2015-02-03-16-38 merged
Andrew Morton (1):
zram-rework-reset-and-destroy-path-fix
Daeseok Youn (1):
mincore: remove unneeded variable 'err'
Joonsoo Kim (2):
mm/compaction: fix wrong order check in compact_finished()
mm/compaction: stop the isolation when we isolate enough freepage
Kirill A. Shutemov (1):
mm: do not use mm->nr_pmds on !MMU configurations
Mel Gorman (1):
mm: remove remaining references to NUMA hinting bits and helpers -fix
Michal Hocko (3):
Reverted "mm/hugetlb: cleanup and rename is_hugetlb_entry_(migration|hwpoisoned)()"
Reverted "mm/hugetlb: fix suboptimal migration/hwpoisoned entry check"
memcg, shmem: fix shmem migration to use lrucare
Minchan Kim (1):
zram: check bd_openers instead of bd_holders
Roman Gushchin (1):
mm/nommu.c: fix arithmetic overflow in __vm_enough_memory()
Sergey Senozhatsky (2):
zram: fix umount-reset_store-mount race condition
zram: rework reset and destroy path
Sudip Mukherjee (1):
MAINTAINERS: remove SUPERH website
Vladimir Davydov (1):
memcg: cleanup static keys decrement
Vlastimil Babka (1):
mm/mempolicy.c: merge alloc_hugepage_vma to alloc_pages_vma
zram: check bd_openers instead of bd_holders
bd_holders is increased only when user open the device file as FMODE_EXCL
so if something opens zram0 as !FMODE_EXCL and request I/O while another
user reset zram0, we can see following warning.
[ 30.683449] zram0: detected capacity change from 0 to 64424509440
[ 33.736869] Buffer I/O error on dev zram0, logical block 180823, lost async page write
[ 33.738814] Buffer I/O error on dev zram0, logical block 180824, lost async page write
[ 33.740654] Buffer I/O error on dev zram0, logical block 180825, lost async page write
[ 33.742551] Buffer I/O error on dev zram0, logical block 180826, lost async page write
[ 33.744153] Buffer I/O error on dev zram0, logical block 180827, lost async page write
[ 33.745807] Buffer I/O error on dev zram0, logical block 180828, lost async page write
[ 33.747419] Buffer I/O error on dev zram0, logical block 180829, lost async page write
[ 33.749060] Buffer I/O error on dev zram0, logical block 180830, lost async page write
[ 33.750687] Buffer I/O error on dev zram0, logical block 180831, lost async page write
[ 33.752286] Buffer I/O error on dev zram0, logical block 180832, lost async page write
[ 33.811590] ------------[ cut here ]------------
[ 33.812038] WARNING: CPU: 11 PID: 1996 at fs/block_dev.c:57 __blkdev_put+0x1d7/0x210()
[ 33.812817] Modules linked in:
[ 33.813142] CPU: 11 PID: 1996 Comm: dd Not tainted 3.19.0-rc6-next-20150202+ #1125
[ 33.813837] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
[ 33.814525] ffffffff81801a2d ffff880061e77db8 ffffffff815b848e 0000000000000001
[ 33.815196] 0000000000000000 ffff880061e77df8 ffffffff8104de2a 0000000000000000
[ 33.815867] ffff88005da287f0 ffff88005da28680 ffff88005da28770 ffff88005da28698
[ 33.816536] Call Trace:
[ 33.816817] [<ffffffff815b848e>] dump_stack+0x45/0x57
[ 33.817304] [<ffffffff8104de2a>] warn_slowpath_common+0x8a/0xc0
[ 33.817829] [<ffffffff8104df1a>] warn_slowpath_null+0x1a/0x20
[ 33.818331] [<ffffffff811b60b7>] __blkdev_put+0x1d7/0x210
[ 33.818797] [<ffffffff811b69c0>] blkdev_put+0x50/0x130
[ 33.819244] [<ffffffff811b6b55>] blkdev_close+0x25/0x30
[ 33.819723] [<ffffffff8118079f>] __fput+0xdf/0x1e0
[ 33.820140] [<ffffffff811808ee>] ____fput+0xe/0x10
[ 33.820576] [<ffffffff81068e07>] task_work_run+0xa7/0xe0
[ 33.821151] [<ffffffff81002b89>] do_notify_resume+0x49/0x60
[ 33.821721] [<ffffffff815bf09d>] int_signal+0x12/0x17
[ 33.822228] ---[ end trace 274fbbc5664827d2 ]---
The warning comes from bdev_write_node in blkdev_put path.
tatic void bdev_write_inode(struct inode *inode)
{
spin_lock(&inode->i_lock);
while (inode->i_state & I_DIRTY) {
spin_unlock(&inode->i_lock);
WARN_ON_ONCE(write_inode_now(inode, true)); <========= here.
spin_lock(&inode->i_lock);
}
spin_unlock(&inode->i_lock);
}
The reason is dd process encounters I/O fails due to sudden block device
disappear so in filemap_check_errors in __writeback_single_inode returns
-EIO.
If we check bd_openers instead of bd_holders, we could address the
problem. When I see the brd, it already have used it rather than
bd_holders so although I'm not a expert of block layer, it seems to be
better.
I can make following warning with below simple script. In addition, I
added msleep(2000) below set_capacity(zram->disk, 0) after applying your
patch to make window huge(Kudos to Ganesh!)
script:
echo $((60<<30)) > /sys/block/zram0/disksize
setsid dd if=/dev/zero of=/dev/zram0 &
sleep 1
setsid echo 1 > /sys/block/zram0/reset
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Ganesh Mahendran <opensource.ganesh@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1 file changed