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    Description

      For a small write(<4K), we will use tiny write and __generic_file_write_iter() will be called to handle it. On newer kernel(4.14 etc), the function is exported and will do something like following:

          |->__generic_file_write_iter
            |->generic_write_perform()
      
       

      If iov_iter_count() passed in is 0, generic_write_perform() will try go to forever loop as bytes copied is always calculated as 0.

      The problem is VFS doesn't always skip IO count zero before it comes to lower layer read/write hook, and we should do it by ourselves.

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            [LU-12382] Deadloop on tiny write
            adilger Andreas Dilger made changes -
            Link New: This issue is related to LU-12721 [ LU-12721 ]
            pjones Peter Jones made changes -
            Labels Original: LTS12
            pjones Peter Jones made changes -
            Link Original: This issue is related to JFC-17 [ JFC-17 ]
            pjones Peter Jones made changes -
            Link New: This issue is related to JFC-20 [ JFC-20 ]
            pjones Peter Jones made changes -
            Fix Version/s New: Lustre 2.12.3 [ 14418 ]
            pjones Peter Jones made changes -
            Labels New: LTS12
            pjones Peter Jones made changes -
            Link Original: This issue is related to JFC-19 [ JFC-19 ]
            pjones Peter Jones made changes -
            Link New: This issue is related to JFC-17 [ JFC-17 ]
            pjones Peter Jones made changes -
            Link Original: This issue is related to JFC-10 [ JFC-10 ]
            pjones Peter Jones made changes -
            Fix Version/s New: Lustre 2.13.0 [ 14290 ]
            Resolution New: Fixed [ 1 ]
            Status Original: Open [ 1 ] New: Resolved [ 5 ]

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              wshilong Wang Shilong (Inactive)
              wshilong Wang Shilong (Inactive)
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                Updated:
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