linux-stable.git/block/bio.c, branch v5.4.76

block/diskstats: more accurate approximation of io_ticks for slow disks

2020-10-07T06:01:29+00:00

commit 2b8bd423614c595540eaadcfbc702afe8e155e50 upstream.

Currently io_ticks is approximated by adding one at each start and end of
requests if jiffies counter has changed. This works perfectly for requests
shorter than a jiffy or if one of requests starts/ends at each jiffy.

If disk executes just one request at a time and they are longer than two
jiffies then only first and last jiffies will be accounted.

Fix is simple: at the end of request add up into io_ticks jiffies passed
since last update rather than just one jiffy.

Example: common HDD executes random read 4k requests around 12ms.

fio --name=test --filename=/dev/sdb --rw=randread --direct=1 --runtime=30 &
iostat -x 10 sdb

Note changes of iostat's "%util" 8,43% -> 99,99% before/after patch:

Before:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0,00     0,00   82,60    0,00   330,40     0,00     8,00     0,96   12,09   12,09    0,00   1,02   8,43

After:

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sdb               0,00     0,00   82,50    0,00   330,00     0,00     8,00     1,00   12,10   12,10    0,00  12,12  99,99

Now io_ticks does not loose time between start and end of requests, but
for queue-depth > 1 some I/O time between adjacent starts might be lost.

For load estimation "%util" is not as useful as average queue length,
but it clearly shows how often disk queue is completely empty.

Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Konstantin Khlebnikov 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe 
From: "Banerjee, Debabrata" 
Signed-off-by: Greg Kroah-Hartman

block: Set same_page to false in __bio_try_merge_page if ret is false

2020-09-17T11:47:44+00:00

[ Upstream commit 2cd896a5e86fc326bda8614b96c0401dcc145868 ]

If we hit the UINT_MAX limit of bio->bi_iter.bi_size and so we are anyway
not merging this page in this bio, then it make sense to make same_page
also as false before returning.

Without this patch, we hit below WARNING in iomap.
This mostly happens with very large memory system and / or after tweaking
vm dirty threshold params to delay writeback of dirty data.

WARNING: CPU: 18 PID: 5130 at fs/iomap/buffered-io.c:74 iomap_page_release+0x120/0x150
 CPU: 18 PID: 5130 Comm: fio Kdump: loaded Tainted: G        W         5.8.0-rc3 #6
 Call Trace:
  __remove_mapping+0x154/0x320 (unreliable)
  iomap_releasepage+0x80/0x180
  try_to_release_page+0x94/0xe0
  invalidate_inode_page+0xc8/0x110
  invalidate_mapping_pages+0x1dc/0x540
  generic_fadvise+0x3c8/0x450
  xfs_file_fadvise+0x2c/0xe0 [xfs]
  vfs_fadvise+0x3c/0x60
  ksys_fadvise64_64+0x68/0xe0
  sys_fadvise64+0x28/0x40
  system_call_exception+0xf8/0x1c0
  system_call_common+0xf0/0x278

Fixes: cc90bc68422 ("block: fix "check bi_size overflow before merge"")
Reported-by: Shivaprasad G Bhat 
Suggested-by: Christoph Hellwig 
Signed-off-by: Anju T Sudhakar 
Signed-off-by: Ritesh Harjani 
Reviewed-by: Ming Lei 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: Fix page_is_mergeable() for compound pages

2020-09-03T09:26:54+00:00

[ Upstream commit d81665198b83e55a28339d1f3e4890ed8a434556 ]

If we pass in an offset which is larger than PAGE_SIZE, then
page_is_mergeable() thinks it's not mergeable with the previous bio_vec,
leading to a large number of bio_vecs being used.  Use a slightly more
obvious test that the two pages are compatible with each other.

Fixes: 52d52d1c98a9 ("block: only allow contiguous page structs in a bio_vec")
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix memleak of bio integrity data

2020-01-26T09:01:09+00:00

[ Upstream commit ece841abbed2da71fa10710c687c9ce9efb6bf69 ]

7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") moves
bio_integrity_free from bio_uninit() to bio_integrity_verify_fn()
and bio_endio(). This way looks wrong because bio may be freed
without calling bio_endio(), for example, blk_rq_unprep_clone() is
called from dm_mq_queue_rq() when the underlying queue of dm-mpath
is busy.

So memory leak of bio integrity data is caused by commit 7c20f11680a4.

Fixes this issue by re-adding bio_integrity_free() to bio_uninit().

Fixes: 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io")
Reviewed-by: Christoph Hellwig 
Signed-off-by Justin Tee 

Add commit log, and simplify/fix the original patch wroten by Justin.

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

fs: move guard_bio_eod() after bio_set_op_attrs

2020-01-17T18:48:21+00:00

commit 83c9c547168e8b914ea6398430473a4de68c52cc upstream.

Commit 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod")
adds bio_truncate() for handling bio EOD. However, bio_truncate()
doesn't use the passed 'op' parameter from guard_bio_eod's callers.

So bio_trunacate() may retrieve wrong 'op', and zering pages may
not be done for READ bio.

Fixes this issue by moving guard_bio_eod() after bio_set_op_attrs()
in submit_bh_wbc() so that bio_truncate() can always retrieve correct
op info.

Meantime remove the 'op' parameter from guard_bio_eod() because it isn't
used any more.

Cc: Carlos Maiolino 
Cc: linux-fsdevel@vger.kernel.org
Fixes: 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod")
Signed-off-by: Ming Lei 
Signed-off-by: Greg Kroah-Hartman 

Fold in kerneldoc and bio_op() change.

Signed-off-by: Jens Axboe

block: add bio_truncate to fix guard_bio_eod

2020-01-09T09:19:54+00:00

[ Upstream commit 85a8ce62c2eabe28b9d76ca4eecf37922402df93 ]

Some filesystem, such as vfat, may send bio which crosses device boundary,
and the worse thing is that the IO request starting within device boundaries
can contain more than one segment past EOD.

Commit dce30ca9e3b6 ("fs: fix guard_bio_eod to check for real EOD errors")
tries to fix this issue by returning -EIO for this situation. However,
this way lets fs user code lose chance to handle -EIO, then sync_inodes_sb()
may hang for ever.

Also the current truncating on last segment is dangerous by updating the
last bvec, given bvec table becomes not immutable any more, and fs bio
users may not retrieve the truncated pages via bio_for_each_segment_all() in
its .end_io callback.

Fixes this issue by supporting multi-segment truncating. And the
approach is simpler:

- just update bio size since block layer can make correct bvec with
the updated bio size. Then bvec table becomes really immutable.

- zero all truncated segments for read bio

Cc: Carlos Maiolino 
Cc: linux-fsdevel@vger.kernel.org
Fixed-by: dce30ca9e3b6 ("fs: fix guard_bio_eod to check for real EOD errors")
Reported-by: syzbot+2b9e54155c8c25d8d165@syzkaller.appspotmail.com
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix "check bi_size overflow before merge"

2019-12-21T10:04:32+00:00

commit cc90bc68422318eb8e75b15cd74bc8d538a7df29 upstream.

This partially reverts commit e3a5d8e386c3fb973fa75f2403622a8f3640ec06.

Commit e3a5d8e386c3 ("check bi_size overflow before merge") adds a bio_full
check to __bio_try_merge_page.  This will cause __bio_try_merge_page to fail
when the last bi_io_vec has been reached.  Instead, what we want here is only
the bi_size overflow check.

Fixes: e3a5d8e386c3 ("block: check bi_size overflow before merge")
Cc: stable@vger.kernel.org # v5.4+
Reviewed-by: Ming Lei 
Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: check bi_size overflow before merge

2019-11-12T14:26:27+00:00

__bio_try_merge_page() may merge a page to bio without bio_full() check
and cause bi_size overflow.

The overflow typically ends up with sd_init_command() warning on zero
segment request with call trace like this:

    ------------[ cut here ]------------
    WARNING: CPU: 2 PID: 1986 at drivers/scsi/scsi_lib.c:1025 scsi_init_io+0x156/0x180
    CPU: 2 PID: 1986 Comm: kworker/2:1H Kdump: loaded Not tainted 5.4.0-rc7 #1
    Workqueue: kblockd blk_mq_run_work_fn
    RIP: 0010:scsi_init_io+0x156/0x180
    RSP: 0018:ffffa11487663bf0 EFLAGS: 00010246
    RAX: 00000000002be0a0 RBX: ffff8e6e9ff30118 RCX: 0000000000000000
    RDX: 00000000ffffffe1 RSI: 0000000000000000 RDI: ffff8e6e9ff30118
    RBP: ffffa11487663c18 R08: ffffa11487663d28 R09: ffff8e6e9ff30150
    R10: 0000000000000001 R11: 0000000000000000 R12: ffff8e6e9ff30000
    R13: 0000000000000001 R14: ffff8e74a1cf1800 R15: ffff8e6e9ff30000
    FS:  0000000000000000(0000) GS:ffff8e6ea7680000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fff18cf0fe8 CR3: 0000000659f0a001 CR4: 00000000001606e0
    Call Trace:
     sd_init_command+0x326/0xb40 [sd_mod]
     scsi_queue_rq+0x502/0xaa0
     ? blk_mq_get_driver_tag+0xe7/0x120
     blk_mq_dispatch_rq_list+0x256/0x5a0
     ? elv_rb_del+0x24/0x30
     ? deadline_remove_request+0x7b/0xc0
     blk_mq_do_dispatch_sched+0xa3/0x140
     blk_mq_sched_dispatch_requests+0xfb/0x170
     __blk_mq_run_hw_queue+0x81/0x130
     blk_mq_run_work_fn+0x1b/0x20
     process_one_work+0x179/0x390
     worker_thread+0x4f/0x3e0
     kthread+0x105/0x140
     ? max_active_store+0x80/0x80
     ? kthread_bind+0x20/0x20
     ret_from_fork+0x35/0x40
    ---[ end trace f9036abf5af4a4d3 ]---
    blk_update_request: I/O error, dev sdd, sector 2875552 op 0x1:(WRITE) flags 0x0 phys_seg 0 prio class 0
    XFS (sdd1): writeback error on sector 2875552

__bio_try_merge_page() should check the overflow before actually doing
merge.

Fixes: 07173c3ec276c ("block: enable multipage bvecs")
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Jun'ichi Nomura 
Signed-off-by: Jens Axboe

block: move same page handling from __bio_add_pc_page to the callers

2019-08-22T13:14:39+00:00

Hiding page refcount manipulation inside a low-level bio helper is
somewhat awkward.  Instead return the same page information to the
callers, where it fits in much better.

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

block: create a bio_try_merge_pc_page helper

2019-08-22T13:14:38+00:00

Passsthrough bio handling should be the same as normal bio handling,
except that we need to take hardware limitations into account.  Thus
use the common try_merge implementation after checking the hardware
limits.  This changes behavior in that we now also check segment
and dma boundary settings for same page merges, which is a little
more work but has no effect as those need to be larger than the
page size.

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