smb: client: parse uid, gid, mode and dev from WSL reparse points

Parse the extended attributes from WSL reparse points to correctly
report uid, gid mode and dev from ther instantiated inodes.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: move most of reparse point handling code to common file

In preparation to add support for creating special files also via WSL
reparse points in next commits.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: prevent updating file size from server if we have a read/write lease

In cases of large directories, the readdir operation may span multiple
round trips to retrieve contents. This introduces a potential race
condition in case of concurrent write and readdir operations. If the
readdir operation initiates before a write has been processed by the
server, it may update the file size attribute to an older value.
Address this issue by avoiding file size updates from readdir when we
have read/write lease.

Scenario:
1) process1: open dir xyz
2) process1: readdir instance 1 on xyz
3) process2: create file.txt for write
4) process2: write x bytes to file.txt
5) process2: close file.txt
6) process2: open file.txt for read
7) process1: readdir 2 - overwrites file.txt inode size to 0
8) process2: read contents of file.txt - bug, short read with 0 bytes

Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: set correct d_type for reparse points under DFS mounts

Send query dir requests with an info level of
SMB_FIND_FILE_FULL_DIRECTORY_INFO rather than
SMB_FIND_FILE_DIRECTORY_INFO when the client is generating its own
inode numbers (e.g. noserverino) so that reparse tags still
can be parsed directly from the responses, but server won't
send UniqueId (server inode number)

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: Share server EOF pos with netfslib

Use cifsi->netfs_ctx.remote_i_size instead of cifsi->server_eof so that
netfslib can refer to it to.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: don't clobber ->i_rdev from cached reparse points

Don't clobber ->i_rdev from valid reparse inodes over readdir(2) as it
can't be provided by query dir responses.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: minor comment cleanup

minor comment cleanup and trivial camelCase removal

Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: stop revalidating reparse points unnecessarily

Query dir responses don't provide enough information on reparse points
such as major/minor numbers and symlink targets other than reparse
tags, however we don't need to unconditionally revalidate them only
because they are reparse points. Instead, revalidate them only when
their ctime or reparse tag has changed.

For instance, Windows Server updates ctime of reparse points when
their data have changed.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: set correct file type from NFS reparse points

Handle all file types in NFS reparse points as specified in MS-FSCC
2.1.2.6 Network File System (NFS) Reparse Data Buffer.

The client is now able to set all file types based on the parsed NFS
reparse point, which used to support only symlinks. This works for
SMB1+.

Before patch:

$ mount.cifs //srv/share /mnt -o ...
$ ls -l /mnt
ls: cannot access 'block': Operation not supported
ls: cannot access 'char': Operation not supported
ls: cannot access 'fifo': Operation not supported
ls: cannot access 'sock': Operation not supported
total 1
l????????? ? ? ? ? ? block
l????????? ? ? ? ? ? char
-rwxr-xr-x 1 root root 5 Nov 18 23:22 f0
l????????? ? ? ? ? ? fifo
l--------- 1 root root 0 Nov 18 23:23 link -> f0
l????????? ? ? ? ? ? sock

After patch:

$ mount.cifs //srv/share /mnt -o ...
$ ls -l /mnt
total 1
brwxr-xr-x 1 root root 123, 123 Nov 18 00:34 block
crwxr-xr-x 1 root root 1234, 1234 Nov 18 00:33 char
-rwxr-xr-x 1 root root 5 Nov 18 23:22 f0
prwxr-xr-x 1 root root 0 Nov 18 23:23 fifo
lrwxr-xr-x 1 root root 0 Nov 18 23:23 link -> f0
srwxr-xr-x 1 root root 0 Nov 19 2023 sock

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: cilent: set reparse mount points as automounts

By doing so we can selectively mark those submounts as 'noserverino'
rather than whole mount and thus avoiding inode collisions in them.

Consider a "test" SMB share that has two mounted NTFS volumes
(vol0 & vol1) inside it.

* Before patch

$ mount.cifs //srv/test /mnt/1 -o ...,serverino
$ ls -li /mnt/1/vol0
total 1
281474976710693 drwxr-xr-x 2 root root 0 Jul 15 00:23 $RECYCLE.BIN
281474976710696 drwxr-xr-x 2 root root 0 Jul 18 18:23 System Volume...
281474976710699 -rwxr-xr-x 1 root root 0 Aug 14 21:53 f0
281474976710700 -rwxr-xr-x 1 root root 0 Aug 15 18:52 f2
281474976710698 drwxr-xr-x 2 root root 0 Aug 12 19:39 foo
281474976710692 -rwxr-xr-x 1 root root 5 Aug 4 21:18 vol0_f0.txt
$ ls -li /mnt/1/vol1
total 0
281474976710693 drwxr-xr-x 2 root root 0 Jul 15 00:23 $RECYCLE.BIN
281474976710696 drwxr-xr-x 2 root root 0 Jul 18 18:23 System Volume...
281474976710698 drwxr-xr-x 2 root root 0 Aug 12 19:39 bar
281474976710699 -rwxr-xr-x 1 root root 0 Aug 14 22:03 f0
281474976710700 -rwxr-xr-x 1 root root 0 Aug 14 22:52 f1
281474976710692 -rwxr-xr-x 1 root root 0 Jul 15 00:23 vol1_f0.txt

* After patch

$ mount.cifs //srv/test /mnt/1 -o ...,serverino
$ ls -li /mnt/1/vol0
total 1
590 drwxr-xr-x 2 root root 0 Jul 15 00:23 $RECYCLE.BIN
594 drwxr-xr-x 2 root root 0 Jul 18 18:23 System Volume Information
591 -rwxr-xr-x 1 root root 0 Aug 14 21:53 f0
592 -rwxr-xr-x 1 root root 0 Aug 15 18:52 f2
593 drwxr-xr-x 2 root root 0 Aug 12 19:39 foo
595 -rwxr-xr-x 1 root root 5 Aug 4 21:18 vol0_f0.txt
$ ls -li /mnt/1/vol1
total 0
596 drwxr-xr-x 2 root root 0 Jul 15 00:23 $RECYCLE.BIN
600 drwxr-xr-x 2 root root 0 Jul 18 18:23 System Volume Information
597 drwxr-xr-x 2 root root 0 Aug 12 19:39 bar
598 -rwxr-xr-x 1 root root 0 Aug 14 22:03 f0
599 -rwxr-xr-x 1 root root 0 Aug 14 22:52 f1
601 -rwxr-xr-x 1 root root 0 Jul 15 00:23 vol1_f0.txt

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: parse reparse point flag in create response

Check for reparse point flag on query info calls as specified in
MS-SMB2 2.2.14.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: move client and server files to common directory fs/smb

Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:

fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>