linux-toradex.git/drivers/block/loop.c, branch v3.7.3

loop: Make explicit loop device destruction lazy

2012-10-30T07:37:31+00:00

xfstests has always had random failures of tests due to loop devices
failing to be torn down and hence leaving filesytems that cannot be
unmounted. This causes test runs to immediately stop.

Over the past 6 or 7 years we've added hacks like explicit unmount
-d commands for loop mounts, losetup -d after unmount -d fails, etc,
but still the problems persist.  Recently, the frequency of loop
related failures increased again to the point that xfstests 259 will
reliably fail with a stray loop device that was not torn down.

That is despite the fact the test is above as simple as it gets -
loop 5 or 6 times running mkfs.xfs with different paramters:

        lofile=$(losetup -f)
        losetup $lofile "$testfile"
        "$MKFS_XFS_PROG" -b size=512 $lofile >/dev/null || echo "mkfs failed!"
        sync
        losetup -d $lofile

And losteup -d $lofile is failing with EBUSY on 1-3 of these loops
every time the test is run.

Turns out that blkid is running simultaneously with losetup -d, and
so it sees an elevated reference count and returns EBUSY.  But why
is blkid running? It's obvious, isn't it? udev has decided to try
and find out what is on the block device as a result of a creation
notification. And it is racing with mkfs, so might still be scanning
the device when mkfs finishes and we try to tear it down.

So, make losetup -d force autoremove behaviour. That is, when the
last reference goes away, tear down the device. xfstests wants it
*gone*, not causing random teardown failures when we know that all
the operations the tests have specifically run on the device have
completed and are no longer referencing the loop device.

Signed-off-by: Dave Chinner 
Signed-off-by: Jens Axboe

userns: Convert loop to use kuid_t instead of uid_t

2012-09-21T10:13:20+00:00

Cc: Jens Axboe 
Acked-by: Serge Hallyn 
Signed-off-by: Eric W. Biederman

blk: fix wrong idr_pre_get() error check in loop.c

2012-07-14T22:39:58+00:00

The idr_pre_get() function never returns a value < 0.  It returns 0 (no
memory) or 1 (OK).

Reported-by: Silva Paulo 
[ Rewrote Silva's patch, but attributing it to Silva anyway  - Linus ]
Signed-off-by: Linus Torvalds

block: remove the second argument of k[un]map_atomic()

2012-03-20T13:48:16+00:00

Signed-off-by: Cong Wang

loop: zero fill bio instead of return -EIO for partial read

2012-02-08T21:07:19+00:00

commit 8268f5a741 ("deny partial write for loop dev fd") tried to fix the
loop device partial read information leak problem.  But it changed the
semantics of read behavior.  When we read beyond the end of the device we
should get 0 bytes, which is normal behavior, we should not just return
-EIO

Instead of returning -EIO, zero out the bio to avoid information leak in
case of partail read.

Signed-off-by: Dave Young 
Reviewed-by: Jeff Moyer 
Tested-by: Jeff Moyer 
Cc: Dmitry Monakhov 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

fs: move code out of buffer.c

2012-01-04T03:54:07+00:00

Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.

Signed-off-by: Nick Piggin 
Cc: Al Viro 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

loop: Fix discard_alignment default setting

2011-12-02T13:47:03+00:00

discard_alignment is not relevant to the loop driver since it is
supposed to be set as a workaround for the old sector 63 alignments.
So set it to zero rather than block size.

Signed-off-by: Lukas Czerner 
Reported-by: Milan Broz 
Signed-off-by: Jens Axboe

loop: fix loop block driver discard and encryption comment

2011-11-25T08:41:25+00:00

The loop driver does not support discard if encryption is enabled,
fix the comment.

Signed-off-by: Dave Young 
Signed-off-by: Jens Axboe

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