smb: client: introduce SMB2_OP_QUERY_WSL_EA

Add a new command to smb2_compound_op() for querying WSL extended
attributes from reparse points.

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

smb: client: add support for WSL reparse points

Add support for creating special files via WSL reparse points when
using 'reparse=wsl' mount option. They're faster than NFS reparse
points because they don't require extra roundtrips to figure out what
->d_type a specific dirent is as such information is already stored in
query dir responses and then making getdents() calls faster.

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

smb: client: reduce number of parameters in smb2_compound_op()

Replace @desired_access, @create_disposition, @create_options and
@mode parameters with a single @oparms.

No functional changes.

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

smb: client: fix potential broken compound request

Now that smb2_compound_op() can accept up to 5 commands in a single
compound request, set the appropriate NextCommand and related flags to
all subsequent commands as well as handling the case where a valid
@cfile is passed and therefore skipping create and close requests in
the compound chain.

This fix a potential broken compound request that could be sent from
smb2_get_reparse_inode() if the client found a valid open
file (@cfile) prior to calling smb2_compound_op().

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

smb: client: retry compound request without reusing lease

There is a shortcoming in the current implementation of the file
lease mechanism exposed when the lease keys were attempted to be
reused for unlink, rename and set_path_size operations for a client. As
per MS-SMB2, lease keys are associated with the file name. Linux smb
client maintains lease keys with the inode. If the file has any hardlinks,
it is possible that the lease for a file be wrongly reused for an
operation on the hardlink or vice versa. In these cases, the mentioned
compound operations fail with STATUS_INVALID_PARAMETER.
This patch adds a fallback to the old mechanism of not sending any
lease with these compound operations if the request with lease key fails
with STATUS_INVALID_PARAMETER.
Resending the same request without lease key should not hurt any
functionality, but might impact performance especially in cases where
the error is not because of the usage of wrong lease key and we might
end up doing an extra roundtrip.

Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: do not defer close open handles to deleted files

When a file/dentry has been deleted before closing all its open
handles, currently, closing them can add them to the deferred
close list. This can lead to problems in creating file with the
same name when the file is re-created before the deferred close
completes. This issue was seen while reusing a client's already
existing lease on a file for compound operations and xfstest 591
failed because of the deferred close handle that remained valid
even after the file was deleted and was being reused to create a
file with the same name. The server in this case returns an error
on open with STATUS_DELETE_PENDING. Recreating the file would
fail till the deferred handles are closed (duration specified in
closetimeo).

This patch fixes the issue by flagging all open handles for the
deleted file (file path to be precise) by setting
status_file_deleted to true in the cifsFileInfo structure. As per
the information classes specified in MS-FSCC, SMB2 query info
response from the server has a DeletePending field, set to true
to indicate that deletion has been requested on that file. If
this is the case, flag the open handles for this file too.

When doing close in cifs_close for each of these handles, check the
value of this boolean field and do not defer close these handles
if the corresponding filepath has been deleted.

Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: reuse file lease key in compound operations

Currently, when a rename, unlink or set path size compound operation
is requested on a file that has a lot of dirty pages to be written
to the server, we do not send the lease key for these requests. As a
result, the server can assume that this request is from a new client, and
send a lease break notification to the same client, on the same
connection. As a response to the lease break, the client can consume
several credits to write the dirty pages to the server. Depending on the
server's credit grant implementation, the server can stop granting more
credits to this connection, and this can cause a deadlock (which can only
be resolved when the lease timer on the server expires).
One of the problems here is that the client is sending no lease key,
even if it has a lease for the file. This patch fixes the problem by
reusing the existing lease key on the file for rename, unlink and set path
size compound operations so that the client does not break its own lease.

A very trivial example could be a set of commands by a client that
maintains open handle (for write) to a file and then tries to copy the
contents of that file to another one, eg.,

tail -f /dev/null > myfile &
mv myfile myfile2

Presently, the network capture on the client shows that the move (or
rename) would trigger a lease break on the same client, for the same file.
With the lease key reused, the lease break request-response overhead is
eliminated, thereby reducing the roundtrips performed for this set of
operations.

The patch fixes the bug described above and also provides perf benefit.

Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: commands that are retried should have replay flag set

MS-SMB2 states that the header flag SMB2_FLAGS_REPLAY_OPERATION
needs to be set when a command needs to be retried, so that
the server is aware that this is a replay for an operation that
appeared before.

This can be very important, for example, for state changing
operations and opens which get retried following a reconnect;
since the client maybe unaware of the status of the previous
open.

This is particularly important for multichannel scenario, since
disconnection of one connection does not mean that the session
is lost. The requests can be replayed on another channel.

This change also makes use of exponential back-off before replays
and also limits the number of retries to "retrans" mount option
value.

Also, this change does not modify the read/write codepath.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: get rid of smb311_posix_query_path_info()

Merge smb311_posix_query_path_info into ->query_path_info() to get rid
of duplicate code.

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

smb: client: parse owner/group when creating reparse points

Parse owner/group when creating special files and symlinks under
SMB3.1.1 POSIX mounts.

Move the parsing of owner/group to smb2_compound_op() so we don't have
to duplicate it in both smb2_get_reparse_inode() and
smb311_posix_query_path_info().

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

smb: client: cleanup smb2_query_reparse_point()

Use smb2_compound_op() with SMB2_OP_GET_REPARSE to get reparse point.

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

smb: client: fix hardlinking of reparse points

The client was sending an SMB2_CREATE request without setting
OPEN_REPARSE_POINT flag thus failing the entire hardlink operation.

Fix this by setting OPEN_REPARSE_POINT in create options for
SMB2_CREATE request when the source inode is a repase point.

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

smb: client: fix renaming of reparse points

The client was sending an SMB2_CREATE request without setting
OPEN_REPARSE_POINT flag thus failing the entire rename operation.

Fix this by setting OPEN_REPARSE_POINT in create options for
SMB2_CREATE request when the source inode is a repase point.

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

smb: client: optimise reparse point querying

Reduce number of roundtrips to server when querying reparse points in
->query_path_info() by sending a single compound request of
create+get_reparse+get_info+close.

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

smb: client: allow creating special files via reparse points

Add support for creating special files (e.g. char/block devices,
sockets, fifos) via NFS reparse points on SMB2+, which are fully
supported by most SMB servers and documented in MS-FSCC.

smb2_get_reparse_inode() creates the file with a corresponding reparse
point buffer set in @iov through a single roundtrip to the server.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311260746.HOJ039BV-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: extend smb2_compound_op() to accept more commands

Make smb2_compound_op() accept up to MAX_COMPOUND(5) commands to be
sent over a single compounded request.

This will allow next commits to read and write reparse files through a
single roundtrip to the server.

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: client: handle STATUS_IO_REPARSE_TAG_NOT_HANDLED

Fix missing set of cifs_open_info_data::reparse_point when SMB2_CREATE
request fails with STATUS_IO_REPARSE_TAG_NOT_HANDLED.

Fixes: 5f71ebc41294 ("smb: client: parse reparse point flag in create response")
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: reduce stack usage in smb2_set_ea()

Clang warns about exceeded stack frame size

fs/smb/client/smb2ops.c:1080:1: warning: stack frame size (1432)
exceeds limit (1024) in 'smb2_set_ea' [-Wframe-larger-than]

Fix this by allocating a structure that will hold most of the large
variables.

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: client: make smb2_compound_op() return resp buffer on success

If @out_iov and @out_buftype are passed, then return compounded
responses regardless whether the request failed or not. This will be
useful for detecting reparse points on SMB2_CREATE responses as
specified in MS-SMB2 2.2.14.

No functional changes.

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

smb: client: move some params to cifs_open_info_data

Instead of passing @adjust_tz and some reparse point related fields as
parameters in ->query_path_info() and
{smb311_posix,cifs}_info_to_fattr() calls, move them to
cifs_open_info_data structure as they can be easily accessed through
@data.

No functional changes.

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

smb: client: fix broken file attrs with nodfs mounts

*_get_inode_info() functions expect -EREMOTE when query path info
calls find a DFS link, regardless whether !CONFIG_CIFS_DFS_UPCALL or
'nodfs' mount option. Otherwise, those files will miss the fake DFS
file attributes.

Before patch

$ mount.cifs //srv/dfs /mnt/1 -o ...,nodfs
$ ls -l /mnt/1
ls: cannot access '/mnt/1/link': Operation not supported
total 0
-rwxr-xr-x 1 root root 0 Jul 26 2022 dfstest2_file1.txt
drwxr-xr-x 2 root root 0 Aug 8 2022 dir1
d????????? ? ? ? ? ? link

After patch

$ mount.cifs //srv/dfs /mnt/1 -o ...,nodfs
$ ls -l /mnt/1
total 0
-rwxr-xr-x 1 root root 0 Jul 26 2022 dfstest2_file1.txt
drwxr-xr-x 2 root root 0 Aug 8 2022 dir1
drwx--x--x 2 root root 0 Jun 26 20:29 link

Fixes: c877ce47e137 ("cifs: reduce roundtrips on create/qinfo requests")
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: prevent use-after-free by freeing the cfile later

In smb2_compound_op we have a possible use-after-free
which can cause hard to debug problems later on.

This was revealed during stress testing with KASAN enabled
kernel. Fixing it by moving the cfile free call to
a few lines below, after the usage.

Fixes: 76894f3e2f71 ("cifs: improve symlink handling for smb2+")
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.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>