Hi, On Mon, Mar 01, 2021 at 05:10:33PM +0100, Greg Kroah-Hartman wrote: > From: Shyam Prasad N <sprasad@xxxxxxxxxxxxx> > > [ Upstream commit a738c93fb1c17e386a09304b517b1c6b2a6a5a8b ] > > While debugging another issue today, Steve and I noticed that if a > subdir for a file share is already mounted on the client, any new > mount of any other subdir (or the file share root) of the same share > results in sharing the cifs superblock, which e.g. can result in > incorrect device name. > > While setting prefix path for the root of a cifs_sb, > CIFS_MOUNT_USE_PREFIX_PATH flag should also be set. > Without it, prepath is not even considered in some places, > and output of "mount" and various /proc/<>/*mount* related > options can be missing part of the device name. > > Signed-off-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx> > Reviewed-by: Aurelien Aptel <aaptel@xxxxxxxx> > Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > fs/cifs/connect.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > index 6285085195c15..632249ce61eba 100644 > --- a/fs/cifs/connect.c > +++ b/fs/cifs/connect.c > @@ -3882,6 +3882,7 @@ int cifs_setup_cifs_sb(struct smb_vol *pvolume_info, > cifs_sb->prepath = kstrdup(pvolume_info->prepath, GFP_KERNEL); > if (cifs_sb->prepath == NULL) > return -ENOMEM; > + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH; > } > > return 0; A user in Debian reported an issue with mounts of DFS shares after an update in Debian from 4.19.177 to 4.181: https://lists.debian.org/debian-user/2021/04/msg00062.html In a test setup i was able to reproduce the issue with 4.19.184 itself (but interestingly not withing the 5.10.y series, checked 5.10.26) which both contain the above commit. 4.19.184 with a738c93fb1c1 ("cifs: Set CIFS_MOUNT_USE_PREFIX_PATH flag on setting cifs_sb->prepath.") reverted fixes the issue. Is there probably some missing prerequisites missing in the 4.19.y brach? I could not test othr versions, but maybe other versions are affected as well as before 4.19.y, as the commit was backported to 4.14.223 as well. Regards, Salvatore
