Hi Hu, On 01/07/2015 11:56 AM, hujianyang wrote: > Hi, > > There maybe some misunderstandings here. I think your patch really > fix an important problem, but not in correct way. > > On 2015/1/6 22:02, Seunghun Lee wrote: >> After patch: >> root@qemux86:~# mount -t overlay overlay -olowerdir=lower:lower2 merged >> mount: warning: merged seems to be mounted read-only. >> root@qemux86:~# mount | grep overlay >> overlay on /home/root/merged type overlay (ro,relatime,lowerdir=lower:lower2) >> root@qemux86:~# mount -o remount,rw merged >> mount: warning: /home/root/merged seems to be mounted read-only. >> root@qemux86:~# mount | grep overlay >> overlay on /home/root/merged type overlay (ro,relatime,lowerdir=lower:lower2) >> root@qemux86:~# echo hi > merged/hi >> -sh: merged/hi: Read-only file system >> root@qemux86:~# >> > If users want a rw mount, can we give them a ro mount? I think it's > wrong, .remount_fs should refuse this request. > > So I think your .remount_fs should check both what users in userpace > want and what kernel can offer, then realize legal requests and > refuse illegal requests. Not changing the requests from users. Many file systems just change flags when user requests read-write remount. (romfs, squashfs, sysv...) I thought this case is similar above filesystems. > Further more, can we replace upper/lower/work directories or mount > point by this .remount_fs? > > If you want to export a new function, I think you should considering > more about these. > > Thanks, > Hu > Yes, you are right. However, this patch is a minimal support to prevent kernel panic when file system is remounted to read-write mode. And many file systems have remount_fs function of this kind. I think what you mentioned is can be added later if it is necessary. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
