Wang, Zhiye posted on Wed, 28 Oct 2015 09:57:29 +0000 as excerpted: > Thank you all for your comments. > > A further question is: if I mount a btrfs file system in "readonly" > mode, will any operation cause the blocks of a file get changed? Note that both bind-mounts and btrfs subvolume mounts can be used to make parts of a filesystem appear in multiple locations in the filesystem tree. Because these different mounts can be separately mounted read-only or writable, there's no guarantee that just because a filesystem or part of it is read-only mounted in one location, it's read-only mounted everywhere it can be accessed, and thus no guarantee that files even on a read-only mounted filesystem or subvolume won't actually change out from under you. However, bind-mounts in particular aren't btrfs specific, so just because btrfs subvolumes add another case in which the above can be true, doesn't mean bind-mounts can't be used on other filesystems to effect the same sort of otherwise read-only file instabilities. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
