https://bugzilla.kernel.org/show_bug.cgi?id=214873 Bug ID: 214873 Summary: man 2 fsync implies possibility to return early Product: Documentation Version: unspecified Hardware: All OS: Linux Status: NEW Severity: low Priority: P1 Component: man-pages Assignee: documentation_man-pages@xxxxxxxxxxxxxxxxxxxx Reporter: sworddragon2@xxxxxxxxx Regression: No The manpage for the fsync system call ( https://man7.org/linux/man-pages/man2/fsync.2.html ) describes as flushing the related caches to a storage device so that the information can even be retrieved after a crash/reboot. But then it does make the statement "The call blocks until the device reports that the transfer has completed." which causes now some interpretation: What happens if the device reports early completion (e.g. via a bugged firmware) of the transfer while the kernel still sees unsent caches in its context? Does fsync() indeed return then as the last referenced sentence implies or does it continue to send the caches the kernel sees to guarantee data integrity as good as possible as the previous documented part might imply? I noticed this discrepancy when reporting a bug against dd ( https://debbugs.gnu.org/cgi/bugreport.cgi?bug=51345 ) that causes dd to return early when it is used with its fsync capability while the kernel still sees caches and consulting the fsync() manpage made it not clear if such a theoretical possibility from the fsync() system call would be intended or not so eventually this part could be slighty enhanced. -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
