Hi all, Recently I've upgraded an older linux box that was still happily running a 3.10.17 kernel; with the new kernel (4.4.14) I can no longer access files on a cifs filesystem if the filenames contain special characters (question mark, in my test case; unix extensions enabled on the samba server). I'm not sure it's a bug, but I haven't been able to find out anything in the kernel changelogs that pointed to a change in behaviour (e.g. a new parameter). To reproduce the problem, I set up a minimal environment with a cut-down smb.conf and mount a samba share that contains a file named "file?" (no quotes, but trailing question mark). The test environment is the same, the only difference is the kernel I boot (same kernel .config). Whereas older kernels behave as I would expect (I can "ls", "stat" and "cat" the oddly-named file), newer ones do mount, ls, stat just fine, but fail on cat 'file?' > /dev/null with a "No such file or directory" error. After trying out a clean build from the latest 4.6.4 kernel to no avail, I narrowed down the large version gap between 3.10.17 and 4.4.14 and found out that something must have changed between 4.0.9 (works ok) and 4.1.1 (doesn't work anymore). Checked kernel changelogs and even diff'ed the two source trees but my untrained eye didn't spot anything obvious. Question. Am I missing something here? With a default samba configuration (unix extensions = yes, mangled names = yes), am I not expected to be able to use filenames containing DOS-reserved characters (such as ? and ") from a unix client without problems? Here's the traced output of my test script on a 4.1.1 kernel (this machine is both the samba server and the cifs client; whitespace sequences shortened): + uname -a Linux darkstar 4.1.1 #1 SMP Wed Jul 20 13:21:28 IST 2016 x86_64 Intel(R) Core(TM) i5-3337U CPU @ 1.80GHz GenuineIntel GNU/Linux + mount.cifs -V mount.cifs version: 5.5 + samba --version Version 4.2.12 + grep . /proc/fs/cifs/LinuxExtensionsEnabled 1 + cat /etc/samba/smb.conf [global]$ workgroup = MYWORKGROUP netbios name = MYSERVER server string = myserver.myworkgroup security = user syslog = 0 printing = bsd load printers = no disable spoolss = yes #unix extensions = yes # default setting anyway #mangled names = yes # default setting anyway [shared] path = /tmp/shared read only = no + ls -l /tmp/shared/ total 12 -rw-r--r-- 1 root root 24 Jul 20 09:53 "file" -rw-r--r-- 1 root root 22 Jul 20 09:53 file -rw-r--r-- 1 root root 23 Jul 20 09:53 file? + mount -t cifs -o username=user,password=pass //localhost/shared /mnt + cd /mnt + ls "file" file file? + stat 'file?' File: 'file?' Size: 23 Blocks: 8 IO Block: 16384 regular file Device: 19h/25d Inode: 1328306 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2016-07-20 09:53:16.608205000 +0100 Modify: 2016-07-20 09:53:10.214392400 +0100 Change: 2016-07-20 09:53:10.214392400 +0100 Birth: - + cat 'file?' cat: file?: No such file or directory ^^ note how stat succeeds, but cat fails (and yes, the argument is properly shell-quoted). Rebooting into a 4.0.9 kernel (same .config) gives me the expected: + cat 'file?' hello, this is <file?> I've also captured pcaps for 4.0.9 and 4.1.1 and loaded them up in wireshark, but found no visible difference (except for the final response from samba). If I set /proc/fs/cifs/cifsFYI to 7, the only difference between a good run (4.0.9 and below) and a bad one (4.1.1+) is a line that reads: Status code returned 0xc0000034 NT_STATUS_OBJECT_NAME_NOT_FOUND Thinking of a problem with my smb.conf, I tried the userspace tool smbclient to browse the share and retrieve the offending file; works as expected -- both with posix disabled + mangled names, and posix enabled + unmangled names: + smbclient -U user //localhost/shared pass -c 'dir; stat FP5AFZ~2; get FP5AFZ~2 /dev/stdout' Domain=[MYWORKGROUP] OS=[Windows 6.1] Server=[Samba 4.2.12] . D 0 Wed Jul 20 09:51:14 2016 .. D 0 Wed Jul 20 14:40:56 2016 file N 22 Wed Jul 20 09:53:10 2016 FP5AFZ~2 N 23 Wed Jul 20 09:53:10 2016 _WHSTP~N N 24 Wed Jul 20 09:53:10 2016 41152832 blocks of size 1024. 10022996 blocks available File: \FP5AFZ~2 Size: 23 Blocks: 8 regular file Inode: 1328306 Links: 1 Access: (0644/-rw-r--r--) Uid: 0 Gid: 0 Access: 2016-07-20 09:53:17 +0100 Modify: 2016-07-20 09:53:10 +0100 Change: 2016-07-20 09:53:10 +0100 getting file \FP5AFZ~2 of size 23 as /dev/stdout (22.5 KiloBytes/sec) hello, this is <file?> + smbclient -U user //localhost/shared pass -c 'posix; dir; stat file?; get file? /dev/stdout' Domain=[MYWORKGROUP] OS=[Windows 6.1] Server=[Samba 4.2.12] Server supports CIFS extensions 1.0 Server supports CIFS capabilities locks acls pathnames posix_path_operations large_read posix_encrypt . D 0 Wed Jul 20 09:51:14 2016 .. D 0 Wed Jul 20 14:40:56 2016 file N 22 Wed Jul 20 09:53:10 2016 file? N 23 Wed Jul 20 09:53:10 2016 "file" N 24 Wed Jul 20 09:53:10 2016 41152832 blocks of size 1024. 10022996 blocks available File: /file? Size: 23 Blocks: 8 regular file Inode: 1328306 Links: 1 Access: (0644/-rw-r--r--) Uid: 0 Gid: 0 Access: 2016-07-20 09:53:17 +0100 Modify: 2016-07-20 09:53:10 +0100 Change: 2016-07-20 09:53:10 +0100 getting file /file? of size 23 as /dev/stdout (22.5 KiloBytes/sec) hello, this is <file?> I am at a loss. Is this a bug? Thanks, Andrea. -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
