]
    __schedule+0x995/0xe20 kernel/sched/core.c:6606
    schedule+0xcb/0x190 kernel/sched/core.c:6682
    wait_on_state fs/btrfs/extent-io-tree.c:707 [inline]
    wait_extent_bit+0x577/0x6f0 fs/btrfs/extent-io-tree.c:751
    lock_extent+0x1c2/0x280 fs/btrfs/extent-io-tree.c:1742
    find_lock_delalloc_range+0x4e6/0x9c0 fs/btrfs/extent_io.c:488
    writepage_delalloc+0x1ef/0x540 fs/btrfs/extent_io.c:1863
    __extent_writepage+0x736/0x14e0 fs/btrfs/extent_io.c:2174
    extent_write_cache_pages+0x983/0x1220 fs/btrfs/extent_io.c:3091
    extent_writepages+0x219/0x540 fs/btrfs/extent_io.c:3211
    do_writepages+0x3c3/0x680 mm/page-writeback.c:2581
    filemap_fdatawrite_wbc+0x11e/0x170 mm/filemap.c:388
    __filemap_fdatawrite_range mm/filemap.c:421 [inline]
    filemap_fdatawrite_range+0x175/0x200 mm/filemap.c:439
    btrfs_fdatawrite_range fs/btrfs/file.c:3850 [inline]
    start_ordered_ops fs/btrfs/file.c:1737 [inline]
    btrfs_sync_file+0x4ff/0x1190 fs/btrfs/file.c:1839
    generic_write_sync include/linux/fs.h:2885 [inline]
    btrfs_do_write_iter+0xcd3/0x1280 fs/btrfs/file.c:1684
    call_write_iter include/linux/fs.h:2189 [inline]
    new_sync_write fs/read_write.c:491 [inline]
    vfs_write+0x7dc/0xc50 fs/read_write.c:584
    ksys_write+0x177/0x2a0 fs/read_write.c:637
    do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
    entry_SYSCALL_64_after_hwframe+0x63/0xcd
   RIP: 0033:0x7f7d4054e9b9
   RSP: 002b:00007f7d404fa2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
   RAX: ffffffffffffffda RBX: 00007f7d405d87a0 RCX: 00007f7d4054e9b9
   RDX: 0000000000000090 RSI: 0000000020000000 RDI: 0000000000000006
   RBP: 00007f7d405a51d0 R08: 0000000000000000 R09: 0000000000000000
   R10: 0000000000000000 R11: 0000000000000246 R12: 61635f65646f6e69
   R13: 65646f7475616f6e R14: 7261637369646f6e R15: 00007f7d405d87a8
    </TASK>
   INFO: task syz-executor361:5697 blocked for more than 145 seconds.
         Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
   "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
   task:syz-executor361 state:D stack:21216 pid:5697  ppid:5119   flags:0x00004004
   Call Trace:
    <TASK>
    context_switch kernel/sched/core.c:5293 [inline]
    __schedule+0x995/0xe20 kernel/sched/core.c:6606
    schedule+0xcb/0x190 kernel/sched/core.c:6682
    rwsem_down_read_slowpath+0x5f9/0x930 kernel/locking/rwsem.c:1095
    __down_read_common+0x54/0x2a0 kernel/locking/rwsem.c:1260
    btrfs_page_mkwrite+0x417/0xc80 fs/btrfs/inode.c:8526
    do_page_mkwrite+0x19e/0x5e0 mm/memory.c:2947
    wp_page_shared+0x15e/0x380 mm/memory.c:3295
    handle_pte_fault mm/memory.c:4949 [inline]
    __handle_mm_fault mm/memory.c:5073 [inline]
    handle_mm_fault+0x1b79/0x26b0 mm/memory.c:5219
    do_user_addr_fault+0x69b/0xcb0 arch/x86/mm/fault.c:1428
    handle_page_fault arch/x86/mm/fault.c:1519 [inline]
    exc_page_fault+0x7a/0x110 arch/x86/mm/fault.c:1575
    asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
   RIP: 0010:copy_user_short_string+0xd/0x40 arch/x86/lib/copy_user_64.S:233
   Code: 74 0a 89 (...)
   RSP: 0018:ffffc9000570f330 EFLAGS: 00050202
   RAX: ffffffff843e6601 RBX: 00007fffffffefc8 RCX: 0000000000000007
   RDX: 0000000000000000 RSI: ffffc9000570f3e0 RDI: 0000000020000120
   RBP: ffffc9000570f490 R08: 0000000000000000 R09: fffff52000ae1e83
   R10: fffff52000ae1e83 R11: 1ffff92000ae1e7c R12: 0000000000000038
   R13: ffffc9000570f3e0 R14: 0000000020000120 R15: ffffc9000570f3e0
    copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
    raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
    _copy_to_user+0xe9/0x130 lib/usercopy.c:34
    copy_to_user include/linux/uaccess.h:169 [inline]
    fiemap_fill_next_extent+0x22e/0x410 fs/ioctl.c:144
    emit_fiemap_extent+0x22d/0x3c0 fs/btrfs/extent_io.c:3458
    fiemap_process_hole+0xa00/0xad0 fs/btrfs/extent_io.c:3716
    extent_fiemap+0xe27/0x2100 fs/btrfs/extent_io.c:3922
    btrfs_fiemap+0x172/0x1e0 fs/btrfs/inode.c:8209
    ioctl_fiemap fs/ioctl.c:219 [inline]
    do_vfs_ioctl+0x185b/0x2980 fs/ioctl.c:810
    __do_sys_ioctl fs/ioctl.c:868 [inline]
    __se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
    do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
    entry_SYSCALL_64_after_hwframe+0x63/0xcd
   RIP: 0033:0x7f7d4054e9b9
   RSP: 002b:00007f7d390d92f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
   RAX: ffffffffffffffda RBX: 00007f7d405d87b0 RCX: 00007f7d4054e9b9
   RDX: 0000000020000100 RSI: 00000000c020660b RDI: 0000000000000005
   RBP: 00007f7d405a51d0 R08: 00007f7d390d9700 R09: 0000000000000000
   R10: 00007f7d390d9700 R11: 0000000000000246 R12: 61635f65646f6e69
   R13: 65646f7475616f6e R14: 7261637369646f6e R15: 00007f7d405d87b8
    </TASK>

What happens is the following:

1) Task A is doing an fsync, enters btrfs_sync_file() and flushes delalloc
   before locking the inode and the i_mmap_lock semaphore, that is, before
   calling btrfs_inode_lock();

2) After task A flushes delalloc and before it calls btrfs_inode_lock(),
   another task dirties a page;

3) Task B starts a fiemap without FIEMAP_FLAG_SYNC, so the page dirtied
   at step 2 remains dirty and unflushed. Then when it enters
   extent_fiemap() and it locks a file range that includes the range of
   the page dirtied in step 2;

4) Task A calls btrfs_inode_lock() and locks the inode (VFS lock) and the
   inode's i_mmap_lock semaphore in write mode. Then it tries to flush
   delalloc by calling start_ordered_ops(), which will block, at
   find_lock_delalloc_range(), when trying to lock the range of the page
   dirtied at step 2, since this range was locked by the fiemap task (at
   step 3);

5) Task B generates a page fault when accessing the user space fiemap
   buffer with a call to fiemap_fill_next_extent().

   The fault handler needs to call btrfs_page_mkwrite() for some other
   page of our inode, and there we deadlock when trying to lock the
   inode's i_mmap_lock semaphore in read mode, since the fsync task locked
   it in write mode (step 4) and the fsync task can not progress because
   it's waiting to lock a file range that is currently locked by us (the
   fiemap task, step 3).

Fix this by taking the inode's lock (VFS lock) in shared mode when
entering fiemap. This effectively serializes fiemap with fsync (except the
most expensive part of fsync, the log sync), preventing this deadlock.

Reported-by: syzbot+cc35f55c41e34c30dcb5@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000032dc7305f2a66f46@google.com/
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-22 12:59:40 +01:00
Josef Bacik
f2e0134b43 btrfs: move the auto defrag code to defrag.c
[ Upstream commit 6e3df18ba7e8e68015dd66bcab326a4b7aaed085 ]

This currently exists in file.c, move it to the more natural location in
defrag.c.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ reformat comments ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 519b7e13b5ae ("btrfs: lock the inode in shared mode before starting fiemap")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-22 12:59:40 +01:00
Anand Jain
51aa10112b btrfs: free device in btrfs_close_devices for a single device filesystem
commit 5f58d783fd7823b2c2d5954d1126e702f94bfc4c upstream.

We have this check to make sure we don't accidentally add older devices
that may have disappeared and re-appeared with an older generation from
being added to an fs_devices (such as a replace source device). This
makes sense, we don't want stale disks in our file system. However for
single disks this doesn't really make sense.

I've seen this in testing, but I was provided a reproducer from a
project that builds btrfs images on loopback devices. The loopback
device gets cached with the new generation, and then if it is re-used to
generate a new file system we'll fail to mount it because the new fs is
"older" than what we have in cache.

Fix this by freeing the cache when closing the device for a single device
filesystem. This will ensure that the mount command passed device path is
scanned successfully during the next mount.

CC: stable@vger.kernel.org # 5.10+
Reported-by: Daan De Meyer <daandemeyer@fb.com>
Signed-off-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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-14 19:11:52 +01:00
Filipe Manana
1ab4bed3fc btrfs: simplify update of last_dir_index_offset when logging a directory
commit 6afaed53cc9adde69d8a76ff5b4d740d5efbc54c upstream.

When logging a directory, we always set the inode's last_dir_index_offset
to the offset of the last dir index item we found. This is using an extra
field in the log context structure, and it makes more sense to update it
only after we insert dir index items, and we could directly update the
inode's last_dir_index_offset field instead.

So make this simpler by updating the inode's last_dir_index_offset only
when we actually insert dir index keys in the log tree, and getting rid
of the last_dir_item_offset field in the log context structure.

Reported-by: David Arendt <admin@prnet.org>
Link: https://lore.kernel.org/linux-btrfs/ae169fc6-f504-28f0-a098-6fa6a4dfb612@leemhuis.info/
Reported-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/Y8voyTXdnPDz8xwY@mail.gmail.com/
Reported-by: Hunter Wardlaw <wardlawhunter@gmail.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1207231
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216851
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-14 19:11:52 +01:00
Alexander Potapenko
8ab575add3 btrfs: zlib: zero-initialize zlib workspace
commit eadd7deca0ad8a83edb2b894d8326c78e78635d6 upstream.

KMSAN reports uses of uninitialized memory in zlib's longest_match()
called on memory originating from zlib_alloc_workspace().
This issue is known by zlib maintainers and is claimed to be harmless,
but to be on the safe side we'd better initialize the memory.

Link: https://zlib.net/zlib_faq.html#faq36
Reported-by: syzbot+14d9e7602ebdf7ec0a60@syzkaller.appspotmail.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-14 19:11:40 +01:00
Josef Bacik
66cf3a8273 btrfs: limit device extents to the device size
commit 3c538de0f2a74d50aff7278c092f88ae59cee688 upstream.

There was a recent regression in btrfs/177 that started happening with
the size class patches ("btrfs: introduce size class to block group
allocator").  This however isn't a regression introduced by those
patches, but rather the bug was uncovered by a change in behavior in
these patches.  The patches triggered more chunk allocations in the
^free-space-tree case, which uncovered a race with device shrink.

The problem is we will set the device total size to the new size, and
use this to find a hole for a device extent.  However during shrink we
may have device extents allocated past this range, so we could
potentially find a hole in a range past our new shrink size.  We don't
actually limit our found extent to the device size anywhere, we assume
that we will not find a hole past our device size.  This isn't true with
shrink as we're relocating block groups and thus creating holes past the
device size.

Fix this by making sure we do not search past the new device size, and
if we wander into any device extents that start after our device size
simply break from the loop and use whatever hole we've already found.

CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-14 19:11:40 +01:00
Al Viro
5a19095103 use less confusing names for iov_iter direction initializers
[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ]

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Stable-dep-of: 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-09 11:28:04 +01:00
Naohiro Aota
c19bd0d897 btrfs: zoned: enable metadata over-commit for non-ZNS setup
[ Upstream commit 85e79ec7b78f863178ca488fd8cb5b3de6347756 ]

The commit 79417d040f4f ("btrfs: zoned: disable metadata overcommit for
zoned") disabled the metadata over-commit to track active zones properly.

However, it also introduced a heavy overhead by allocating new metadata
block groups and/or flushing dirty buffers to release the space
reservations. Specifically, a workload (write only without any sync
operations) worsen its performance from 343.77 MB/sec (v5.19) to 182.89
MB/sec (v6.0).

The performance is still bad on current misc-next which is 187.95 MB/sec.
And, with this patch applied, it improves back to 326.70 MB/sec (+73.82%).

This patch introduces a new fs_info->flag BTRFS_FS_NO_OVERCOMMIT to
indicate it needs to disable the metadata over-commit. The flag is enabled
when a device with max active zones limit is loaded into a file-system.

Fixes: 79417d040f4f ("btrfs: zoned: disable metadata overcommit for zoned")
CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-02-01 08:34:34 +01:00
Filipe Manana
1004fc90f0 btrfs: fix race between quota rescan and disable leading to NULL pointer deref
commit b7adbf9ada3513d2092362c8eac5cddc5b651f5c upstream.

If we have one task trying to start the quota rescan worker while another
one is trying to disable quotas, we can end up hitting a race that results
in the quota rescan worker doing a NULL pointer dereference. The steps for
this are the following:

1) Quotas are enabled;

2) Task A calls the quota rescan ioctl and enters btrfs_qgroup_rescan().
   It calls qgroup_rescan_init() which returns 0 (success) and then joins a
   transaction and commits it;

3) Task B calls the quota disable ioctl and enters btrfs_quota_disable().
   It clears the bit BTRFS_FS_QUOTA_ENABLED from fs_info->flags and calls
   btrfs_qgroup_wait_for_completion(), which returns immediately since the
   rescan worker is not yet running.
   Then it starts a transaction and locks fs_info->qgroup_ioctl_lock;

4) Task A queues the rescan worker, by calling btrfs_queue_work();

5) The rescan worker starts, and calls rescan_should_stop() at the start
   of its while loop, which results in 0 iterations of the loop, since
   the flag BTRFS_FS_QUOTA_ENABLED was cleared from fs_info->flags by
   task B at step 3);

6) Task B sets fs_info->quota_root to NULL;

7) The rescan worker tries to start a transaction and uses
   fs_info->quota_root as the root argument for btrfs_start_transaction().
   This results in a NULL pointer dereference down the call chain of
   btrfs_start_transaction(). The stack trace is something like the one
   reported in Link tag below:

   general protection fault, probably for non-canonical address 0xdffffc0000000041: 0000 [#1] PREEMPT SMP KASAN
   KASAN: null-ptr-deref in range [0x0000000000000208-0x000000000000020f]
   CPU: 1 PID: 34 Comm: kworker/u4:2 Not tainted 6.1.0-syzkaller-13872-gb6bb9676f216 #0
   Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
   Workqueue: btrfs-qgroup-rescan btrfs_work_helper
   RIP: 0010:start_transaction+0x48/0x10f0 fs/btrfs/transaction.c:564
   Code: 48 89 fb 48 (...)
   RSP: 0018:ffffc90000ab7ab0 EFLAGS: 00010206
   RAX: 0000000000000041 RBX: 0000000000000208 RCX: ffff88801779ba80
   RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
   RBP: dffffc0000000000 R08: 0000000000000001 R09: fffff52000156f5d
   R10: fffff52000156f5d R11: 1ffff92000156f5c R12: 0000000000000000
   R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000003
   FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 00007f2bea75b718 CR3: 000000001d0cc000 CR4: 00000000003506e0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   Call Trace:
    <TASK>
    btrfs_qgroup_rescan_worker+0x3bb/0x6a0 fs/btrfs/qgroup.c:3402
    btrfs_work_helper+0x312/0x850 fs/btrfs/async-thread.c:280
    process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
    worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
    kthread+0x266/0x300 kernel/kthread.c:376
    ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
    </TASK>
   Modules linked in:

So fix this by having the rescan worker function not attempt to start a
transaction if it didn't do any rescan work.

Reported-by: syzbot+96977faa68092ad382c4@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000e5454b05f065a803@google.com/
Fixes: e804861bd4e6 ("btrfs: fix deadlock between quota disable and qgroup rescan worker")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
8af00fc7b6 btrfs: fix invalid leaf access due to inline extent during lseek
commit 1f55ee6d0901d915801618bda0af4e5b937e3db7 upstream.

During lseek, for SEEK_DATA and SEEK_HOLE modes, we access the disk_bytenr
of an extent without checking its type. However inline extents have their
data starting the offset of the disk_bytenr field, so accessing that field
when we have an inline extent can result in either of the following:

1) Interpret the inline extent's data as a disk_bytenr value;

2) In case the inline data is less than 8 bytes, we access part of some
   other item in the leaf, or unused space in the leaf;

3) In case the inline data is less than 8 bytes and the extent item is
   the first item in the leaf, we can access beyond the leaf's limit.

So fix this by not accessing the disk_bytenr field if we have an inline
extent.

Fixes: b6e833567ea1 ("btrfs: make hole and data seeking a lot more efficient")
Reported-by: Matthias Schoepfer <matthias.schoepfer@googlemail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216908
Link: https://lore.kernel.org/linux-btrfs/7f25442f-b121-2a3a-5a3d-22bcaae83cd4@leemhuis.info/
CC: stable@vger.kernel.org # 6.1
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Qu Wenruo
bb2c2e6253 btrfs: qgroup: do not warn on record without old_roots populated
commit 75181406b4eafacc531ff2ee5fb032bd93317e2b upstream.

[BUG]
There are some reports from the mailing list that since v6.1 kernel, the
WARN_ON() inside btrfs_qgroup_account_extent() gets triggered during
rescan:

  WARNING: CPU: 3 PID: 6424 at fs/btrfs/qgroup.c:2756 btrfs_qgroup_account_extents+0x1ae/0x260 [btrfs]
  CPU: 3 PID: 6424 Comm: snapperd Tainted: P           OE      6.1.2-1-default #1 openSUSE Tumbleweed 05c7a1b1b61d5627475528f71f50444637b5aad7
  RIP: 0010:btrfs_qgroup_account_extents+0x1ae/0x260 [btrfs]
  Call Trace:
   <TASK>
  btrfs_commit_transaction+0x30c/0xb40 [btrfs c39c9c546c241c593f03bd6d5f39ea1b676250f6]
   ? start_transaction+0xc3/0x5b0 [btrfs c39c9c546c241c593f03bd6d5f39ea1b676250f6]
  btrfs_qgroup_rescan+0x42/0xc0 [btrfs c39c9c546c241c593f03bd6d5f39ea1b676250f6]
   btrfs_ioctl+0x1ab9/0x25c0 [btrfs c39c9c546c241c593f03bd6d5f39ea1b676250f6]
   ? __rseq_handle_notify_resume+0xa9/0x4a0
   ? mntput_no_expire+0x4a/0x240
   ? __seccomp_filter+0x319/0x4d0
   __x64_sys_ioctl+0x90/0xd0
   do_syscall_64+0x5b/0x80
   ? syscall_exit_to_user_mode+0x17/0x40
   ? do_syscall_64+0x67/0x80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  RIP: 0033:0x7fd9b790d9bf
   </TASK>

[CAUSE]
Since commit e15e9f43c7ca ("btrfs: introduce
BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting"), if
our qgroup is already in inconsistent state, we will no longer do the
time-consuming backref walk.

This can leave some qgroup records without a valid old_roots ulist.
Normally this is fine, as btrfs_qgroup_account_extents() would also skip
those records if we have NO_ACCOUNTING flag set.

But there is a small window, if we have NO_ACCOUNTING flag set, and
inserted some qgroup_record without a old_roots ulist, but then the user
triggered a qgroup rescan.

During btrfs_qgroup_rescan(), we firstly clear NO_ACCOUNTING flag, then
commit current transaction.

And since we have a qgroup_record with old_roots = NULL, we trigger the
WARN_ON() during btrfs_qgroup_account_extents().

[FIX]
Unfortunately due to the introduction of NO_ACCOUNTING flag, the
assumption that every qgroup_record would have its old_roots populated
is no longer correct.

Fix the false alerts and drop the WARN_ON().

Reported-by: Lukas Straub <lukasstraub2@web.de>
Reported-by: HanatoK <summersnow9403@gmail.com>
Fixes: e15e9f43c7ca ("btrfs: introduce BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting")
CC: stable@vger.kernel.org # 6.1
Link: https://lore.kernel.org/linux-btrfs/2403c697-ddaf-58ad-3829-0335fc89df09@gmail.com/
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
34fe5b527e btrfs: do not abort transaction on failure to update log root
commit 09e44868f1e03c7825ca4283256abedc95e249a3 upstream.

When syncing a log, if we fail to update a log root in the log root tree,
we are aborting the transaction if the failure was not -ENOSPC. This is
excessive because there is a chance that a transaction commit can succeed,
and therefore avoid to turn the filesystem into RO mode. All we need to be
careful about is to mark the log for a full commit, which we already do,
to make sure no one commits a super block pointing to an outdated log root
tree.

So don't abort the transaction if we fail to update a log root in the log
root tree, and log an error if the failure is not -ENOSPC, so that it does
not go completely unnoticed.

CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
23ffd7fc23 btrfs: do not abort transaction on failure to write log tree when syncing log
commit 16199ad9eb6db60a6b10794a09fc1ac6d09312ff upstream.

When syncing the log, if we fail to write log tree extent buffers, we mark
the log for a full commit and abort the transaction. However we don't need
to abort the transaction, all we really need to do is to make sure no one
can commit a superblock pointing to new log tree roots. Just because we
got a failure writing extent buffers for a log tree, it does not mean we
will also fail to do a transaction commit.

One particular case is if due to a bug somewhere, when writing log tree
extent buffers, the tree checker detects some corruption and the writeout
fails because of that. Aborting the transaction can be very disruptive for
a user, specially if the issue happened on a root filesystem. One example
is the scenario in the Link tag below, where an isolated corruption on log
tree leaves was causing transaction aborts when syncing the log.

Link: https://lore.kernel.org/linux-btrfs/ae169fc6-f504-28f0-a098-6fa6a4dfb612@leemhuis.info/
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
076fb040d4 btrfs: add missing setup of log for full commit at add_conflicting_inode()
commit 94cd63ae679973edeb5ea95ec25a54467c3e54c8 upstream.

When logging conflicting inodes, if we reach the maximum limit of inodes,
we return BTRFS_LOG_FORCE_COMMIT to force a transaction commit. However
we don't mark the log for full commit (with btrfs_set_log_full_commit()),
which means that once we leave the log transaction and before we commit
the transaction, some other task may sync the log, which is incomplete
as we have not logged all conflicting inodes, leading to some inconsistent
in case that log ends up being replayed.

So also call btrfs_set_log_full_commit() at add_conflicting_inode().

Fixes: e09d94c9e448 ("btrfs: log conflicting inodes without holding log mutex of the initial inode")
CC: stable@vger.kernel.org # 6.1
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
f4c0df59e0 btrfs: fix directory logging due to race with concurrent index key deletion
commit 8bb6898da6271d82d8e76d8088d66b971a7dcfa6 upstream.

Sometimes we log a directory without holding its VFS lock, so while we
logging it, dir index entries may be added or removed. This typically
happens when logging a dentry from a parent directory that points to a
new directory, through log_new_dir_dentries(), or when while logging
some other inode we also need to log its parent directories (through
btrfs_log_all_parents()).

This means that while we are at log_dir_items(), we may not find a dir
index key we found before, because it was deleted in the meanwhile, so
a call to btrfs_search_slot() may return 1 (key not found). In that case
we return from log_dir_items() with a success value (the variable 'err'
has a value of 0). This can lead to a few problems, specially in the case
where the variable 'last_offset' has a value of (u64)-1 (and it's
initialized to that when it was declared):

1) By returning from log_dir_items() with success (0) and a value of
   (u64)-1 for '*last_offset_ret', we end up not logging any other dir
   index keys that follow the missing, just deleted, index key. The
   (u64)-1 value makes log_directory_changes() not call log_dir_items()
   again;

2) Before returning with success (0), log_dir_items(), will log a dir
   index range item covering a range from the last old dentry index
   (stored in the variable 'last_old_dentry_offset') to the value of
   'last_offset'. If 'last_offset' has a value of (u64)-1, then it means
   if the log is persisted and replayed after a power failure, it will
   cause deletion of all the directory entries that have an index number
   between last_old_dentry_offset + 1 and (u64)-1;

3) We can end up returning from log_dir_items() with
   ctx->last_dir_item_offset having a lower value than
   inode->last_dir_index_offset, because the former is set to the current
   key we are processing at process_dir_items_leaf(), and at the end of
   log_directory_changes() we set inode->last_dir_index_offset to the
   current value of ctx->last_dir_item_offset. So if for example a
   deletion of a lower dir index key happened, we set
   ctx->last_dir_item_offset to that index value, then if we return from
   log_dir_items() because btrfs_search_slot() returned 1, we end up
   returning from log_dir_items() with success (0) and then
   log_directory_changes() sets inode->last_dir_index_offset to a lower
   value than it had before.
   This can result in unpredictable and unexpected behaviour when we
   need to log again the directory in the same transaction, and can result
   in ending up with a log tree leaf that has duplicated keys, as we do
   batch insertions of dir index keys into a log tree.

So fix this by making log_dir_items() move on to the next dir index key
if it does not find the one it was looking for.

Reported-by: David Arendt <admin@prnet.org>
Link: https://lore.kernel.org/linux-btrfs/ae169fc6-f504-28f0-a098-6fa6a4dfb612@leemhuis.info/
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Filipe Manana
168492decb btrfs: fix missing error handling when logging directory items
commit 6d3d970b2735b967650d319be27268fedc5598d1 upstream.

When logging a directory, at log_dir_items(), if we get an error when
attempting to search the subvolume tree for a dir index item, we end up
returning 0 (success) from log_dir_items() because 'err' is left with a
value of 0.

This can lead to a few problems, specially in the case the variable
'last_offset' has a value of (u64)-1 (and it's initialized to that when
it was declared):

1) By returning from log_dir_items() with success (0) and a value of
   (u64)-1 for '*last_offset_ret', we end up not logging any other dir
   index keys that follow the missing, just deleted, index key. The
   (u64)-1 value makes log_directory_changes() not call log_dir_items()
   again;

2) Before returning with success (0), log_dir_items(), will log a dir
   index range item covering a range from the last old dentry index
   (stored in the variable 'last_old_dentry_offset') to the value of
   'last_offset'. If 'last_offset' has a value of (u64)-1, then it means
   if the log is persisted and replayed after a power failure, it will
   cause deletion of all the directory entries that have an index number
   between last_old_dentry_offset + 1 and (u64)-1;

3) We can end up returning from log_dir_items() with
   ctx->last_dir_item_offset having a lower value than
   inode->last_dir_index_offset, because the former is set to the current
   key we are processing at process_dir_items_leaf(), and at the end of
   log_directory_changes() we set inode->last_dir_index_offset to the
   current value of ctx->last_dir_item_offset. So if for example a
   deletion of a lower dir index key happened, we set
   ctx->last_dir_item_offset to that index value, then if we return from
   log_dir_items() because btrfs_search_slot() returned an error, we end up
   returning without any error from log_dir_items() and then
   log_directory_changes() sets inode->last_dir_index_offset to a lower
   value than it had before.
   This can result in unpredictable and unexpected behaviour when we
   need to log again the directory in the same transaction, and can result
   in ending up with a log tree leaf that has duplicated keys, as we do
   batch insertions of dir index keys into a log tree.

Fix this by setting 'err' to the value of 'ret' in case
btrfs_search_slot() or btrfs_previous_item() returned an error. That will
result in falling back to a full transaction commit.

Reported-by: David Arendt <admin@prnet.org>
Link: https://lore.kernel.org/linux-btrfs/ae169fc6-f504-28f0-a098-6fa6a4dfb612@leemhuis.info/
Fixes: e02119d5a7b4 ("Btrfs: Add a write ahead tree log to optimize synchronous operations")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Qu Wenruo
6ec8411329 btrfs: add extra error messages to cover non-ENOMEM errors from device_add_list()
commit ed02363fbbed52a3f5ea0d188edd09045a806eb5 upstream.

[BUG]
When test case btrfs/219 (aka, mount a registered device but with a lower
generation) failed, there is not any useful information for the end user
to find out what's going wrong.

The mount failure just looks like this:

  #  mount -o loop /tmp/219.img2 /mnt/btrfs/
  mount: /mnt/btrfs: mount(2) system call failed: File exists.
         dmesg(1) may have more information after failed mount system call.

While the dmesg contains nothing but the loop device change:

  loop1: detected capacity change from 0 to 524288

[CAUSE]
In device_list_add() we have a lot of extra checks to reject invalid
cases.

That function also contains the regular device scan result like the
following prompt:

  BTRFS: device fsid 6222333e-f9f1-47e6-b306-55ddd4dcaef4 devid 1 transid 8 /dev/loop0 scanned by systemd-udevd (3027)

But unfortunately not all errors have their own error messages, thus if
we hit something wrong in device_add_list(), there may be no error
messages at all.

[FIX]
Add errors message for all non-ENOMEM errors.

For ENOMEM, I'd say we're in a much worse situation, and there should be
some OOM messages way before our call sites.

CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-24 07:24:36 +01:00
Qu Wenruo
853ffa1511 btrfs: always report error in run_one_delayed_ref()
[ Upstream commit 39f501d68ec1ed5cd5c66ac6ec2a7131c517bb92 ]

Currently we have a btrfs_debug() for run_one_delayed_ref() failure, but
if end users hit such problem, there will be no chance that
btrfs_debug() is enabled.  This can lead to very little useful info for
debugging.

This patch will:

- Add extra info for error reporting
  Including:
  * logical bytenr
  * num_bytes
  * type
  * action
  * ref_mod

- Replace the btrfs_debug() with btrfs_err()

- Move the error reporting into run_one_delayed_ref()
  This is to avoid use-after-free, the @node can be freed in the caller.

This error should only be triggered at most once.

As if run_one_delayed_ref() failed, we trigger the error message, then
causing the call chain to error out:

btrfs_run_delayed_refs()
`- btrfs_run_delayed_refs()
   `- btrfs_run_delayed_refs_for_head()
      `- run_one_delayed_ref()

And we will abort the current transaction in btrfs_run_delayed_refs().
If we have to run delayed refs for the abort transaction,
run_one_delayed_ref() will just cleanup the refs and do nothing, thus no
new error messages would be output.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-24 07:24:31 +01:00
Qu Wenruo
53e9d6851b btrfs: handle case when repair happens with dev-replace
[ Upstream commit d73a27b86fc722c28a26ec64002e3a7dc86d1c07 ]

[BUG]
There is a bug report that a BUG_ON() in btrfs_repair_io_failure()
(originally repair_io_failure() in v6.0 kernel) got triggered when
replacing a unreliable disk:

  BTRFS warning (device sda1): csum failed root 257 ino 2397453 off 39624704 csum 0xb0d18c75 expected csum 0x4dae9c5e mirror 3
  kernel BUG at fs/btrfs/extent_io.c:2380!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 9 PID: 3614331 Comm: kworker/u257:2 Tainted: G           OE      6.0.0-5-amd64 #1  Debian 6.0.10-2
  Hardware name: Micro-Star International Co., Ltd. MS-7C60/TRX40 PRO WIFI (MS-7C60), BIOS 2.70 07/01/2021
  Workqueue: btrfs-endio btrfs_end_bio_work [btrfs]
  RIP: 0010:repair_io_failure+0x24a/0x260 [btrfs]
  Call Trace:
   <TASK>
   clean_io_failure+0x14d/0x180 [btrfs]
   end_bio_extent_readpage+0x412/0x6e0 [btrfs]
   ? __switch_to+0x106/0x420
   process_one_work+0x1c7/0x380
   worker_thread+0x4d/0x380
   ? rescuer_thread+0x3a0/0x3a0
   kthread+0xe9/0x110
   ? kthread_complete_and_exit+0x20/0x20
   ret_from_fork+0x22/0x30

[CAUSE]

Before the BUG_ON(), we got some read errors from the replace target
first, note the mirror number (3, which is beyond RAID1 duplication,
thus it's read from the replace target device).

Then at the BUG_ON() location, we are trying to writeback the repaired
sectors back the failed device.

The check looks like this:

		ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
				      &map_length, &bioc, mirror_num);
		if (ret)
			goto out_counter_dec;
		BUG_ON(mirror_num != bioc->mirror_num);

But inside btrfs_map_block(), we can modify bioc->mirror_num especially
for dev-replace:

	if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
	    !need_full_stripe(op) && dev_replace->tgtdev != NULL) {
		ret = get_extra_mirror_from_replace(fs_info, logical, *length,
						    dev_replace->srcdev->devid,
						    &mirror_num,
					    &physical_to_patch_in_first_stripe);
		patch_the_first_stripe_for_dev_replace = 1;
	}

Thus if we're repairing the replace target device, we're going to
trigger that BUG_ON().

But in reality, the read failure from the replace target device may be
that, our replace hasn't reached the range we're reading, thus we're
reading garbage, but with replace running, the range would be properly
filled later.

Thus in that case, we don't need to do anything but let the replace
routine to handle it.

[FIX]
Instead of a BUG_ON(), just skip the repair if we're repairing the
device replace target device.

Reported-by: 小太 <nospam@kota.moe>
Link: https://lore.kernel.org/linux-btrfs/CACsxjPYyJGQZ+yvjzxA1Nn2LuqkYqTCcUH43S=+wXhyf8S00Ag@mail.gmail.com/
CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-12 12:02:55 +01:00
Sasha Levin
e92536de04 btrfs: fix an error handling path in btrfs_defrag_leaves()
[ Upstream commit db0a4a7b8e95f9312a59a67cbd5bc589f090e13d ]

All error handling paths end to 'out', except this memory allocation
failure.

This is spurious. So branch to the error handling path also in this case.
It will add a call to:

	memset(&root->defrag_progress, 0,
	       sizeof(root->defrag_progress));

Fixes: 6702ed490ca0 ("Btrfs: Add run time btree defrag, and an ioctl to force btree defrag")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-12 12:01:56 +01:00
Qu Wenruo
def94d5966 btrfs: fix compat_ro checks against remount
commit 2ba48b20049b5a76f34a85f853c9496d1b10533a upstream.

[BUG]
Even with commit 81d5d61454c3 ("btrfs: enhance unsupported compat RO
flags handling"), btrfs can still mount a fs with unsupported compat_ro
flags read-only, then remount it RW:

  # btrfs ins dump-super /dev/loop0 | grep compat_ro_flags -A 3
  compat_ro_flags		0x403
			( FREE_SPACE_TREE |
			  FREE_SPACE_TREE_VALID |
			  unknown flag: 0x400 )

  # mount /dev/loop0 /mnt/btrfs
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/loop0, missing codepage or helper program, or other error.
         dmesg(1) may have more information after failed mount system call.
  ^^^ RW mount failed as expected ^^^

  # dmesg -t | tail -n5
  loop0: detected capacity change from 0 to 1048576
  BTRFS: device fsid cb5b82f5-0fdd-4d81-9b4b-78533c324afa devid 1 transid 7 /dev/loop0 scanned by mount (1146)
  BTRFS info (device loop0): using crc32c (crc32c-intel) checksum algorithm
  BTRFS info (device loop0): using free space tree
  BTRFS error (device loop0): cannot mount read-write because of unknown compat_ro features (0x403)
  BTRFS error (device loop0): open_ctree failed

  # mount /dev/loop0 -o ro /mnt/btrfs
  # mount -o remount,rw /mnt/btrfs
  ^^^ RW remount succeeded unexpectedly ^^^

[CAUSE]
Currently we use btrfs_check_features() to check compat_ro flags against
our current mount flags.

That function get reused between open_ctree() and btrfs_remount().

But for btrfs_remount(), the super block we passed in still has the old
mount flags, thus btrfs_check_features() still believes we're mounting
read-only.

[FIX]
Replace the existing @sb argument with @is_rw_mount.

As originally we only use @sb to determine if the mount is RW.

Now it's callers' responsibility to determine if the mount is RW, and
since there are only two callers, the check is pretty simple:

- caller in open_ctree()
  Just pass !sb_rdonly().

- caller in btrfs_remount()
  Pass !(*flags & SB_RDONLY), as our check should be against the new
  flags.

Now we can correctly reject the RW remount:

  # mount /dev/loop0 -o ro /mnt/btrfs
  # mount -o remount,rw /mnt/btrfs
  mount: /mnt/btrfs: mount point not mounted or bad option.
         dmesg(1) may have more information after failed mount system call.
  # dmesg -t | tail -n 1
  BTRFS error (device loop0: state M): cannot mount read-write because of unknown compat_ro features (0x403)

Reported-by: Chung-Chiang Cheng <shepjeng@gmail.com>
Fixes: 81d5d61454c3 ("btrfs: enhance unsupported compat RO flags handling")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-12 12:01:56 +01:00
Filipe Manana
427a36cf81 btrfs: fix off-by-one in delalloc search during lseek
commit 2f2e84ca60660402bd81d0859703567c59556e6a upstream.

During lseek, when searching for delalloc in a range that represents a
hole and that range has a length of 1 byte, we end up not doing the actual
delalloc search in the inode's io tree, resulting in not correctly
reporting the offset with data or a hole. This actually only happens when
the start offset is 0 because with any other start offset we round it down
by sector size.

Reproducer:

  $ mkfs.btrfs -f /dev/sdc
  $ mount /dev/sdc /mnt/sdc

  $ xfs_io -f -c "pwrite -q 0 1" /mnt/sdc/foo

  $ xfs_io -c "seek -d 0" /mnt/sdc/foo
  Whence   Result
  DATA	   EOF

It should have reported an offset of 0 instead of EOF.

Fix this by updating btrfs_find_delalloc_in_range() and count_range_bits()
to deal with inclusive ranges properly. These functions are already
supposed to work with inclusive end offsets, they just got it wrong in a
couple places due to off-by-one mistakes.

A test case for fstests will be added later.

Reported-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/20221223020509.457113-1-joanbrugueram@gmail.com/
Fixes: b6e833567ea1 ("btrfs: make hole and data seeking a lot more efficient")
CC: stable@vger.kernel.org # 6.1
Tested-by: Joan Bruguera Micó <joanbrugueram@gmail.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-12 12:01:56 +01:00
Sasha Levin
0af9640736 btrfs: replace strncpy() with strscpy()
[ Upstream commit 63d5429f68a3d4c4aa27e65a05196c17f86c41d6 ]

Using strncpy() on NUL-terminated strings are deprecated.  To avoid
possible forming of non-terminated string strscpy() should be used.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-12 12:01:55 +01:00
Boris Burkov
a94b90ac1f btrfs: fix resolving backrefs for inline extent followed by prealloc
commit 560840afc3e63bbe5d9c5ef6b2ecf8f3589adff6 upstream.

If a file consists of an inline extent followed by a regular or prealloc
extent, then a legitimate attempt to resolve a logical address in the
non-inline region will result in add_all_parents reading the invalid
offset field of the inline extent. If the inline extent item is placed
in the leaf eb s.t. it is the first item, attempting to access the
offset field will not only be meaningless, it will go past the end of
the eb and cause this panic:

  [17.626048] BTRFS warning (device dm-2): bad eb member end: ptr 0x3fd4 start 30834688 member offset 16377 size 8
  [17.631693] general protection fault, probably for non-canonical address 0x5088000000000: 0000 [#1] SMP PTI
  [17.635041] CPU: 2 PID: 1267 Comm: btrfs Not tainted 5.12.0-07246-g75175d5adc74-dirty #199
  [17.637969] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [17.641995] RIP: 0010:btrfs_get_64+0xe7/0x110
  [17.649890] RSP: 0018:ffffc90001f73a08 EFLAGS: 00010202
  [17.651652] RAX: 0000000000000001 RBX: ffff88810c42d000 RCX: 0000000000000000
  [17.653921] RDX: 0005088000000000 RSI: ffffc90001f73a0f RDI: 0000000000000001
  [17.656174] RBP: 0000000000000ff9 R08: 0000000000000007 R09: c0000000fffeffff
  [17.658441] R10: ffffc90001f73790 R11: ffffc90001f73788 R12: ffff888106afe918
  [17.661070] R13: 0000000000003fd4 R14: 0000000000003f6f R15: cdcdcdcdcdcdcdcd
  [17.663617] FS:  00007f64e7627d80(0000) GS:ffff888237c80000(0000) knlGS:0000000000000000
  [17.666525] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [17.668664] CR2: 000055d4a39152e8 CR3: 000000010c596002 CR4: 0000000000770ee0
  [17.671253] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [17.673634] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [17.676034] PKRU: 55555554
  [17.677004] Call Trace:
  [17.677877]  add_all_parents+0x276/0x480
  [17.679325]  find_parent_nodes+0xfae/0x1590
  [17.680771]  btrfs_find_all_leafs+0x5e/0xa0
  [17.682217]  iterate_extent_inodes+0xce/0x260
  [17.683809]  ? btrfs_inode_flags_to_xflags+0x50/0x50
  [17.685597]  ? iterate_inodes_from_logical+0xa1/0xd0
  [17.687404]  iterate_inodes_from_logical+0xa1/0xd0
  [17.689121]  ? btrfs_inode_flags_to_xflags+0x50/0x50
  [17.691010]  btrfs_ioctl_logical_to_ino+0x131/0x190
  [17.692946]  btrfs_ioctl+0x104a/0x2f60
  [17.694384]  ? selinux_file_ioctl+0x182/0x220
  [17.695995]  ? __x64_sys_ioctl+0x84/0xc0
  [17.697394]  __x64_sys_ioctl+0x84/0xc0
  [17.698697]  do_syscall_64+0x33/0x40
  [17.700017]  entry_SYSCALL_64_after_hwframe+0x44/0xae
  [17.701753] RIP: 0033:0x7f64e72761b7
  [17.709355] RSP: 002b:00007ffefb067f58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  [17.712088] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f64e72761b7
  [17.714667] RDX: 00007ffefb067fb0 RSI: 00000000c0389424 RDI: 0000000000000003
  [17.717386] RBP: 00007ffefb06d188 R08: 000055d4a390d2b0 R09: 00007f64e7340a60
  [17.719938] R10: 0000000000000231 R11: 0000000000000246 R12: 0000000000000001
  [17.722383] R13: 0000000000000000 R14: 00000000c0389424 R15: 000055d4a38fd2a0
  [17.724839] Modules linked in:

Fix the bug by detecting the inline extent item in add_all_parents and
skipping to the next extent item.

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:38 +01:00
void0red
169a4cf468 btrfs: fix extent map use-after-free when handling missing device in read_one_chunk
commit 1742e1c90c3da344f3bb9b1f1309b3f47482756a upstream.

Store the error code before freeing the extent_map. Though it's
reference counted structure, in that function it's the first and last
allocation so this would lead to a potential use-after-free.

The error can happen eg. when chunk is stored on a missing device and
the degraded mount option is missing.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216721
Reported-by: eriri <1527030098@qq.com>
Fixes: adfb69af7d8c ("btrfs: add_missing_dev() should return the actual error")
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: void0red <void0red@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:38 +01:00
Josef Bacik
712b093816 btrfs: fix uninitialized parent in insert_state
commit d7c9e1be2876f63fb2178a24e0c1d5733ff98d47 upstream.

I don't know how this isn't caught when we build this in the kernel, but
while syncing extent-io-tree.c into btrfs-progs I got an error because
parent could potentially be uninitialized when we link in a new node,
specifically when the extent_io_tree is empty.  This means we could have
garbage in the parent color.  I don't know what the ramifications are of
that, but it's probably not great, so fix this by initializing parent to
NULL.  I spot checked all of our other usages in btrfs and we appear to
be doing the correct thing everywhere else.

Fixes: c7e118cf98c7 ("btrfs: open code rbtree search in insert_state")
CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-01-07 11:11:38 +01:00
Filipe Manana
1baf3370e2 btrfs: do not BUG_ON() on ENOMEM when dropping extent items for a range
commit 162d053e15fe985f754ef495a96eb3db970c43ed upstream.

If we get -ENOMEM while dropping file extent items in a given range, at
btrfs_drop_extents(), due to failure to allocate memory when attempting to
increment the reference count for an extent or drop the reference count,
we handle it with a BUG_ON(). This is excessive, instead we can simply
abort the transaction and return the error to the caller. In fact most
callers of btrfs_drop_extents(), directly or indirectly, already abort
the transaction if btrfs_drop_extents() returns any error.

Also, we already have error paths at btrfs_drop_extents() that may return
-ENOMEM and in those cases we abort the transaction, like for example
anything that changes the b+tree may return -ENOMEM due to a failure to
allocate a new extent buffer when COWing an existing extent buffer, such
as a call to btrfs_duplicate_item() for example.

So replace the BUG_ON() calls with proper logic to abort the transaction
and return the error.

Reported-by: syzbot+0b1fb6b0108c27419f9f@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000089773e05ee4b9cb4@google.com/
CC: stable@vger.kernel.org # 5.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-12-31 13:33:11 +01:00
Josef Bacik
ef7cf3c923 btrfs: do not panic if we can't allocate a prealloc extent state
[ Upstream commit 5a75034e71ef5ec0fce983afcb6c9cb0147cd5b9 ]

We sometimes have to allocate new extent states when clearing or setting
new bits in an extent io tree.  Generally we preallocate this before
taking the tree spin lock, but we can use this preallocated extent state
sometimes and then need to try to do a GFP_ATOMIC allocation under the
lock.

Unfortunately sometimes this fails, and then we hit the BUG_ON() and
bring the box down.  This happens roughly 20 times a week in our fleet.

However the vast majority of callers use GFP_NOFS, which means that if
this GFP_ATOMIC allocation fails, we could simply drop the spin lock, go
back and allocate a new extent state with our given gfp mask, and begin
again from where we left off.

For the remaining callers that do not use GFP_NOFS, they are generally
using GFP_NOWAIT, which still allows for some reclaim.  So allow these
allocations to attempt to happen outside of the spin lock so we don't
need to rely on GFP_ATOMIC allocations.

This in essence creates an infinite loop for anything that isn't
GFP_NOFS.  To address this we may want to migrate to using mempools for
extent states so that we will always have emergency reserves in order to
make our allocations.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:32:58 +01:00
Linus Torvalds
3eaea0db25 for-6.1-rc6-tag
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Merge tag 'for-6.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix a regression in nowait + buffered write

 - in zoned mode fix endianness when comparing super block generation

 - locking and lockdep fixes:
     - fix potential sleeping under spinlock when setting qgroup limit
     - lockdep warning fixes when btrfs_path is freed after copy_to_user
     - do not modify log tree while holding a leaf from fs tree locked

 - fix freeing of sysfs files of static features on error

 - use kv.alloc for zone map allocation as a fallback to avoid warnings
   due to high order allocation

 - send, avoid unaligned encoded writes when attempting to clone range

* tag 'for-6.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs()
  btrfs: do not modify log tree while holding a leaf from fs tree locked
  btrfs: use kvcalloc in btrfs_get_dev_zone_info
  btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
  btrfs: send: avoid unaligned encoded writes when attempting to clone range
  btrfs: zoned: fix missing endianness conversion in sb_write_pointer
  btrfs: free btrfs_path before copying subvol info to userspace
  btrfs: free btrfs_path before copying fspath to userspace
  btrfs: free btrfs_path before copying inodes to userspace
  btrfs: free btrfs_path before copying root refs to userspace
  btrfs: fix assertion failure and blocking during nowait buffered write
2022-11-25 13:24:05 -08:00
Zhen Lei
ffdbb44f2f btrfs: sysfs: normalize the error handling branch in btrfs_init_sysfs()
Although kset_unregister() can eventually remove all attribute files,
explicitly rolling back with the matching function makes the code logic
look clearer.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:52:22 +01:00
Filipe Manana
796787c978 btrfs: do not modify log tree while holding a leaf from fs tree locked
When logging an inode in full mode, or when logging xattrs or when logging
the dir index items of a directory, we are modifying the log tree while
holding a read lock on a leaf from the fs/subvolume tree. This can lead to
a deadlock in rare circumstances, but it is a real possibility, and it was
recently reported by syzbot with the following trace from lockdep:

   WARNING: possible circular locking dependency detected
   6.1.0-rc5-next-20221116-syzkaller #0 Not tainted
   ------------------------------------------------------
   syz-executor.1/16154 is trying to acquire lock:
   ffff88807e3084a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256

   but task is already holding lock:
   ffff88807df33078 (btrfs-log-00){++++}-{3:3}, at: __btrfs_tree_lock+0x32/0x3d0 fs/btrfs/locking.c:197

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #2 (btrfs-log-00){++++}-{3:3}:
          down_read_nested+0x9e/0x450 kernel/locking/rwsem.c:1634
          __btrfs_tree_read_lock+0x32/0x350 fs/btrfs/locking.c:135
          btrfs_tree_read_lock fs/btrfs/locking.c:141 [inline]
          btrfs_read_lock_root_node+0x82/0x3a0 fs/btrfs/locking.c:280
          btrfs_search_slot_get_root fs/btrfs/ctree.c:1678 [inline]
          btrfs_search_slot+0x3ca/0x2c70 fs/btrfs/ctree.c:1998
          btrfs_lookup_csum+0x116/0x3f0 fs/btrfs/file-item.c:209
          btrfs_csum_file_blocks+0x40e/0x1370 fs/btrfs/file-item.c:1021
          log_csums.isra.0+0x244/0x2d0 fs/btrfs/tree-log.c:4258
          copy_items.isra.0+0xbfb/0xed0 fs/btrfs/tree-log.c:4403
          copy_inode_items_to_log+0x13d6/0x1d90 fs/btrfs/tree-log.c:5873
          btrfs_log_inode+0xb19/0x4680 fs/btrfs/tree-log.c:6495
          btrfs_log_inode_parent+0x890/0x2a20 fs/btrfs/tree-log.c:6982
          btrfs_log_dentry_safe+0x59/0x80 fs/btrfs/tree-log.c:7083
          btrfs_sync_file+0xa41/0x13c0 fs/btrfs/file.c:1921
          vfs_fsync_range+0x13e/0x230 fs/sync.c:188
          generic_write_sync include/linux/fs.h:2856 [inline]
          iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128
          btrfs_direct_write fs/btrfs/file.c:1536 [inline]
          btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668
          call_write_iter include/linux/fs.h:2160 [inline]
          do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735
          do_iter_write+0x182/0x700 fs/read_write.c:861
          vfs_iter_write+0x74/0xa0 fs/read_write.c:902
          iter_file_splice_write+0x745/0xc90 fs/splice.c:686
          do_splice_from fs/splice.c:764 [inline]
          direct_splice_actor+0x114/0x180 fs/splice.c:931
          splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886
          do_splice_direct+0x1ab/0x280 fs/splice.c:974
          do_sendfile+0xb19/0x1270 fs/read_write.c:1255
          __do_sys_sendfile64 fs/read_write.c:1323 [inline]
          __se_sys_sendfile64 fs/read_write.c:1309 [inline]
          __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309
          do_syscall_x64 arch/x86/entry/common.c:50 [inline]
          do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
          entry_SYSCALL_64_after_hwframe+0x63/0xcd

   -> #1 (btrfs-tree-00){++++}-{3:3}:
          __lock_release kernel/locking/lockdep.c:5382 [inline]
          lock_release+0x371/0x810 kernel/locking/lockdep.c:5688
          up_write+0x2a/0x520 kernel/locking/rwsem.c:1614
          btrfs_tree_unlock_rw fs/btrfs/locking.h:189 [inline]
          btrfs_unlock_up_safe+0x1e3/0x290 fs/btrfs/locking.c:238
          search_leaf fs/btrfs/ctree.c:1832 [inline]
          btrfs_search_slot+0x265e/0x2c70 fs/btrfs/ctree.c:2074
          btrfs_insert_empty_items+0xbd/0x1c0 fs/btrfs/ctree.c:4133
          btrfs_insert_delayed_item+0x826/0xfa0 fs/btrfs/delayed-inode.c:746
          btrfs_insert_delayed_items fs/btrfs/delayed-inode.c:824 [inline]
          __btrfs_commit_inode_delayed_items fs/btrfs/delayed-inode.c:1111 [inline]
          __btrfs_run_delayed_items+0x280/0x590 fs/btrfs/delayed-inode.c:1153
          flush_space+0x147/0xe90 fs/btrfs/space-info.c:728
          btrfs_async_reclaim_metadata_space+0x541/0xc10 fs/btrfs/space-info.c:1086
          process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
          worker_thread+0x669/0x1090 kernel/workqueue.c:2436
          kthread+0x2e8/0x3a0 kernel/kthread.c:376
          ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

   -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
          check_prev_add kernel/locking/lockdep.c:3097 [inline]
          check_prevs_add kernel/locking/lockdep.c:3216 [inline]
          validate_chain kernel/locking/lockdep.c:3831 [inline]
          __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055
          lock_acquire kernel/locking/lockdep.c:5668 [inline]
          lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
          __mutex_lock_common kernel/locking/mutex.c:603 [inline]
          __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747
          __btrfs_release_delayed_node.part.0+0xa1/0xf30 fs/btrfs/delayed-inode.c:256
          __btrfs_release_delayed_node fs/btrfs/delayed-inode.c:251 [inline]
          btrfs_release_delayed_node fs/btrfs/delayed-inode.c:281 [inline]
          btrfs_remove_delayed_node+0x52/0x60 fs/btrfs/delayed-inode.c:1285
          btrfs_evict_inode+0x511/0xf30 fs/btrfs/inode.c:5554
          evict+0x2ed/0x6b0 fs/inode.c:664
          dispose_list+0x117/0x1e0 fs/inode.c:697
          prune_icache_sb+0xeb/0x150 fs/inode.c:896
          super_cache_scan+0x391/0x590 fs/super.c:106
          do_shrink_slab+0x464/0xce0 mm/vmscan.c:843
          shrink_slab_memcg mm/vmscan.c:912 [inline]
          shrink_slab+0x388/0x660 mm/vmscan.c:991
          shrink_node_memcgs mm/vmscan.c:6088 [inline]
          shrink_node+0x93d/0x1f30 mm/vmscan.c:6117
          shrink_zones mm/vmscan.c:6355 [inline]
          do_try_to_free_pages+0x3b4/0x17a0 mm/vmscan.c:6417
          try_to_free_mem_cgroup_pages+0x3a4/0xa70 mm/vmscan.c:6732
          reclaim_high.constprop.0+0x182/0x230 mm/memcontrol.c:2393
          mem_cgroup_handle_over_high+0x190/0x520 mm/memcontrol.c:2578
          try_charge_memcg+0xe0c/0x12f0 mm/memcontrol.c:2816
          try_charge mm/memcontrol.c:2827 [inline]
          charge_memcg+0x90/0x3b0 mm/memcontrol.c:6889
          __mem_cgroup_charge+0x2b/0x90 mm/memcontrol.c:6910
          mem_cgroup_charge include/linux/memcontrol.h:667 [inline]
          __filemap_add_folio+0x615/0xf80 mm/filemap.c:852
          filemap_add_folio+0xaf/0x1e0 mm/filemap.c:934
          __filemap_get_folio+0x389/0xd80 mm/filemap.c:1976
          pagecache_get_page+0x2e/0x280 mm/folio-compat.c:104
          find_or_create_page include/linux/pagemap.h:612 [inline]
          alloc_extent_buffer+0x2b9/0x1580 fs/btrfs/extent_io.c:4588
          btrfs_init_new_buffer fs/btrfs/extent-tree.c:4869 [inline]
          btrfs_alloc_tree_block+0x2e1/0x1320 fs/btrfs/extent-tree.c:4988
          __btrfs_cow_block+0x3b2/0x1420 fs/btrfs/ctree.c:440
          btrfs_cow_block+0x2fa/0x950 fs/btrfs/ctree.c:595
          btrfs_search_slot+0x11b0/0x2c70 fs/btrfs/ctree.c:2038
          btrfs_update_root+0xdb/0x630 fs/btrfs/root-tree.c:137
          update_log_root fs/btrfs/tree-log.c:2841 [inline]
          btrfs_sync_log+0xbfb/0x2870 fs/btrfs/tree-log.c:3064
          btrfs_sync_file+0xdb9/0x13c0 fs/btrfs/file.c:1947
          vfs_fsync_range+0x13e/0x230 fs/sync.c:188
          generic_write_sync include/linux/fs.h:2856 [inline]
          iomap_dio_complete+0x73a/0x920 fs/iomap/direct-io.c:128
          btrfs_direct_write fs/btrfs/file.c:1536 [inline]
          btrfs_do_write_iter+0xba2/0x1470 fs/btrfs/file.c:1668
          call_write_iter include/linux/fs.h:2160 [inline]
          do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735
          do_iter_write+0x182/0x700 fs/read_write.c:861
          vfs_iter_write+0x74/0xa0 fs/read_write.c:902
          iter_file_splice_write+0x745/0xc90 fs/splice.c:686
          do_splice_from fs/splice.c:764 [inline]
          direct_splice_actor+0x114/0x180 fs/splice.c:931
          splice_direct_to_actor+0x335/0x8a0 fs/splice.c:886
          do_splice_direct+0x1ab/0x280 fs/splice.c:974
          do_sendfile+0xb19/0x1270 fs/read_write.c:1255
          __do_sys_sendfile64 fs/read_write.c:1323 [inline]
          __se_sys_sendfile64 fs/read_write.c:1309 [inline]
          __x64_sys_sendfile64+0x259/0x2c0 fs/read_write.c:1309
          do_syscall_x64 arch/x86/entry/common.c:50 [inline]
          do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
          entry_SYSCALL_64_after_hwframe+0x63/0xcd

   other info that might help us debug this:

   Chain exists of:
     &delayed_node->mutex --> btrfs-tree-00 --> btrfs-log-00

   Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(btrfs-log-00);
                                  lock(btrfs-tree-00);
                                  lock(btrfs-log-00);
     lock(&delayed_node->mutex);

Holding a read lock on a leaf from a fs/subvolume tree creates a nasty
lock dependency when we are COWing extent buffers for the log tree and we
have two tasks modifying the log tree, with each one in one of the
following 2 scenarios:

1) Modifying the log tree triggers an extent buffer allocation while
   holding a write lock on a parent extent buffer from the log tree.
   Allocating the pages for an extent buffer, or the extent buffer
   struct, can trigger inode eviction and finally the inode eviction
   will trigger a release/remove of a delayed node, which requires
   taking the delayed node's mutex;

2) Allocating a metadata extent for a log tree can trigger the async
   reclaim thread and make us wait for it to release enough space and
   unblock our reservation ticket. The reclaim thread can start flushing
   delayed items, and that in turn results in the need to lock delayed
   node mutexes and in the need to write lock extent buffers of a
   subvolume tree - all this while holding a write lock on the parent
   extent buffer in the log tree.

So one task in scenario 1) running in parallel with another task in
scenario 2) could lead to a deadlock, one wanting to lock a delayed node
mutex while having a read lock on a leaf from the subvolume, while the
other is holding the delayed node's mutex and wants to write lock the same
subvolume leaf for flushing delayed items.

Fix this by cloning the leaf of the fs/subvolume tree, release/unlock the
fs/subvolume leaf and use the clone leaf instead.

Reported-by: syzbot+9b7c21f486f5e7f8d029@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/000000000000ccc93c05edc4d8cf@google.com/
CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:52:15 +01:00
Christoph Hellwig
8fe97d47b5 btrfs: use kvcalloc in btrfs_get_dev_zone_info
Otherwise the kernel memory allocator seems to be unhappy about failing
order 6 allocations for the zones array, that cause 100% reproducible
mount failures in my qemu setup:

  [26.078981] mount: page allocation failure: order:6, mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO), nodemask=(null)
  [26.079741] CPU: 0 PID: 2965 Comm: mount Not tainted 6.1.0-rc5+ #185
  [26.080181] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
  [26.080950] Call Trace:
  [26.081132]  <TASK>
  [26.081291]  dump_stack_lvl+0x56/0x6f
  [26.081554]  warn_alloc+0x117/0x140
  [26.081808]  ? __alloc_pages_direct_compact+0x1b5/0x300
  [26.082174]  __alloc_pages_slowpath.constprop.0+0xd0e/0xde0
  [26.082569]  __alloc_pages+0x32a/0x340
  [26.082836]  __kmalloc_large_node+0x4d/0xa0
  [26.083133]  ? trace_kmalloc+0x29/0xd0
  [26.083399]  kmalloc_large+0x14/0x60
  [26.083654]  btrfs_get_dev_zone_info+0x1b9/0xc00
  [26.083980]  ? _raw_spin_unlock_irqrestore+0x28/0x50
  [26.084328]  btrfs_get_dev_zone_info_all_devices+0x54/0x80
  [26.084708]  open_ctree+0xed4/0x1654
  [26.084974]  btrfs_mount_root.cold+0x12/0xde
  [26.085288]  ? lock_is_held_type+0xe2/0x140
  [26.085603]  legacy_get_tree+0x28/0x50
  [26.085876]  vfs_get_tree+0x1d/0xb0
  [26.086139]  vfs_kern_mount.part.0+0x6c/0xb0
  [26.086456]  btrfs_mount+0x118/0x3a0
  [26.086728]  ? lock_is_held_type+0xe2/0x140
  [26.087043]  legacy_get_tree+0x28/0x50
  [26.087323]  vfs_get_tree+0x1d/0xb0
  [26.087587]  path_mount+0x2ba/0xbe0
  [26.087850]  ? _raw_spin_unlock_irqrestore+0x38/0x50
  [26.088217]  __x64_sys_mount+0xfe/0x140
  [26.088506]  do_syscall_64+0x35/0x80
  [26.088776]  entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-23 16:51:50 +01:00
ChenXiaoSong
f7e942b5bb btrfs: qgroup: fix sleep from invalid context bug in btrfs_qgroup_inherit()
Syzkaller reported BUG as follows:

  BUG: sleeping function called from invalid context at
       include/linux/sched/mm.h:274
  Call Trace:
   <TASK>
   dump_stack_lvl+0xcd/0x134
   __might_resched.cold+0x222/0x26b
   kmem_cache_alloc+0x2e7/0x3c0
   update_qgroup_limit_item+0xe1/0x390
   btrfs_qgroup_inherit+0x147b/0x1ee0
   create_subvol+0x4eb/0x1710
   btrfs_mksubvol+0xfe5/0x13f0
   __btrfs_ioctl_snap_create+0x2b0/0x430
   btrfs_ioctl_snap_create_v2+0x25a/0x520
   btrfs_ioctl+0x2a1c/0x5ce0
   __x64_sys_ioctl+0x193/0x200
   do_syscall_64+0x35/0x80

Fix this by calling qgroup_dirty() on @dstqgroup, and update limit item in
btrfs_run_qgroups() later outside of the spinlock context.

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:57:52 +01:00
Filipe Manana
a11452a370 btrfs: send: avoid unaligned encoded writes when attempting to clone range
When trying to see if we can clone a file range, there are cases where we
end up sending two write operations in case the inode from the source root
has an i_size that is not sector size aligned and the length from the
current offset to its i_size is less than the remaining length we are
trying to clone.

Issuing two write operations when we could instead issue a single write
operation is not incorrect. However it is not optimal, specially if the
extents are compressed and the flag BTRFS_SEND_FLAG_COMPRESSED was passed
to the send ioctl. In that case we can end up sending an encoded write
with an offset that is not sector size aligned, which makes the receiver
fallback to decompressing the data and writing it using regular buffered
IO (so re-compressing the data in case the fs is mounted with compression
enabled), because encoded writes fail with -EINVAL when an offset is not
sector size aligned.

The following example, which triggered a bug in the receiver code for the
fallback logic of decompressing + regular buffer IO and is fixed by the
patchset referred in a Link at the bottom of this changelog, is an example
where we have the non-optimal behaviour due to an unaligned encoded write:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/sdj
   MNT=/mnt/sdj

   mkfs.btrfs -f $DEV > /dev/null
   mount -o compress $DEV $MNT

   # File foo has a size of 33K, not aligned to the sector size.
   xfs_io -f -c "pwrite -S 0xab 0 33K" $MNT/foo

   xfs_io -f -c "pwrite -S 0xcd 0 64K" $MNT/bar

   # Now clone the first 32K of file bar into foo at offset 0.
   xfs_io -c "reflink $MNT/bar 0 0 32K" $MNT/foo

   # Snapshot the default subvolume and create a full send stream (v2).
   btrfs subvolume snapshot -r $MNT $MNT/snap

   btrfs send --compressed-data -f /tmp/test.send $MNT/snap

   echo -e "\nFile bar in the original filesystem:"
   od -A d -t x1 $MNT/snap/bar

   umount $MNT
   mkfs.btrfs -f $DEV > /dev/null
   mount $DEV $MNT

   echo -e "\nReceiving stream in a new filesystem..."
   btrfs receive -f /tmp/test.send $MNT

   echo -e "\nFile bar in the new filesystem:"
   od -A d -t x1 $MNT/snap/bar

   umount $MNT

Before this patch, the send stream included one regular write and one
encoded write for file 'bar', with the later being not sector size aligned
and causing the receiver to fallback to decompression + buffered writes.
The output of the btrfs receive command in verbose mode (-vvv):

   (...)
   mkfile o258-7-0
   rename o258-7-0 -> bar
   utimes
   clone bar - source=foo source offset=0 offset=0 length=32768
   write bar - offset=32768 length=1024
   encoded_write bar - offset=33792, len=4096, unencoded_offset=33792, unencoded_file_len=31744, unencoded_len=65536, compression=1, encryption=0
   encoded_write bar - falling back to decompress and write due to errno 22 ("Invalid argument")
   (...)

This patch avoids the regular write followed by an unaligned encoded write
so that we end up sending a single encoded write that is aligned. So after
this patch the stream content is (output of btrfs receive -vvv):

   (...)
   mkfile o258-7-0
   rename o258-7-0 -> bar
   utimes
   clone bar - source=foo source offset=0 offset=0 length=32768
   encoded_write bar - offset=32768, len=4096, unencoded_offset=32768, unencoded_file_len=32768, unencoded_len=65536, compression=1, encryption=0
   (...)

So we get more optimal behaviour and avoid the silent data loss bug in
versions of btrfs-progs affected by the bug referred by the Link tag
below (btrfs-progs v5.19, v5.19.1, v6.0 and v6.0.1).

Link: https://lore.kernel.org/linux-btrfs/cover.1668529099.git.fdmanana@suse.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:41:41 +01:00
Christoph Hellwig
c51f0e6a12 btrfs: zoned: fix missing endianness conversion in sb_write_pointer
generation is an on-disk __le64 value, so use btrfs_super_generation to
convert it to host endian before comparing it.

Fixes: 12659251ca5d ("btrfs: implement log-structured superblock for ZONED mode")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-21 14:40:40 +01:00
Anand Jain
013c1c5585 btrfs: free btrfs_path before copying subvol info to userspace
btrfs_ioctl_get_subvol_info() frees the search path after the userspace
copy from the temp buffer @subvol_info. This can lead to a lock splat
warning.

Fix this by freeing the path before we copy it to userspace.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2022-11-15 17:15:45 +01:00