hesela.devPatchgroup
A patchgroup is Featherstitch's application-visible collection of filesystem changes used to express persistence dependencies between operations.
In the research API, pg_depend(Q, P) orders P before Q and seals P against further engagement. P cannot be engaged again once Q depends on it, so the system has its complete change set rather than an indefinitely extendable predecessor. pg_sync requests persistence; pg_close releases the identifier. [1]
A dependency does not make the whole application update atomic. See the existing metadata-ordering analysis for the distinction. [2]
Relations
Limitations
- The patch abstraction itself does not provide atomic block writes. [1]
Citations
- Frost et al. Generalized File System Dependencies. SOSP 2007, sections 3, 5 and 8; figure 11.
- Hesela: Soft updates and metadata ordering
Sources & caveats
- Source review, not a reproduction of the historical implementation. The publication year is not asserted as an invention date.