Commit Graph

4066 Commits

Author SHA1 Message Date
David Howells
483529f320 Fix a warning about a malformed kernel doc comment in cifs
Fix by removing the extra asterisk.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-28 10:30:21 -06:00
Steve French
51620150ca cifs: update internal module number
To 2.35

Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 23:14:34 -06:00
Steve French
52d005337b smb3: send NTLMSSP version information
For improved debugging it can be helpful to send version information
as other clients do during NTLMSSP negotiation. See protocol document
MS-NLMP section 2.2.1.1

Set the major and minor versions based on the kernel version, and the
BuildNumber based on the internal cifs.ko module version number,
and following the recommendation in the protocol documentation
(MS-NLMP section 2.2.10) we set the NTLMRevisionCurrent field to 15.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 23:14:15 -06:00
David Howells
70431bfd82 cifs: Support fscache indexing rewrite
Change the cifs filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in cifs.

The following changes have been made:

 (1) The fscache_netfs struct is no more, and there's no need to register
     the filesystem as a whole.

 (2) The session cookie is now an fscache_volume cookie, allocated with
     fscache_acquire_volume().  That takes three parameters: a string
     representing the "volume" in the index, a string naming the cache to
     use (or NULL) and a u64 that conveys coherency metadata for the
     volume.

     For cifs, I've made it render the volume name string as:

	"cifs,<ipaddress>,<sharename>"

     where the sharename has '/' characters replaced with ';'.

     This probably needs rethinking a bit as the total name could exceed
     the maximum filename component length.

     Further, the coherency data is currently just set to 0.  It needs
     something else doing with it - I wonder if it would suffice simply to
     sum the resource_id, vol_create_time and vol_serial_number or maybe
     hash them.

 (3) The fscache_cookie_def is no more and needed information is passed
     directly to fscache_acquire_cookie().  The cache no longer calls back
     into the filesystem, but rather metadata changes are indicated at
     other times.

     fscache_acquire_cookie() is passed the same keying and coherency
     information as before.

 (4) The functions to set/reset cookies are removed and
     fscache_use_cookie() and fscache_unuse_cookie() are used instead.

     fscache_use_cookie() is passed a flag to indicate if the cookie is
     opened for writing.  fscache_unuse_cookie() is passed updates for the
     metadata if we changed it (ie. if the file was opened for writing).

     These are called when the file is opened or closed.

 (5) cifs_setattr_*() are made to call fscache_resize() to change the size
     of the cache object.

 (6) The functions to read and write data are stubbed out pending a
     conversion to use netfslib.

Changes
=======
ver #8:
 - Abstract cache invalidation into a helper function.
 - Fix some checkpatch warnings[3].

ver #7:
 - Removed the accidentally added-back call to get the super cookie in
   cifs_root_iget().
 - Fixed the right call to cifs_fscache_get_super_cookie() to take account
   of the "-o fsc" mount flag.

ver #6:
 - Moved the change of gfpflags_allow_blocking() to current_is_kswapd() for
   cifs here.
 - Fixed one of the error paths in cifs_atomic_open() to jump around the
   call to use the cookie.
 - Fixed an additional successful return in the middle of cifs_open() to
   use the cookie on the way out.
 - Only get a volume cookie (and thus inode cookies) when "-o fsc" is
   supplied to mount.

ver #5:
 - Fixed a couple of bits of cookie handling[2]:
   - The cookie should be released in cifs_evict_inode(), not
     cifsFileInfo_put_final().  The cookie needs to persist beyond file
     closure so that writepages will be able to write to it.
   - fscache_use_cookie() needs to be called in cifs_atomic_open() as it is
     for cifs_open().

ver #4:
 - Fixed the use of sizeof with memset.
 - tcon->vol_create_time is __le64 so doesn't need cpu_to_le64().

ver #3:
 - Canonicalise the cifs coherency data to make the cache portable.
 - Set volume coherency data.

ver #2:
 - Use gfpflags_allow_blocking() rather than using flag directly.
 - Upgraded to -rc4 to allow for upstream changes[1].
 - fscache_acquire_volume() now returns errors.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Steve French <smfrench@gmail.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=23b55d673d7527b093cd97b7c217c82e70cd1af0 [1]
Link: https://lore.kernel.org/r/3419813.1641592362@warthog.procyon.org.uk/ [2]
Link: https://lore.kernel.org/r/CAH2r5muTanw9pJqzAHd01d9A8keeChkzGsCEH6=0rHutVLAF-A@mail.gmail.com/ [3]
Link: https://lore.kernel.org/r/163819671009.215744.11230627184193298714.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906982979.143852.10672081929614953210.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967187187.1823006.247415138444991444.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021579335.640689.2681324337038770579.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/3462849.1641593783@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/1318953.1642024578@warthog.procyon.org.uk/ # v6
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:21:08 -06:00
Shyam Prasad N
ba978e8325 cifs: cifs_ses_mark_for_reconnect should also update reconnect bits
Recent restructuring of cifs_reconnect introduced a helper func
named cifs_ses_mark_for_reconnect, which updates the state of tcp
session for all the channels of a session for reconnect.

However, this does not update the session state and chans_need_reconnect
bitmask. This change fixes that.

Also, cifs_mark_tcp_sess_for_reconnect should mark set the bitmask
for all channels when the whole session is marked for reconnect.
Fixed that here too.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:58 -06:00
Shyam Prasad N
47de760655 cifs: update tcpStatus during negotiate and sess setup
Till the end of SMB session setup, update tcpStatus and
avoid updating session status field. There was a typo in
cifs_setup_session, which caused ses->status to be updated
instead. This was causing issues during reconnect.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:55 -06:00
Shyam Prasad N
c1604da708 cifs: make status checks in version independent callers
The status of tcp session, smb session and tcon have the
same flow, irrespective of the SMB version used. Hence
these status checks and updates should happen in the
version independent callers of these commands.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:55 -06:00
Shyam Prasad N
ece0767641 cifs: remove repeated state change in dfs tree connect
cifs_tree_connect checks and sets the tidStatus for the tcon.
cifs_tree_connect also calls a dfs specific tree connect
function, which also does similar checks. This should
not happen. Removing it with this change.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:55 -06:00
Shyam Prasad N
e154cb7b0a cifs: fix the cifs_reconnect path for DFS
Recently, the cifs_reconnect code was refactored into
two branches for regular vs dfs codepath. Some of my
recent changes were missing in the dfs path, namely the
code to enable periodic DNS query, and a missing lock.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:55 -06:00
Muhammad Usama Anjum
8a409cda97 cifs: remove unused variable ses_selected
ses_selected is being declared and set at several places. It is not
being used. Remove it.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:54 -06:00
Shyam Prasad N
88b024f556 cifs: protect all accesses to chan_* with chan_lock
A spin lock called chan_lock was introduced recently.
But not all accesses were protected. Doing that with
this change.

To make sure that a channel is not freed when in use,
we need to introduce a ref count. But today, we don't
ever free channels.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:54 -06:00
Shyam Prasad N
a05885ce13 cifs: fix the connection state transitions with multichannel
Recent changes to multichannel required some adjustments in
the way connection states transitioned during/after reconnect.

Also some minor fixes:
1. A pending switch of GlobalMid_Lock to cifs_tcp_ses_lock
2. Relocations of the code that logs reconnect
3. Changed some code in allocate_mid to suit the new scheme

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:54 -06:00
Shyam Prasad N
3663c9045f cifs: check reconnects for channels of active tcons too
With the new multichannel logic, when a channel needs reconnection,
the tree connect and other channels can still be active.
This fix will handle cases of checking for channel reconnect,
when the tcon does not need reconnect.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-19 11:10:54 -06:00
Ronnie Sahlberg
5455b9ecaf cifs: serialize all mount attempts
RHBZ: 2008434

Some servers, such as Windows2016 have a very low number of concurrent mounts that
they allow from each client.
This can be a problem if you have a more than a handful (==3 in this case)
of cifs entries in your fstab and cause a number of the mounts there to randomly fail.

Add a global mutex and use it to serialize all mount attempts.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-18 00:10:03 -06:00
Eugene Korenevsky
a2809d0e16 cifs: quirk for STATUS_OBJECT_NAME_INVALID returned for non-ASCII dfs refs
Windows SMB server responds with STATUS_OBJECT_NAME_INVALID code to
SMB2 QUERY_INFO request for "\<server>\<dfsname>\<linkpath>" DFS reference,
where <dfsname> contains non-ASCII unicode symbols.

Check such DFS reference and emulate -EREMOTE if it is actual.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215440
Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-17 13:28:25 -06:00
Eugene Korenevsky
7eacba3b00 cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty
alloc_path_with_tree_prefix() concatenates tree prefix and the path.
Windows CIFS client does not add separator after the tree prefix if the path
is empty. Let's do the same.

This fixes mounting DFS namespaces with names containing non-ASCII symbols.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215440
Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-17 13:28:05 -06:00
Yang Li
74ce6135ae cifs: clean up an inconsistent indenting
Eliminate the follow smatch warning:
fs/cifs/sess.c:1581 sess_auth_rawntlmssp_authenticate() warn:
inconsistent indenting

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-17 12:00:37 -06:00
Shyam Prasad N
e3548aaf41 cifs: free ntlmsspblob allocated in negotiate
One of my previous fixes:
cifs: send workstation name during ntlmssp session setup
...changed the prototype of build_ntlmssp_negotiate_blob
from being allocated by the caller to being allocated within
the function. The caller needs to free this object too.
While SMB2 version of the caller did it, I forgot to free
for the SMB1 version. Fixing that here.

Fixes: 49bd49f983 ("cifs: send workstation name during ntlmssp session setup")
Cc: stable@vger.kernel.org # 5.16
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-17 11:56:19 -06:00
Linus Torvalds
0c947b893d 13 cifs/smb3 fixes, mostly multichannel, reconnect relate
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Merge tag '5.17-rc-part1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs updates from Steve French:

 - multichannel patches mostly related to improving reconnect behavior

 - minor cleanup patches

* tag '5.17-rc-part1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix FILE_BOTH_DIRECTORY_INFO definition
  cifs: move superblock magic defitions to magic.h
  cifs: Fix smb311_update_preauth_hash() kernel-doc comment
  cifs: avoid race during socket reconnect between send and recv
  cifs: maintain a state machine for tcp/smb/tcon sessions
  cifs: fix hang on cifs_get_next_mid()
  cifs: take cifs_tcp_ses_lock for status checks
  cifs: reconnect only the connection and not smb session where possible
  cifs: add WARN_ON for when chan_count goes below minimum
  cifs: adjust DebugData to use chans_need_reconnect for conn status
  cifs: use the chans_need_reconnect bitmap for reconnect status
  cifs: track individual channel status using chans_need_reconnect
  cifs: remove redundant assignment to pointer p
2022-01-17 09:53:21 +02:00
Linus Torvalds
35ce8ae9ae Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull signal/exit/ptrace updates from Eric Biederman:
 "This set of changes deletes some dead code, makes a lot of cleanups
  which hopefully make the code easier to follow, and fixes bugs found
  along the way.

  The end-game which I have not yet reached yet is for fatal signals
  that generate coredumps to be short-circuit deliverable from
  complete_signal, for force_siginfo_to_task not to require changing
  userspace configured signal delivery state, and for the ptrace stops
  to always happen in locations where we can guarantee on all
  architectures that the all of the registers are saved and available on
  the stack.

  Removal of profile_task_ext, profile_munmap, and profile_handoff_task
  are the big successes for dead code removal this round.

  A bunch of small bug fixes are included, as most of the issues
  reported were small enough that they would not affect bisection so I
  simply added the fixes and did not fold the fixes into the changes
  they were fixing.

  There was a bug that broke coredumps piped to systemd-coredump. I
  dropped the change that caused that bug and replaced it entirely with
  something much more restrained. Unfortunately that required some
  rebasing.

  Some successes after this set of changes: There are few enough calls
  to do_exit to audit in a reasonable amount of time. The lifetime of
  struct kthread now matches the lifetime of struct task, and the
  pointer to struct kthread is no longer stored in set_child_tid. The
  flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
  removed. Issues where task->exit_code was examined with
  signal->group_exit_code should been examined were fixed.

  There are several loosely related changes included because I am
  cleaning up and if I don't include them they will probably get lost.

  The original postings of these changes can be found at:
     https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org

  I trimmed back the last set of changes to only the obviously correct
  once. Simply because there was less time for review than I had hoped"

* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
  ptrace/m68k: Stop open coding ptrace_report_syscall
  ptrace: Remove unused regs argument from ptrace_report_syscall
  ptrace: Remove second setting of PT_SEIZED in ptrace_attach
  taskstats: Cleanup the use of task->exit_code
  exit: Use the correct exit_code in /proc/<pid>/stat
  exit: Fix the exit_code for wait_task_zombie
  exit: Coredumps reach do_group_exit
  exit: Remove profile_handoff_task
  exit: Remove profile_task_exit & profile_munmap
  signal: clean up kernel-doc comments
  signal: Remove the helper signal_group_exit
  signal: Rename group_exit_task group_exec_task
  coredump: Stop setting signal->group_exit_task
  signal: Remove SIGNAL_GROUP_COREDUMP
  signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
  signal: Make coredump handling explicit in complete_signal
  signal: Have prepare_signal detect coredumps using signal->core_state
  signal: Have the oom killer detect coredumps using signal->core_state
  exit: Move force_uaccess back into do_exit
  exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
  ...
2022-01-17 05:49:30 +02:00
Eugene Korenevsky
9bbf8662a2 cifs: fix FILE_BOTH_DIRECTORY_INFO definition
The size of FILE_BOTH_DIRECTORY_INFO.ShortName must be 24 bytes, not 12
(see MS-FSCC documentation).

Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-15 10:08:47 -06:00
Jeff Layton
dea2903719 cifs: move superblock magic defitions to magic.h
Help userland apps to identify cifs and smb2 mounts.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-15 10:08:44 -06:00
Yang Li
3ac5f2f257 cifs: Fix smb311_update_preauth_hash() kernel-doc comment
Add the description of @server in smb311_update_preauth_hash()
kernel-doc comment to remove warning found by running scripts/kernel-doc,
which is caused by using 'make W=1'.
fs/cifs/smb2misc.c:856: warning: Function parameter or member 'server'
not described in 'smb311_update_preauth_hash'

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-15 10:08:33 -06:00
Linus Torvalds
8834147f95 fscache rewrite
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Merge tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull fscache rewrite from David Howells:
 "This is a set of patches that rewrites the fscache driver and the
  cachefiles driver, significantly simplifying the code compared to
  what's upstream, removing the complex operation scheduling and object
  state machine in favour of something much smaller and simpler.

  The series is structured such that the first few patches disable
  fscache use by the network filesystems using it, remove the cachefiles
  driver entirely and as much of the fscache driver as can be got away
  with without causing build failures in the network filesystems.

  The patches after that recreate fscache and then cachefiles,
  attempting to add the pieces in a logical order. Finally, the
  filesystems are reenabled and then the very last patch changes the
  documentation.

  [!] Note: I have dropped the cifs patch for the moment, leaving local
      caching in cifs disabled. I've been having trouble getting that
      working. I think I have it done, but it needs more testing (there
      seem to be some test failures occurring with v5.16 also from
      xfstests), so I propose deferring that patch to the end of the
      merge window.

  WHY REWRITE?
  ============

  Fscache's operation scheduling API was intended to handle sequencing
  of cache operations, which were all required (where possible) to run
  asynchronously in parallel with the operations being done by the
  network filesystem, whilst allowing the cache to be brought online and
  offline and to interrupt service for invalidation.

  With the advent of the tmpfile capacity in the VFS, however, an
  opportunity arises to do invalidation much more simply, without having
  to wait for I/O that's actually in progress: Cachefiles can simply
  create a tmpfile, cut over the file pointer for the backing object
  attached to a cookie and abandon the in-progress I/O, dismissing it
  upon completion.

  Future work here would involve using Omar Sandoval's vfs_link() with
  AT_LINK_REPLACE[1] to allow an extant file to be displaced by a new
  hard link from a tmpfile as currently I have to unlink the old file
  first.

  These patches can also simplify the object state handling as I/O
  operations to the cache don't all have to be brought to a stop in
  order to invalidate a file. To that end, and with an eye on to writing
  a new backing cache model in the future, I've taken the opportunity to
  simplify the indexing structure.

  I've separated the index cookie concept from the file cookie concept
  by C type now. The former is now called a "volume cookie" (struct
  fscache_volume) and there is a container of file cookies. There are
  then just the two levels. All the index cookie levels are collapsed
  into a single volume cookie, and this has a single printable string as
  a key. For instance, an AFS volume would have a key of something like
  "afs,example.com,1000555", combining the filesystem name, cell name
  and volume ID. This is freeform, but must not have '/' chars in it.

  I've also eliminated all pointers back from fscache into the network
  filesystem. This required the duplication of a little bit of data in
  the cookie (cookie key, coherency data and file size), but it's not
  actually that much. This gets rid of problems with making sure we keep
  netfs data structures around so that the cache can access them.

  These patches mean that most of the code that was in the drivers
  before is simply gone and those drivers are now almost entirely new
  code. That being the case, there doesn't seem any particular reason to
  try and maintain bisectability across it. Further, there has to be a
  point in the middle where things are cut over as there's a single
  point everything has to go through (ie. /dev/cachefiles) and it can't
  be in use by two drivers at once.

  ISSUES YET OUTSTANDING
  ======================

  There are some issues still outstanding, unaddressed by this patchset,
  that will need fixing in future patchsets, but that don't stop this
  series from being usable:

  (1) The cachefiles driver needs to stop using the backing filesystem's
      metadata to store information about what parts of the cache are
      populated. This is not reliable with modern extent-based
      filesystems.

      Fixing this is deferred to a separate patchset as it involves
      negotiation with the network filesystem and the VM as to how much
      data to download to fulfil a read - which brings me on to (2)...

  (2) NFS (and CIFS with the dropped patch) do not take account of how
      the cache would like I/O to be structured to meet its granularity
      requirements. Previously, the cache used page granularity, which
      was fine as the network filesystems also dealt in page
      granularity, and the backing filesystem (ext4, xfs or whatever)
      did whatever it did out of sight. However, we now have folios to
      deal with and the cache will now have to store its own metadata to
      track its contents.

      The change I'm looking at making for cachefiles is to store
      content bitmaps in one or more xattrs and making a bit in the map
      correspond to something like a 256KiB block. However, the size of
      an xattr and the fact that they have to be read/updated in one go
      means that I'm looking at covering 1GiB of data per 512-byte map
      and storing each map in an xattr. Cachefiles has the potential to
      grow into a fully fledged filesystem of its very own if I'm not
      careful.

      However, I'm also looking at changing things even more radically
      and going to a different model of how the cache is arranged and
      managed - one that's more akin to the way, say, openafs does
      things - which brings me on to (3)...

  (3) The way cachefilesd does culling is very inefficient for large
      caches and it would be better to move it into the kernel if I can
      as cachefilesd has to keep asking the kernel if it can cull a
      file. Changing the way the backend works would allow this to be
      addressed.

  BITS THAT MAY BE CONTROVERSIAL
  ==============================

  There are some bits I've added that may be controversial:

  (1) I've provided a flag, S_KERNEL_FILE, that cachefiles uses to check
      if a files is already being used by some other kernel service
      (e.g. a duplicate cachefiles cache in the same directory) and
      reject it if it is. This isn't entirely necessary, but it helps
      prevent accidental data corruption.

      I don't want to use S_SWAPFILE as that has other effects, but
      quite possibly swapon() should set S_KERNEL_FILE too.

      Note that it doesn't prevent userspace from interfering, though
      perhaps it should. (I have made it prevent a marked directory from
      being rmdir-able).

  (2) Cachefiles wants to keep the backing file for a cookie open whilst
      we might need to write to it from network filesystem writeback.
      The problem is that the network filesystem unuses its cookie when
      its file is closed, and so we have nothing pinning the cachefiles
      file open and it will get closed automatically after a short time
      to avoid EMFILE/ENFILE problems.

      Reopening the cache file, however, is a problem if this is being
      done due to writeback triggered by exit(). Some filesystems will
      oops if we try to open a file in that context because they want to
      access current->fs or suchlike.

      To get around this, I added the following:

      (A) An inode flag, I_PINNING_FSCACHE_WB, to be set on a network
          filesystem inode to indicate that we have a usage count on the
          cookie caching that inode.

      (B) A flag in struct writeback_control, unpinned_fscache_wb, that
          is set when __writeback_single_inode() clears the last dirty
          page from i_pages - at which point it clears
          I_PINNING_FSCACHE_WB and sets this flag.

          This has to be done here so that clearing I_PINNING_FSCACHE_WB
          can be done atomically with the check of PAGECACHE_TAG_DIRTY
          that clears I_DIRTY_PAGES.

      (C) A function, fscache_set_page_dirty(), which if it is not set,
          sets I_PINNING_FSCACHE_WB and calls fscache_use_cookie() to
          pin the cache resources.

      (D) A function, fscache_unpin_writeback(), to be called by
          ->write_inode() to unuse the cookie.

      (E) A function, fscache_clear_inode_writeback(), to be called when
          the inode is evicted, before clear_inode() is called. This
          cleans up any lingering I_PINNING_FSCACHE_WB.

      The network filesystem can then use these tools to make sure that
      fscache_write_to_cache() can write locally modified data to the
      cache as well as to the server.

      For the future, I'm working on write helpers for netfs lib that
      should allow this facility to be removed by keeping track of the
      dirty regions separately - but that's incomplete at the moment and
      is also going to be affected by folios, one way or another, since
      it deals with pages"

Link: https://lore.kernel.org/all/510611.1641942444@warthog.procyon.org.uk/
Tested-by: Dominique Martinet <asmadeus@codewreck.org> # 9p
Tested-by: kafs-testing@auristor.com # afs
Tested-by: Jeff Layton <jlayton@kernel.org> # ceph
Tested-by: Dave Wysochanski <dwysocha@redhat.com> # nfs
Tested-by: Daire Byrne <daire@dneg.com> # nfs

* tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (67 commits)
  9p, afs, ceph, nfs: Use current_is_kswapd() rather than gfpflags_allow_blocking()
  fscache: Add a tracepoint for cookie use/unuse
  fscache: Rewrite documentation
  ceph: add fscache writeback support
  ceph: conversion to new fscache API
  nfs: Implement cache I/O by accessing the cache directly
  nfs: Convert to new fscache volume/cookie API
  9p: Copy local writes to the cache when writing to the server
  9p: Use fscache indexing rewrite and reenable caching
  afs: Skip truncation on the server of data we haven't written yet
  afs: Copy local writes to the cache when writing to the server
  afs: Convert afs to use the new fscache API
  fscache, cachefiles: Display stat of culling events
  fscache, cachefiles: Display stats of no-space events
  cachefiles: Allow cachefiles to actually function
  fscache, cachefiles: Store the volume coherency data
  cachefiles: Implement the I/O routines
  cachefiles: Implement cookie resize for truncate
  cachefiles: Implement begin and end I/O operation
  cachefiles: Implement backing file wrangling
  ...
2022-01-12 13:45:12 -08:00
Shyam Prasad N
bda487ac4b cifs: avoid race during socket reconnect between send and recv
When a TCP connection gets reestablished by the sender in cifs_reconnect,
There is a chance for race condition with demultiplex thread waiting in
cifs_readv_from_socket on the old socket. It will now return -ECONNRESET.

This condition is handled by comparing socket pointer before and after
sock_recvmsg. If the socket pointer has changed, we should not call
cifs_reconnect again, but instead retry with new socket.

Also fixed another bug in my prev mchan commits.
We should always reestablish session (even if binding) on a channel
that needs reconnection.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-07 20:09:23 -06:00
Shyam Prasad N
73f9bfbe3d cifs: maintain a state machine for tcp/smb/tcon sessions
If functions like cifs_negotiate_protocol, cifs_setup_session,
cifs_tree_connect are called in parallel on different channels,
each of these will be execute the requests. This maybe unnecessary
in some cases, and only the first caller may need to do the work.

This is achieved by having more states for the tcp/smb/tcon session
status fields. And tracking the state of reconnection based on the
state machine.

For example:
for tcp connections:
CifsNew/CifsNeedReconnect ->
  CifsNeedNegotiate ->
    CifsInNegotiate ->
      CifsNeedSessSetup ->
        CifsInSessSetup ->
          CifsGood

for smb sessions:
CifsNew/CifsNeedReconnect ->
  CifsGood

for tcon:
CifsNew/CifsNeedReconnect ->
  CifsInFilesInvalidate ->
    CifsNeedTcon ->
      CifsInTcon ->
        CifsGood

If any channel reconnect sees that it's in the middle of
transition to CifsGood, then they can skip the function.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-07 20:09:22 -06:00
Enzo Matsumiya
1913e1116a cifs: fix hang on cifs_get_next_mid()
Mount will hang if using SMB1 and DFS.

This is because every call to get_next_mid() will, unconditionally,
mark tcpStatus to CifsNeedReconnect before even establishing the
initial connect, because "reconnect" variable was not initialized.

Initializing "reconnect" to false fix this issue.

Fixes: 220c5bc25d87 ("cifs: take cifs_tcp_ses_lock for status checks")
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-07 20:07:11 -06:00
Shyam Prasad N
080dc5e565 cifs: take cifs_tcp_ses_lock for status checks
While checking/updating status for tcp ses, smb ses or tcon,
we take GlobalMid_Lock. This doesn't make any sense.
Replaced it with cifs_tcp_ses_lock.

Ideally, we should take a spin lock per struct.
But since tcp ses, smb ses and tcon objects won't add up to a lot,
I think there should not be too much contention.

Also, in few other places, these are checked without locking.
Added locking for these.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-07 20:07:07 -06:00
David Howells
01491a7565 fscache, cachefiles: Disable configuration
Disable fscache and cachefiles in Kconfig whilst it is rewritten.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819576672.215744.12444272479560406780.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906882835.143852.11073015983885872901.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967075113.1823006.277316290062782998.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021481179.640689.2004199594774033658.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:21:44 +00:00
Shyam Prasad N
183eea2ee5 cifs: reconnect only the connection and not smb session where possible
With the new per-channel bitmask for reconnect, we have an option to
reconnect the tcp session associated with the channel without reconnecting
the smb session. i.e. if there are still channels to operate on, we can
continue to use the smb session and tcon.

However, there are cases where it makes sense to reconnect the smb session
even when there are active channels underneath. For example for
SMB session expiry.

With this patch, we'll have an option to do either, and use the correct
option for specific cases.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:46 -06:00
Shyam Prasad N
2e0fa298d1 cifs: add WARN_ON for when chan_count goes below minimum
chan_count keeps track of the total number of channels.
Since at least the primary channel will always be connected,
this value can never go below 1. Warn if that happens.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:46 -06:00
Shyam Prasad N
66eb0c6e66 cifs: adjust DebugData to use chans_need_reconnect for conn status
Use ses->chans_need_reconnect bitmask to print the connection
status of each channel under an SMB session.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:46 -06:00
Shyam Prasad N
f486ef8e20 cifs: use the chans_need_reconnect bitmap for reconnect status
We use the concept of "binding" when one of the secondary channel
is in the process of connecting/reconnecting to the server. Till this
binding process completes, and the channel is bound to an existing session,
we redirect traffic from other established channels on the binding channel,
effectively blocking all traffic till individual channels get reconnected.

With my last set of commits, we can get rid of this binding serialization.
We now have a bitmap of connection states for each channel. We will use
this bitmap instead for tracking channel status.

Having a bitmap also now enables us to keep the session alive, as long
as even a single channel underneath is alive.

Unfortunately, this also meant that we need to supply the tcp connection
info for the channel during all negotiate and session setup functions.
These changes have resulted in a slightly bigger code churn.
However, I expect perf and robustness improvements in the mchan scenario
after this change.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:46 -06:00
Shyam Prasad N
d1a931ce2e cifs: track individual channel status using chans_need_reconnect
We needed a way to identify the channels under the smb session
which are in reconnect, so that the traffic to other channels
can continue. So I replaced the bool need_reconnect with
a bitmask identifying all the channels that need reconnection
(named chans_need_reconnect). When a channel needs reconnection,
the bit corresponding to the index of the server in ses->chans
is used to set this bitmask. Checking if no channels or all
the channels need reconnect then becomes very easy.

Also wrote some helper macros for checking and setting the bits.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:46 -06:00
Colin Ian King
0b66fa776c cifs: remove redundant assignment to pointer p
The pointer p is being assigned with a value that is never read. The
pointer is being re-assigned a different value inside the do-while
loop. The assignment is redundant and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-01-02 20:38:45 -06:00
Thiago Rafael Becker
a31080899d cifs: sanitize multiple delimiters in prepath
mount.cifs can pass a device with multiple delimiters in it. This will
cause rename(2) to fail with ENOENT.

V2:
  - Make sanitize_path more readable.
  - Fix multiple delimiters between UNC and prepath.
  - Avoid a memory leak if a bad user starts putting a lot of delimiters
    in the path on purpose.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2031200
Fixes: 24e0a1eff9 ("cifs: switch to new mount api")
Cc: stable@vger.kernel.org # 5.11+
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Thiago Rafael Becker <trbecker@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-17 19:16:49 -06:00
Shyam Prasad N
b774302e88 cifs: ignore resource_id while getting fscache super cookie
We have a cyclic dependency between fscache super cookie
and root inode cookie. The super cookie relies on
tcon->resource_id, which gets populated from the root inode
number. However, fetching the root inode initializes inode
cookie as a child of super cookie, which is yet to be populated.

resource_id is only used as auxdata to check the validity of
super cookie. We can completely avoid setting resource_id to
remove the circular dependency. Since vol creation time and
vol serial numbers are used for auxdata, we should be fine.
Additionally, there will be auxiliary data check for each
inode cookie as well.

Fixes: 5bf91ef03d ("cifs: wait for tcon resource_id before getting fscache super")
CC: David Howells <dhowells@redhat.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-17 19:09:06 -06:00
Eric W. Biederman
ca3574bd65 exit: Rename module_put_and_exit to module_put_and_kthread_exit
Update module_put_and_exit to call kthread_exit instead of do_exit.

Change the name to reflect this change in functionality.  All of the
users of module_put_and_exit are causing the current kthread to exit
so this change makes it clear what is happening.  There is no
functional change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2021-12-13 12:04:45 -06:00
Paulo Alcantara
9de0737d5b cifs: fix ntlmssp auth when there is no key exchange
Warn on the lack of key exchange during NTLMSSP authentication rather
than aborting it as there are some servers that do not set it in
CHALLENGE message.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-08 16:48:43 -06:00
Shyam Prasad N
bbb9db5e2a cifs: avoid use of dstaddr as key for fscache client cookie
server->dstaddr can change when the DNS mapping for the
server hostname changes. But conn_id is a u64 counter
that is incremented each time a new TCP connection
is setup. So use only that as a key.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-03 12:38:25 -06:00
Shyam Prasad N
2adc82006b cifs: add server conn_id to fscache client cookie
The fscache client cookie uses the server address
(and port) as the cookie key. This is a problem when
nosharesock is used. Two different connections will
use duplicate cookies. Avoid this by adding
server->conn_id to the key, so that it's guaranteed
that cookie will not be duplicated.

Also, for secondary channels of a session, copy the
fscache pointer from the primary channel. The primary
channel is guaranteed not to go away as long as secondary
channels are in use.  Also addresses minor problem found
by kernel test robot.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-03 12:36:04 -06:00
Shyam Prasad N
5bf91ef03d cifs: wait for tcon resource_id before getting fscache super
The logic for initializing tcon->resource_id is done inside
cifs_root_iget. fscache super cookie relies on this for aux
data. So we need to push the fscache initialization to this
later point during mount.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-03 12:29:59 -06:00
Paulo Alcantara
65de262a20 cifs: fix missed refcounting of ipc tcon
Fix missed refcounting of IPC tcon used for getting domain-based DFS
root referrals.  We want to keep it alive as long as mount is active
and can be refreshed.  For standalone DFS root referrals it wouldn't
be a problem as the client ends up having an IPC tcon for both mount
and cache.

Fixes: c88f7dcd6d ("cifs: support nested dfs links over reconnect")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Enzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-12-03 12:29:10 -06:00
Steve French
0b03fe6d3a cifs: update internal version number
To 2.34

Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-23 10:07:15 -06:00
Steve French
350f4a562e smb2: clarify rc initialization in smb2_reconnect
It is clearer to initialize rc at the beginning of the function.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-23 10:07:00 -06:00
Shyam Prasad N
5112d80c16 cifs: populate server_hostname for extra channels
Recently, a new field got added to the smb3_fs_context struct
named server_hostname. While creating extra channels, pick up
this field from primary channel.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-23 10:05:39 -06:00
Shyam Prasad N
b9ad6b5b68 cifs: nosharesock should be set on new server
Recent fix to maintain a nosharesock state on the
server struct caused a regression. It updated this
field in the old tcp session, and not the new one.

This caused the multichannel scenario to misbehave.

Fixes: c9f1c19cf7 (cifs: nosharesock should not share socket with future sessions)
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-23 10:04:49 -06:00
Paulo Alcantara
8ae87bbeb5 cifs: introduce cifs_ses_mark_for_reconnect() helper
Use new cifs_ses_mark_for_reconnect() helper to mark all session
channels for reconnect instead of duplicating it in different places.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-16 10:57:08 -06:00
Steve French
446e21482e cifs: protect srv_count with cifs_tcp_ses_lock
Updates to the srv_count field are protected elsewhere
with the cifs_tcp_ses_lock spinlock.  Add one missing place
(cifs_get_tcp_sesion).

CC: Shyam Prasad N <sprasad@microsoft.com>
Addresses-Coverity: 1494149 ("Data Race Condition")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-16 10:46:22 -06:00
Steve French
0226487ad8 cifs: move debug print out of spinlock
It is better to print debug messages outside of the chan_lock
spinlock where possible.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Addresses-Coverity: 1493854 ("Thread deadlock")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-16 10:46:09 -06:00