linux/block/blk-lib.c
Coly Li b35fd7422c 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: 9b15d109a6 ("block: improve discard bio alignment in __blkdev_issue_discard()")
Fixes: c52abf5630 ("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>
2020-08-05 17:15:47 -06:00

442 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Functions related to generic helpers functions
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/scatterlist.h>
#include "blk.h"
struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
{
struct bio *new = bio_alloc(gfp, nr_pages);
if (bio) {
bio_chain(bio, new);
submit_bio(bio);
}
return new;
}
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, int flags,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
struct bio *bio = *biop;
unsigned int op;
sector_t bs_mask, part_offset = 0;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secure_erase(q))
return -EOPNOTSUPP;
op = REQ_OP_SECURE_ERASE;
} else {
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
op = REQ_OP_DISCARD;
}
/* In case the discard granularity isn't set by buggy device driver */
if (WARN_ON_ONCE(!q->limits.discard_granularity)) {
char dev_name[BDEVNAME_SIZE];
bdevname(bdev, dev_name);
pr_err_ratelimited("%s: Error: discard_granularity is 0.\n", dev_name);
return -EOPNOTSUPP;
}
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
if (!nr_sects)
return -EINVAL;
/* In case the discard request is in a partition */
if (bdev->bd_partno)
part_offset = bdev->bd_part->start_sect;
while (nr_sects) {
sector_t granularity_aligned_lba, req_sects;
sector_t sector_mapped = sector + part_offset;
granularity_aligned_lba = round_up(sector_mapped,
q->limits.discard_granularity >> SECTOR_SHIFT);
/*
* Check whether the discard bio starts at a discard_granularity
* aligned LBA,
* - If no: set (granularity_aligned_lba - sector_mapped) to
* bi_size of the first split bio, then the second bio will
* start at a discard_granularity aligned LBA on the device.
* - If yes: use bio_aligned_discard_max_sectors() as the max
* possible bi_size of the first split bio. Then when this bio
* is split in device drive, the split ones are very probably
* to be aligned to discard_granularity of the device's queue.
*/
if (granularity_aligned_lba == sector_mapped)
req_sects = min_t(sector_t, nr_sects,
bio_aligned_discard_max_sectors(q));
else
req_sects = min_t(sector_t, nr_sects,
granularity_aligned_lba - sector_mapped);
WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
bio = blk_next_bio(bio, 0, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio_set_op_attrs(bio, op, 0);
bio->bi_iter.bi_size = req_sects << 9;
sector += req_sects;
nr_sects -= req_sects;
/*
* We can loop for a long time in here, if someone does
* full device discards (like mkfs). Be nice and allow
* us to schedule out to avoid softlocking if preempt
* is disabled.
*/
cond_resched();
}
*biop = bio;
return 0;
}
EXPORT_SYMBOL(__blkdev_issue_discard);
/**
* blkdev_issue_discard - queue a discard
* @bdev: blockdev to issue discard for
* @sector: start sector
* @nr_sects: number of sectors to discard
* @gfp_mask: memory allocation flags (for bio_alloc)
* @flags: BLKDEV_DISCARD_* flags to control behaviour
*
* Description:
* Issue a discard request for the sectors in question.
*/
int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
&bio);
if (!ret && bio) {
ret = submit_bio_wait(bio);
if (ret == -EOPNOTSUPP)
ret = 0;
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);
/**
* __blkdev_issue_write_same - generate number of bios with same page
* @bdev: target blockdev
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @page: page containing data to write
* @biop: pointer to anchor bio
*
* Description:
* Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
*/
static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct page *page,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
unsigned int max_write_same_sectors;
struct bio *bio = *biop;
sector_t bs_mask;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
if (!bdev_write_same(bdev))
return -EOPNOTSUPP;
/* Ensure that max_write_same_sectors doesn't overflow bi_size */
max_write_same_sectors = bio_allowed_max_sectors(q);
while (nr_sects) {
bio = blk_next_bio(bio, 1, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio->bi_vcnt = 1;
bio->bi_io_vec->bv_page = page;
bio->bi_io_vec->bv_offset = 0;
bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
if (nr_sects > max_write_same_sectors) {
bio->bi_iter.bi_size = max_write_same_sectors << 9;
nr_sects -= max_write_same_sectors;
sector += max_write_same_sectors;
} else {
bio->bi_iter.bi_size = nr_sects << 9;
nr_sects = 0;
}
cond_resched();
}
*biop = bio;
return 0;
}
/**
* blkdev_issue_write_same - queue a write same operation
* @bdev: target blockdev
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @page: page containing data
*
* Description:
* Issue a write same request for the sectors in question.
*/
int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask,
struct page *page)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
&bio);
if (ret == 0 && bio) {
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(blkdev_issue_write_same);
static int __blkdev_issue_write_zeroes(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop, unsigned flags)
{
struct bio *bio = *biop;
unsigned int max_write_zeroes_sectors;
struct request_queue *q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
/* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
if (max_write_zeroes_sectors == 0)
return -EOPNOTSUPP;
while (nr_sects) {
bio = blk_next_bio(bio, 0, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio->bi_opf = REQ_OP_WRITE_ZEROES;
if (flags & BLKDEV_ZERO_NOUNMAP)
bio->bi_opf |= REQ_NOUNMAP;
if (nr_sects > max_write_zeroes_sectors) {
bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
nr_sects -= max_write_zeroes_sectors;
sector += max_write_zeroes_sectors;
} else {
bio->bi_iter.bi_size = nr_sects << 9;
nr_sects = 0;
}
cond_resched();
}
*biop = bio;
return 0;
}
/*
* Convert a number of 512B sectors to a number of pages.
* The result is limited to a number of pages that can fit into a BIO.
* Also make sure that the result is always at least 1 (page) for the cases
* where nr_sects is lower than the number of sectors in a page.
*/
static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
{
sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
return min(pages, (sector_t)BIO_MAX_PAGES);
}
static int __blkdev_issue_zero_pages(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
struct bio *bio = *biop;
int bi_size = 0;
unsigned int sz;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
while (nr_sects != 0) {
bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
while (nr_sects != 0) {
sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
nr_sects -= bi_size >> 9;
sector += bi_size >> 9;
if (bi_size < sz)
break;
}
cond_resched();
}
*biop = bio;
return 0;
}
/**
* __blkdev_issue_zeroout - generate number of zero filed write bios
* @bdev: blockdev to issue
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @biop: pointer to anchor bio
* @flags: controls detailed behavior
*
* Description:
* Zero-fill a block range, either using hardware offload or by explicitly
* writing zeroes to the device.
*
* If a device is using logical block provisioning, the underlying space will
* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
*
* If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
* -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
*/
int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
unsigned flags)
{
int ret;
sector_t bs_mask;
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
biop, flags);
if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
return ret;
return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
biop);
}
EXPORT_SYMBOL(__blkdev_issue_zeroout);
/**
* blkdev_issue_zeroout - zero-fill a block range
* @bdev: blockdev to write
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @flags: controls detailed behavior
*
* Description:
* Zero-fill a block range, either using hardware offload or by explicitly
* writing zeroes to the device. See __blkdev_issue_zeroout() for the
* valid values for %flags.
*/
int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
{
int ret = 0;
sector_t bs_mask;
struct bio *bio;
struct blk_plug plug;
bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
retry:
bio = NULL;
blk_start_plug(&plug);
if (try_write_zeroes) {
ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
gfp_mask, &bio, flags);
} else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
gfp_mask, &bio);
} else {
/* No zeroing offload support */
ret = -EOPNOTSUPP;
}
if (ret == 0 && bio) {
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
if (ret && try_write_zeroes) {
if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
try_write_zeroes = false;
goto retry;
}
if (!bdev_write_zeroes_sectors(bdev)) {
/*
* Zeroing offload support was indicated, but the
* device reported ILLEGAL REQUEST (for some devices
* there is no non-destructive way to verify whether
* WRITE ZEROES is actually supported).
*/
ret = -EOPNOTSUPP;
}
}
return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);