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  1. Lustre
  2. LU-10704

open(2) with O_CREAT takes 60s (timeout) with virus scanning application

    Details

    • Type: Bug
    • Status: Open
    • Priority: Minor
    • Resolution: Unresolved
    • Affects Version/s: Upstream
    • Fix Version/s: None
    • Labels:
    • Severity:
      3
    • Rank (Obsolete):
      9223372036854775807

      Description

      On the client when Lustre creates a file, we create the inode and instantiate the dentry in ll_create_it(), it's still hidden by lld->lld_invalid. Next lookup could discover it, however this brings an issue for some applications. like virus scanning, for example https://www.f-secure.com/en/web/business_global/downloads/linux-security

      f-secure does real time scanning using fanotify. When client creates a file using open(2) with O_CREAT, the process will wait in fanotify until f-secure scanning thread does its job:

      [<ffffffff8124b785>] fanotify_handle_event+0x1e5/0x330
      [<ffffffff81247e15>] fsnotify+0x285/0x510
      [<ffffffff812b4936>] security_file_open+0x66/0x70
      [<ffffffff81200539>] do_dentry_open+0xb9/0x2e0
      [<ffffffff8120078f>] finish_open+0x2f/0x40
      [<ffffffffc0a31506>] ll_atomic_open+0x1d6/0x11f0 [lustre]
      [<ffffffff812121bd>] do_last+0xa4d/0x12c0
      [<ffffffff81212af2>] path_openat+0xc2/0x490
      [<ffffffff8121508b>] do_filp_open+0x4b/0xb0
      [<ffffffff81201bc3>] do_sys_open+0xf3/0x1f0
      [<ffffffff81201cde>] SyS_open+0x1e/0x20
      [<ffffffff816b89fd>] system_call_fastpath+0x16/0x1b
      [<ffffffffffffffff>] 0xffffffffffffffff

      The scanning thread will try to do lookup, the dcache lookup will fail because lld->lld_invalid, so it tries lookup_real, which requires i_mutex holding by the thread creating the file and waiting for the scanning thread.

      Eventually scanning thread will be killed by f-secure after the timeout, and file creation could finish. Any thread tries to take i_mutex on the parent will block during the timeout.

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            • Assignee:
              dongyang Dongyang Li
              Reporter:
              lidongyang Li Dongyang (Inactive)
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              Dates

              • Created:
                Updated: