Commit Graph

267 Commits

Author SHA1 Message Date
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
8bd25b61c5 smb: client: set correct d_type for reparse DFS/DFSR and mount point
Set correct dirent->d_type for IO_REPARSE_TAG_DFS{,R} and
IO_REPARSE_TAG_MOUNT_POINT 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
78e26bec4d 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>
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
Dan Carpenter
e0e1e09b2c smb: client: Fix a NULL vs IS_ERR() check in wsl_set_xattrs()
This was intended to be an IS_ERR() check.  The ea_create_context()
function doesn't return NULL.

Fixes: 1eab17fe485c ("smb: client: add support for WSL reparse points")
Reviewed-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
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
6914d288c6 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>
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
71f15c90e7 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>
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
dbfdff402d smb3: update allocation size more accurately on write completion
Changes to allocation size are approximated for extending writes of cached
files until the server returns the actual value (on SMB3 close or query info
for example), but it was setting the estimated value for number of blocks
to larger than the file size even if the file is likely sparse which
breaks various xfstests (e.g. generic/129, 130, 221, 228).

When i_size and i_blocks are updated in write completion do not increase
allocation size more than what was written (rounded up to 512 bytes).

Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:33:54 -05:00
Chengming Zhou
9537155b71 smb: remove SLAB_MEM_SPREAD flag usage
The SLAB_MEM_SPREAD flag is already a no-op as of 6.8-rc1, remove
its usage so we can delete it from slab. No functional change.

Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-0-02f1753e8303@suse.cz/

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-03-10 19:33:53 -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
Bharath SM
e4b61f3b1c 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>
2024-03-10 19:33:53 -05:00
Linus Torvalds
66a97c2ec9 We still have some races in filesystem methods when exposed to RCU
pathwalk.  This series is a result of code audit (the second round
 of it) and it should deal with most of that stuff.  Exceptions: ntfs3
 ->d_hash()/->d_compare() and ceph_d_revalidate().  Up to maintainers (a
 note for NTFS folks - when documentation says that a method may not block,
 it *does* imply that blocking allocations are to be avoided.  Really).
 
 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull RCU pathwalk fixes from Al Viro:
 "We still have some races in filesystem methods when exposed to RCU
  pathwalk. This series is a result of code audit (the second round of
  it) and it should deal with most of that stuff.

  Still pending: ntfs3 ->d_hash()/->d_compare() and ceph_d_revalidate().
  Up to maintainers (a note for NTFS folks - when documentation says
  that a method may not block, it *does* imply that blocking allocations
  are to be avoided. Really)"

[ More explanations for people who aren't familiar with the vagaries of
  RCU path walking: most of it is hidden from filesystems, but if a
  filesystem actively participates in the low-level path walking it
  needs to make sure the fields involved in that walk are RCU-safe.

  That "actively participate in low-level path walking" includes things
  like having its own ->d_hash()/->d_compare() routines, or by having
  its own directory permission function that doesn't just use the common
  helpers.  Having a ->d_revalidate() function will also have this issue.

  Note that instead of making everything RCU safe you can also choose to
  abort the RCU pathwalk if your operation cannot be done safely under
  RCU, but that obviously comes with a performance penalty. One common
  pattern is to allow the simple cases under RCU, and abort only if you
  need to do something more complicated.

  So not everything needs to be RCU-safe, and things like the inode etc
  that the VFS itself maintains obviously already are. But these fixes
  tend to be about properly RCU-delaying things like ->s_fs_info that
  are maintained by the filesystem and that got potentially released too
  early.   - Linus ]

* tag 'pull-fixes.pathwalk-rcu-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ext4_get_link(): fix breakage in RCU mode
  cifs_get_link(): bail out in unsafe case
  fuse: fix UAF in rcu pathwalks
  procfs: make freeing proc_fs_info rcu-delayed
  procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
  nfs: fix UAF on pathwalk running into umount
  nfs: make nfs_set_verifier() safe for use in RCU pathwalk
  afs: fix __afs_break_callback() / afs_drop_open_mmap() race
  hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info
  exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper
  affs: free affs_sb_info with kfree_rcu()
  rcu pathwalk: prevent bogus hard errors from may_lookup()
  fs/super.c: don't drop ->s_user_ns until we free struct super_block itself
2024-02-25 09:29:05 -08:00
Al Viro
0511fdb4a3 cifs_get_link(): bail out in unsafe case
->d_revalidate() bails out there, anyway.  It's not enough
to prevent getting into ->get_link() in RCU mode, but that
could happen only in a very contrieved setup.  Not worth
trying to do anything fancy here unless ->d_revalidate()
stops kicking out of RCU mode at least in some cases.

Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:32 -05:00
Steve French
4860abb91f smb: Fix regression in writes when non-standard maximum write size negotiated
The conversion to netfs in the 6.3 kernel caused a regression when
maximum write size is set by the server to an unexpected value which is
not a multiple of 4096 (similarly if the user overrides the maximum
write size by setting mount parm "wsize", but sets it to a value that
is not a multiple of 4096).  When negotiated write size is not a
multiple of 4096 the netfs code can skip the end of the final
page when doing large sequential writes, causing data corruption.

This section of code is being rewritten/removed due to a large
netfs change, but until that point (ie for the 6.3 kernel until now)
we can not support non-standard maximum write sizes.

Add a warning if a user specifies a wsize on mount that is not
a multiple of 4096 (and round down), also add a change where we
round down the maximum write size if the server negotiates a value
that is not a multiple of 4096 (we also have to check to make sure that
we do not round it down to zero).

Reported-by: R. Diez" <rdiez-2006@rd10.de>
Fixes: d08089f649 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Suggested-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Acked-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Tested-by: Matthew Ruffell <matthew.ruffell@canonical.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # v6.3+
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-15 22:19:23 -06:00
Paulo Alcantara
8bde59b20d smb: client: handle path separator of created SMB symlinks
Convert path separator to CIFS_DIR_SEP(cifs_sb) from symlink target
before sending it over the wire otherwise the created SMB symlink may
become innaccesible from server side.

Fixes: 514d793e27 ("smb: client: allow creating symlinks via reparse points")
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-12 12:47:21 -06:00
Paulo Alcantara
4508ec1735 smb: client: set correct id, uid and cruid for multiuser automounts
When uid, gid and cruid are not specified, we need to dynamically
set them into the filesystem context used for automounting otherwise
they'll end up reusing the values from the parent mount.

Fixes: 9fd29a5bae ("cifs: use fs_context for automounts")
Reported-by: Shane Nehring <snehring@iastate.edu>
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2259257
Cc: stable@vger.kernel.org # 6.2+
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-12 12:46:49 -06:00
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
Dan Carpenter
cffe487026 cifs: fix underflow in parse_server_interfaces()
In this loop, we step through the buffer and after each item we check
if the size_left is greater than the minimum size we need.  However,
the problem is that "bytes_left" is type ssize_t while sizeof() is type
size_t.  That means that because of type promotion, the comparison is
done as an unsigned and if we have negative bytes left the loop
continues instead of ending.

Fixes: fe856be475 ("CIFS: parse and store info on iface queries")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-11 19:07:08 -06:00
Steve French
a5cc98eba2 smb3: clarify mount warning
When a user tries to use the "sec=krb5p" mount parameter to encrypt
data on connection to a server (when authenticating with Kerberos), we
indicate that it is not supported, but do not note the equivalent
recommended mount parameter ("sec=krb5,seal") which turns on encryption
for that mount (and uses Kerberos for auth).  Update the warning message.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-09 14:43:27 -06:00
Shyam Prasad N
a39c757bf0 cifs: handle cases where multiple sessions share connection
Based on our implementation of multichannel, it is entirely
possible that a server struct may not be found in any channel
of an SMB session.

In such cases, we should be prepared to move on and search for
the server struct in the next session.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-09 14:43:25 -06:00
Shyam Prasad N
c6e02eefd6 cifs: change tcon status when need_reconnect is set on it
When a tcon is marked for need_reconnect, the intention
is to have it reconnected.

This change adjusts tcon->status in cifs_tree_connect
when need_reconnect is set. Also, this change has a minor
correction in resetting need_reconnect on success. It makes
sure that it is done with tc_lock held.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-09 14:43:23 -06:00
Paulo Alcantara
55c7788c37 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>
2024-02-08 10:50:40 -06:00
Steve French
45be0882c5 smb3: add missing null server pointer check
Address static checker warning in cifs_ses_get_chan_index():
    warn: variable dereferenced before check 'server'
To be consistent, and reduce risk, we should add another check
for null server pointer.

Fixes: 88675b22d3 ("cifs: do not search for channel if server is terminating")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-08 10:50:40 -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
6aac002bcf cifs: failure to add channel on iface should bump up weight
After the interface selection policy change to do a weighted
round robin, each iface maintains a weight_fulfilled. When the
weight_fulfilled reaches the total weight for the iface, we know
that the weights can be reset and ifaces can be allocated from
scratch again.

During channel allocation failures on a particular channel,
weight_fulfilled is not incremented. If a few interfaces are
inactive, we could end up in a situation where the active
interfaces are all allocated for the total_weight, and inactive
ones are all that remain. This can cause a situation where
no more channels can be allocated further.

This change fixes it by increasing weight_fulfilled, even when
channel allocation failure happens. This could mean that if
there are temporary failures in channel allocation, the iface
weights may not strictly be adhered to. But that's still okay.

Fixes: a6d8fb54a5 ("cifs: distribute channels across interfaces based on speed")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-01 12:13:05 -06:00
Shyam Prasad N
88675b22d3 cifs: do not search for channel if server is terminating
In order to scale down the channels, the following sequence
of operations happen:
1. server struct is marked for terminate
2. the channel is deallocated in the ses->chans array
3. at a later point the cifsd thread actually terminates the server

Between 2 and 3, there can be calls to find the channel for
a server struct. When that happens, there can be an ugly warning
that's logged. But this is expected.

So this change does two things:
1. in cifs_ses_get_chan_index, if server->terminate is set, return
2. always make sure server->terminate is set with chan_lock held

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-01 12:12:17 -06:00
Shyam Prasad N
e77e15fa5e cifs: avoid redundant calls to disable multichannel
When the server reports query network interface info call
as unsupported following a tree connect, it means that
multichannel is unsupported, even if the server capabilities
report otherwise.

When this happens, cifs_chan_skip_or_disable is called to
disable multichannel on the client. However, we only need
to call this when multichannel is currently setup.

Fixes: f591062bdb ("cifs: handle servers that still advertise multichannel after disabling")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-02-01 12:10:57 -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
Linus Torvalds
d1bba17e20 Nine cifs/smb client fixes
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Merge tag '6.8-rc1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client fixes from Steve French:
 "Nine cifs/smb client fixes

   - Four network error fixes (three relating to replays of requests
     that need to be retried, and one fixing some places where we were
     returning the wrong rc up the stack on network errors)

   - Two multichannel fixes including locking fix and case where subset
     of channels need reconnect

   - netfs integration fixup: share remote i_size with netfslib

   - Two small cleanups (one for addressing a clang warning)"

* tag '6.8-rc1-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix stray unlock in cifs_chan_skip_or_disable
  cifs: set replay flag for retries of write command
  cifs: commands that are retried should have replay flag set
  cifs: helper function to check replayable error codes
  cifs: translate network errors on send to -ECONNABORTED
  cifs: cifs_pick_channel should try selecting active channels
  cifs: Share server EOF pos with netfslib
  smb: Work around Clang __bdos() type confusion
  smb: client: delete "true", "false" defines
2024-01-27 09:02:42 -08:00
Shyam Prasad N
993d1c346b cifs: fix stray unlock in cifs_chan_skip_or_disable
A recent change moved the code that decides to skip
a channel or disable multichannel entirely, into a
helper function.

During this, a mutex_unlock of the session_mutex
should have been removed. Doing that here.

Fixes: f591062bdb ("cifs: handle servers that still advertise multichannel after disabling")
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
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
Shyam Prasad N
a68106a692 cifs: translate network errors on send to -ECONNABORTED
When the network stack returns various errors, we today bubble
up the error to the user (in case of soft mounts).

This change translates all network errors except -EINTR and
-EAGAIN to -ECONNABORTED. A similar approach is taken when
we receive network errors when reading from the socket.

The change also forces the cifsd thread to reconnect during
it's next activity.

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
Shyam Prasad N
fc43a8ac39 cifs: cifs_pick_channel should try selecting active channels
cifs_pick_channel today just selects a channel based
on the policy of least loaded channel. However, it
does not take into account if the channel needs
reconnect. As a result, we can have failures in send
that can be completely avoided.

This change doesn't make a channel a candidate for
this selection if it needs reconnect.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-23 19:03:46 -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
Kees Cook
8deb05c84b smb: Work around Clang __bdos() type confusion
Recent versions of Clang gets confused about the possible size of the
"user" allocation, and CONFIG_FORTIFY_SOURCE ends up emitting a
warning[1]:

repro.c:126:4: warning: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
  126 |                         __write_overflow_field(p_size_field, size);
      |                         ^

for this memset():

        int len;
        __le16 *user;
	...
        len = ses->user_name ? strlen(ses->user_name) : 0;
        user = kmalloc(2 + (len * 2), GFP_KERNEL);
	...
	if (len) {
		...
	} else {
		memset(user, '\0', 2);
	}

While Clang works on this bug[2], switch to using a direct assignment,
which avoids memset() entirely which both simplifies the code and silences
the false positive warning. (Making "len" size_t also silences the
warning, but the direct assignment seems better.)

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1966 [1]
Link: https://github.com/llvm/llvm-project/issues/77813 [2]
Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@manguebit.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-23 18:56:16 -06:00
Alexey Dobriyan
5d390df3bd smb: client: delete "true", "false" defines
Kernel has its own official true/false definitions.

The defines aren't even used in this file.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-23 12:41:02 -06:00
David Howells
c40497d823 cifs: Don't use certain unnecessary folio_*() functions
Filesystems should use folio->index and folio->mapping, instead of
folio_index(folio), folio_mapping() and folio_file_mapping() since
they know that it's in the pagecache.

Change this automagically with:

perl -p -i -e 's/folio_mapping[(]([^)]*)[)]/\1->mapping/g' fs/smb/client/*.c
perl -p -i -e 's/folio_file_mapping[(]([^)]*)[)]/\1->mapping/g' fs/smb/client/*.c
perl -p -i -e 's/folio_index[(]([^)]*)[)]/\1->index/g' fs/smb/client/*.c

Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Ronnie Sahlberg <lsahlber@redhat.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: Tom Talpey <tom@talpey.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
2024-01-22 21:57:13 +00:00
Linus Torvalds
7a39682022 Various smb client fixes, including multichannel and for SMB3.1.1 POSIX extensions
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Merge tag 'v6.8-rc-part2-smb-client' of git://git.samba.org/sfrench/cifs-2.6

Pull smb client updates from Steve French:
 "Various smb client fixes, including multichannel and for SMB3.1.1
  POSIX extensions:

   - debugging improvement (display start time for stats)

   - two reparse point handling fixes

   - various multichannel improvements and fixes

   - SMB3.1.1 POSIX extensions open/create parsing fix

   - retry (reconnect) improvement including new retrans mount parm, and
     handling of two additional return codes that need to be retried on

   - two minor cleanup patches and another to remove duplicate query
     info code

   - two documentation cleanup, and one reviewer email correction"

* tag 'v6.8-rc-part2-smb-client' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update iface_last_update on each query-and-update
  cifs: handle servers that still advertise multichannel after disabling
  cifs: new mount option called retrans
  cifs: reschedule periodic query for server interfaces
  smb: client: don't clobber ->i_rdev from cached reparse points
  smb: client: get rid of smb311_posix_query_path_info()
  smb: client: parse owner/group when creating reparse points
  smb: client: fix parsing of SMB3.1.1 POSIX create context
  cifs: update known bugs mentioned in kernel docs for cifs
  cifs: new nt status codes from MS-SMB2
  cifs: pick channel for tcon and tdis
  cifs: open_cached_dir should not rely on primary channel
  smb3: minor documentation updates
  Update MAINTAINERS email address
  cifs: minor comment cleanup
  smb3: show beginning time for per share stats
  cifs: remove redundant variable tcon_exist
2024-01-20 16:48:07 -08:00
Linus Torvalds
16df6e07d6 vfs-6.8.netfs
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Merge tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This extends the netfs helper library that network filesystems can use
  to replace their own implementations. Both afs and 9p are ported. cifs
  is ready as well but the patches are way bigger and will be routed
  separately once this is merged. That will remove lots of code as well.

  The overal goal is to get high-level I/O and knowledge of the page
  cache and ouf of the filesystem drivers. This includes knowledge about
  the existence of pages and folios

  The pull request converts afs and 9p. This removes about 800 lines of
  code from afs and 300 from 9p. For 9p it is now possible to do writes
  in larger than a page chunks. Additionally, multipage folio support
  can be turned on for 9p. Separate patches exist for cifs removing
  another 2000+ lines. I've included detailed information in the
  individual pulls I took.

  Summary:

   - Add NFS-style (and Ceph-style) locking around DIO vs buffered I/O
     calls to prevent these from happening at the same time.

   - Support for direct and unbuffered I/O.

   - Support for write-through caching in the page cache.

   - O_*SYNC and RWF_*SYNC writes use write-through rather than writing
     to the page cache and then flushing afterwards.

   - Support for write-streaming.

   - Support for write grouping.

   - Skip reads for which the server could only return zeros or EOF.

   - The fscache module is now part of the netfs library and the
     corresponding maintainer entry is updated.

   - Some helpers from the fscache subsystem are renamed to mark them as
     belonging to the netfs library.

   - Follow-up fixes for the netfs library.

   - Follow-up fixes for the 9p conversion"

* tag 'vfs-6.8.netfs' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (50 commits)
  netfs: Fix wrong #ifdef hiding wait
  cachefiles: Fix signed/unsigned mixup
  netfs: Fix the loop that unmarks folios after writing to the cache
  netfs: Fix interaction between write-streaming and cachefiles culling
  netfs: Count DIO writes
  netfs: Mark netfs_unbuffered_write_iter_locked() static
  netfs: Fix proc/fs/fscache symlink to point to "netfs" not "../netfs"
  netfs: Rearrange netfs_io_subrequest to put request pointer first
  9p: Use length of data written to the server in preference to error
  9p: Do a couple of cleanups
  9p: Fix initialisation of netfs_inode for 9p
  cachefiles: Fix __cachefiles_prepare_write()
  9p: Use netfslib read/write_iter
  afs: Use the netfs write helpers
  netfs: Export the netfs_sreq tracepoint
  netfs: Optimise away reads above the point at which there can be no data
  netfs: Implement a write-through caching option
  netfs: Provide a launder_folio implementation
  netfs: Provide a writepages implementation
  netfs, cachefiles: Pass upper bound length to allow expansion
  ...
2024-01-19 09:10:23 -08:00
Shyam Prasad N
78e727e58e cifs: update iface_last_update on each query-and-update
iface_last_update was an unused field when it was introduced.
Later, when we had periodic update of server interface list,
this field was used regularly to decide when to update next.

However, with the new logic of updating the interfaces, it
becomes crucial that this field be updated whenever
parse_server_interfaces runs successfully.

This change updates this field when either the server does
not support query of interfaces; so that we do not query
the interfaces repeatedly. It also updates the field when
the function reaches the end.

Fixes: aa45dadd34 ("cifs: change iface_list from array to sorted linked list")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-19 10:33:21 -06:00
Shyam Prasad N
f591062bdb cifs: handle servers that still advertise multichannel after disabling
Some servers like Azure SMB servers always advertise multichannel
capability in server capabilities list. Such servers return error
STATUS_NOT_IMPLEMENTED for ioctl calls to query server interfaces,
and expect clients to consider that as a sign that they do not support
multichannel.

We already handled this at mount time. Soon after the tree connect,
we query server interfaces. And when server returned STATUS_NOT_IMPLEMENTED,
we kept interface list as empty. When cifs_try_adding_channels gets
called, it would not find any interfaces, so will not add channels.

For the case where an active multichannel mount exists, and multichannel
is disabled by such a server, this change will now allow the client
to disable secondary channels on the mount. It will check the return
status of query server interfaces call soon after a tree reconnect.
If the return status is EOPNOTSUPP, then instead of the check to add
more channels, we'll disable the secondary channels instead.

For better code reuse, this change also moves the common code for
disabling multichannel to a helper function.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2024-01-19 10:33:17 -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