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  1. 01 Apr, 2019 1 commit
    • Steve French's avatar
      SMB3: Allow persistent handle timeout to be configurable on mount · ca567eb2
      Steve French authored 
      Reconnecting after server or network failure can be improved
(to maintain availability and protect data integrity) by allowing
the client to choose the default persistent (or resilient)
handle timeout in some use cases.  Today we default to 0 which lets
the server pick the default timeout (usually 120 seconds) but this
can be problematic for some workloads.  Add the new mount parameter
to cifs.ko for SMB3 mounts "handletimeout" which enables the user
to override the default handle timeout for persistent (mount
option "persistenthandles") or resilient handles (mount option
"resilienthandles").  Maximum allowed is 16 minutes (960000 ms).
Units for the timeout are expressed in milliseconds. See
section 2.2.14.2.12 and 2.2.31.3 of the MS-SMB2 protocol
specification for more information.
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
      ca567eb2
  3. 15 Mar, 2019 1 commit
  5. 06 Mar, 2019 2 commits
  7. 05 Mar, 2019 5 commits
    • Pavel Shilovsky's avatar
      CIFS: Count SMB3 credits for malformed pending responses · 66265f13
      Pavel Shilovsky authored 
      Even if a response is malformed, we should count credits
granted by the server to avoid miscalculations and unnecessary
reconnects due to client or server bugs. If the response has
been received partially, the session will be reconnected anyway
on the next iteration of the demultiplex thread, so counting
credits for such cases shouldn't break things.
Signed-off-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
      66265f13
    • Steve French's avatar
      smb3: make default i/o size for smb3 mounts larger · e8506d25
      Steve French authored 
      We negotiate rsize mounts (and it can be overridden by user) to
typically 4MB, so using larger default I/O sizes from userspace
(changing to 1MB default i/o size returned by stat) the
performance is much better (and not just for long latency
network connections) in most use cases for SMB3 than the default I/O
size (which ends up being 128K for cp and can be even smaller for cp).
This can be 4x slower or worse depending on network latency.

By changing inode->blocksize from 32K (which was perhaps ok
for very old SMB1/CIFS) to a larger value, 1MB (but still less than
max size negotiated with the server which is 4MB, in order to minimize
risk) it significantly increases performance for the
noncached case, and slightly increases it for the cached case.
This can be changed by the user on mount (specifying bsize=
values from 16K to 16MB) to tune better for performance
for applications that depend on blocksize.
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
      e8506d25
    • Ronnie Sahlberg's avatar
      cifs: add credits from unmatched responses/messages · eca00452
      Ronnie Sahlberg authored 
      We should add any credits granted to us from unmatched server responses.
Signed-off-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
      eca00452
    • Ronnie Sahlberg's avatar
      cifs: replace snprintf with scnprintf · 74ea5f98
      Ronnie Sahlberg authored 
      a trivial patch that replaces all use of snprintf with scnprintf.
scnprintf() is generally seen as a safer function to use than
snprintf for many use cases.

In our case, there is no actual difference between the two since we never
look at the return value. Thus we did not have any of the bugs that
scnprintf protects against and the patch does nothing.

However, for people reading our code it will be a receipt that we
have done our due dilligence and checked our code for this type of bugs.

See the presentation "Making C Less Dangerous In The Linux Kernel"
at this years LCA
Signed-off-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
      74ea5f98
    • Yao Liu's avatar
      cifs: Fix NULL pointer dereference of devname · 68e2672f
      Yao Liu authored 
      There is a NULL pointer dereference of devname in strspn()

The oops looks something like:

  CIFS: Attempting to mount (null)
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
  ...
  RIP: 0010:strspn+0x0/0x50
  ...
  Call Trace:
   ? cifs_parse_mount_options+0x222/0x1710 [cifs]
   ? cifs_get_volume_info+0x2f/0x80 [cifs]
   cifs_setup_volume_info+0x20/0x190 [cifs]
   cifs_get_volume_info+0x50/0x80 [cifs]
   cifs_smb3_do_mount+0x59/0x630 [cifs]
   ? ida_alloc_range+0x34b/0x3d0
   cifs_do_mount+0x11/0x20 [cifs]
   mount_fs+0x52/0x170
   vfs_kern_mount+0x6b/0x170
   do_mount+0x216/0xdc0
   ksys_mount+0x83/0xd0
   __x64_sys_mount+0x25/0x30
   do_syscall_64+0x65/0x220
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fix this by adding a NULL check on devname in cifs_parse_devname()
Signed-off-by: default avatarYao Liu <yotta.liu@ucloud.cn>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
      68e2672f
  9. 24 Jan, 2019 1 commit
  11. 10 Jan, 2019 1 commit
  13. 03 Jan, 2019 1 commit
  15. 28 Dec, 2018 8 commits
  17. 24 Dec, 2018 5 commits
  19. 24 Oct, 2018 4 commits
  21. 23 Oct, 2018 1 commit
    • David Howells's avatar
      iov_iter: Separate type from direction and use accessor functions · aa563d7b
      David Howells authored 
      In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements.  This makes it easier to add further
iterator types.  Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself.  Only the direction is required.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      aa563d7b
  23. 02 Oct, 2018 2 commits
  25. 03 Sep, 2018 1 commit
  27. 10 Aug, 2018 1 commit
  29. 07 Aug, 2018 4 commits
  31. 05 Jul, 2018 1 commit
    • Lars Persson's avatar
      cifs: Fix use after free of a mid_q_entry · 696e420b
      Lars Persson authored 
      With protocol version 2.0 mounts we have seen crashes with corrupt mid
entries. Either the server->pending_mid_q list becomes corrupt with a
cyclic reference in one element or a mid object fetched by the
demultiplexer thread becomes overwritten during use.

Code review identified a race between the demultiplexer thread and the
request issuing thread. The demultiplexer thread seems to be written
with the assumption that it is the sole user of the mid object until
it calls the mid callback which either wakes the issuer task or
deletes the mid.

This assumption is not true because the issuer task can be woken up
earlier by a signal. If the demultiplexer thread has proceeded as far
as setting the mid_state to MID_RESPONSE_RECEIVED then the issuer
thread will happily end up calling cifs_delete_mid while the
demultiplexer thread still is using the mid object.

Inserting a delay in the cifs demultiplexer thread widens the race
window and makes reproduction of the race very easy:

		if (server->large_buf)
			buf = server->bigbuf;

+		usleep_range(500, 4000);

		server->lstrp = jiffies;

To resolve this I think the proper solution involves putting a
reference count on the mid object. This patch makes sure that the
demultiplexer thread holds a reference until it has finished
processing the transaction.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarLars Persson <larper@axis.com>
Acked-by: default avatarPaulo Alcantara <palcantara@suse.de>
Reviewed-by: default avatarRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
      696e420b
  33. 15 Jun, 2018 1 commit
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