From: Wang Yugui <wangyugui@e16-tech.com>
To: Qu Wenruo <wqu@suse.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] Revert "btrfs: compression: don't try to compress if we don't have enough pages"
Date: Fri, 27 Aug 2021 11:41:54 +0800 [thread overview]
Message-ID: <20210827114153.19CB.409509F4@e16-tech.com> (raw)
In-Reply-To: <20210825054142.11579-1-wqu@suse.com>
Hi,
With this patch, kernel panic when xfstest btrfs/244
#btrfs version: 5.13.x (with some patches from 5.14), although shown as 5.10.61.
[ 131.802619] BUG: kernel NULL pointer dereference, address:
0000000000000000
[ 131.810837] #PF: supervisor read access in kernel mode
[ 131.817026] #PF: error_code(0x0000) - not-present page
[ 131.823240] PGD 0 P4D 0
[ 131.826521] Oops: 0000 [#1] SMP NOPTI
[ 131.831029] CPU: 37 PID: 4434 Comm: btrfs Not tainted 5.10.61-1.el7.x86_64 #1
[ 131.839478] Hardware name: Dell Inc. PowerEdge T620/02CD1V, BIOS 2.9.0 12/06/2019
[ 131.848315] RIP: 0010:btrfs_rm_device+0x248/0x4f0 [btrfs]
[ 131.854805] Code: 8b 45 30 48 89 df 48 83 40 48 01 e8 92 cb 14 ea e9 e2 fe ff ff b9 08 00 00 00 48 c7 c7 f7
9a a4 c0 4c 89 e6 41 bf 06 00 00 00 <f3> a6 0f 97 c0 1c 00 84 c0 0f 84 be fe ff ff e9 b6 fe ff ff 48 89
[ 131.876730] RSP: 0018:ffff9ff54e01fd80 EFLAGS: 00010246
[ 131.883000] RAX: fffffffffffffffe RBX: ffff8c0b0a8cd000 RCX: 0000000000000008
[ 131.891463] RDX: fffffffffffffffe RSI: 0000000000000000 RDI: ffffffffc0a49af7
[ 131.899854] RBP: fffffffffffffffe R08: ffff8c0d4872f400 R09: 0000000000001000
[ 131.908262] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 131.916686] R13: 0000000000000003 R14: ffff8c0d4872f400 R15: 0000000000000006
[ 131.925070] FS: 00007ffa0f6029c0(0000) GS:ffff8c1abfc80000(0000) knlGS:0000000000000000
[ 131.934608] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 131.941449] CR2: 0000000000000000 CR3: 0000002179c4e001 CR4: 00000000001706e0
[ 131.949883] Call Trace:
[ 131.953090] ? __check_object_size+0x162/0x180
[ 131.958593] btrfs_ioctl+0x1870/0x2fd0 [btrfs]
[ 131.963997] ? do_fault+0x22e/0x490
[ 131.968370] ? __handle_mm_fault+0x5e8/0x7c0
[ 131.973582] ? __x64_sys_ioctl+0x84/0xc0
[ 131.978370] __x64_sys_ioctl+0x84/0xc0
[ 131.982999] do_syscall_64+0x33/0x40
[ 131.987445] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 131.993511] RIP: 0033:0x7ffa0e16762b
[ 131.997925] Code: 0f 1e fa 48 8b 05 5d b8 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00
00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2d b8 2c 00 f7 d8 64 89 01 48
[ 132.019844] RSP: 002b:00007ffe18adeeb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 132.028777] RAX: ffffffffffffffda RBX: 00007ffe18ae1070 RCX: 00007ffa0e16762b
[ 132.037222] RDX: 00007ffe18adfee0 RSI: 000000005000943a RDI: 0000000000000003
[ 132.045715] RBP: 00007ffe18adfee0 R08: 00007ffe18ae3221 R09: 0000000000000000
[ 132.054134] R10: 00007ffa0e1e51e0 R11: 0000000000000246 R12: 0000000000000001
[ 132.062617] R13: 0000000000000000 R14: 0000000000000003 R15: 00007ffe18ae1078
[ 132.071037] Modules linked in: dm_flakey rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache rfkill iTCO_wdt int
el_pmc_bxt intel_rapl_msr iTCO_vendor_support dcdbas intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powe
rclamp coretemp ipmi_ssif kvm_intel kvm irqbypass rapl intel_cstate ipmi_si mei_me ipmi_devintf intel_uncore j
oydev ipmi_msghandler mei lpc_ich acpi_power_meter nvme_rdma nvme_fabrics rdma_cm iw_cm ib_cm rdmavt nfsd rdma
_rxe ib_uverbs ip6_udp_tunnel udp_tunnel ib_core auth_rpcgss nfs_acl lockd grace nfs_ssc ip_tables xfs mgag200
drm_kms_helper btrfs cec crct10dif_pclmul crc32_pclmul crc32c_intel xor raid6_pq drm bnx2x nvme mpt3sas ghash
_clmulni_intel igb pcspkr mdio megaraid_sas nvme_core raid_class dca i2c_algo_bit scsi_transport_sas wmi dm_mu
ltipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua sunrpc i2c_dev
[ 132.155588] CR2: 0000000000000000
[ 132.159878] ---[ end trace 5ad61f759e33fdff ]---
[ 132.169659] RIP: 0010:btrfs_rm_device+0x248/0x4f0 [btrfs]
[ 132.176237] Code: 8b 45 30 48 89 df 48 83 40 48 01 e8 92 cb 14 ea e9 e2 fe ff ff b9 08 00 00 00 48 c7 c7 f7
9a a4 c0 4c 89 e6 41 bf 06 00 00 00 <f3> a6 0f 97 c0 1c 00 84 c0 0f 84 be fe ff ff e9 b6 fe ff ff 48 89
[ 132.198409] RSP: 0018:ffff9ff54e01fd80 EFLAGS: 00010246
[ 132.204856] RAX: fffffffffffffffe RBX: ffff8c0b0a8cd000 RCX: 0000000000000008
[ 132.213467] RDX: fffffffffffffffe RSI: 0000000000000000 RDI: ffffffffc0a49af7
[ 132.222039] RBP: fffffffffffffffe R08: ffff8c0d4872f400 R09: 0000000000001000
[ 132.230657] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 132.239222] R13: 0000000000000003 R14: ffff8c0d4872f400 R15: 0000000000000006
[ 132.247813] FS: 00007ffa0f6029c0(0000) GS:ffff8c1abfc80000(0000) knlGS:0000000000000000
[ 132.257461] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 132.264459] CR2: 0000000000000000 CR3: 0000002179c4e001 CR4: 00000000001706e0
[ 132.273009] Kernel panic - not syncing: Fatal exception
[ 132.447157] Kernel Offset: 0x29000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xfffff
fffbfffffff)
[ 132.462761] ---[ end Kernel panic - not syncing: Fatal exception ]---
Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/08/27
> This reverts commit f2165627319ffd33a6217275e5690b1ab5c45763.
>
> [BUG]
> It's no longer possible to create compressed inline extent after commit
> f2165627319f ("btrfs: compression: don't try to compress if we don't
> have enough pages").
>
> [CAUSE]
> For compression code, there are several possible reasons we have a range
> that needs to be compressed while it's no more than one page.
>
> - Compressed inline write
> The data is always smaller than one sector.
>
> - Compressed subpage write
> For the incoming subpage compressed write support, we require page
> alignment of the delalloc range.
> And for 64K page size, we can compress just one page into smaller
> sectors.
>
> For those reasons, the requirement for the data to be more than one page
> is not correct, and is already causing regression for compressed inline
> data writeback.
>
> [FIX]
> Fix it by reverting the offending commit.
>
> Fixes: f2165627319f ("btrfs: compression: don't try to compress if we don't have enough pages")
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
> fs/btrfs/inode.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 2aa9646bce56..2b7fe98adec2 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -632,7 +632,7 @@ static noinline int compress_file_range(struct async_chunk *async_chunk)
> * inode has not been flagged as nocompress. This flag can
> * change at any time if we discover bad compression ratios.
> */
> - if (nr_pages > 1 && inode_need_compress(BTRFS_I(inode), start, end)) {
> + if (inode_need_compress(BTRFS_I(inode), start, end)) {
> WARN_ON(pages);
> pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS);
> if (!pages) {
> --
> 2.32.0
next prev parent reply other threads:[~2021-08-27 3:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-25 5:41 [PATCH] Revert "btrfs: compression: don't try to compress if we don't have enough pages" Qu Wenruo
2021-08-25 11:55 ` David Sterba
2021-08-25 12:06 ` Qu Wenruo
2021-08-25 13:04 ` David Sterba
2021-08-27 3:41 ` Wang Yugui [this message]
2021-08-27 4:03 ` Wang Yugui
2021-08-27 5:04 ` Qu Wenruo
2021-08-27 8:35 ` David Sterba
2021-08-27 9:31 ` Qu Wenruo
2021-08-27 10:12 ` David Sterba
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