• Bart Van Assche's avatar
    dm zoned: avoid triggering reclaim from inside dmz_map() · 2d0b2d64
    Bart Van Assche authored
    This patch avoids that lockdep reports the following:
    
    ======================================================
    WARNING: possible circular locking dependency detected
    4.18.0-rc1 #62 Not tainted
    ------------------------------------------------------
    kswapd0/84 is trying to acquire lock:
    00000000c313516d (&xfs_nondir_ilock_class){++++}, at: xfs_free_eofblocks+0xa2/0x1e0
    
    but task is already holding lock:
    00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
    
    which lock already depends on the new lock.
    
    the existing dependency chain (in reverse order) is:
    
    -> #2 (fs_reclaim){+.+.}:
      kmem_cache_alloc+0x2c/0x2b0
      radix_tree_node_alloc.constprop.19+0x3d/0xc0
      __radix_tree_create+0x161/0x1c0
      __radix_tree_insert+0x45/0x210
      dmz_map+0x245/0x2d0 [dm_zoned]
      __map_bio+0x40/0x260
      __split_and_process_non_flush+0x116/0x220
      __split_and_process_bio+0x81/0x180
      __dm_make_request.isra.32+0x5a/0x100
      generic_make_request+0x36e/0x690
      submit_bio+0x6c/0x140
      mpage_readpages+0x19e/0x1f0
      read_pages+0x6d/0x1b0
      __do_page_cache_readahead+0x21b/0x2d0
      force_page_cache_readahead+0xc4/0x100
      generic_file_read_iter+0x7c6/0xd20
      __vfs_read+0x102/0x180
      vfs_read+0x9b/0x140
      ksys_read+0x55/0xc0
      do_syscall_64+0x5a/0x1f0
      entry_SYSCALL_64_after_hwframe+0x49/0xbe
    
    -> #1 (&dmz->chunk_lock){+.+.}:
      dmz_map+0x133/0x2d0 [dm_zoned]
      __map_bio+0x40/0x260
      __split_and_process_non_flush+0x116/0x220
      __split_and_process_bio+0x81/0x180
      __dm_make_request.isra.32+0x5a/0x100
      generic_make_request+0x36e/0x690
      submit_bio+0x6c/0x140
      _xfs_buf_ioapply+0x31c/0x590
      xfs_buf_submit_wait+0x73/0x520
      xfs_buf_read_map+0x134/0x2f0
      xfs_trans_read_buf_map+0xc3/0x580
      xfs_read_agf+0xa5/0x1e0
      xfs_alloc_read_agf+0x59/0x2b0
      xfs_alloc_pagf_init+0x27/0x60
      xfs_bmap_longest_free_extent+0x43/0xb0
      xfs_bmap_btalloc_nullfb+0x7f/0xf0
      xfs_bmap_btalloc+0x428/0x7c0
      xfs_bmapi_write+0x598/0xcc0
      xfs_iomap_write_allocate+0x15a/0x330
      xfs_map_blocks+0x1cf/0x3f0
      xfs_do_writepage+0x15f/0x7b0
      write_cache_pages+0x1ca/0x540
      xfs_vm_writepages+0x65/0xa0
      do_writepages+0x48/0xf0
      __writeback_single_inode+0x58/0x730
      writeback_sb_inodes+0x249/0x5c0
      wb_writeback+0x11e/0x550
      wb_workfn+0xa3/0x670
      process_one_work+0x228/0x670
      worker_thread+0x3c/0x390
      kthread+0x11c/0x140
      ret_from_fork+0x3a/0x50
    
    -> #0 (&xfs_nondir_ilock_class){++++}:
      down_read_nested+0x43/0x70
      xfs_free_eofblocks+0xa2/0x1e0
      xfs_fs_destroy_inode+0xac/0x270
      dispose_list+0x51/0x80
      prune_icache_sb+0x52/0x70
      super_cache_scan+0x127/0x1a0
      shrink_slab.part.47+0x1bd/0x590
      shrink_node+0x3b5/0x470
      balance_pgdat+0x158/0x3b0
      kswapd+0x1ba/0x600
      kthread+0x11c/0x140
      ret_from_fork+0x3a/0x50
    
    other info that might help us debug this:
    
    Chain exists of:
      &xfs_nondir_ilock_class --> &dmz->chunk_lock --> fs_reclaim
    
    Possible unsafe locking scenario:
    
         CPU0                    CPU1
         ----                    ----
    lock(fs_reclaim);
                                 lock(&dmz->chunk_lock);
                                 lock(fs_reclaim);
    lock(&xfs_nondir_ilock_class);
    
    *** DEADLOCK ***
    
    3 locks held by kswapd0/84:
     #0: 00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
     #1: 000000000f8208f5 (shrinker_rwsem){++++}, at: shrink_slab.part.47+0x3f/0x590
     #2: 00000000cacefa54 (&type->s_umount_key#43){.+.+}, at: trylock_super+0x16/0x50
    
    stack backtrace:
    CPU: 7 PID: 84 Comm: kswapd0 Not tainted 4.18.0-rc1 #62
    Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015
    Call Trace:
     dump_stack+0x85/0xcb
     print_circular_bug.isra.36+0x1ce/0x1db
     __lock_acquire+0x124e/0x1310
     lock_acquire+0x9f/0x1f0
     down_read_nested+0x43/0x70
     xfs_free_eofblocks+0xa2/0x1e0
     xfs_fs_destroy_inode+0xac/0x270
     dispose_list+0x51/0x80
     prune_icache_sb+0x52/0x70
     super_cache_scan+0x127/0x1a0
     shrink_slab.part.47+0x1bd/0x590
     shrink_node+0x3b5/0x470
     balance_pgdat+0x158/0x3b0
     kswapd+0x1ba/0x600
     kthread+0x11c/0x140
     ret_from_fork+0x3a/0x50
    Reported-by: default avatarMasato Suzuki <masato.suzuki@wdc.com>
    Fixes: 4218a955 ("dm zoned: use GFP_NOIO in I/O path")
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
    Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
    2d0b2d64
dm-zoned-target.c 23.2 KB