Details
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Improvement
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Resolution: Unresolved
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Minor
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None
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None
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None
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9223372036854775807
Description
If directory layout is changed, client may send request to wrong MDT based on the old layout, e.g. directory split from 2 stripes to 3 stripes, client created a sub file under stripe2 in old layout, but this file should be located on stripe3 in new layout.
To avoid such race, client can pack parent layout version in request, and MDT will compare layout version before processing, if mismatch, return -EAGAIN with a certain flag to client, and client can update directory layout and try again.
Combined with FID map in LU-7607, directory layout change may become opaque to user applications in most cases.