The quilt patch titled
Subject: fsdax: force clear dirty mark if CoW
has been removed from the -mm tree. Its filename was
fsdax-force-clear-dirty-mark-if-cow.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Subject: fsdax: force clear dirty mark if CoW
Date: Fri, 24 Mar 2023 10:28:00 +0000
XFS allows CoW on non-shared extents to combat fragmentation[1]. The old
non-shared extent could be mwrited before, its dax entry is marked dirty.
This results in a WARNing:
[ 28.512349] ------------[ cut here ]------------
[ 28.512622] WARNING: CPU: 2 PID: 5255 at fs/dax.c:390 dax_insert_entry+0x342/0x390
[ 28.513050] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 nfs lockd grace fscache netfs nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables
[ 28.515462] CPU: 2 PID: 5255 Comm: fsstress Kdump: loaded Not tainted 6.3.0-rc1-00001-g85e1481e19c1-dirty #117
[ 28.515902] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Arch Linux 1.16.1-1-1 04/01/2014
[ 28.516307] RIP: 0010:dax_insert_entry+0x342/0x390
[ 28.516536] Code: 30 5b 5d 41 5c 41 5d 41 5e 41 5f c3 cc cc cc cc 48 8b 45 20 48 83 c0 01 e9 e2 fe ff ff 48 8b 45 20 48 83 c0 01 e9 cd fe ff ff <0f> 0b e9 53 ff ff ff 48 8b 7c 24 08 31 f6 e8 1b 61 a1 00 eb 8c 48
[ 28.517417] RSP: 0000:ffffc9000845fb18 EFLAGS: 00010086
[ 28.517721] RAX: 0000000000000053 RBX: 0000000000000155 RCX: 000000000018824b
[ 28.518113] RDX: 0000000000000000 RSI: ffffffff827525a6 RDI: 00000000ffffffff
[ 28.518515] RBP: ffffea00062092c0 R08: 0000000000000000 R09: ffffc9000845f9c8
[ 28.518905] R10: 0000000000000003 R11: ffffffff82ddb7e8 R12: 0000000000000155
[ 28.519301] R13: 0000000000000000 R14: 000000000018824b R15: ffff88810cfa76b8
[ 28.519703] FS: 00007f14a0c94740(0000) GS:ffff88817bd00000(0000) knlGS:0000000000000000
[ 28.520148] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 28.520472] CR2: 00007f14a0c8d000 CR3: 000000010321c004 CR4: 0000000000770ee0
[ 28.520863] PKRU: 55555554
[ 28.521043] Call Trace:
[ 28.521219] <TASK>
[ 28.521368] dax_fault_iter+0x196/0x390
[ 28.521595] dax_iomap_pte_fault+0x19b/0x3d0
[ 28.521852] __xfs_filemap_fault+0x234/0x2b0
[ 28.522116] __do_fault+0x30/0x130
[ 28.522334] do_fault+0x193/0x340
[ 28.522586] __handle_mm_fault+0x2d3/0x690
[ 28.522975] handle_mm_fault+0xe6/0x2c0
[ 28.523259] do_user_addr_fault+0x1bc/0x6f0
[ 28.523521] exc_page_fault+0x60/0x140
[ 28.523763] asm_exc_page_fault+0x22/0x30
[ 28.524001] RIP: 0033:0x7f14a0b589ca
[ 28.524225] Code: c5 fe 7f 07 c5 fe 7f 47 20 c5 fe 7f 47 40 c5 fe 7f 47 60 c5 f8 77 c3 66 0f 1f 84 00 00 00 00 00 40 0f b6 c6 48 89 d1 48 89 fa <f3> aa 48 89 d0 c5 f8 77 c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90
[ 28.525198] RSP: 002b:00007fff1dea1c98 EFLAGS: 00010202
[ 28.525505] RAX: 000000000000001e RBX: 000000000014a000 RCX: 0000000000006046
[ 28.525895] RDX: 00007f14a0c82000 RSI: 000000000000001e RDI: 00007f14a0c8d000
[ 28.526290] RBP: 000000000000006f R08: 0000000000000004 R09: 000000000014a000
[ 28.526681] R10: 0000000000000008 R11: 0000000000000246 R12: 028f5c28f5c28f5c
[ 28.527067] R13: 8f5c28f5c28f5c29 R14: 0000000000011046 R15: 00007f14a0c946c0
[ 28.527449] </TASK>
[ 28.527600] ---[ end trace 0000000000000000 ]---
To be able to delete this entry, clear its dirty mark before
invalidate_inode_pages2_range().
[1] https://lore.kernel.org/linux-xfs/20230321151339.GA11376@frogsfrogsfrogs/
Link: https://lkml.kernel.org/r/1679653680-2-1-git-send-email-ruansy.fnst@xxxxxxxxxxx
Fixes: f80e1668888f3 ("fsdax: invalidate pages when CoW")
Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
--- a/fs/dax.c~fsdax-force-clear-dirty-mark-if-cow
+++ a/fs/dax.c
@@ -781,6 +781,33 @@ out:
return ret;
}
+static int __dax_clear_dirty_range(struct address_space *mapping,
+ pgoff_t start, pgoff_t end)
+{
+ XA_STATE(xas, &mapping->i_pages, start);
+ unsigned int scanned = 0;
+ void *entry;
+
+ xas_lock_irq(&xas);
+ xas_for_each(&xas, entry, end) {
+ entry = get_unlocked_entry(&xas, 0);
+ xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY);
+ xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE);
+ put_unlocked_entry(&xas, entry, WAKE_NEXT);
+
+ if (++scanned % XA_CHECK_SCHED)
+ continue;
+
+ xas_pause(&xas);
+ xas_unlock_irq(&xas);
+ cond_resched();
+ xas_lock_irq(&xas);
+ }
+ xas_unlock_irq(&xas);
+
+ return 0;
+}
+
/*
* Delete DAX entry at @index from @mapping. Wait for it
* to be unlocked before deleting it.
@@ -1440,6 +1467,16 @@ static loff_t dax_iomap_iter(const struc
* written by write(2) is visible in mmap.
*/
if (iomap->flags & IOMAP_F_NEW || cow) {
+ /*
+ * Filesystem allows CoW on non-shared extents. The src extents
+ * may have been mmapped with dirty mark before. To be able to
+ * invalidate its dax entries, we need to clear the dirty mark
+ * in advance.
+ */
+ if (cow)
+ __dax_clear_dirty_range(iomi->inode->i_mapping,
+ pos >> PAGE_SHIFT,
+ (end - 1) >> PAGE_SHIFT);
invalidate_inode_pages2_range(iomi->inode->i_mapping,
pos >> PAGE_SHIFT,
(end - 1) >> PAGE_SHIFT);
_
Patches currently in -mm which might be from ruansy.fnst@xxxxxxxxxxx are
