On Tue, Dec 14, 2021 at 05:24:44PM +0300, Vladimir Sementsov-Ogievskiy wrote: > > What does it mean didn't help? > > I tried it, but the bug remains as it was.. As I understand, > dropping O_NONBLOCK by fcntl just removes this flag, to change > further behavior of device to non-blocking. But it doesn't do any > additional actions in driver. Hmm ... > > The solution based on blkid_safe_open() means that we have to modify > > many applications. For example, systemd/udevd uses > > > > fd = open(devnode, O_RDONLY|O_CLOEXEC|O_NONBLOCK); > > r = blkid_probe_set_device(pr, fd, offset, 0); > > Hmm, yes, that's not very good :( > > > > > The same is probably in many other places (mkfs-like programs, etc.). > > > > What do you think? > > > > Maybe be we can get filename from fd reading it from /proc, then do > open() and than dup() to old fd.. But that's even more dirty to do > in a library call. Yes, re-open() sounds like a possible way. The dup() is not necessary. The library already support private FD for probing. See blkid_new_probe_from_filename() and BLKID_FL_PRIVATE_FD. It's also often used when the library probe whole-disk device (when you probe sda1 than it also reads data from partition table on sda). In this case it opens a separate FD. It's for floppies (0.001% of all cases). IMHO re-open is good enough and better than force changes in all applications :-) I'll try to prepare a patch and ask you for test/review. Thanks! Karel -- Karel Zak <kzak@xxxxxxxxxx> http://karelzak.blogspot.com
