Hi, On 2022-04-28 11:26:36 +0200, Thomas Schmitt wrote: > Vincent Lefevre wrote: > > and one with > > openat(AT_FDCWD, "….out", O_WRONLY|O_CREAT|O_APPEND, 0666 <unfinished ...> > > <... openat resumed>) = 3 > > about 30 seconds later. > > Oh. So the script was still running when the file finally appeared to lt, > tail, and ll ?
Yes, the script takes several dozens of minutes to complete on this machine. > Is the text snippet "<unfinished ...> <... openat resumed>" literally in > the output of strace ? (Or does stand for some other text ?) Yes, this is just from raw copy-paste, no editing. I suppose that the scheduler interrupted the system call. > Did you check the kernel logs for unusual events around 2022-04-26 14:43 ? Yes, actually the systemd journal (which gives additional information). Nothing at this time: [...] Apr 26 14:42:16 cventin su[662519]: pam_unix(su:session): session closed for user root Apr 26 14:45:01 cventin CRON[768983]: pam_unix(cron:session): session opened for user root(uid=0) by (uid=0) [...] When I looked at it, I found I/O errors with sr0 and sr1 that occurred a bit later. I initially thought of a possible hardware problem, but they were common and unrelated. They are triggered by Wine, which is executed by my script (as I also test MPFR under Wine). My bug report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1010209 (either the kernel is really doing silly things, or this should just be debug information that should not be in the logs by default). > > This doesn't explain why the birth time of the file was 30 seconds > > late. > > I developed the theory that it might be an effect of journaling. Like: > Inode creation fails on storage device level, journal records the ongoing > write requests and virtual memory serves the read requests, 30 seconds > later journal creates inode at its final place on the storage device. > But as it looks in > https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Journal_.28jbd2.29 > the journal is a mere data cache with no own means to create inodes and their > timestamps. I initially thought about journaling too. > Still i deem it the most plausible theory that the inode to which the script > wrote in its first second is not the same inode to which it later wrote and > which finally shows up with shell tools. I don't see how this is possible, except if you mean VFS inode (with no concept of birth time) and ext4 inode. See my other mail about that. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
