Messages in this thread | | | Date | Tue, 3 Oct 2023 12:25:58 -0700 | Subject | Re: [PATCH 2/4] readv.2: Document RWF_ATOMIC flag | From | Bart Van Assche <> |
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On 9/29/23 02:37, John Garry wrote: > +.BR RWF_ATOMIC " (since Linux 6.7)" > +Allows block-based filesystems to indicate that write operations will be issued > +with torn-write protection. Torn-write protection means that for a power or any > +other hardware failure, all or none of the data from the write will be stored, > +but never a mix of old and new data. This flag is meaningful only for > +.BR pwritev2 (), > +and its effect applies only to the data range written by the system call. > +The total write length must be power-of-2 and must be sized between > +stx_atomic_write_unit_min and stx_atomic_write_unit_max, both inclusive. The > +write must be at a natural offset within the file with respect to the total > +write length. Torn-write protection only works with > +.B O_DIRECT > +flag, i.e. buffered writes are not supported. To guarantee consistency from > +the write between a file's in-core state with the storage device,
It seems wrong to me to start the first sentence with "Allows". Atomic behavior should be mandatory if RWF_ATOMIC has been set.
Additionally, shouldn't it be documented what value will be stored in errno if the atomic write has been rejected?
Thanks,
Bart.
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