Quoting Vincent Lefevre (vinc...@vinc17.net): > On 2015-04-20 13:04:41 -0500, David Wright wrote: > > Quoting Vincent Lefevre (vinc...@vinc17.net): > > > But with the current solution (no automatic moving of an entry), you > > > can't miss an entry that hasn't been removed. [...] > > ...so if you happen to be reading the entry for file5 at the > > time I typed mv, you'll get the entry for file4 twice, under > > two different names. (Or the opposite.) > > OK, so, if the rename(2) system call can reorder the entries (this is > not quite clear because one doesn't see the empty entries here),
No, and you wouldn't *normally* see them with readdir, I'd suppose. > then > there is already a problem with the file system. Getting an entry > twice under different names is not much a problem, IMHO, because one > can look at the inode number; there's a race condition, but at worst, > one can just miss a *new* inode (whose number has been reassigned). > Missing an existing entry is a problem. ...easily demonstrated with ~ $ for j in 1 2 3 4 5 6 ; do mkdir /tmp/testdir/file$j ; done ~ $ ls -lU /tmp/testdir total 24 drwxr-x--- 2 david david 4096 Apr 21 10:58 file1 drwxr-x--- 2 david david 4096 Apr 21 10:58 file4 drwxr-x--- 2 david david 4096 Apr 21 10:58 file5 drwxr-x--- 2 david david 4096 Apr 21 10:58 file6 drwxr-x--- 2 david david 4096 Apr 21 10:58 file2 drwxr-x--- 2 david david 4096 Apr 21 10:58 file3 ~ $ mv -i /tmp/testdir/file3 /tmp/testdir/file3file3file3file3file3file3file3file3file3file3file3file3file3 ~ $ ls -lU /tmp/testdir total 24 drwxr-x--- 2 david david 4096 Apr 21 10:58 file1 drwxr-x--- 2 david david 4096 Apr 21 10:58 file4 drwxr-x--- 2 david david 4096 Apr 21 10:58 file5 drwxr-x--- 2 david david 4096 Apr 21 10:58 file3file3file3file3file3file3file3file3file3file3file3file3file3 drwxr-x--- 2 david david 4096 Apr 21 10:58 file6 drwxr-x--- 2 david david 4096 Apr 21 10:58 file2 ~ $ where file3 goes AWOL. > What do the backup systems do? I don't know. Lock the directory and slurp it (if it's not too big), otherwise check the modification time before and after reading it, and reread it if necessary, maybe... Cheers, David. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: https://lists.debian.org/20150421160558.GA32498@alum
