Commit graph

130 commits

Author SHA1 Message Date
Stefan Metzmacher
b608e2c318 smb/client: remove unused rq_iter_size from struct smb_rqst
Reviewed-by: David Howells <dhowells@redhat.com>
Fixes: d08089f649 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-25 09:06:25 -05:00
ChenXiaoSong
5e51224d2a smb/client: fix typo: GlobalMid_Sem -> GlobalMid_Lock
The comments have typos, fix that to not confuse readers.

Signed-off-by: ChenXiaoSong <chenxiaosong@kylinos.cn>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-22 15:44:19 -05:00
Xiaxi Shen
bdcffe4be7 Fix spelling errors in Server Message Block
Fixed typos in various files under fs/smb/client/

Signed-off-by: Xiaxi Shen <shenxiaxi26@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-08 11:15:33 -05:00
Steve French
1b5487aefb smb3: fix setting SecurityFlags when encryption is required
Setting encryption as required in security flags was broken.
For example (to require all mounts to be encrypted by setting):

  "echo 0x400c5 > /proc/fs/cifs/SecurityFlags"

Would return "Invalid argument" and log "Unsupported security flags"
This patch fixes that (e.g. allowing overriding the default for
SecurityFlags  0x00c5, including 0x40000 to require seal, ie
SMB3.1.1 encryption) so now that works and forces encryption
on subsequent mounts.

Acked-by: Bharath SM <bharathsm@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-08 11:14:53 -05:00
David Howells
cd93650798 cifs: Remove cifs_aio_ctx
Remove struct cifs_aio_ctx and its associated alloc/release functions as it
is no longer used, the functions being taken over by netfslib.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-08-02 10:55:45 -05:00
David Howells
519be98971 cifs: Add a tracepoint to track credits involved in R/W requests
Add a tracepoint to track the credit changes and server in_flight value
involved in the lifetime of a R/W request, logging it against the
request/subreq debugging ID.  This requires the debugging IDs to be
recorded in the cifs_credits struct.

The tracepoint can be enabled with:

	echo 1 >/sys/kernel/debug/tracing/events/cifs/smb3_rw_credits/enable

Also add a three-state flag to struct cifs_credits to note if we're
interested in determining when the in_flight contribution ends and, if so,
to track whether we've decremented the contribution yet.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-07-19 11:08:57 -05:00
Steve French
d2346e2836 cifs: fix setting SecurityFlags to true
If you try to set /proc/fs/cifs/SecurityFlags to 1 it
will set them to CIFSSEC_MUST_NTLMV2 which no longer is
relevant (the less secure ones like lanman have been removed
from cifs.ko) and is also missing some flags (like for
signing and encryption) and can even cause mount to fail,
so change this to set it to Kerberos in this case.

Also change the description of the SecurityFlags to remove mention
of flags which are no longer supported.

Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-07-13 09:24:27 -05:00
David Howells
3f59138580 cifs: Move the 'pid' from the subreq to the req
Move the reference pid from the cifs_io_subrequest struct to the
cifs_io_request struct as it's the same for all subreqs of a particular
request.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-06-20 15:25:08 -05:00
David Howells
969b3010cb cifs: Only pick a channel once per read request
In cifs, only pick a channel when setting up a read request rather than
doing so individually for every subrequest and instead use that channel for
all.  This mirrors what the code in v6.9 does.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-06-20 15:21:44 -05:00
Steve French
14b1cd2534 cifs: Fix locking in cifs_strict_readv()
Fix to take the i_rwsem (through the netfs locking wrappers) before taking
cinode->lock_sem.

Fixes: 3ee1a1fc39 ("cifs: Cut over to using netfslib")
Reported-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-05-13 17:02:05 -05:00
David Howells
742b3443e2 cifs: Remove some code that's no longer used, part 1
Remove some code that was #if'd out with the netfslib conversion.  This is
split into parts for file.c as the diff generator otherwise produces a hard
to read diff for part of it where a big chunk is cut out.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:21 +01:00
David Howells
3ee1a1fc39 cifs: Cut over to using netfslib
Make the cifs filesystem use netfslib to handle reading and writing on
behalf of cifs.  The changes include:

 (1) Various read_iter/write_iter type functions are turned into wrappers
     around netfslib API functions or are pointed directly at those
     functions:

	cifs_file_direct{,_nobrl}_ops switch to use
	netfs_unbuffered_read_iter and netfs_unbuffered_write_iter.

Large pieces of code that will be removed are #if'd out and will be removed
in subsequent patches.

[?] Why does cifs mark the page dirty in the destination buffer of a DIO
    read?  Should that happen automatically?  Does netfs need to do that?

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:21 +01:00
David Howells
69c3c023af cifs: Implement netfslib hooks
Provide implementation of the netfslib hooks that will be used by netfslib
to ask cifs to set up and perform operations.  Of particular note are

 (*) cifs_clamp_length() - This is used to negotiate the size of the next
     subrequest in a read request, taking into account the credit available
     and the rsize.  The credits are attached to the subrequest.

 (*) cifs_req_issue_read() - This is used to issue a subrequest that has
     been set up and clamped.

 (*) cifs_prepare_write() - This prepares to fill a subrequest by picking a
     channel, reopening the file and requesting credits so that we can set
     the maximum size of the subrequest and also sets the maximum number of
     segments if we're doing RDMA.

 (*) cifs_issue_write() - This releases any unneeded credits and issues an
     asynchronous data write for the contiguous slice of file covered by
     the subrequest.  This should possibly be folded in to all
     ->async_writev() ops and that called directly.

 (*) cifs_begin_writeback() - This gets the cached writable handle through
     which we do writeback (this does not affect writethrough, unbuffered
     or direct writes).

At this point, cifs is not wired up to actually *use* netfslib; that will
be done in a subsequent patch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:21 +01:00
David Howells
c20c0d7325 cifs: Make add_credits_and_wake_if() clear deducted credits
Make add_credits_and_wake_if() clear the amount of credits in the
cifs_credits struct after it has returned them to the overall counter.
This allows add_credits_and_wake_if() to be called multiple times during
the error handling and cleanup without accidentally returning the credits
again and again.

Note that the wake_up() in add_credits_and_wake_if() may also be
superfluous as ->add_credits() also does a wake on the request_q.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
2024-05-01 18:08:21 +01:00
David Howells
edea94a697 cifs: Add mempools for cifs_io_request and cifs_io_subrequest structs
Add mempools for the allocation of cifs_io_request and cifs_io_subrequest
structs for netfslib to use so that it can guarantee eventual allocation in
writeback.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:20 +01:00
David Howells
56257334e8 cifs: Make wait_mtu_credits take size_t args
Make the wait_mtu_credits functions use size_t for the size and num
arguments rather than unsigned int as netfslib uses size_t/ssize_t for
arguments and return values to allow for extra capacity.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-mm@kvack.org
2024-05-01 18:08:19 +01:00
David Howells
ab58fbdeeb cifs: Use more fields from netfs_io_subrequest
Use more fields from netfs_io_subrequest instead of those incorporated into
cifs_io_subrequest from cifs_readdata and cifs_writedata.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:19 +01:00
David Howells
a975a2f22c cifs: Replace cifs_writedata with a wrapper around netfs_io_subrequest
Replace the cifs_writedata struct with the same wrapper around
netfs_io_subrequest that was used to replace cifs_readdata.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:18 +01:00
David Howells
753b67eb63 cifs: Replace cifs_readdata with a wrapper around netfs_io_subrequest
Netfslib has a facility whereby the allocation for netfs_io_subrequest can
be increased to so that filesystem-specific data can be tagged on the end.

Prepare to use this by making a struct, cifs_io_subrequest, that wraps
netfs_io_subrequest, and absorb struct cifs_readdata into it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
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: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
2024-05-01 18:08:18 +01:00
David Howells
afc23febd5 cifs: Add tracing for the cifs_tcon struct refcounting
Add tracing for the refcounting/lifecycle of the cifs_tcon struct, marking
different events with different labels and giving each tcon its own debug
ID so that the tracelines corresponding to individual tcons can be
distinguished.  This can be enabled with:

	echo 1 >/sys/kernel/debug/tracing/events/cifs/smb3_tcon_ref/enable

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-19 16:02:09 -05:00
David Howells
dad80c6bff cifs: Fix reacquisition of volume cookie on still-live connection
During mount, cifs_mount_get_tcon() gets a tcon resource connection record
and then attaches an fscache volume cookie to it.  However, it does this
irrespective of whether or not the tcon returned from cifs_get_tcon() is a
new record or one that's already in use.  This leads to a warning about a
volume cookie collision and a leaked volume cookie because tcon->fscache
gets reset.

Fix this be adding a mutex and a "we've already tried this" flag and only
doing it once for the lifetime of the tcon.

[!] Note: Looking at cifs_mount_get_tcon(), a more general solution may
actually be required.  Reacquiring the volume cookie isn't the only thing
that function does: it also partially reinitialises the tcon record without
any locking - which may cause live filesystem ops already using the tcon
through a previous mount to malfunction.

This can be reproduced simply by something like:

    mount //example.com/test /xfstest.test -o user=shares,pass=xxx,fsc
    mount //example.com/test /mnt -o user=shares,pass=xxx,fsc

Fixes: 70431bfd82 ("cifs: Support fscache indexing rewrite")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-19 15:37:47 -05:00
Steve French
35f834265e smb3: fix broken reconnect when password changing on the server by allowing password rotation
There are various use cases that are becoming more common in which password
changes are scheduled on a server(s) periodically but the clients connected
to this server need to stay connected (even in the face of brief network
reconnects) due to mounts which can not be easily unmounted and mounted at
will, and servers that do password rotation do not always have the ability
to tell the clients exactly when to the new password will be effective,
so add support for an alt password ("password2=") on mount (and also
remount) so that we can anticipate the upcoming change to the server
without risking breaking existing mounts.

An alternative would have been to use the kernel keyring for this but the
processes doing the reconnect do not have access to the keyring but do
have access to the ses structure.

Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-11 16:03:48 -05:00
Paulo Alcantara
ca545b7f08 smb: client: fix potential UAF in cifs_debug_files_proc_show()
Skip sessions that are being teared down (status == SES_EXITING) to
avoid UAF.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-03 14:43:34 -05:00
Ritvik Budhiraja
173217bd73 smb3: retrying on failed server close
In the current implementation, CIFS close sends a close to the
server and does not check for the success of the server close.
This patch adds functionality to check for server close return
status and retries in case of an EBUSY or EAGAIN error.

This can help avoid handle leaks

Cc: stable@vger.kernel.org
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-03 14:43:24 -05:00
Paulo Alcantara
062a7f0ff4 smb: client: guarantee refcounted children from parent session
Avoid potential use-after-free bugs when walking DFS referrals,
mounting and performing DFS failover by ensuring that all children
from parent @tcon->ses are also refcounted.  They're all needed across
the entire DFS mount.  Get rid of @tcon->dfs_ses_list while we're at
it, too.

Cc: stable@vger.kernel.org # 6.4+
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404021527.ZlRkIxgv-lkp@intel.com/
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-04-02 10:09:57 -05:00
David Howells
5b142b37c7 cifs: Move some extern decls from .c files to .h
Move the following:

        extern mempool_t *cifs_sm_req_poolp;
        extern mempool_t *cifs_req_poolp;
        extern mempool_t *cifs_mid_poolp;
        extern bool disable_legacy_dialects;

from various .c files to cifsglob.h.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-20 11:49:24 -05:00
Shyam Prasad N
13c0a74747 cifs: make sure server interfaces are requested only for SMB3+
Some code paths for querying server interfaces make a false
assumption that it will only get called for SMB3+. Since this
function now can get called from a generic code paths, the correct
thing to do is to have specific handler for this functionality
per SMB dialect, and call this handler.

This change adds such a handler and implements this handler only
for SMB 3.0 and 3.1.1.

Cc: stable@vger.kernel.org
Cc: Jan Čermák <sairon@sairon.cz>
Reported-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-14 13:54:27 -05:00
Enzo Matsumiya
8fe7062b7d smb: client: negotiate compression algorithms
Change "compress=" mount option to a boolean flag, that, if set,
will enable negotiating compression algorithms with the server.

Do not de/compress anything for now.

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:52:42 -05:00
Paulo Alcantara
1e5f424071 smb: client: return reparse type in /proc/mounts
Add support for returning reparse mount option in /proc/mounts.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402262152.YZOwDlCM-lkp@intel.com/
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:33:58 -05:00
Paulo Alcantara
ea41367b2a 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>
2024-03-10 19:33:58 -05:00
Paulo Alcantara
5a4b09ecf8 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>
2024-03-10 19:33:58 -05:00
Paulo Alcantara
fa792d8d23 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>
2024-03-10 19:33:58 -05:00
Paulo Alcantara
c520ba7573 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>
2024-03-10 19:33:57 -05:00
Paulo Alcantara
eb90e8ecb2 smb: client: introduce reparse mount option
Allow the user to create special files and symlinks by choosing
between WSL and NFS reparse points via 'reparse={nfs,wsl}' mount
options.  If unset or 'reparse=default', the client will default to
creating them via NFS reparse points.

Creating WSL reparse points isn't supported yet, so simply return
error when attempting to mount with 'reparse=wsl' for now.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:33:54 -05:00
Meetakshi Setiya
ffceb7640c 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>
2024-03-10 19:33:54 -05:00
Meetakshi Setiya
2c7d399e55 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>
2024-03-10 19:33:54 -05:00
Steve French
c1eb537bf4 cifs: allow changing password during remount
There are cases where a session is disconnected and password has changed
on the server (or expired) for this user and this currently can not
be fixed without unmount and mounting again.  This patch allows
remount to change the password (for the non Kerberos case, Kerberos
ticket refresh is handled differently) when the session is disconnected
and the user can not reconnect due to still using old password.

Future patches should also allow us to setup the keyring (cifscreds)
to have an "alternate password" so we would be able to change
the password before the session drops (without the risk of races
between when the password changes and the disconnect occurs -
ie cases where the old password is still needed because the new
password has not fully rolled out to all servers yet).

Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:33:53 -05:00
Shyam Prasad N
79520587fe cifs: update the same create_guid on replay
File open requests made to the server contain a
CreateGuid, which is used by the server to identify
the open request. If the same request needs to be
replayed, it needs to be sent with the same CreateGuid
in the durable handle v2 context.

Without doing so, we could end up leaking handles on
the server when:
1. multichannel is used AND
2. connection goes down, but not for all channels

This is because the replayed open request would have a
new CreateGuid and the server will treat this as a new
request and open a new handle.

This change fixes this by reusing the existing create_guid
stored in the cached fid struct.

REF: MS-SMB2 4.9 Replay Create Request on an Alternate Channel

Fixes: 4f1fffa237 ("cifs: commands that are retried should have replay flag set")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-11 19:07:08 -06:00
Paulo Alcantara
11d4d1dba3 smb: client: increase number of PDUs allowed in a compound request
With the introduction of SMB2_OP_QUERY_WSL_EA, the client may now send
5 commands in a single compound request in order to query xattrs from
potential WSL reparse points, which should be fine as we currently
allow up to 5 PDUs in a single compound request.  However, if
encryption is enabled (e.g. 'seal' mount option) or enforced by the
server, current MAX_COMPOUND(5) won't be enough as we require an extra
PDU for the transform header.

Fix this by increasing MAX_COMPOUND to 7 and, while we're at it, add
an WARN_ON_ONCE() and return -EIO instead of -ENOMEM in case we
attempt to send a compound request that couldn't include the extra
transform header.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-01 12:15:51 -06:00
Shyam Prasad N
ee36a3b345 cifs: make sure that channel scaling is done only once
Following a successful cifs_tree_connect, we have the code
to scale up/down the number of channels in the session.
However, it is not protected by a lock today.

As a result, this code can be executed by several processes
that select the same channel. The core functions handle this
well, as they pick chan_lock. However, we've seen cases where
smb2_reconnect throws some warnings.

To fix that, this change introduces a flags bitmap inside the
cifs_ses structure. A new flag type is used to ensure that
only one process enters this section at any time.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-31 16:52:03 -06:00
Shyam Prasad N
4cdad80261 cifs: set replay flag for retries of write command
Similar to the rest of the commands, this is a change
to add replay flags on retry. This one does not add a
back-off, considering that we may want to flush a write
ASAP to the server. Considering that this will be a
flush of cached pages, the retrans value is also not
honoured.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-23 20:23:29 -06:00
Shyam Prasad N
4f1fffa237 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>
2024-01-23 20:23:29 -06:00
Shyam Prasad N
64cc377b76 cifs: helper function to check replayable error codes
The code to check for replay is not just -EAGAIN. In some
cases, the send request or receive response may result in
network errors, which we're now mapping to -ECONNABORTED.

This change introduces a helper function which checks
if the error returned in one of the above two errors.
And all checks for replays will now use this helper.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-23 20:23:28 -06:00
David Howells
966cc171c8 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>
2024-01-23 18:59:05 -06:00
Shyam Prasad N
ce09f8d8a7 cifs: new mount option called retrans
We have several places in the code where we treat the
error -EAGAIN very differently. Some code retry for
arbitrary number of times.

Introducing this new mount option named "retrans", so
that all these handlers of -EAGAIN can retry a fixed
number of times. This applies only to soft mounts.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-19 10:31:57 -06:00
Paulo Alcantara
858e74876c 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>
2024-01-19 10:30:53 -06:00
Steve French
d8392c203e smb3: show beginning time for per share stats
In analyzing problems, one missing piece of debug data is when the
mount occurred.  A related problem is when collecting stats we don't
know the  period of time the stats covered, ie when this set of stats
for the tcon started to be collected.  To make debugging easier track
the stats begin time. Set it when the mount occurred at mount time,
and reset it to current time whenever stats are reset. For example,

...
1) \\localhost\test
SMBs: 14 since 2024-01-17 22:17:30 UTC
Bytes read: 0  Bytes written: 0
Open files: 0 total (local), 0 open on server
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
...
2) \\localhost\scratch
SMBs: 24 since 2024-01-17 22:16:04 UTC
Bytes read: 0  Bytes written: 0
Open files: 0 total (local), 0 open on server
TreeConnects: 1 total 0 failed
TreeDisconnects: 0 total 0 failed
...

Note the time "since ... UTC" is now displayed in /proc/fs/cifs/Stats
for each share that is mounted.

Suggested-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-18 12:07:51 -06:00
Paulo Alcantara
6d039984c1 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>
2024-01-07 15:46:06 -06:00
Paulo Alcantara
514d793e27 smb: client: allow creating symlinks via reparse points
Add support for creating symlinks via IO_REPARSE_TAG_SYMLINK reparse
points in SMB2+.

These are fully supported by most SMB servers and documented in
MS-FSCC.  Also have the advantage of requiring fewer roundtrips as
their symlink targets can be parsed directly from CREATE responses on
STATUS_STOPPED_ON_SYMLINK errors.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311260838.nx5mkj1j-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-07 15:46:06 -06:00
Paulo Alcantara
5408990aa6 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>
2024-01-07 15:46:06 -06:00