On Mon, Apr 28, 2014 at 10:33:40AM -0500, Eric Sandeen wrote: > On 4/26/14, 7:00 PM, Theodore Ts'o wrote: > > If mke2fs needs to ask the user for permission, and the user doesn't > > type anything for five seconds, proceed as if the user had said yes. > > > > This will allow us to add more stringent checks without breaking > > existing scripts (much). > > Hm, this sounds a little dangerous - "-F" overrides a lot. Actually, if you take a look at what we use proceed_question() for, it doesn't actually override anything (up until now) that might lead to data loss. It's for things like trying to create an file system with a block size greater than 4k on an x86 platform, creating a file system larger than the apparent block size, etc. The main goal was to make sure the user actually *sees* the darned message. Perhaps the only case where proceed_question() can prevent data loss is the one where the user typo's /dev/sda3 as /dev/sda. Everything else is in the category of "we want to make sure the user sees the warning". The motivation behind this is adding this safety check: % ./misc/mke2fs -t ext4 -L test-filesystem /dev/sdc3 8M mke2fs 1.42.9 (4-Feb-2014) /dev/sdc3 contains a ext4 file system labelled 'test-filesystem' Proceed anyway (or wait 5 seconds) ? (y,n) Previously, we would blithely blow away /dev/sdc3 without even giving a warning. So if stdin (fd 0) is not a tty, we skip this test entirely --- otherwise existing scripts would fail. However, if a script is attached to a tty, we would end up stalling the script waiting for the user to answer yes/no where previously no question would be asked at all. This is the case where it's important that proceed_question() will now pause five seconds, and then continue. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
