On Tue, Apr 06, 2021 at 01:38:24PM +0200, Salvatore Bonaccorso wrote: > 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. If there is a missing patch, we will be glad to take it, does 5.4 also have this problem? thanks, greg k-h
