Details
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Story
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Resolution: Fixed
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Blocker
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Lustre 2.4.0
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6961
Description
On client, file are flagged DIRTY when BRW are sent to OST, but this could be too late.
If all writes are done in page cache only and no flush is triggered before the file is closed by user-space program, the close RPC will be send no DIRTY flag packed in it.
SOM avoids this be sending a DONE_WRITING RPC later, after all pages have been successfully flushed. But this implies to maintain IOEpoch and so on. DIRTY flag should be kept simple.
To fix this we need to flag the file DIRTY as soon as the RPC write goes to cache. This could lead to file being DIRTY even if I/O is dropped for some reasons but this is acceptable for HSM.