linux-stable.git/drivers/block/nbd.c, branch linux-3.2.y

nbd: only set MSG_MORE when we have more to send

2017-03-16T02:18:45+00:00

commit d61b7f972dab2a7d187c38254845546dfc8eed85 upstream.

A user noticed that write performance was horrible over loopback and we
traced it to an inversion of when we need to set MSG_MORE.  It should be
set when we have more bvec's to send, not when we are on the last bvec.
This patch made the test go from 20 iops to 78k iops.

Signed-off-by: Josef Bacik 
Fixes: 429a787be679 ("nbd: fix use-after-free of rq/bio in the xmit path")
Signed-off-by: Jens Axboe 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

nbd: fix use-after-free of rq/bio in the xmit path

2017-03-16T02:18:45+00:00

commit 429a787be6793554ee02aacc7e1f11ebcecc4453 upstream.

For writes, we can get a completion in while we're still iterating
the request and bio chain. If that happens, we're reading freed
memory and we can crash.

Break out after the last segment and avoid having the iterator
read freed memory.

Reviewed-by: Josef Bacik 
Signed-off-by: Jens Axboe 
[bwh: Backported to 3.2:
 - bio_for_each_segment() uses iterator of type int
 - Open-code bio_iter_last()
 - Adjust context]
Signed-off-by: Ben Hutchings

nbd: fix possible memory leak

2015-05-09T22:16:30+00:00

commit ff6b8090e26ef7649ef0cc6b42389141ef48b0cf upstream.

we have already allocated memory for nbd_dev, but we were not
releasing that memory and just returning the error value.

Signed-off-by: Sudip Mukherjee 
Acked-by: Paul Clements 
Signed-off-by: Markus Pargmann 
Signed-off-by: Ben Hutchings

nbd: correct disconnect behavior

2013-07-27T04:34:29+00:00

commit c378f70adbc1bbecd9e6db145019f14b2f688c7c upstream.

Currently, when a disconnect is requested by the user (via NBD_DISCONNECT
ioctl) the return from NBD_DO_IT is undefined (it is usually one of
several error codes).  This means that nbd-client does not know if a
manual disconnect was performed or whether a network error occurred.
Because of this, nbd-client's persist mode (which tries to reconnect after
error, but not after manual disconnect) does not always work correctly.

This change fixes this by causing NBD_DO_IT to always return 0 if a user
requests a disconnect.  This means that nbd-client can correctly either
persist the connection (if an error occurred) or disconnect (if the user
requested it).

Signed-off-by: Paul Clements 
Acked-by: Rob Landley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: adjust device pointer name]
Signed-off-by: Ben Hutchings

block: do not pass disk names as format strings

2013-07-27T04:34:28+00:00

commit ffc8b30866879ed9ba62bd0a86fecdbd51cd3d19 upstream.

Disk names may contain arbitrary strings, so they must not be
interpreted as format strings.  It seems that only md allows arbitrary
strings to be used for disk names, but this could allow for a local
memory corruption from uid 0 into ring 0.

CVE-2013-2851

Signed-off-by: Kees Cook 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: adjust device pointer name in nbd.c]
Signed-off-by: Ben Hutchings

nbd: fsync and kill block device on shutdown

2013-03-06T03:24:17+00:00

commit 3a2d63f87989e01437ba994df5f297528c353d7d upstream.

There are two problems with shutdown in the NBD driver.

1: Receiving the NBD_DISCONNECT ioctl does not sync the filesystem.

   This patch adds the sync operation into __nbd_ioctl()'s
   NBD_DISCONNECT handler.  This is useful because BLKFLSBUF is restricted
   to processes that have CAP_SYS_ADMIN, and the NBD client may not
   possess it (fsync of the block device does not sync the filesystem,
   either).

2: Once we clear the socket we have no guarantee that later reads will
   come from the same backing storage.

   The patch adds calls to kill_bdev() in __nbd_ioctl()'s socket
   clearing code so the page cache is cleaned, lest reads that hit on the
   page cache will return stale data from the previously-accessible disk.

Example:

    # qemu-nbd -r -c/dev/nbd0 /dev/sr0
    # file -s /dev/nbd0
    /dev/stdin: # UDF filesystem data (version 1.5) etc.
    # qemu-nbd -d /dev/nbd0
    # qemu-nbd -r -c/dev/nbd0 /dev/sda
    # file -s /dev/nbd0
    /dev/stdin: # UDF filesystem data (version 1.5) etc.

While /dev/sda has:

    # file -s /dev/sda
    /dev/sda: x86 boot sector; etc.

Signed-off-by: Paolo Bonzini 
Acked-by: Paul Clements 
Cc: Alex Bligh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2:
 - Adjusted context
 - s/\bnbd\b/lo/
 - Incorporate export of kill_bdev() from commit ff01bb483265
   ('fs: move code out of buffer.c')]
Signed-off-by: Ben Hutchings

nbd: clear waiting_queue on shutdown

2012-10-10T02:30:46+00:00

commit fded4e090c60100d709318896c79816d68d5b47d upstream.

Fix a serious but uncommon bug in nbd which occurs when there is heavy
I/O going to the nbd device while, at the same time, a failure (server,
network) or manual disconnect of the nbd connection occurs.

There is a small window between the time that the nbd_thread is stopped
and the socket is shutdown where requests can continue to be queued to
nbd's internal waiting_queue.  When this happens, those requests are
never completed or freed.

The fix is to clear the waiting_queue on shutdown of the nbd device, in
the same way that the nbd request queue (queue_head) is already being
cleared.

Signed-off-by: Paul Clements 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: local nbd_device pointers are called 'lo' not 'nbd']
Signed-off-by: Ben Hutchings

nbd-replace-some-printk-with-dev_warn-and-dev_info-checkpatch-fixes

2011-08-19T12:48:28+00:00

ERROR: code indent should use tabs where possible
#30: FILE: drivers/block/nbd.c:578:
+^I        dev_info(disk_to_dev(lo->disk), "NBD_DISCONNECT\n");$

total: 1 errors, 0 warnings, 35 lines checked

NOTE: whitespace errors detected, you may wish to use scripts/cleanpatch or
      scripts/cleanfile

./patches/nbd-replace-some-printk-with-dev_warn-and-dev_info.patch has style problems, please review.

If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

Please run checkpatch prior to sending patches

Cc: Paul Clements 
Cc: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

nbd: replace some printk with dev_warn() and dev_info()

2011-08-19T12:48:28+00:00

Signed-off-by: WANG Cong 
Cc: Paul Clements 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

nbd: lower the loglevel of an error message

2011-08-19T12:48:28+00:00

This is only an error, no need to use KERN_CRIT log level.

Signed-off-by: WANG Cong 
Cc: Paul Clements 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe