linux-stable.git/drivers/block/loop.c, branch v4.1.45

loop: return proper error from loop_queue_rq()

2017-01-13T01:56:53+00:00

[ Upstream commit b4a567e8114327518c09f5632339a5954ab975a3 ]

->queue_rq() should return one of the BLK_MQ_RQ_QUEUE_* constants, not
an errno.

f4aa4c7bbac6 ("block: loop: convert to per-device workqueue")
Signed-off-by: Omar Sandoval 
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe 

Signed-off-by: Sasha Levin

block: loop: avoiding too many pending per work I/O

2015-08-03T16:29:07+00:00

commit 4d4e41aef9429872ea3b105e83426941f7185ab6 upstream.

If there are too many pending per work I/O, too many
high priority work thread can be generated so that
system performance can be effected.

This patch limits the max_active parameter of workqueue as 16.

This patch fixes Fedora 22 live booting performance
regression when it is booted from squashfs over dm
based on loop, and looks the following reasons are
related with the problem:

- not like other filesyststems(such as ext4), squashfs
is a bit special, and I observed that increasing I/O jobs
to access file in squashfs only improve I/O performance a
little, but it can make big difference for ext4

- nested loop: both squashfs.img and ext3fs.img are mounted
as loop block, and ext3fs.img is inside the squashfs

- during booting, lots of tasks may run concurrently

Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: loop: convert to per-device workqueue

2015-08-03T16:29:07+00:00

commit f4aa4c7bbac6c4afdd4adccf90898c1a3685396d upstream.

Documentation/workqueue.txt:
	If there is dependency among multiple work items used
	during memory reclaim, they should be queued to separate
	wq each with WQ_MEM_RECLAIM.

Loop devices can be stacked, so we have to convert to per-device
workqueue. One example is Fedora live CD.

Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
Cc: Justin M. Forbes 
Signed-off-by: Ming Lei 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: destroy bdi before blockdev is unregistered.

2015-04-27T16:27:20+00:00

Because of the peculiar way that md devices are created (automatically
when the device node is opened), a new device can be created and
registered immediately after the
	blk_unregister_region(disk_devt(disk), disk->minors);
call in del_gendisk().

Therefore it is important that all visible artifacts of the previous
device are removed before this call.  In particular, the 'bdi'.

Since:
commit c4db59d31e39ea067c32163ac961e9c80198fd37
Author: Christoph Hellwig 
    fs: don't reassign dirty inodes to default_backing_dev_info

moved the
   device_unregister(bdi->dev);
call from bdi_unregister() to bdi_destroy() it has been quite easy to
lose a race and have a new (e.g.) "md127" be created after the
blk_unregister_region() call and before bdi_destroy() is ultimately
called by the final 'put_disk', which must come after del_gendisk().

The new device finds that the bdi name is already registered in sysfs
and complains

> [ 9627.630029] WARNING: CPU: 18 PID: 3330 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5a/0x70()
> [ 9627.630032] sysfs: cannot create duplicate filename '/devices/virtual/bdi/9:127'

We can fix this by moving the bdi_destroy() call out of
blk_release_queue() (which can happen very late when a refcount
reaches zero) and into blk_cleanup_queue() - which happens exactly when the md
device driver calls it.

Then it is only necessary for md to call blk_cleanup_queue() before
del_gendisk().  As loop.c devices are also created on demand by
opening the device node, we make the same change there.

Fixes: c4db59d31e39ea067c32163ac961e9c80198fd37
Reported-by: Azat Khuzhin 
Cc: Christoph Hellwig 
Cc: stable@vger.kernel.org (v4.0)
Signed-off-by: NeilBrown 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: loop: switch to VFS ITER_BVEC

2015-04-15T19:06:33+00:00

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

switch /dev/loop to vfs_iter_write()

2015-04-12T02:29:39+00:00

all writable files that might be used as backing store for /dev/loop
already support ->write_iter()

Signed-off-by: Al Viro

loop: add blk-mq.h include

2015-01-02T22:20:25+00:00

Looks like we pull it in through other ways on x86, but we fail
on sparc:

In file included from drivers/block/cryptoloop.c:30:0:
drivers/block/loop.h:63:24: error: field 'tag_set' has incomplete type
struct blk_mq_tag_set tag_set;

Add the include to loop.h, kill it from loop.c.

Signed-off-by: Jens Axboe

block: loop: don't handle REQ_FUA explicitly

2015-01-02T22:07:49+00:00

block core handles REQ_FUA by its flush state machine, so
won't do it in loop explicitly.

Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: loop: introduce lo_discard() and lo_req_flush()

2015-01-02T22:07:49+00:00

No behaviour change, just move the handling for REQ_DISCARD
and REQ_FLUSH in these two functions.

Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: loop: say goodby to bio

2015-01-02T22:07:49+00:00

Switch to block request completely.

Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe