Now that the atomic command is formally supported, document it. Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx> --- HOWTO.rst | 14 ++++++++++++++ fio.1 | 13 +++++++++++++ 2 files changed, 27 insertions(+) diff --git a/HOWTO.rst b/HOWTO.rst index a363206d..c6c9b306 100644 --- a/HOWTO.rst +++ b/HOWTO.rst @@ -2501,6 +2501,20 @@ with the caveat that when used on the command line, they must come after the For direct I/O, requests will only succeed if cache invalidation isn't required, file blocks are fully allocated and the disk request could be issued immediately. +.. option:: atomic=bool : [pvsync2] [libaio] [io_uring] + + This option means that writes are issued with torn-write protection, meaning + that for a power fail or kernel crash, all or none of the data from the write + will be stored, but never a mix of old and new data. Torn-write protection is + also known as atomic writes. + + This option sets the RWF_ATOMIC flag (supported from the 6.11 Linux kernel) on + a per-IO basis. + + Writes with RWF_ATOMIC set will be rejected by the kernel when the file does + not support torn-write protection. To learn a file's torn-write limits, issue + statx with STATX_WRITE_ATOMIC. + .. option:: fdp=bool : [io_uring_cmd] [xnvme] Enable Flexible Data Placement mode for write commands. diff --git a/fio.1 b/fio.1 index a4ab07ed..6e5bed9d 100644 --- a/fio.1 +++ b/fio.1 @@ -2266,6 +2266,19 @@ cached data. Currently the RWF_NOWAIT flag does not supported for cached write. For direct I/O, requests will only succeed if cache invalidation isn't required, file blocks are fully allocated and the disk request could be issued immediately. .TP +.BI (pvsync2,libaio,io_uring)atomic \fR=\fPbool +This option means that writes are issued with torn-write protection, meaning +that for a power fail or kernel crash, all or none of the data from the write +will be stored, but never a mix of old and new data. Torn-write protection is +also known as atomic writes. + +This option sets the RWF_ATOMIC flag (supported from the 6.11 Linux kernel) on +a per-IO basis. + +Writes with RWF_ATOMIC set will be rejected by the kernel when the file does +not support torn-write protection. To learn a file's torn-write limits, issue +statx with STATX_WRITE_ATOMIC. +.TP .BI (io_uring_cmd,xnvme)fdp \fR=\fPbool Enable Flexible Data Placement mode for write commands. .TP -- 2.31.1
