Commit Graph

577 Commits

Author SHA1 Message Date
David Howells 46f5cbdef7 cifs: Fix the readahead conversion to manage the batch when reading from cache
Fix the readahead conversion to correctly manage the last batch skipping
when reading from cache.  This involves a readahead batch of one page or
one folio, so set the batch size according to the number of constituent
pages (should be 1 for a filesystem that doesn't do multipage folios yet).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <smfrench@gmail.com>
Reviewed-by: Rohith Surabattula <rohiths.msft@gmail.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-02-01 10:36:22 -06:00
David Howells 0174ee9947 cifs: Implement cache I/O by accessing the cache directly
Move cifs to using fscache DIO API instead of the old upstream I/O API as
that has been removed.  This is a stopgap solution as the intention is that
at sometime in the future, the cache will move to using larger blocks and
won't be able to store individual pages in order to deal with the potential
for data corruption due to the backing filesystem being able insert/remove
bridging blocks of zeros into its extent list[1].

cifs then reads and writes cache pages synchronously and one page at a time.

The preferred change would be to use the netfs lib, but the new I/O API can
be used directly.  It's just that as the cache now needs to track data for
itself, caching blocks may exceed page size...

This code is somewhat borrowed from my "fallback I/O" patchset[2].

Signed-off-by: David Howells <dhowells@redhat.com>
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://lore.kernel.org/r/YO17ZNOcq+9PajfQ@mit.edu [1]
Link: https://lore.kernel.org/r/202112100957.2oEDT20W-lkp@intel.com/ [2]
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-02-01 10:29:18 -06:00
David Howells 052e04a52d cifs: Transition from ->readpages() to ->readahead()
Transition the cifs filesystem from using the old ->readpages() method to
using the new ->readahead() method.

For the moment, this removes any invocation of fscache to read data from
the local cache, leaving that to another patch.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <smfrench@gmail.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Reviewed-by: Rohith Surabattula <rohiths@microsoft.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
2022-02-01 10:29:18 -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
Steve French 71e6864eac smb3: do not error on fsync when readonly
Linux allows doing a flush/fsync on a file open for read-only,
but the protocol does not allow that.  If the file passed in
on the flush is read-only try to find a writeable handle for
the same inode, if that is not possible skip sending the
fsync call to the server to avoid breaking the apps.

Reported-by: Julian Sikorski <belegdol@gmail.com>
Tested-by: Julian Sikorski <belegdol@gmail.com>
Suggested-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-11-10 16:28:27 -06:00
Jens Axboe 6b19b766e8 fs: get rid of the res2 iocb->ki_complete argument
The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.

Now that everybody is passing in zero, kill off the extra argument.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-25 10:36:24 -06:00
Steve French 4f22262280 cifs: Clear modified attribute bit from inode flags
Clear CIFS_INO_MODIFIED_ATTR bit from inode flags after
updating mtime and ctime

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-23 16:16:19 -05:00
Dan Carpenter e946d3c887 cifs: fix a sign extension bug
The problem is the mismatched types between "ctx->total_len" which is
an unsigned int, "rc" which is an int, and "ctx->rc" which is a
ssize_t.  The code does:

	ctx->rc = (rc == 0) ? ctx->total_len : rc;

We want "ctx->rc" to store the negative "rc" error code.  But what
happens is that "rc" is type promoted to a high unsigned int and
'ctx->rc" will store the high positive value instead of a negative
value.

The fix is to change "rc" from an int to a ssize_t.

Fixes: c610c4b619 ("CIFS: Add asynchronous write support through kernel AIO")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-21 20:51:50 -05:00
Rohith Surabattula 35866f3f77 cifs: Not to defer close on file when lock is set
Close file immediately when lock is set.

Cc: stable@vger.kernel.org # 5.13+
Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-17 16:59:41 -05:00
Steve French 099dd788e3 cifs: remove pathname for file from SPDX header
checkpatch complains about source files with filenames (e.g. in
these cases just below the SPDX header in comments at the top of
various files in fs/cifs). It also is helpful to change this now
so will be less confusing when the parent directory is renamed
e.g. from fs/cifs to fs/smb_client (or fs/smbfs)

Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-13 14:51:10 -05:00
Shyam Prasad N 18d04062f8 cifs: enable fscache usage even for files opened as rw
So far, the fscache implementation we had supports only
a small set of use cases. Particularly for files opened
with O_RDONLY.

This commit enables it even for rw based file opens. It
also enables the reuse of cached data in case of mount
option (cache=singleclient) where it is guaranteed that
this is the only client (and server) which operates on
the files. There's also a single line change in fscache.c
to get around a bug seen in fscache.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-08-25 15:45:10 -05:00
Rohith Surabattula 9e992755be cifs: Call close synchronously during unlink/rename/lease break.
During unlink/rename/lease break, deferred work for close is
scheduled immediately but in an asynchronous manner which might
lead to race with actual(unlink/rename) commands.

This change will schedule close synchronously which will avoid
the race conditions with other commands.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org # 5.13
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-08-12 11:29:58 -05:00
Steve French f2a26a3cff SMB3: fix readpage for large swap cache
readpage was calculating the offset of the page incorrectly
for the case of large swapcaches.

    loff_t offset = (loff_t)page->index << PAGE_SHIFT;

As pointed out by Matthew Wilcox, this needs to use
page_file_offset() to calculate the offset instead.
Pages coming from the swap cache have page->index set
to their index within the swapcache, not within the backing
file.  For a sufficiently large swapcache, we could have
overlapping values of page->index within the same backing file.

Suggested by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: <stable@vger.kernel.org> # v5.7+
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-07-26 22:35:25 -05:00
Steve French 929be906fa cifs: use SPDX-Licence-Identifier
Add SPDX license identifier and replace license boilerplate.
Corrects various checkpatch errors with the older format for
noting the LGPL license.

Signed-off-by: Steve French <stfrench@microsoft.com>
2021-06-20 21:28:17 -05:00
Rohith Surabattula 9687c85dfb Fix KASAN identified use-after-free issue.
[  612.157429] ==================================================================
[  612.158275] BUG: KASAN: use-after-free in process_one_work+0x90/0x9b0
[  612.158801] Read of size 8 at addr ffff88810a31ca60 by task kworker/2:9/2382

[  612.159611] CPU: 2 PID: 2382 Comm: kworker/2:9 Tainted: G
OE     5.13.0-rc2+ #98
[  612.159623] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.14.0-1.fc33 04/01/2014
[  612.159640] Workqueue:  0x0 (deferredclose)
[  612.159669] Call Trace:
[  612.159685]  dump_stack+0xbb/0x107
[  612.159711]  print_address_description.constprop.0+0x18/0x140
[  612.159733]  ? process_one_work+0x90/0x9b0
[  612.159743]  ? process_one_work+0x90/0x9b0
[  612.159754]  kasan_report.cold+0x7c/0xd8
[  612.159778]  ? lock_is_held_type+0x80/0x130
[  612.159789]  ? process_one_work+0x90/0x9b0
[  612.159812]  kasan_check_range+0x145/0x1a0
[  612.159834]  process_one_work+0x90/0x9b0
[  612.159877]  ? pwq_dec_nr_in_flight+0x110/0x110
[  612.159914]  ? spin_bug+0x90/0x90
[  612.159967]  worker_thread+0x3b6/0x6c0
[  612.160023]  ? process_one_work+0x9b0/0x9b0
[  612.160038]  kthread+0x1dc/0x200
[  612.160051]  ? kthread_create_worker_on_cpu+0xd0/0xd0
[  612.160092]  ret_from_fork+0x1f/0x30

[  612.160399] Allocated by task 2358:
[  612.160757]  kasan_save_stack+0x1b/0x40
[  612.160768]  __kasan_kmalloc+0x9b/0xd0
[  612.160778]  cifs_new_fileinfo+0xb0/0x960 [cifs]
[  612.161170]  cifs_open+0xadf/0xf20 [cifs]
[  612.161421]  do_dentry_open+0x2aa/0x6b0
[  612.161432]  path_openat+0xbd9/0xfa0
[  612.161441]  do_filp_open+0x11d/0x230
[  612.161450]  do_sys_openat2+0x115/0x240
[  612.161460]  __x64_sys_openat+0xce/0x140

When mod_delayed_work is called to modify the delay of pending work,
it might return false and queue a new work when pending work is
already scheduled or when try to grab pending work failed.

So, Increase the reference count when new work is scheduled to
avoid use-after-free.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-05-20 12:20:42 -05:00
Rohith Surabattula 0ab95c2510 Defer close only when lease is enabled.
When smb2 lease parameter is disabled on server. Server grants
batch oplock instead of RHW lease by default on open, inode page cache
needs to be zapped immediatley upon close as cache is not valid.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-05-19 21:11:28 -05:00
Rohith Surabattula 860b69a9d7 Fix kernel oops when CONFIG_DEBUG_ATOMIC_SLEEP is enabled.
Removed oplock_break_received flag which was added to achieve
synchronization between oplock handler and open handler by earlier commit.

It is not needed because there is an existing lock open_file_lock to achieve
the same. find_readable_file takes open_file_lock and then traverses the
openFileList. Similarly, cifs_oplock_break while closing the deferred
handle (i.e cifsFileInfo_put) takes open_file_lock and then sends close
to the server.

Added comments for better readability.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-05-19 21:11:26 -05:00
Linus Torvalds 7c9e41e0ef 10 CIFS/SMB3 changesets including some important multichannel fixes, as well as support for handle leases (deferred close) and shutdown support
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Merge tag '5.13-rc-smb3-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs updates from Steve French:
 "Ten CIFS/SMB3 changes - including two marked for stable - including
  some important multichannel fixes, as well as support for handle
  leases (deferred close) and shutdown support:

   - some important multichannel fixes

   - support for handle leases (deferred close)

   - shutdown support (which is also helpful since it enables multiple
     xfstests)

   - enable negotiating stronger encryption by default (GCM256)

   - improve wireshark debugging by allowing more options for root to
     dump decryption keys

  SambaXP and the SMB3 Plugfest test event are going on now so I am
  expecting more patches over the next few days due to extra testing
  (including more multichannel fixes)"

* tag '5.13-rc-smb3-part2' of git://git.samba.org/sfrench/cifs-2.6:
  fs/cifs: Fix resource leak
  Cifs: Fix kernel oops caused by deferred close for files.
  cifs: fix regression when mounting shares with prefix paths
  cifs: use echo_interval even when connection not ready.
  cifs: detect dead connections only when echoes are enabled.
  smb3.1.1: allow dumping keys for multiuser mounts
  smb3.1.1: allow dumping GCM256 keys to improve debugging of encrypted shares
  cifs: add shutdown support
  cifs: Deferred close for files
  smb3.1.1: enable negotiating stronger encryption by default
2021-05-05 13:37:07 -07:00
Rohith Surabattula 78c09634f7 Cifs: Fix kernel oops caused by deferred close for files.
Fix regression issue caused by deferred close for files.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-05-04 11:53:15 -05:00
Steve French 087f757b01 cifs: add shutdown support
Various filesystem support the shutdown ioctl which is used by various
xfstests. The shutdown ioctl sets a flag on the superblock which
prevents open, unlink, symlink, hardlink, rmdir, create etc.
on the file system until unmount and remounted. The two flags supported
in this patch are:

  FSOP_GOING_FLAGS_LOGFLUSH and FSOP_GOING_FLAGS_NOLOGFLUSH

which require very little other than blocking new operations (since
we do not cache writes to metadata on the client with cifs.ko).
FSOP_GOING_FLAGS_DEFAULT is not supported yet, but could be added in
the future but would need to call syncfs or equivalent to write out
pending data on the mount.

With this patch various xfstests now work including tests 043 through
046 for example.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2021-05-03 11:21:22 -05:00
Rohith Surabattula c3f207ab29 cifs: Deferred close for files
When file is closed, SMB2 close request is not sent to server
immediately and is deferred for acregmax defined interval. When file is
reopened by same process for read or write, the file handle
is reused if an oplock is held.

When client receives a oplock/lease break, file is closed immediately
if reference count is zero, else oplock is downgraded.

Signed-off-by: Rohith Surabattula <rohiths@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-05-03 11:20:35 -05:00
Linus Torvalds d1466bc583 Merge branch 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs inode type handling updates from Al Viro:
 "We should never change the type bits of ->i_mode or the method tables
  (->i_op and ->i_fop) of a live inode.

  Unfortunately, not all filesystems took care to prevent that"

* 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  spufs: fix bogosity in S_ISGID handling
  9p: missing chunk of "fs/9p: Don't update file type when updating file attributes"
  openpromfs: don't do unlock_new_inode() until the new inode is set up
  hostfs_mknod(): don't bother with init_special_inode()
  cifs: have cifs_fattr_to_inode() refuse to change type on live inode
  cifs: have ->mkdir() handle race with another client sanely
  do_cifs_create(): don't set ->i_mode of something we had not created
  gfs2: be careful with inode refresh
  ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode
  orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap...
  vboxsf: don't allow to change the inode type
  afs: Fix updating of i_mode due to 3rd party change
  ceph: don't allow type or device number to change on non-I_NEW inodes
  ceph: fix up error handling with snapdirs
  new helper: inode_wrong_type()
2021-04-27 10:57:42 -07:00
Al Viro f6a9bc336b cifs: allocate buffer in the caller of build_path_from_dentry()
build_path_from_dentry() open-codes dentry_path_raw().  The reason
we can't use dentry_path_raw() in there (and postprocess the
result as needed) is that the callers of build_path_from_dentry()
expect that the object to be freed on cleanup and the string to
be used are at the same address.  That's painful, since the path
is naturally built end-to-beginning - we start at the leaf and
go through the ancestors, accumulating the pathname.

Life would be easier if we left the buffer allocation to callers.
It wouldn't be exact-sized buffer, but none of the callers keep
the result for long - it's always freed before the caller returns.
So there's no need to do exact-sized allocation; better use
__getname()/__putname(), same as we do for pathname arguments
of syscalls.  What's more, there's no need to do allocation under
spinlocks, so GFP_ATOMIC is not needed.

Next patch will replace the open-coded dentry_path_raw() (in
build_path_from_dentry_optional_prefix()) with calling the real
thing.  This patch only introduces wrappers for allocating/freeing
the buffers and switches to new calling conventions:
	build_path_from_dentry(dentry, buf)
expects buf to be address of a page-sized object or NULL,
return value is a pathname built inside that buffer on success,
ERR_PTR(-ENOMEM) if buf is NULL and ERR_PTR(-ENAMETOOLONG) if
the pathname won't fit into page.  Note that we don't need to
check for failure when allocating the buffer in the caller -
build_path_from_dentry() will do the right thing.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-04-25 16:28:23 -05:00
Al Viro 8e33cf20ce cifs: make build_path_from_dentry() return const char *
... and adjust the callers.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-04-25 16:28:23 -05:00
Al Viro f6f1f17907 cifs: constify pathname arguments in a bunch of helpers
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-04-25 16:28:23 -05:00
Ronnie Sahlberg cee8f4f6fc cifs: revalidate mapping when we open files for SMB1 POSIX
RHBZ: 1933527

Under SMB1 + POSIX, if an inode is reused on a server after we have read and
cached a part of a file, when we then open the new file with the
re-cycled inode there is a chance that we may serve the old data out of cache
to the application.
This only happens for SMB1 (deprecated) and when posix are used.
The simplest solution to avoid this race is to force a revalidate
on smb1-posix open.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-03-26 18:04:58 -05:00
Al Viro 4d66952a20 cifs: have cifs_fattr_to_inode() refuse to change type on live inode
... instead of trying to do that in the callers (and missing some,
at that)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2021-03-12 22:15:20 -05:00
Steve French b438fcf128 cifs: change confusing field serverName (to ip_addr)
ses->serverName is not the server name, but the string form
of the ip address of the server.  Change the name to ip_addr
to avoid confusion (and fix the array length to match
maximum length of ipv6 address).

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-02-22 21:20:43 -06:00
Ronnie Sahlberg 522aa3b575 cifs: move [brw]size from cifs_sb to cifs_sb->ctx
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-12-14 09:26:30 -06:00
Ronnie Sahlberg 8401e93678 cifs: remove [gu]id/backup[gu]id/file_mode/dir_mode from cifs_sb
We can already access these from cifs_sb->ctx so we no longer need
a local copy in cifs_sb.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-12-14 09:16:23 -06:00
Steve French 607dfc79c3 cifs: remove various function description warnings
When compiling with W=1 I noticed various functions that
did not follow proper style in describing (in the comments)
the parameters passed in to the function. For example:

fs/cifs/inode.c:2236: warning: Function parameter or member 'mode' not described in 'cifs_wait_bit_killable'

I did not address the style warnings in two of the six files
(connect.c and misc.c) in order to reduce risk of merge
conflict with pending patches. We can update those later.

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-12-14 09:16:23 -06:00
yangerkun 2e98c01846 cifs: remove the retry in cifs_poxis_lock_set
The caller of cifs_posix_lock_set will do retry(like
fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
So the retry in cifs_poxis_lock_set seems duplicated, remove it to
make a cleanup.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: NeilBrown <neilb@suse.de>
2020-07-07 23:51:16 -05:00
Zhang Xiaoxu 95a3d8f3af cifs: Fix double add page to memcg when cifs_readpages
When xfstests generic/451, there is an BUG at mm/memcontrol.c:
  page:ffffea000560f2c0 refcount:2 mapcount:0 mapping:000000008544e0ea
       index:0xf
  mapping->aops:cifs_addr_ops dentry name:"tst-aio-dio-cycle-write.451"
  flags: 0x2fffff80000001(locked)
  raw: 002fffff80000001 ffffc90002023c50 ffffea0005280088 ffff88815cda0210
  raw: 000000000000000f 0000000000000000 00000002ffffffff ffff88817287d000
  page dumped because: VM_BUG_ON_PAGE(page->mem_cgroup)
  page->mem_cgroup:ffff88817287d000
  ------------[ cut here ]------------
  kernel BUG at mm/memcontrol.c:2659!
  invalid opcode: 0000 [#1] SMP
  CPU: 2 PID: 2038 Comm: xfs_io Not tainted 5.8.0-rc1 #44
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_
    073836-buildvm-ppc64le-16.ppc.4
  RIP: 0010:commit_charge+0x35/0x50
  Code: 0d 48 83 05 54 b2 02 05 01 48 89 77 38 c3 48 c7
        c6 78 4a ea ba 48 83 05 38 b2 02 05 01 e8 63 0d9
  RSP: 0018:ffffc90002023a50 EFLAGS: 00010202
  RAX: 0000000000000000 RBX: ffff88817287d000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffff88817ac97ea0 RDI: ffff88817ac97ea0
  RBP: ffffea000560f2c0 R08: 0000000000000203 R09: 0000000000000005
  R10: 0000000000000030 R11: ffffc900020237a8 R12: 0000000000000000
  R13: 0000000000000001 R14: 0000000000000001 R15: ffff88815a1272c0
  FS:  00007f5071ab0800(0000) GS:ffff88817ac80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000055efcd5ca000 CR3: 000000015d312000 CR4: 00000000000006e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   mem_cgroup_charge+0x166/0x4f0
   __add_to_page_cache_locked+0x4a9/0x710
   add_to_page_cache_locked+0x15/0x20
   cifs_readpages+0x217/0x1270
   read_pages+0x29a/0x670
   page_cache_readahead_unbounded+0x24f/0x390
   __do_page_cache_readahead+0x3f/0x60
   ondemand_readahead+0x1f1/0x470
   page_cache_async_readahead+0x14c/0x170
   generic_file_buffered_read+0x5df/0x1100
   generic_file_read_iter+0x10c/0x1d0
   cifs_strict_readv+0x139/0x170
   new_sync_read+0x164/0x250
   __vfs_read+0x39/0x60
   vfs_read+0xb5/0x1e0
   ksys_pread64+0x85/0xf0
   __x64_sys_pread64+0x22/0x30
   do_syscall_64+0x69/0x150
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f5071fcb1af
  Code: Bad RIP value.
  RSP: 002b:00007ffde2cdb8e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011
  RAX: ffffffffffffffda RBX: 00007ffde2cdb990 RCX: 00007f5071fcb1af
  RDX: 0000000000001000 RSI: 000055efcd5ca000 RDI: 0000000000000003
  RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000001000 R11: 0000000000000293 R12: 0000000000000001
  R13: 000000000009f000 R14: 0000000000000000 R15: 0000000000001000
  Modules linked in:
  ---[ end trace 725fa14a3e1af65c ]---

Since commit 3fea5a499d ("mm: memcontrol: convert page cache to a new
mem_cgroup_charge() API") not cancel the page charge, the pages maybe
double add to pagecache:
thread1                       | thread2
cifs_readpages
readpages_get_pages
 add_to_page_cache_locked(head,index=n)=0
                              | readpages_get_pages
                              | add_to_page_cache_locked(head,index=n+1)=0
 add_to_page_cache_locked(head, index=n+1)=-EEXIST
 then, will next loop with list head page's
 index=n+1 and the page->mapping not NULL
readpages_get_pages
add_to_page_cache_locked(head, index=n+1)
 commit_charge
  VM_BUG_ON_PAGE

So, we should not do the next loop when any page add to page cache
failed.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-06-23 12:04:52 -05:00
Steve French d313852d7a smb311: add support for using info level for posix extensions query
Adds calls to the newer info level for query info using SMB3.1.1 posix extensions.
The remaining two places that call the older query info (non-SMB3.1.1 POSIX)
require passing in the fid and can be updated in a later patch.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2020-06-12 08:54:12 -05:00
Linus Torvalds 3803d5e4d3 22 changesets, 2 for stable. Includes big performance improvement for large i/o when using multichannel, also includes DFS fixes
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Merge tag '5.8-rc-smb3-fixes-part-1' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs updates from Steve French:
 "22 changesets, 2 for stable.

  Includes big performance improvement for large i/o when using
  multichannel, also includes DFS fixes"

* tag '5.8-rc-smb3-fixes-part-1' of git://git.samba.org/sfrench/cifs-2.6: (22 commits)
  cifs: update internal module version number
  cifs: multichannel: try to rebind when reconnecting a channel
  cifs: multichannel: use pointer for binding channel
  smb3: remove static checker warning
  cifs: multichannel: move channel selection above transport layer
  cifs: multichannel: always zero struct cifs_io_parms
  cifs: dump Security Type info in DebugData
  smb3: fix incorrect number of credits when ioctl MaxOutputResponse > 64K
  smb3: default to minimum of two channels when multichannel specified
  cifs: multichannel: move channel selection in function
  cifs: fix minor typos in comments and log messages
  smb3: minor update to compression header definitions
  cifs: minor fix to two debug messages
  cifs: Standardize logging output
  smb3: Add new parm "nodelete"
  cifs: move some variables off the stack in smb2_ioctl_query_info
  cifs: reduce stack use in smb2_compound_op
  cifs: get rid of unused parameter in reconn_setup_dfs_targets()
  cifs: handle hostnames that resolve to same ip in failover
  cifs: set up next DFS target before generic_ip_connect()
  ...
2020-06-05 16:40:53 -07:00
Aurelien Aptel 352d96f3ac cifs: multichannel: move channel selection above transport layer
Move the channel (TCP_Server_Info*) selection from the tranport
layer to higher in the call stack so that:

- credit handling is done with the server that will actually be used
  to send.
  * ->wait_mtu_credit
  * ->set_credits / set_credits
  * ->add_credits / add_credits
  * add_credits_and_wake_if

- potential reconnection (smb2_reconnect) done when initializing a
  request is checked and done with the server that will actually be
  used to send.

To do this:

- remove the cifs_pick_channel() call out of compound_send_recv()

- select channel and pass it down by adding a cifs_pick_channel(ses)
  call in:
  - smb311_posix_mkdir
  - SMB2_open
  - SMB2_ioctl
  - __SMB2_close
  - query_info
  - SMB2_change_notify
  - SMB2_flush
  - smb2_async_readv  (if none provided in context param)
  - SMB2_read         (if none provided in context param)
  - smb2_async_writev (if none provided in context param)
  - SMB2_write        (if none provided in context param)
  - SMB2_query_directory
  - send_set_info
  - SMB2_oplock_break
  - SMB311_posix_qfs_info
  - SMB2_QFS_info
  - SMB2_QFS_attr
  - smb2_lockv
  - SMB2_lease_break
    - smb2_compound_op
  - smb2_set_ea
  - smb2_ioctl_query_info
  - smb2_query_dir_first
  - smb2_query_info_comound
  - smb2_query_symlink
  - cifs_writepages
  - cifs_write_from_iter
  - cifs_send_async_read
  - cifs_read
  - cifs_readpages

- add TCP_Server_Info *server param argument to:
  - cifs_send_recv
  - compound_send_recv
  - SMB2_open_init
  - SMB2_query_info_init
  - SMB2_set_info_init
  - SMB2_close_init
  - SMB2_ioctl_init
  - smb2_iotcl_req_init
  - SMB2_query_directory_init
  - SMB2_notify_init
  - SMB2_flush_init
  - build_qfs_info_req
  - smb2_hdr_assemble
  - smb2_reconnect
  - fill_small_buf
  - smb2_plain_req_init
  - __smb2_plain_req_init

The read/write codepath is different than the rest as it is using
pages, io iterators and async calls. To deal with those we add a
server pointer in the cifs_writedata/cifs_readdata/cifs_io_parms
context struct and set it in:

- cifs_writepages      (wdata)
- cifs_write_from_iter (wdata)
- cifs_readpages       (rdata)
- cifs_send_async_read (rdata)

The [rw]data->server pointer is eventually copied to
cifs_io_parms->server to pass it down to SMB2_read/SMB2_write.
If SMB2_read/SMB2_write is called from a different place that doesn't
set the server field it will pick a channel.

Some places do not pick a channel and just use ses->server or
cifs_ses_server(ses). All cifs_ses_server(ses) calls are in codepaths
involving negprot/sess.setup.

- SMB2_negotiate         (binding channel)
- SMB2_sess_alloc_buffer (binding channel)
- SMB2_echo              (uses provided one)
- SMB2_logoff            (uses master)
- SMB2_tdis              (uses master)

(list not exhaustive)

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-06-04 13:50:55 -05:00
Aurelien Aptel 7c06514afd cifs: multichannel: always zero struct cifs_io_parms
SMB2_read/SMB2_write check and use cifs_io_parms->server, which might
be uninitialized memory.

This change makes all callers zero-initialize the struct.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-06-04 13:50:55 -05:00
Johannes Weiner 6058eaec81 mm: fold and remove lru_cache_add_anon() and lru_cache_add_file()
They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().

[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-03 20:09:48 -07:00
Joe Perches a0a3036b81 cifs: Standardize logging output
Use pr_fmt to standardize all logging for fs/cifs.

Some logging output had no CIFS: specific prefix.

Now all output has one of three prefixes:

o CIFS:
o CIFS: VFS:
o Root-CIFS:

Miscellanea:

o Convert printks to pr_<level>
o Neaten macro definitions
o Remove embedded CIFS: prefixes from formats
o Convert "illegal" to "invalid"
o Coalesce formats
o Add missing '\n' format terminations
o Consolidate multiple cifs_dbg continuations into single calls
o More consistent use of upper case first word output logging
o Multiline statement argument alignment and wrapping

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-06-01 00:10:18 -05:00
Steve French 9bd21d4b1a cifs: Fix null pointer check in cifs_read
Coverity scan noted a redundant null check

Coverity-id: 728517
Reported-by: Coverity <scan-admin@coverity.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
2020-05-14 10:30:03 -05:00
Steve French 4e8aea30f7 smb3: enable swap on SMB3 mounts
Add experimental support for allowing a swap file to be on an SMB3
mount.  There are use cases where swapping over a secure network
filesystem is preferable. In some cases there are no local
block devices large enough, and network block devices can be
hard to setup and secure.  And in some cases there are no
local block devices at all (e.g. with the recent addition of
remote boot over SMB3 mounts).

There are various enhancements that can be added later e.g.:
- doing a mandatory byte range lock over the swapfile (until
the Linux VFS is modified to notify the file system that an open
is for a swapfile, when the file can be opened "DENY_ALL" to prevent
others from opening it).
- pinning more buffers in the underlying transport to minimize memory
allocations in the TCP stack under the fs
- documenting how to create ACLs (on the server) to secure the
swapfile (or adding additional tools to cifs-utils to make it easier)

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-04-10 13:32:32 -05:00
Yilu Lin 97adda8b3a CIFS: Fix bug which the return value by asynchronous read is error
This patch is used to fix the bug in collect_uncached_read_data()
that rc is automatically converted from a signed number to an
unsigned number when the CIFS asynchronous read fails.
It will cause ctx->rc is error.

Example:
Share a directory and create a file on the Windows OS.
Mount the directory to the Linux OS using CIFS.
On the CIFS client of the Linux OS, invoke the pread interface to
deliver the read request.

The size of the read length plus offset of the read request is greater
than the maximum file size.

In this case, the CIFS server on the Windows OS returns a failure
message (for example, the return value of
smb2.nt_status is STATUS_INVALID_PARAMETER).

After receiving the response message, the CIFS client parses
smb2.nt_status to STATUS_INVALID_PARAMETER
and converts it to the Linux error code (rdata->result=-22).

Then the CIFS client invokes the collect_uncached_read_data function to
assign the value of rdata->result to rc, that is, rc=rdata->result=-22.

The type of the ctx->total_len variable is unsigned integer,
the type of the rc variable is integer, and the type of
the ctx->rc variable is ssize_t.

Therefore, during the ternary operation, the value of rc is
automatically converted to an unsigned number. The final result is
ctx->rc=4294967274. However, the expected result is ctx->rc=-22.

Signed-off-by: Yilu Lin <linyilu@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
2020-03-22 22:49:10 -05:00
Linus Torvalds dcf23ac3e8 locks: reinstate locks_delete_block optimization
There is measurable performance impact in some synthetic tests due to
commit 6d390e4b5d (locks: fix a potential use-after-free problem when
wakeup a waiter). Fix the race condition instead by clearing the
fl_blocker pointer after the wake_up, using explicit acquire/release
semantics.

This does mean that we can no longer use the clearing of fl_blocker as
the wait condition, so switch the waiters over to checking whether the
fl_blocked_member list_head is empty.

Reviewed-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Fixes: 6d390e4b5d (locks: fix a potential use-after-free problem when wakeup a waiter)
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-18 13:03:38 -07:00
Aurelien Aptel 86f740f2ae cifs: fix rename() by ensuring source handle opened with DELETE bit
To rename a file in SMB2 we open it with the DELETE access and do a
special SetInfo on it. If the handle is missing the DELETE bit the
server will fail the SetInfo with STATUS_ACCESS_DENIED.

We currently try to reuse any existing opened handle we have with
cifs_get_writable_path(). That function looks for handles with WRITE
access but doesn't check for DELETE, making rename() fail if it finds
a handle to reuse. Simple reproducer below.

To select handles with the DELETE bit, this patch adds a flag argument
to cifs_get_writable_path() and find_writable_file() and the existing
'bool fsuid_only' argument is converted to a flag.

The cifsFileInfo struct only stores the UNIX open mode but not the
original SMB access flags. Since the DELETE bit is not mapped in that
mode, this patch stores the access mask in cifs_fid on file open,
which is accessible from cifsFileInfo.

Simple reproducer:

	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <unistd.h>
	#define E(s) perror(s), exit(1)

	int main(int argc, char *argv[])
	{
		int fd, ret;
		if (argc != 3) {
			fprintf(stderr, "Usage: %s A B\n"
			"create&open A in write mode, "
			"rename A to B, close A\n", argv[0]);
			return 0;
		}

		fd = openat(AT_FDCWD, argv[1], O_WRONLY|O_CREAT|O_SYNC, 0666);
		if (fd == -1) E("openat()");

		ret = rename(argv[1], argv[2]);
		if (ret) E("rename()");

		ret = close(fd);
		if (ret) E("close()");

		return ret;
	}

$ gcc -o bugrename bugrename.c
$ ./bugrename /mnt/a /mnt/b
rename(): Permission denied

Fixes: 8de9e86c67 ("cifs: create a helper to find a writeable handle by path name")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-02-24 14:20:38 -06:00
Steve French 2391ca41b4 smb3: add one more dynamic tracepoint missing from strict fsync path
We didn't have a dynamic trace point for catching errors in
file_write_and_wait_range error cases in cifs_strict_fsync.

Since not all apps check for write behind errors, it can be
important for debugging to be able to trace these error
paths.

Suggested-and-reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-06 17:21:23 -06:00
Steve French f2bf09e97b cifs: Add tracepoints for errors on flush or fsync
Makes it easier to debug errors on writeback that happen later,
and are being returned on flush or fsync

For example:
  writetest-17829 [002] .... 13583.407859: cifs_flush_err: ino=90 rc=-28

Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-05 18:24:19 -06:00
Amir Goldstein 0f060936e4 SMB3: Backup intent flag missing from some more ops
When "backup intent" is requested on the mount (e.g. backupuid or
backupgid mount options), the corresponding flag was missing from
some of the operations.

Change all operations to use the macro cifs_create_options() to
set the backup intent flag if needed.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-02-03 16:12:47 -06:00
David Howells 6629400a22 cifs: Don't use iov_iter::type directly
Don't use iov_iter::type directly, but rather use the new accessor
functions that have been added.  This allows the .type field to be split
and rearranged without the need to update the filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Steve French 43f8a6a74e smb3: query attributes on file close
Since timestamps on files on most servers can be updated at
close, and since timestamps on our dentries default to one
second we can have stale timestamps in some common cases
(e.g. open, write, close, stat, wait one second, stat - will
show different mtime for the first and second stat).

The SMB2/SMB3 protocol allows querying timestamps at close
so add the code to request timestamp and attr information
(which is cheap for the server to provide) to be returned
when a file is closed (it is not needed for the many
paths that call SMB2_close that are from compounded
query infos and close nor is it needed for some of
the cases where a directory close immediately follows a
directory open.

Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
2019-12-03 15:48:02 -06:00
Pavel Shilovsky 6f582b273e CIFS: Fix NULL-pointer dereference in smb2_push_mandatory_locks
Currently when the client creates a cifsFileInfo structure for
a newly opened file, it allocates a list of byte-range locks
with a pointer to the new cfile and attaches this list to the
inode's lock list. The latter happens before initializing all
other fields, e.g. cfile->tlink. Thus a partially initialized
cifsFileInfo structure becomes available to other threads that
walk through the inode's lock list. One example of such a thread
may be an oplock break worker thread that tries to push all
cached byte-range locks. This causes NULL-pointer dereference
in smb2_push_mandatory_locks() when accessing cfile->tlink:

[598428.945633] BUG: kernel NULL pointer dereference, address: 0000000000000038
...
[598428.945749] Workqueue: cifsoplockd cifs_oplock_break [cifs]
[598428.945793] RIP: 0010:smb2_push_mandatory_locks+0xd6/0x5a0 [cifs]
...
[598428.945834] Call Trace:
[598428.945870]  ? cifs_revalidate_mapping+0x45/0x90 [cifs]
[598428.945901]  cifs_oplock_break+0x13d/0x450 [cifs]
[598428.945909]  process_one_work+0x1db/0x380
[598428.945914]  worker_thread+0x4d/0x400
[598428.945921]  kthread+0x104/0x140
[598428.945925]  ? process_one_work+0x380/0x380
[598428.945931]  ? kthread_park+0x80/0x80
[598428.945937]  ret_from_fork+0x35/0x40

Fix this by reordering initialization steps of the cifsFileInfo
structure: initialize all the fields first and then add the new
byte-range lock list to the inode's lock list.

Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-12-02 15:15:00 -06:00