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f2fs: use spin_{,un}lock_irq{save,restore}
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commit d1aa245 upstream.

generic/361 reports below warning, this is because: once, there is
someone entering into critical region of sbi.cp_lock, if write_end_io.
f2fs_stop_checkpoint is invoked from an triggered IRQ, we will encounter
deadlock.

So this patch changes to use spin_{,un}lock_irq{save,restore} to create
critical region without IRQ enabled to avoid potential deadlock.

 irq event stamp: 83391573
 loop: Write error at byte offset 438729728, length 1024.
 hardirqs last  enabled at (83391573): [<c1809752>] restore_all+0xf/0x65
 hardirqs last disabled at (83391572): [<c1809eac>] reschedule_interrupt+0x30/0x3c
 loop: Write error at byte offset 438860288, length 1536.
 softirqs last  enabled at (83389244): [<c180cc4e>] __do_softirq+0x1ae/0x476
 softirqs last disabled at (83389237): [<c101ca7c>] do_softirq_own_stack+0x2c/0x40
 loop: Write error at byte offset 438990848, length 2048.
 ================================
 WARNING: inconsistent lock state
 4.12.0-rc2+ #30 Tainted: G           O
 --------------------------------
 inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
 xfs_io/7959 [HC1[1]:SC0[0]:HE0:SE1] takes:
  (&(&sbi->cp_lock)->rlock){?.+...}, at: [<f96f96cc>] f2fs_stop_checkpoint+0x1c/0x50 [f2fs]
 {HARDIRQ-ON-W} state was registered at:
   __lock_acquire+0x527/0x7b0
   lock_acquire+0xae/0x220
   _raw_spin_lock+0x42/0x50
   do_checkpoint+0x165/0x9e0 [f2fs]
   write_checkpoint+0x33f/0x740 [f2fs]
   __f2fs_sync_fs+0x92/0x1f0 [f2fs]
   f2fs_sync_fs+0x12/0x20 [f2fs]
   sync_filesystem+0x67/0x80
   generic_shutdown_super+0x27/0x100
   kill_block_super+0x22/0x50
   kill_f2fs_super+0x3a/0x40 [f2fs]
   deactivate_locked_super+0x3d/0x70
   deactivate_super+0x40/0x60
   cleanup_mnt+0x39/0x70
   __cleanup_mnt+0x10/0x20
   task_work_run+0x69/0x80
   exit_to_usermode_loop+0x57/0x85
   do_fast_syscall_32+0x18c/0x1b0
   entry_SYSENTER_32+0x4c/0x7b
 irq event stamp: 1957420
 hardirqs last  enabled at (1957419): [<c1808f37>] _raw_spin_unlock_irq+0x27/0x50
 hardirqs last disabled at (1957420): [<c1809f9c>] call_function_single_interrupt+0x30/0x3c
 softirqs last  enabled at (1953784): [<c180cc4e>] __do_softirq+0x1ae/0x476
 softirqs last disabled at (1953773): [<c101ca7c>] do_softirq_own_stack+0x2c/0x40

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&(&sbi->cp_lock)->rlock);
   <Interrupt>
     lock(&(&sbi->cp_lock)->rlock);

  *** DEADLOCK ***

 2 locks held by xfs_io/7959:
  #0:  (sb_writers#13){.+.+.+}, at: [<c11fd7ca>] vfs_write+0x16a/0x190
  #1:  (&sb->s_type->i_mutex_key#16){+.+.+.}, at: [<f96e33f5>] f2fs_file_write_iter+0x25/0x140 [f2fs]

 stack backtrace:
 CPU: 2 PID: 7959 Comm: xfs_io Tainted: G           O    4.12.0-rc2+ #30
 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
 Call Trace:
  dump_stack+0x5f/0x92
  print_usage_bug+0x1d3/0x1dd
  ? check_usage_backwards+0xe0/0xe0
  mark_lock+0x23d/0x280
  __lock_acquire+0x699/0x7b0
  ? __this_cpu_preempt_check+0xf/0x20
  ? trace_hardirqs_off_caller+0x91/0xe0
  lock_acquire+0xae/0x220
  ? f2fs_stop_checkpoint+0x1c/0x50 [f2fs]
  _raw_spin_lock+0x42/0x50
  ? f2fs_stop_checkpoint+0x1c/0x50 [f2fs]
  f2fs_stop_checkpoint+0x1c/0x50 [f2fs]
  f2fs_write_end_io+0x147/0x150 [f2fs]
  bio_endio+0x7a/0x1e0
  blk_update_request+0xad/0x410
  blk_mq_end_request+0x16/0x60
  lo_complete_rq+0x3c/0x70
  __blk_mq_complete_request_remote+0x11/0x20
  flush_smp_call_function_queue+0x6d/0x120
  ? debug_smp_processor_id+0x12/0x20
  generic_smp_call_function_single_interrupt+0x12/0x30
  smp_call_function_single_interrupt+0x25/0x40
  call_function_single_interrupt+0x37/0x3c
 EIP: _raw_spin_unlock_irq+0x2d/0x50
 EFLAGS: 00000296 CPU: 2
 EAX: 00000001 EBX: d2ccc51c ECX: 00000001 EDX: c1aacebd
 ESI: 00000000 EDI: 00000000 EBP: c96c9d1c ESP: c96c9d18
  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
  ? inherit_task_group.isra.98.part.99+0x6b/0xb0
  __add_to_page_cache_locked+0x1d4/0x290
  add_to_page_cache_lru+0x38/0xb0
  pagecache_get_page+0x8e/0x200
  f2fs_write_begin+0x96/0xf00 [f2fs]
  ? trace_hardirqs_on_caller+0xdd/0x1c0
  ? current_time+0x17/0x50
  ? trace_hardirqs_on+0xb/0x10
  generic_perform_write+0xa9/0x170
  __generic_file_write_iter+0x1a2/0x1f0
  ? f2fs_preallocate_blocks+0x137/0x160 [f2fs]
  f2fs_file_write_iter+0x6e/0x140 [f2fs]
  ? __lock_acquire+0x429/0x7b0
  __vfs_write+0xc1/0x140
  vfs_write+0x9b/0x190
  SyS_pwrite64+0x63/0xa0
  do_fast_syscall_32+0xa1/0x1b0
  entry_SYSENTER_32+0x4c/0x7b
 EIP: 0xb7786c61
 EFLAGS: 00000293 CPU: 2
 EAX: ffffffda EBX: 00000003 ECX: 08416000 EDX: 00001000
 ESI: 18b24000 EDI: 00000000 EBP: 00000003 ESP: bf9b36b0
  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b

Fixes: aaec2b1 ("f2fs: introduce cp_lock to protect updating of ckpt_flags")
Signed-off-by: Chao Yu <[email protected]>
Signed-off-by: Jaegeuk Kim <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@chaseyu @gregkh
chaseyu authored and gregkh committed Jul 27, 2017
1 parent d0f0ccf commit 65483db
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Showing 2 changed files with 18 additions and 11 deletions.
11 changes: 6 additions & 5 deletions fs/f2fs/checkpoint.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1051,8 +1051,9 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
{
unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num;
struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
unsigned long flags;

spin_lock(&sbi->cp_lock);
spin_lock_irqsave(&sbi->cp_lock, flags);

if ((cpc->reason & CP_UMOUNT) &&
le32_to_cpu(ckpt->cp_pack_total_block_count) >
Expand Down Expand Up @@ -1083,14 +1084,14 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
/* set this flag to activate crc|cp_ver for recovery */
__set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG);

spin_unlock(&sbi->cp_lock);
spin_unlock_irqrestore(&sbi->cp_lock, flags);
}

static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
{
struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
struct f2fs_nm_info *nm_i = NM_I(sbi);
unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num;
unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num, flags;
block_t start_blk;
unsigned int data_sum_blocks, orphan_blocks;
__u32 crc32 = 0;
Expand Down Expand Up @@ -1132,12 +1133,12 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)

/* 2 cp + n data seg summary + orphan inode blocks */
data_sum_blocks = npages_for_summary_flush(sbi, false);
spin_lock(&sbi->cp_lock);
spin_lock_irqsave(&sbi->cp_lock, flags);
if (data_sum_blocks < NR_CURSEG_DATA_TYPE)
__set_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);
else
__clear_ckpt_flags(ckpt, CP_COMPACT_SUM_FLAG);
spin_unlock(&sbi->cp_lock);
spin_unlock_irqrestore(&sbi->cp_lock, flags);

orphan_blocks = GET_ORPHAN_BLOCKS(orphan_num);
ckpt->cp_pack_start_sum = cpu_to_le32(1 + cp_payload_blks +
Expand Down
18 changes: 12 additions & 6 deletions fs/f2fs/f2fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1228,9 +1228,11 @@ static inline void __set_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)

static inline void set_ckpt_flags(struct f2fs_sb_info *sbi, unsigned int f)
{
spin_lock(&sbi->cp_lock);
unsigned long flags;

spin_lock_irqsave(&sbi->cp_lock, flags);
__set_ckpt_flags(F2FS_CKPT(sbi), f);
spin_unlock(&sbi->cp_lock);
spin_unlock_irqrestore(&sbi->cp_lock, flags);
}

static inline void __clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)
Expand All @@ -1244,22 +1246,26 @@ static inline void __clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f

static inline void clear_ckpt_flags(struct f2fs_sb_info *sbi, unsigned int f)
{
spin_lock(&sbi->cp_lock);
unsigned long flags;

spin_lock_irqsave(&sbi->cp_lock, flags);
__clear_ckpt_flags(F2FS_CKPT(sbi), f);
spin_unlock(&sbi->cp_lock);
spin_unlock_irqrestore(&sbi->cp_lock, flags);
}

static inline void disable_nat_bits(struct f2fs_sb_info *sbi, bool lock)
{
unsigned long flags;

set_sbi_flag(sbi, SBI_NEED_FSCK);

if (lock)
spin_lock(&sbi->cp_lock);
spin_lock_irqsave(&sbi->cp_lock, flags);
__clear_ckpt_flags(F2FS_CKPT(sbi), CP_NAT_BITS_FLAG);
kfree(NM_I(sbi)->nat_bits);
NM_I(sbi)->nat_bits = NULL;
if (lock)
spin_unlock(&sbi->cp_lock);
spin_unlock_irqrestore(&sbi->cp_lock, flags);
}

static inline bool enabled_nat_bits(struct f2fs_sb_info *sbi,
Expand Down

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