linux-toradex.git/drivers/block/loop.c, branch v3.2-rc5

loop: cleanup set_status interface

2011-11-16T08:21:49+00:00

1) Anyone who has read access to loopdev has permission to call set_status
   and may change important parameters such as lo_offset, lo_sizelimit and
   so on, which contradicts to read access pattern and definitely equals
   to write access pattern.
2) Add lo_offset over i_size check to prevent blkdev_size overflow.
   ##Testcase_bagin
   #dd if=/dev/zero of=./file bs=1k count=1
   #losetup /dev/loop0 ./file
   /* userspace_application */
   struct loop_info64 loinf;
   fd = open("/dev/loop0", O_RDONLY);
   ioctl(fd, LOOP_GET_STATUS64, &loinf);
   /* Set offset to any value which is bigger than i_size, and sizelimit
    * to nonzero value*/
   loinf.lo_offset = 4096*1024;
   loinf.lo_sizelimit = 1024;
   ioctl(fd, LOOP_SET_STATUS64, &loinf);
   /* After this loop device will have size similar to 0x7fffffffffxxxx */
   #blockdev --getsz /dev/loop0
   ##OUTPUT: 36028797018955968
   ##Testcase_end

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Dmitry Monakhov 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

loop: prevent information leak after failed read

2011-11-16T08:21:48+00:00

If read was not fully successful we have to fail whole bio to prevent
information leak of old pages

##Testcase_begin
dd if=/dev/zero of=./file bs=1M count=1
losetup /dev/loop0 ./file -o 4096
truncate -s 0 ./file
# OOps loop offset is now beyond i_size, so read will silently fail.
# So bio's pages would not be cleared, may which result in information leak.
hexdump -C /dev/loop0
##testcase_end

Signed-off-by: Dmitry Monakhov 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

Merge branch 'for-3.2/drivers' of git://git.kernel.dk/linux-block

2011-11-05T00:22:14+00:00

* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits)
  virtio-blk: use ida to allocate disk index
  hpsa: add small delay when using PCI Power Management to reset for kump
  cciss: add small delay when using PCI Power Management to reset for kump
  xen/blkback: Fix two races in the handling of barrier requests.
  xen/blkback: Check for proper operation.
  xen/blkback: Fix the inhibition to map pages when discarding sector ranges.
  xen/blkback: Report VBD_WSECT (wr_sect) properly.
  xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests.
  xen-blkfront: plug device number leak in xlblk_init() error path
  xen-blkfront: If no barrier or flush is supported, use invalid operation.
  xen-blkback: use kzalloc() in favor of kmalloc()+memset()
  xen-blkback: fixed indentation and comments
  xen-blkfront: fix a deadlock while handling discard response
  xen-blkfront: Handle discard requests.
  xen-blkback: Implement discard requests ('feature-discard')
  xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
  drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()
  drivers/block/loop.c: emit uevent on auto release
  drivers/block/cpqarray.c: use pci_dev->revision
  loop: always allow userspace partitions and optionally support automatic scanning
  ...

Fic up trivial header file includsion conflict in drivers/block/loop.c

Merge branch 'for-linus' into for-3.2/core

2011-10-24T14:24:38+00:00

Merge branch 'v3.1-rc10' into for-3.2/core

2011-10-19T12:30:42+00:00

Conflicts:
	block/blk-core.c
	include/linux/blkdev.h

Signed-off-by: Jens Axboe

loop: remove the incorrect write_begin/write_end shortcut

2011-10-17T10:57:20+00:00

Currently the loop device tries to call directly into write_begin/write_end
instead of going through ->write if it can.  This is a fairly nasty shortcut
as write_begin and write_end are only callbacks for the generic write code
and expect to be called with filesystem specific locks held.

This code currently causes various issues for clustered filesystems as it
doesn't take the required cluster locks, and it also causes issues for XFS
as it doesn't properly lock against the swapext ioctl as called by the
defragmentation tools.  This in case causes data corruption if
defragmentation hits a busy loop device in the wrong time window, as
reported by RH QA.

The reason why we have this shortcut is that it saves a data copy when
doing a transformation on the loop device, which is the technical term
for using cryptoloop (or an XOR transformation).  Given that cryptoloop
has been deprecated in favour of dm-crypt my opinion is that we should
simply drop this shortcut instead of finding complicated ways to to
introduce a formal interface for this shortcut.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()

2011-09-21T08:02:13+00:00

If the loop device is associated (lo->lo_state == Lo_bound), it will have
a valid bdev pointed to by lo->lo_device.  There is no reason to ever pass
an additional block_device pointer.

Signed-off-by: Ayan George 
Cc: Phillip Susi 
Cc: Jens Axboe 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

drivers/block/loop.c: emit uevent on auto release

2011-09-21T08:02:13+00:00

The loopback driver failed to emit the change uevent when auto releasing
the device.  Fixed lo_release() to pass the bdev to loop_clr_fd() so it
can emit the event.

Signed-off-by: Phillip Susi 
Cc: Jens Axboe 
Cc: Ayan George 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

block: remove support for bio remapping from ->make_request

2011-09-12T10:12:01+00:00

There is very little benefit in allowing to let a ->make_request
instance update the bios device and sector and loop around it in
__generic_make_request when we can archive the same through calling
generic_make_request from the driver and letting the loop in
generic_make_request handle it.

Note that various drivers got the return value from ->make_request and
returned non-zero values for errors.

Signed-off-by: Christoph Hellwig 
Acked-by: NeilBrown 
Signed-off-by: Jens Axboe

loop: always allow userspace partitions and optionally support automatic scanning

2011-08-23T18:12:04+00:00

Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.

Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.

The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.

  # grep . /sys/class/block/loop1/loop/*
  /sys/block/loop1/loop/autoclear:0
  /sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
  /sys/block/loop1/loop/offset:0
  /sys/block/loop1/loop/partscan:1
  /sys/block/loop1/loop/sizelimit:0

  # ls -l /dev/loop*
  brw-rw---- 1 root disk   7,   0 Aug 14 20:22 /dev/loop0
  brw-rw---- 1 root disk   7,   1 Aug 14 20:23 /dev/loop1
  brw-rw---- 1 root disk 259,   0 Aug 14 20:23 /dev/loop1p1
  brw-rw---- 1 root disk 259,   1 Aug 14 20:23 /dev/loop1p2
  brw-rw---- 1 root disk   7,  99 Aug 14 20:23 /dev/loop99
  brw-rw---- 1 root disk 259,   2 Aug 14 20:23 /dev/loop99p1
  brw-rw---- 1 root disk 259,   3 Aug 14 20:23 /dev/loop99p2
  crw------T 1 root root  10, 237 Aug 14 20:22 /dev/loop-control

Cc: Karel Zak  
Cc: Davidlohr Bueso 
Acked-By: Tejun Heo 
Signed-off-by: Kay Sievers 
Signed-off-by: Jens Axboe