As you noted, Apple's fsync() behavior is defensible if PLP is assumed. Committing through the PLP cache isn't how these drives are meant to operate - hence the poor behavior of F_FULLSYNC.
But this isn't specific to Macs and iDevices. Some non-PLP drives also struggle with sync writes on FreeBSD [1]. Most enterprises running RDBMS mandate PLP for both performance and reliability. I understand why this is frustrating for porting Linux, but Apple is allowed to make strong assumptions about how their hardware interoperates.
But this isn't specific to Macs and iDevices. Some non-PLP drives also struggle with sync writes on FreeBSD [1]. Most enterprises running RDBMS mandate PLP for both performance and reliability. I understand why this is frustrating for porting Linux, but Apple is allowed to make strong assumptions about how their hardware interoperates.
[1] https://www.truenas.com/community/threads/slog-and-power-los...