On Sun, Sep 30, 2012 at 05:58:11AM +0000, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > This patch re-adds the ability to optionally run in buffered FILEIO mode > (eg: w/o O_DSYNC) for device backends in order to once again use the > Linux buffered cache as a write-back storage mechanism. > > This difference with this patch is that fd_create_virtdevice() now > forces the explicit setting of emulate_write_cache=1 when buffered FILEIO > operation has been enabled. What this lacks is a clear reason why you would enable this inherently unsafe mode. While there is some clear precedence to allow people doing stupid thing I'd least like a rationale for it, and it being documented as unsafe. > + /* Indention error. > + * Optionally allow fd_buffered_io=1 to be enabled for people > + * who know what they are doing w/o O_DSYNC. > + */ This comment doesn't explain at all what's going on here. It should be something like /* * Unsafe mode allows disabling data integrity by not forcing * data out to disk in writethrough cache mode. Only to be used * for benchmark cheating or similar purposes. */ > #define FBDF_HAS_PATH 0x01 > #define FBDF_HAS_SIZE 0x02 > +#define FDBD_USE_BUFFERED_IO 0x04 This should be named BDBD_UNSAFE -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
