Revert "blk-lib: check for kill signal"

This reverts commit 8a08c5fd89b447a7de7eb293a7a274c46b932ba2.

It turns out while this is a perfectly valid and long overdue thing to do
for user initiated discards / zeroing from the ioctl handler, it actually
breaks file system use of the discard helper by interrupting in places
the file system doesn't expect, and by leaving the bio chain in a state
that the file system callers of (at least) __blkdev_issue_discard do
not expect.

Revert the change for now, we'll redo it for the next merge window
after refactoring the code to better split the file system vs ioctl
callers and cleaning up a few other loose ends.

Reported-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20240314021623.1908895-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-lib: check for kill signal

Some of these block operations can access a significant capacity and
take longer than the user expected. A user may change their mind about
wanting to run that command and attempt to kill the process and do
something else with their device. But since the task is uninterruptable,
they have to wait for it to finish, which could be many hours.

Check for a fatal signal at each iteration so the user doesn't have to
wait for their regretted operation to complete naturally.

Reported-by: Conrad Meyer <conradmeyer@meta.com>
Tested-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240223155910.3622666-5-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup __blkdev_issue_write_zeroes

Use min to calculate the next number of sectors like everyone else.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240223155910.3622666-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: blkdev_issue_secure_erase loop style

Use consistent coding style in this file. All the other loops for the
same purpose use "while (nr_sects)", so they win.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240223155910.3622666-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk-lib: fix blkdev_issue_secure_erase

There's a bug in blkdev_issue_secure_erase. The statement
"unsigned int len = min_t(sector_t, nr_sects, max_sectors);"
sets the variable "len" to the length in sectors, but the statement
"bio->bi_iter.bi_size = len" treats it as if it were in bytes.
The statements "sector += len << SECTOR_SHIFT" and "nr_sects -= len <<
SECTOR_SHIFT" are thinko.

This patch fixes it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v5.19
Fixes: 44abff2c0b97 ("block: decouple REQ_OP_SECURE_ERASE from REQ_OP_DISCARD")
Link: https://lore.kernel.org/r/alpine.LRH.2.02.2209141549480.28100@file01.intranet.prod.int.rdu2.redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: stop using bdevname in __blkdev_issue_discard

Just use the %pg format specifier instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220713055317.1888500-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: decouple REQ_OP_SECURE_ERASE from REQ_OP_DISCARD

Secure erase is a very different operation from discard in that it is
a data integrity operation vs hint. Fully split the limits and helper
infrastructure to make the separation more clear.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nifs2]
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> [f2fs]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Chao Yu <chao@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-27-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add a bdev_discard_granularity helper

Abstract away implementation details from file systems by providing a
block_device based helper to retrieve the discard granularity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Link: https://lore.kernel.org/r/20220415045258.199825-26-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove QUEUE_FLAG_DISCARD

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: refactor discard bio size limiting

Move all the logic to limit the discard bio size into a common helper
so that it is better documented.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-23-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

scsi: block: Remove REQ_OP_WRITE_SAME support

No more users of REQ_OP_WRITE_SAME or drivers implementing it are left,
so remove the infrastructure.

[mkp: fold in and tweak sysfs reporting fix]

Link: https://lore.kernel.org/r/20220209082828.2629273-8-hch@lst.de
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

blk-lib: don't check bdev_get_queue() NULL check

Based on the comment present in the bdev_get_queue()
bdev->bd_queue can never be NULL. Remove the NULL check for the local
variable q that is set from bdev_get_queue() for discard, write_same,
and write_zeroes.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220215115247.11717-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a block_device and opf to blk_next_bio

All callers need to set the block_device and operation, so lift that into
the common code.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220124091107.642561-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move blk_next_bio to bio.c

Keep blk_next_bio next to the core bio infrastructure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: export blk_next_bio()

The block layer provides emulation of zone management operations
targeting all zones of a zoned block device only for the zone reset
operation (REQ_OP_ZONE_RESET). In order to correctly implement
exporting of zoned block devices with NVMeOF, emulating zone management
operations targeting all zones of a device is also necessary for the
open, close and finish zone operations (REQ_OP_ZONE_OPEN,
REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH).

Instead of duplicating the code, export the existing helper from block
layer so we can use a bio chaining pattern that is present in the block
layer for REQ_OP_ZONE RESET all emulation in the NVMeOF zoned block
device backend.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

block: rename BIO_MAX_PAGES to BIO_MAX_VECS

Ever since the addition of multipage bio_vecs BIO_MAX_PAGES has been
horribly confusingly misnamed. Rename it to BIO_MAX_VECS to stop
confusing users of the bio API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210311110137.1132391-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move the start_sect field to struct block_device

Move the start_sect field to struct block_device in preparation
of killing struct hd_struct.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add a bdev_is_partition helper

Add a littler helper to make the somewhat arcane bd_contains checks a
little more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: check queue's limits.discard_granularity in __blkdev_issue_discard()

If create a loop device with a backing NVMe SSD, current loop device
driver doesn't correctly set its queue's limits.discard_granularity and
leaves it as 0. If a discard request at LBA 0 on this loop device, in
__blkdev_issue_discard() the calculated req_sects will be 0, and a zero
length discard request will trigger a BUG() panic in generic block layer
code at block/blk-mq.c:563.

[ 955.565006][ C39] ------------[ cut here ]------------
[ 955.559660][ C39] invalid opcode: 0000 [#1] SMP NOPTI
[ 955.622171][ C39] CPU: 39 PID: 248 Comm: ksoftirqd/39 Tainted: G E 5.8.0-default+ #40
[ 955.622171][ C39] Hardware name: Lenovo ThinkSystem SR650 -[7X05CTO1WW]-/-[7X05CTO1WW]-, BIOS -[IVE160M-2.70]- 07/17/2020
[ 955.622175][ C39] RIP: 0010:blk_mq_end_request+0x107/0x110
[ 955.622177][ C39] Code: 48 8b 03 e9 59 ff ff ff 48 89 df 5b 5d 41 5c e9 9f ed ff ff 48 8b 35 98 3c f4 00 48 83 c7 10 48 83 c6 19 e8 cb 56 c9 ff eb cb <0f> 0b 0f 1f 80 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41 56 41 54
[ 955.622179][ C39] RSP: 0018:ffffb1288701fe28 EFLAGS: 00010202
[ 955.749277][ C39] RAX: 0000000000000001 RBX: ffff956fffba5080 RCX: 0000000000004003
[ 955.749278][ C39] RDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000000
[ 955.749279][ C39] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
[ 955.749279][ C39] R10: ffffb1288701fd28 R11: 0000000000000001 R12: ffffffffa8e05160
[ 955.749280][ C39] R13: 0000000000000004 R14: 0000000000000004 R15: ffffffffa7ad3a1e
[ 955.749281][ C39] FS: 0000000000000000(0000) GS:ffff95bfbda00000(0000) knlGS:0000000000000000
[ 955.749282][ C39] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 955.749282][ C39] CR2: 00007f6f0ef766a8 CR3: 0000005a37012002 CR4: 00000000007606e0
[ 955.749283][ C39] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 955.749284][ C39] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 955.749284][ C39] PKRU: 55555554
[ 955.749285][ C39] Call Trace:
[ 955.749290][ C39] blk_done_softirq+0x99/0xc0
[ 957.550669][ C39] __do_softirq+0xd3/0x45f
[ 957.550677][ C39] ? smpboot_thread_fn+0x2f/0x1e0
[ 957.550679][ C39] ? smpboot_thread_fn+0x74/0x1e0
[ 957.550680][ C39] ? smpboot_thread_fn+0x14e/0x1e0
[ 957.550684][ C39] run_ksoftirqd+0x30/0x60
[ 957.550687][ C39] smpboot_thread_fn+0x149/0x1e0
[ 957.886225][ C39] ? sort_range+0x20/0x20
[ 957.886226][ C39] kthread+0x137/0x160
[ 957.886228][ C39] ? kthread_park+0x90/0x90
[ 957.886231][ C39] ret_from_fork+0x22/0x30
[ 959.117120][ C39] ---[ end trace 3dacdac97e2ed164 ]---

This is the procedure to reproduce the panic,
# modprobe scsi_debug delay=0 dev_size_mb=2048 max_queue=1
# losetup -f /dev/nvme0n1 --direct-io=on
# blkdiscard /dev/loop0 -o 0 -l 0x200

This patch fixes the issue by checking q->limits.discard_granularity in
__blkdev_issue_discard() before composing the discard bio. If the value
is 0, then prints a warning oops information and returns -EOPNOTSUPP to
the caller to indicate that this buggy device driver doesn't support
discard request.

Fixes: 9b15d109a6b2 ("block: improve discard bio alignment in __blkdev_issue_discard()")
Fixes: c52abf563049 ("loop: Better discard support for block devices")
Reported-and-suggested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Enzo Matsumiya <ematsumiya@suse.com>
Cc: Evan Green <evgreen@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Xiao Ni <xni@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: improve discard bio alignment in __blkdev_issue_discard()

This patch improves discard bio split for address and size alignment in
__blkdev_issue_discard(). The aligned discard bio may help underlying
device controller to perform better discard and internal garbage
collection, and avoid unnecessary internal fragment.

Current discard bio split algorithm in __blkdev_issue_discard() may have
non-discarded fregment on device even the discard bio LBA and size are
both aligned to device's discard granularity size.

Here is the example steps on how to reproduce the above problem.
- On a VMWare ESXi 6.5 update3 installation, create a 51GB virtual disk
with thin mode and give it to a Linux virtual machine.
- Inside the Linux virtual machine, if the 50GB virtual disk shows up as
/dev/sdb, fill data into the first 50GB by,
# dd if=/dev/zero of=/dev/sdb bs=4096 count=13107200
- Discard the 50GB range from offset 0 on /dev/sdb,
# blkdiscard /dev/sdb -o 0 -l 53687091200
- Observe the underlying mapping status of the device
# sg_get_lba_status /dev/sdb -m 1048 --lba=0
descriptor LBA: 0x0000000000000000 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000000000800 blocks: 16773120 deallocated
descriptor LBA: 0x0000000000fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000001000000 blocks: 8386560 deallocated
descriptor LBA: 0x00000000017ff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000001800000 blocks: 8386560 deallocated
descriptor LBA: 0x0000000001fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000002000000 blocks: 8386560 deallocated
descriptor LBA: 0x00000000027ff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000002800000 blocks: 8386560 deallocated
descriptor LBA: 0x0000000002fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000003000000 blocks: 8386560 deallocated
descriptor LBA: 0x00000000037ff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000003800000 blocks: 8386560 deallocated
descriptor LBA: 0x0000000003fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000004000000 blocks: 8386560 deallocated
descriptor LBA: 0x00000000047ff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000004800000 blocks: 8386560 deallocated
descriptor LBA: 0x0000000004fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000005000000 blocks: 8386560 deallocated
descriptor LBA: 0x00000000057ff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000005800000 blocks: 8386560 deallocated
descriptor LBA: 0x0000000005fff800 blocks: 2048 mapped (or unknown)
descriptor LBA: 0x0000000006000000 blocks: 6291456 deallocated
descriptor LBA: 0x0000000006600000 blocks: 0 deallocated

Although the discard bio starts at LBA 0 and has 50<<30 bytes size which
are perfect aligned to the discard granularity, from the above list
these are many 1MB (2048 sectors) internal fragments exist unexpectedly.

The problem is in __blkdev_issue_discard(), an improper algorithm causes
an improper bio size which is not aligned.

25 int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
26 sector_t nr_sects, gfp_t gfp_mask, int flags,
27 struct bio **biop)
28 {
29 struct request_queue *q = bdev_get_queue(bdev);
[snipped]
56
57 while (nr_sects) {
58 sector_t req_sects = min_t(sector_t, nr_sects,
59 bio_allowed_max_sectors(q));
60
61 WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
62
63 bio = blk_next_bio(bio, 0, gfp_mask);
64 bio->bi_iter.bi_sector = sector;
65 bio_set_dev(bio, bdev);
66 bio_set_op_attrs(bio, op, 0);
67
68 bio->bi_iter.bi_size = req_sects << 9;
69 sector += req_sects;
70 nr_sects -= req_sects;
[snipped]
79 }
80
81 *biop = bio;
82 return 0;
83 }
84 EXPORT_SYMBOL(__blkdev_issue_discard);

At line 58-59, to discard a 50GB range, req_sects is set as return value
of bio_allowed_max_sectors(q), which is 8388607 sectors. In the above
case, the discard granularity is 2048 sectors, although the start LBA
and discard length are aligned to discard granularity, req_sects never
has chance to be aligned to discard granularity. This is why there are
some still-mapped 2048 sectors fragment in every 4 or 8 GB range.

If req_sects at line 58 is set to a value aligned to discard_granularity
and close to UNIT_MAX, then all consequent split bios inside device
driver are (almostly) aligned to discard_granularity of the device
queue. The 2048 sectors still-mapped fragment will disappear.

This patch introduces bio_aligned_discard_max_sectors() to return the
the value which is aligned to q->limits.discard_granularity and closest
to UINT_MAX. Then this patch replaces bio_allowed_max_sectors() with
this new routine to decide a more proper split bio length.

But we still need to handle the situation when discard start LBA is not
aligned to q->limits.discard_granularity, otherwise even the length is
aligned, current code may still leave 2048 fragment around every 4GB
range. Therefore, to calculate req_sects, firstly the start LBA of
discard range is checked (including partition offset), if it is not
aligned to discard granularity, the first split location should make
sure following bio has bi_sector aligned to discard granularity. Then
there won't be still-mapped fragment in the middle of the discard range.

The above is how this patch improves discard bio alignment in
__blkdev_issue_discard(). Now with this patch, after discard with same
command line mentiond previously, sg_get_lba_status returns,
descriptor LBA: 0x0000000000000000 blocks: 106954752 deallocated
descriptor LBA: 0x0000000006600000 blocks: 0 deallocated

We an see there is no 2048 sectors segment anymore, everything is clean.

Reported-and-tested-by: Acshai Manoj <acshai.manoj@microfocus.com>
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Xiao Ni <xni@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Enzo Matsumiya <ematsumiya@suse.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix 32 bit overflow in __blkdev_issue_discard()

A discard cleanup merged into 4.20-rc2 causes fstests xfs/259 to
fall into an endless loop in the discard code. The test is creating
a device that is exactly 2^32 sectors in size to test mkfs boundary
conditions around the 32 bit sector overflow region.

mkfs issues a discard for the entire device size by default, and
hence this throws a sector count of 2^32 into
blkdev_issue_discard(). It takes the number of sectors to discard as
a sector_t - a 64 bit value.

The commit ba5d73851e71 ("block: cleanup __blkdev_issue_discard")
takes this sector count and casts it to a 32 bit value before
comapring it against the maximum allowed discard size the device
has. This truncates away the upper 32 bits, and so if the lower 32
bits of the sector count is zero, it starts issuing discards of
length 0. This causes the code to fall into an endless loop, issuing
a zero length discards over and over again on the same sector.

Fixes: ba5d73851e71 ("block: cleanup __blkdev_issue_discard")
Tested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>

Killed pointless WARN_ON().

Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: make sure writesame bio is aligned with logical block size

Obviously the created writesame bio has to be aligned with logical block
size, and use bio_allowed_max_sectors() to retrieve this number.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Xiao Ni <xni@redhat.com>
Cc: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Fixes: b49a0871be31a745b2ef ("block: remove split code in blkdev_issue_{discard,write_same}")
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: cleanup __blkdev_issue_discard()

Cleanup __blkdev_issue_discard() a bit:

- remove local variable of 'end_sect'
- remove code block of 'fail'

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Xiao Ni <xni@redhat.com>
Cc: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: make sure discard bio is aligned with logical block size

Obviously the created discard bio has to be aligned with logical block size.

This patch introduces the helper of bio_allowed_max_sectors() for
this purpose.

Cc: stable@vger.kernel.org
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Xiao Ni <xni@redhat.com>
Cc: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Fixes: 744889b7cbb56a6 ("block: don't deal with discard limit in blkdev_issue_discard()")
Fixes: a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks")
Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Tested-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Improve zone reset execution

There is no need to synchronously execute all REQ_OP_ZONE_RESET BIOs
necessary to reset a range of zones. Similarly to what is done for
discard BIOs in blk-lib.c, all zone reset BIOs can be chained and
executed asynchronously and a synchronous call done only for the last
BIO of the chain.

Modify blkdev_reset_zones() to operate similarly to
blkdev_issue_discard() using the next_bio() helper for chaining BIOs. To
avoid code duplication of that function in blk_zoned.c, rename
next_bio() into blk_next_bio() and declare it as a block internal
function in blk.h.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: don't deal with discard limit in blkdev_issue_discard()

blk_queue_split() does respect this limit via bio splitting, so no
need to do that in blkdev_issue_discard(), then we can align to
normal bio submit(bio_add_page() & submit_bio()).

More importantly, this patch fixes one issue introduced in a22c4d7e34402cc
("block: re-add discard_granularity and alignment checks"), in which
zero discard bio may be generated in case of zero alignment.

Fixes: a22c4d7e34402ccdf3 ("block: re-add discard_granularity and alignment checks")
Cc: stable@vger.kernel.org
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Xiao Ni <xni@redhat.com>
Tested-by: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix infinite loop if the device loses discard capability

If __blkdev_issue_discard is in progress and a device mapper device is
reloaded with a table that doesn't support discard,
q->limits.max_discard_sectors is set to zero. This results in infinite
loop in __blkdev_issue_discard.

This patch checks if max_discard_sectors is zero and aborts with
-EOPNOTSUPP.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Zdenek Kabelac <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: break discard submissions into the user defined size

Don't build discards bigger than what the user asked for, if the
user decided to limit the size by writing to 'discard_max_bytes'.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add bdev_read_only() checks to common helpers

Similar to blkdev_write_iter(), return -EPERM if the partition is
read-only. This covers ioctl(), fallocate() and most in-kernel users
but isn't meant to be exhaustive -- everything else will be caught in
generic_make_request_checks(), fail with -EIO and can be fixed later.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

block: cope with WRITE ZEROES failing in blkdev_issue_zeroout()

sd_config_write_same() ignores ->max_ws_blocks == 0 and resets it to
permit trying WRITE SAME on older SCSI devices, unless ->no_write_same
is set. Because REQ_OP_WRITE_ZEROES is implemented in terms of WRITE
SAME, blkdev_issue_zeroout() may fail with -EREMOTEIO:

$ fallocate -zn -l 1k /dev/sdg
fallocate: fallocate failed: Remote I/O error
$ fallocate -zn -l 1k /dev/sdg # OK
$ fallocate -zn -l 1k /dev/sdg # OK

The following calls succeed because sd_done() sets ->no_write_same in
response to a sense that would become BLK_STS_TARGET/-EREMOTEIO, causing
__blkdev_issue_zeroout() to fall back to generating ZERO_PAGE bios.

This means blkdev_issue_zeroout() must cope with WRITE ZEROES failing
and fall back to manually zeroing, unless BLKDEV_ZERO_NOFALLBACK is
specified. For BLKDEV_ZERO_NOFALLBACK case, return -EOPNOTSUPP if
sd_done() has just set ->no_write_same thus indicating lack of offload
support.

Fixes: c20cfc27a473 ("block: stop using blkdev_issue_write_same for zeroing")
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: factor out __blkdev_issue_zero_pages()

blkdev_issue_zeroout() will use this in !BLKDEV_ZERO_NOFALLBACK case.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix integer overflow in __blkdev_sectors_to_bio_pages()

Fix possible integer overflow in __blkdev_sectors_to_bio_pages if
sector_t is 32-bit.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 615d22a51c04 ("block: Fix __blkdev_issue_zeroout loop")
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: replace bi_bdev with a gendisk pointer and partitions index

This way we don't need a block_device structure to submit I/O. The
block_device has different life time rules from the gendisk and
request_queue and is usually only available when the block device node
is open. Other callers need to explicitly create one (e.g. the lightnvm
passthrough code, or the new nvme multipathing code).

For the actual I/O path all that we need is the gendisk, which exists
once per block device. But given that the block layer also does
partition remapping we additionally need a partition index, which is
used for said remapping in generic_make_request.

Note that all the block drivers generally want request_queue or
sometimes the gendisk, so this removes a layer of indirection all
over the stack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Fix __blkdev_issue_zeroout loop

The BIO issuing loop in __blkdev_issue_zeroout() is allocating BIOs
with a maximum number of bvec (pages) equal to

min(nr_sects, (sector_t)BIO_MAX_PAGES)

This works since the requested number of bvecs will always be limited
to the absolute maximum number supported (BIO_MAX_PAGES), but this is
ineficient as too many bvec entries may be requested due to the
different units being used in the min() operation (number of sectors vs
number of pages).
To fix this, introduce the helper __blkdev_sectors_to_bio_pages() to
correctly calculate the number of bvecs for zeroout BIOs as the issuing
loop progresses. The calculation is done using consistent units and
makes sure that the number of pages return is at least 1 (for cases
where the number of sectors is less that the number of sectors in
a page).

Also remove a trailing space after the bit shift in the internal loop
min() call.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the discard_zeroes_data flag

Now that we use the proper REQ_OP_WRITE_ZEROES operation everywhere we can
kill this hack.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: stop using discards for zeroing

Now that we have REQ_OP_WRITE_ZEROES implemented for all devices that
support efficient zeroing, we can remove the call to blkdev_issue_discard.
This means we only have two ways of zeroing left and can simplify the
code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add a new BLKDEV_ZERO_NOFALLBACK flag

This avoids fallbacks to explicit zeroing in (__)blkdev_issue_zeroout if
the caller doesn't want them.

Also clean up the convoluted check for the return condition that this
new flag is added to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add a REQ_NOUNMAP flag for REQ_OP_WRITE_ZEROES

If this flag is set logical provisioning capable device should
release space for the zeroed blocks if possible, if it is not set
devices should keep the blocks anchored.

Also remove an out of sync kerneldoc comment for a static function
that would have become even more out of data with this change.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add a flags argument to (__)blkdev_issue_zeroout

Turn the existing discard flag into a new BLKDEV_ZERO_UNMAP flag with
similar semantics, but without referring to diѕcard.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: stop using blkdev_issue_write_same for zeroing

We'll always use the WRITE ZEROES code for zeroing now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: correct documentation for blkdev_issue_discard() flags

BLKDEV_IFL_* flags no longer exist; blkdev_issue_discard() now actually
takes BLKDEV_DISCARD_* flags.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: don't try Write Same from __blkdev_issue_zeroout

Write Same can return an error asynchronously if it turns out the
underlying SCSI device does not support Write Same, which makes a
proper fallback to other methods in __blkdev_issue_zeroout impossible.
Thus only issue a Write Same from blkdev_issue_zeroout an don't try it
at all from __blkdev_issue_zeroout as a non-invasive workaround.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Junichi Nomura <j-nomura@ce.jp.nec.com>
Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout")
Tested-by: Junichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: don't try to discard from __blkdev_issue_zeroout

Discard can return -EIO asynchronously if the alignment for the request
isn't suitable for the driver, which makes a proper fallback to other
methods in __blkdev_issue_zeroout impossible. Thus only issue a sync
discard from blkdev_issue_zeroout an don't try discard at all from
__blkdev_issue_zeroout as a non-invasive workaround.

One more reason why abusing discard for zeroing must die..

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Eryu Guan <eguan@redhat.com>
Fixes: e73c23ff ("block: add async variant of blkdev_issue_zeroout")
Signed-off-by: Jens Axboe <axboe@fb.com>

block: improve handling of the magic discard payload

Instead of allocating a single unused biovec for discard requests, send
them down without any payload. Instead we allow the driver to add a
"special" payload using a biovec embedded into struct request (unioned
over other fields never used while in the driver), and overloading
the number of segments for this case.

This has a couple of advantages:

- we don't have to allocate the bio_vec
- the amount of special casing for discard requests in the block
layer is significantly reduced
- using this same scheme for other request types is trivial,
which will be important for implementing the new WRITE_ZEROES
op on devices where it actually requires a payload (e.g. SCSI)
- we can get rid of playing games with the request length, as
we'll never touch it and completions will work just fine
- it will allow us to support ranged discard operations in the
future by merging non-contiguous discard bios into a single
request
- last but not least it removes a lot of code

This patch is the common base for my WIP series for ranges discards and to
remove discard_zeroes_data in favor of always using REQ_OP_WRITE_ZEROES,
so it would be good to get it in quickly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add support for REQ_OP_WRITE_ZEROES

This adds a new block layer operation to zero out a range of
LBAs. This allows to implement zeroing for devices that don't use
either discard with a predictable zero pattern or WRITE SAME of zeroes.
The prominent example of that is NVMe with the Write Zeroes command,
but in the future, this should also help with improving the way
zeroing discards work. For this operation, suitable entry is exported in
sysfs which indicate the number of maximum bytes allowed in one
write zeroes operation by the device.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add async variant of blkdev_issue_zeroout

Similar to __blkdev_issue_discard this variant allows submitting
the final bio asynchronously and chaining multiple ranges
into a single completion.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: better op and flags encoding

Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields. This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits. Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: require write_same and discard requests align to logical block size

Make sure that the offset and length arguments that we're using to
construct WRITE SAME and DISCARD requests are actually aligned to the
logical block size. Failure to do this causes other errors in other parts
of the block layer or the SCSI layer because disks don't support partial
logical block writes.

Link: http://lkml.kernel.org/r/147518379026.22791.4437508871355153928.stgit@birch.djwong.org
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Mike Snitzer <snitzer@redhat.com> # tweaked header
Cc: Brian Foster <bfoster@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

block: don't ignore -EOPNOTSUPP blkdev_issue_write_same

WRITE SAME is a data integrity operation and we can't simply ignore
errors.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: introduce BLKDEV_DISCARD_ZERO to fix zeroout

Currently blkdev_issue_zeroout cascades down from discards (if the driver
guarantees that discards zero data), to WRITE SAME and then to a loop
writing zeroes. Unfortunately we ignore run-time EOPNOTSUPP errors in the
block layer blkdev_issue_discard helper to work around DM volumes that
may have mixed discard support underneath.

This patch intoroduces a new BLKDEV_DISCARD_ZERO flag to
blkdev_issue_discard that indicates we are called for zeroing operation.
This allows both to ignore the EOPNOTSUPP hack and actually consolidating
the discard_zeroes_data check into the function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add a separate operation type for secure erase

Instead of overloading the discard support with the REQ_SECURE flag.
Use the opportunity to rename the queue flag as well, and remove the
dead checks for this flag in the RAID 1 and RAID 10 drivers that don't
claim support for secure erase.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block discard: use bio set op accessor

This converts the block issue discard helper and users to use
the bio_set_op_attrs accessor and only pass in the operation flags
like REQ_SEQURE.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block, fs, mm, drivers: use bio set/get op accessors

This patch converts the simple bi_rw use cases in the block,
drivers, mm and fs code to set/get the bio operation using
bio_set_op_attrs/bio_op

These should be simple one or two liner cases, so I just did them
in one patch. The next patches handle the more complicated
cases in a module per patch.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/fs/drivers: remove rw argument from submit_bio

This has callers of submit_bio/submit_bio_wait set the bio->bi_rw
instead of passing it in. This makes that use the same as
generic_make_request and how we set the other bio fields.

Signed-off-by: Mike Christie <mchristi@redhat.com>

Fixed up fs/ext4/crypto.c

Signed-off-by: Jens Axboe <axboe@fb.com>

block: missing bio_put following submit_bio_wait

submit_bio_wait() gives the caller an opportunity to examine
struct bio and so expects the caller to issue the put_bio()

This fixes a memory leak reported by a few people in 4.7-rc2
kmemleak report after 9082e87bfbf8 ("block: remove struct bio_batch")

Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Larry Finger@lwfinger.net
Tested-by: David Drysdale <drysdale@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: reinstate early return of -EOPNOTSUPP from blkdev_issue_discard

Commit 38f25255330 ("block: add __blkdev_issue_discard") incorrectly
disallowed the early return of -EOPNOTSUPP if the device doesn't support
discard (or secure discard). This early return of -EOPNOTSUPP has
always been part of blkdev_issue_discard() interface so there isn't a
good reason to break that behaviour -- especially when it can be easily
reinstated.

The nuance of allowing early return of -EOPNOTSUPP vs disallowing late
return of -EOPNOTSUPP is: if the overall device never advertised support
for discards and one is issued to the device it is beneficial to inform
the caller that discards are not supported via -EOPNOTSUPP. But if a
device advertises discard support it means that at least a subset of the
device does have discard support -- but it could be that discards issued
to some regions of a stacked device will not be supported. In that case
the late return of -EOPNOTSUPP must be disallowed.

Fixes: 38f25255330 ("block: add __blkdev_issue_discard")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add __blkdev_issue_discard

This is a version of blkdev_issue_discard which doesn't wait for
the I/O to complete, but instead allows the caller to submit
the final bio and/or chain it to others.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagig@grimberg.me>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: remove struct bio_batch

It can be replaced with a combination of bio_chain and submit_bio_wait.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Sagi Grimberg <sagig@grimberg.me>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: re-add discard_granularity and alignment checks

In commit b49a087("block: remove split code in
blkdev_issue_{discard,write_same}"), discard_granularity and alignment
checks were removed. Ideally, with bio late splitting, the upper layers
shouldn't need to depend on device's limits.

Christoph reported a discard regression on the HGST Ultrastar SN100 NVMe
device when mkfs.xfs. We have not found the root cause yet.

This patch re-adds discard_granularity and alignment checks by reverting
the related changes in commit b49a087. The good thing is now we can
remove the 2G discard size cap and just use UINT_MAX to avoid bi_size
overflow.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: remove split code in blkdev_issue_{discard,write_same}

The split code in blkdev_issue_{discard,write_same} can go away
now that any driver that cares does the split. We have to make
sure bio size doesn't overflow.

For discard, we set max discard sectors to (1<<31)>>9 to ensure
it doesn't overflow bi_size and hopefully it is of the proper
granularity as long as the granularity is a power of two.

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add a bi_error field to struct bio

Currently we have two different ways to signal an I/O error on a BIO:

(1) by clearing the BIO_UPTODATE flag
(2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario. Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: Quiesce zeroout wrapper

blkdev_issue_zeroout() printed a warning if a device failed a discard or
write same request despite advertising support for these. That's fine
for SCSI since we'll disable these commands if we get an error back from
the disk saying that they are not supported. And consequently the
warning only gets printed once.

There are other types of block devices that support discard, however,
and these may return -EOPNOTSUPP for each command but leave discard
enabled in the queue limits. This will cause a warning message for every
blkdev_issue_zeroout() invocation.

Remove the offending warning messages.

Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: Add discard flag to blkdev_issue_zeroout() function

blkdev_issue_discard() will zero a given block range. This is done by
way of explicit writing, thus provisioning or allocating the blocks on
disk.

There are use cases where the desired behavior is to zero the blocks but
unprovision them if possible. The blocks must deterministically contain
zeroes when they are subsequently read back.

This patch adds a flag to blkdev_issue_zeroout() that provides this
variant. If the discard flag is set and a block device guarantees
discard_zeroes_data we will use REQ_DISCARD to clear the block range. If
the device does not support discard_zeroes_data or if the discard
request fails we will fall back to first REQ_WRITE_SAME and then a
regular REQ_WRITE.

Also update the callers of blkdev_issue_zero() to reflect the new flag
and make sb_issue_zeroout() prefer the discard approach.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-lib.c: make __blkdev_issue_zeroout static

__blkdev_issue_zeroout is only used in blk-lib.c

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>

block: add cond_resched() to potentially long running ioctl discard loop

When mkfs issues a full device discard and the device only
supports discards of a smallish size, we can loop in
blkdev_issue_discard() for a long time. If preempt isn't enabled,
this can turn into a softlock situation and the kernel will
start complaining.

Add an explicit cond_resched() at the end of the loop to avoid
that.

Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

block: Abstract out bvec iterator

Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Benny Halevy <bhalevy@tonian.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchand@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Peng Tao <tao.peng@emc.com>
Cc: Andy Adamson <andros@netapp.com>
Cc: fanchaoting <fanchaoting@cn.fujitsu.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Pankaj Kumar <pankaj.km@samsung.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Mel Gorman <mgorman@suse.de>6

block: Do not call sector_div() with a 64-bit divisor

do_div() (called by sector_div() if CONFIG_LBDAF=y) is meant for divisions
of 64-bit number by 32-bit numbers. Passing 64-bit divisor types caused
issues in the past on 32-bit platforms, cfr. commit
ea077b1b96e073eac5c3c5590529e964767fc5f7 ("m68k: Truncate base in
do_div()").

As queue_limits.max_discard_sectors and .discard_granularity are unsigned
int, max_discard_sectors and granularity should be unsigned int.
As bdev_discard_alignment() returns int, alignment should be int.
Now 2 calls to sector_div() can be replaced by 32-bit arithmetic:
- The 64-bit modulo operation can become a 32-bit modulo operation,
- The 64-bit division and multiplication can be replaced by a 32-bit
modulo operation and a subtraction.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: account iowait time when waiting for completion of IO request

Using wait_for_completion() for waiting for a IO request to be executed
results in wrong iowait time accounting. For example, a system having
the only task doing write() and fdatasync() on a block device can be
reported being idle instead of iowaiting as it should because
blkdev_issue_flush() calls wait_for_completion() which in turn calls
schedule() that does not increment the iowait proc counter and thus does
not turn on iowait time accounting.

The patch makes block layer use wait_for_completion_io() instead of
wait_for_completion() where appropriate to account iowait time
correctly.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: add plug for blkdev_issue_discard

Last post of this patch appears lost, so I resend this.

Now discard merge works, add plug for blkdev_issue_discard. This will help
discard request merge especially for raid0 case. In raid0, a big discard
request is split to small requests, and if correct plug is added, such small
requests can be merged in low layer.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: discard granularity might not be power of 2

In MD raid case, discard granularity might not be power of 2, for example, a
4-disk raid5 has 3*chunk_size discard granularity. Correct the calculation for
such cases.

Reported-by: Neil Brown <neilb@suse.de>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Make blkdev_issue_zeroout use WRITE SAME

If the device supports WRITE SAME, use that to optimize zeroing of
blocks. If the device does not support WRITE SAME or if the operation
fails, fall back to writing zeroes the old-fashioned way.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Implement support for WRITE SAME

The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.

This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: split discard into aligned requests

When a disk has large discard_granularity and small max_discard_sectors,
discards are not split with optimal alignment. In the limit case of
discard_granularity == max_discard_sectors, no request could be aligned
correctly, so in fact you might end up with no discarded logical blocks
at all.

Another example that helps showing the condition in the patch is with
discard_granularity == 64, max_discard_sectors == 128. A request that is
submitted for 256 sectors 2..257 will be split in two: 2..129, 130..257.
However, only 2 aligned blocks out of 3 are included in the request;
128..191 may be left intact and not discarded. With this patch, the
first request will be truncated to ensure good alignment of what's left,
and the split will be 2..127, 128..255, 256..257. The patch will also
take into account the discard_alignment.

At most one extra request will be introduced, because the first request
will be reduced by at most granularity-1 sectors, and granularity
must be less than max_discard_sectors. Subsequent requests will run
on round_down(max_discard_sectors, granularity) sectors, as in the
current code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: reorganize rounding of max_discard_sectors

Mostly a preparation for the next patch.

In principle this fixes an infinite loop if max_discard_sectors < granularity,
but that really shouldn't happen.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: fix patch import error in max_discard_sectors check

A '!' snuck in before the unlikely, rendering it useless.

Reported-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: eliminate potential for infinite loop in blkdev_issue_discard

Due to the recently identified overflow in read_capacity_16() it was
possible for max_discard_sectors to be zero but still have discards
enabled on the associated device's queue.

Eliminate the possibility for blkdev_issue_discard to infinitely loop.

Interestingly this issue wasn't identified until a device, whose
discard_granularity was 0 due to read_capacity_16 overflow, was consumed
by blk_stack_limits() to construct limits for a higher-level DM
multipath device. The multipath device's resulting limits never had the
discard limits stacked because blk_stack_limits() will only do so if
the bottom device's discard_granularity != 0. This resulted in the
multipath device's limits.max_discard_sectors being 0.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

blkdev: Do not return -EOPNOTSUPP if discard is supported

Currently we return -EOPNOTSUPP in blkdev_issue_discard() if any of the
bio fails due to underlying device not supporting discard request.
However, if the device is for example dm device composed of devices
which some of them support discard and some of them does not, it is ok
for some bios to fail with EOPNOTSUPP, but it does not mean that discard
is not supported at all.

This commit removes the check for bios failed with EOPNOTSUPP and change
blkdev_issue_discard() to return operation not supported if and only if
the device does not actually supports it, not just part of the device as
some bios might indicate.

This change also fixes problem with BLKDISCARD ioctl() which now works
correctly on such dm devices.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
CC: Jens Axboe <jaxboe@fusionio.com>
CC: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

blkdev: Simple cleanup in blkdev_issue_zeroout()

In blkdev_issue_zeroout() we are submitting regular WRITE bios, so we do
not need to check for -EOPNOTSUPP specifically in case of error. Also
there is no need to have label submit: because there is no way to jump
out from the while cycle without an error and we really want to exit,
rather than try again. And also remove the check for (sz == 0) since at
that point sz can never be zero.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
CC: Dmitry Monakhov <dmonakhov@openvz.org>
CC: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

blkdev: Submit discard bio in batches in blkdev_issue_discard()

Currently we are waiting for every submitted REQ_DISCARD bio separately,
but it can have unwanted consequences of repeatedly flushing the queue,
so we rather submit bios in batches and wait for the entire batch, hence
narrowing the window of other ios going in.

Use bio_batch_end_io() and struct bio_batch for that purpose, the same
is used by blkdev_issue_zeroout(). Also change bio_batch_end_io() so we
always set !BIO_UPTODATE in the case of error and remove the check for
bb, since we are the only user of this function and we always set this.

Remove bio_get()/bio_put() from the blkdev_issue_discard() since
bio_alloc() and bio_batch_end_io() is doing the same thing, hence it is
not needed anymore.

I have done simple dd testing with surprising results. The script I have
used is:

for i in $(seq 10); do
echo $i
dd if=/dev/sdb1 of=/dev/sdc1 bs=4k &
sleep 5
done
/usr/bin/time -f %e ./blkdiscard /dev/sdc1

Running time of BLKDISCARD on the whole device:
with patch without patch
0.95 15.58

So we can see that in this artificial test the kernel with the patch
applied is approx 16x faster in discarding the device.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
CC: Dmitry Monakhov <dmonakhov@openvz.org>
CC: Jens Axboe <jaxboe@fusionio.com>
CC: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: remove obsolete comments for blkdev_issue_zeroout.

barrier is already removed, so remove the obsolete comments
in blkdev_issue_zeroout.

Cc: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: fix mis-synchronisation in blkdev_issue_zeroout()

BZ29402
https://bugzilla.kernel.org/show_bug.cgi?id=29402

We can hit serious mis-synchronization in bio completion path of
blkdev_issue_zeroout() leading to a panic.

The problem is that when we are going to wait_for_completion() in
blkdev_issue_zeroout() we check if the bb.done equals issued (number of
submitted bios). If it does, we can skip the wait_for_completition()
and just out of the function since there is nothing to wait for.
However, there is a ordering problem because bio_batch_end_io() is
calling atomic_inc(&bb->done) before complete(), hence it might seem to
blkdev_issue_zeroout() that all bios has been completed and exit. At
this point when bio_batch_end_io() is going to call complete(bb->wait),
bb and wait does not longer exist since it was allocated on stack in
blkdev_issue_zeroout() ==> panic!

(thread 1) (thread 2)
bio_batch_end_io() blkdev_issue_zeroout()
if(bb) { ...
if (bb->end_io) ...
bb->end_io(bio, err); ...
atomic_inc(&bb->done); ...
... while (issued != atomic_read(&bb.done))
... (let issued == bb.done)
... (do the rest of the function)
... return ret;
complete(bb->wait);
^^^^^^^^
panic

We can fix this easily by simplifying bio_batch and completion counting.

Also remove bio_end_io_t *end_io since it is not used.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reported-by: Eric Whitney <eric.whitney@hp.com>
Tested-by: Eric Whitney <eric.whitney@hp.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
CC: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: fix kernel-doc format for blkdev_issue_zeroout

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: remove BLKDEV_IFL_WAIT

All the blkdev_issue_* helpers can only sanely be used for synchronous
caller. To issue cache flushes or barriers asynchronously the caller needs
to set up a bio by itself with a completion callback to move the asynchronous
state machine ahead. So drop the BLKDEV_IFL_WAIT flag that is always
specified when calling blkdev_issue_* and also remove the now unused flags
argument to blkdev_issue_flush and blkdev_issue_zeroout. For
blkdev_issue_discard we need to keep it for the secure discard flag, which
gains a more descriptive name and loses the bitops vs flag confusion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: remove the BLKDEV_IFL_BARRIER flag

Remove support for barriers on discards, which is unused now. Also
remove the DISCARD_NOBARRIER I/O type in favour of just setting the
rw flags up locally in blkdev_issue_discard.

tj: Also remove DISCARD_SECURE and use REQ_SECURE directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: add secure discard

Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

blkdev: fix blkdev_issue_zeroout return value

- If function called without barrier option retvalue is incorrect

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: fix problem with sending down discard that isn't of correct granularity

If the queue doesn't have a limit set, or it just set UINT_MAX like
we default to, we coud be sending down a discard request that isn't
of the correct granularity if the block size is > 512b.

Fix this by adjusting max_discard_sectors down to the proper
alignment.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: don't allocate a payload for discard request

Allocating a fixed payload for discard requests always was a horrible hack,
and it's not coming to byte us when adding support for discard in DM/MD.

So change the code to leave the allocation of a payload to the lowlevel
driver. Unfortunately that means we'll need another hack, which allows
us to update the various block layer length fields indicating that we
have a payload. Instead of hiding this in sd.c, which we already partially
do for UNMAP support add a documented helper in the core block layer for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

block: fix bad use of min() on different types

Just cast the page size to sector_t, that will always fit.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

blkdev: add blkdev_issue_zeroout helper function

- Add bio_batch helper primitive. This is rather generic primitive
for submitting/waiting a complex request which consists of several
bios.
- blkdev_issue_zeroout() generate number of zero filed write bios.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

blkdev: move blkdev_issue helper functions to separate file

Move blkdev_issue_discard from blk-barrier.c because it is
not barrier related.
Later the file will be populated by other helpers.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>