> -----Original Message----- > From: Al Viro [mailto:viro@xxxxxxxxxxxxxxxx] On Behalf Of Al Viro > Sent: Saturday, January 10, 2015 4:37 AM > To: Pranay Srivastava > Cc: Lukáš Czerner; Stefan Hajnoczi; kzak@xxxxxxxxxx; Dexuan Cui; linux- > fsdevel@xxxxxxxxxxxxxxx; linux-ext4 > Subject: Re: Can one file system be R/W mounted multiple times in Linux? > > On Sat, Jan 10, 2015 at 01:01:19AM +0530, Pranay Srivastava wrote: > > > It's not the mount. If you see mount_bdev it checks for this and uses > > the existing super block from the first mount > > for all subsequent mounts of that block device. > > > > When block devices differ, as in with 2 loop devices they have > > different bdev and that's why it doesn't work with 2 > > loop devices. > > What Lukas is suggesting is for mount(8) to spot an existing loop device with > the desired backing store and reuse it, rather than try and set the new one > up. That's where -o loop is handled - it's gone before mount(2) might see > it. The problem is in races... Thank you all for the pretty informative discussion! I think now I know when it's safe and when it's unsafe... :-) Thanks, -- Dexuan -- 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
