iomap: Revert "fs/iomap.c: get/put the page in iomap_page_create/release()"
This commit is contained in:
Salvatore Bonaccorso
parent
be9c4f49fd
commit
6886800dea
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@ -207,6 +207,10 @@ linux (4.19.12-1) UNRELEASED; urgency=medium
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[ Bastian Blank ]
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* Ignore various ABI changes.
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[ Salvatore Bonaccorso ]
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* iomap: Revert "fs/iomap.c: get/put the page in
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iomap_page_create/release()"
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-- Uwe Kleine-König <ukleinek@debian.org> Mon, 17 Dec 2018 11:27:32 +0100
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linux (4.19.9-1) unstable; urgency=medium
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111
debian/patches/bugfix/all/iomap-Revert-fs-iomap.c-get-put-the-page-in-iomap_pa.patch
vendored
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111
debian/patches/bugfix/all/iomap-Revert-fs-iomap.c-get-put-the-page-in-iomap_pa.patch
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@ -0,0 +1,111 @@
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From: Dave Chinner <dchinner@redhat.com>
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Date: Thu, 20 Dec 2018 23:23:24 +1100
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Subject: iomap: Revert "fs/iomap.c: get/put the page in
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iomap_page_create/release()"
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Origin: https://git.kernel.org/linus/a837eca2412051628c0529768c9bc4f3580b040e
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This reverts commit 61c6de667263184125d5ca75e894fcad632b0dd3.
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The reverted commit added page reference counting to iomap page
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structures that are used to track block size < page size state. This
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was supposed to align the code with page migration page accounting
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assumptions, but what it has done instead is break XFS filesystems.
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Every fstests run I've done on sub-page block size XFS filesystems
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has since picking up this commit 2 days ago has failed with bad page
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state errors such as:
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# ./run_check.sh "-m rmapbt=1,reflink=1 -i sparse=1 -b size=1k" "generic/038"
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....
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SECTION -- xfs
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FSTYP -- xfs (debug)
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PLATFORM -- Linux/x86_64 test1 4.20.0-rc6-dgc+
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MKFS_OPTIONS -- -f -m rmapbt=1,reflink=1 -i sparse=1 -b size=1k /dev/sdc
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MOUNT_OPTIONS -- /dev/sdc /mnt/scratch
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generic/038 454s ...
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run fstests generic/038 at 2018-12-20 18:43:05
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XFS (sdc): Unmounting Filesystem
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XFS (sdc): Mounting V5 Filesystem
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XFS (sdc): Ending clean mount
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BUG: Bad page state in process kswapd0 pfn:3a7fa
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page:ffffea0000ccbeb0 count:0 mapcount:0 mapping:ffff88800d9b6360 index:0x1
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flags: 0xfffffc0000000()
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raw: 000fffffc0000000 dead000000000100 dead000000000200 ffff88800d9b6360
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raw: 0000000000000001 0000000000000000 00000000ffffffff
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page dumped because: non-NULL mapping
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CPU: 0 PID: 676 Comm: kswapd0 Not tainted 4.20.0-rc6-dgc+ #915
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Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014
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Call Trace:
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dump_stack+0x67/0x90
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bad_page.cold.116+0x8a/0xbd
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free_pcppages_bulk+0x4bf/0x6a0
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free_unref_page_list+0x10f/0x1f0
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shrink_page_list+0x49d/0xf50
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shrink_inactive_list+0x19d/0x3b0
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shrink_node_memcg.constprop.77+0x398/0x690
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? shrink_slab.constprop.81+0x278/0x3f0
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shrink_node+0x7a/0x2f0
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kswapd+0x34b/0x6d0
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? node_reclaim+0x240/0x240
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kthread+0x11f/0x140
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? __kthread_bind_mask+0x60/0x60
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ret_from_fork+0x24/0x30
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Disabling lock debugging due to kernel taint
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....
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The failures are from anyway that frees pages and empties the
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per-cpu page magazines, so it's not a predictable failure or an easy
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to debug failure.
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generic/038 is a reliable reproducer of this problem - it has a 9 in
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10 failure rate on one of my test machines. Failure on other
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machines have been at random points in fstests runs but every run
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has ended up tripping this problem. Hence generic/038 was used to
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bisect the failure because it was the most reliable failure.
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It is too close to the 4.20 release (not to mention holidays) to
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try to diagnose, fix and test the underlying cause of the problem,
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so reverting the commit is the only option we have right now. The
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revert has been tested against a current tot 4.20-rc7+ kernel across
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multiple machines running sub-page block size XFs filesystems and
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none of the bad page state failures have been seen.
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Signed-off-by: Dave Chinner <dchinner@redhat.com>
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Cc: Piotr Jaroszynski <pjaroszynski@nvidia.com>
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Cc: Christoph Hellwig <hch@lst.de>
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Cc: William Kucharski <william.kucharski@oracle.com>
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Cc: Darrick J. Wong <darrick.wong@oracle.com>
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Cc: Brian Foster <bfoster@redhat.com>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/iomap.c | 7 -------
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1 file changed, 7 deletions(-)
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diff --git a/fs/iomap.c b/fs/iomap.c
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index 5bc172f3dfe8..d6bc98ae8d35 100644
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--- a/fs/iomap.c
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+++ b/fs/iomap.c
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@@ -116,12 +116,6 @@ iomap_page_create(struct inode *inode, struct page *page)
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atomic_set(&iop->read_count, 0);
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atomic_set(&iop->write_count, 0);
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bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
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-
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- /*
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- * migrate_page_move_mapping() assumes that pages with private data have
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- * their count elevated by 1.
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- */
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- get_page(page);
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set_page_private(page, (unsigned long)iop);
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SetPagePrivate(page);
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return iop;
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@@ -138,7 +132,6 @@ iomap_page_release(struct page *page)
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WARN_ON_ONCE(atomic_read(&iop->write_count));
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ClearPagePrivate(page);
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set_page_private(page, 0);
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- put_page(page);
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kfree(iop);
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}
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--
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2.20.1
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@ -98,6 +98,7 @@ bugfix/all/fs-add-module_softdep-declarations-for-hard-coded-cr.patch
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bugfix/all/partially-revert-usb-kconfig-using-select-for-usb_co.patch
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bugfix/all/kbuild-include-addtree-remove-quotes-before-matching-path.patch
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debian/revert-objtool-fix-config_stack_validation-y-warning.patch
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bugfix/all/iomap-Revert-fs-iomap.c-get-put-the-page-in-iomap_pa.patch
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# Miscellaneous features
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