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Sharing disk sector between 2 Files

yu_shangyu_shang Member Posts: 41
edited June 2022 in NTFSD

I have 2 file objects (Fo1 and Fo2).
1. Fo1 is created (IoCreateStreamFileObject) from partition device (PartDO)
2. Fo2 is created (NtCreateFile) on file system device (VDO)
3. Both file objects are cached (CcInitializeCacheMap)
Obviously Fo1 is a superset of Fo2 , in my understanding , in this configuration , when a read is issued to Fo2
1. file system driver will calculate the sector(s) to read
2. lookup , map and copy the sector(s) from Fo1, and complete the request
2.1. the data is cached in Fo2
My question is, does this mean there are duplicates between Fo1 and Fo2?
If so , can I just share the cached page(s) of Fo1 with Fo2? Many thanks!


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