* FAILED: patch "[PATCH] btrfs: cleanup cow block on error" failed to apply to 4.4-stable tree
@ 2020-11-03 13:57 gregkh
2020-12-01 17:11 ` Sudip Mukherjee
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2020-11-03 13:57 UTC (permalink / raw)
To: josef, dsterba, fdmanana; +Cc: stable
The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 572c83acdcdafeb04e70aa46be1fa539310be20c Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 29 Sep 2020 08:53:54 -0400
Subject: [PATCH] btrfs: cleanup cow block on error
In fstest btrfs/064 a transaction abort in __btrfs_cow_block could lead
to a system lockup. It gets stuck trying to write back inodes, and the
write back thread was trying to lock an extent buffer:
$ cat /proc/2143497/stack
[<0>] __btrfs_tree_lock+0x108/0x250
[<0>] lock_extent_buffer_for_io+0x35e/0x3a0
[<0>] btree_write_cache_pages+0x15a/0x3b0
[<0>] do_writepages+0x28/0xb0
[<0>] __writeback_single_inode+0x54/0x5c0
[<0>] writeback_sb_inodes+0x1e8/0x510
[<0>] wb_writeback+0xcc/0x440
[<0>] wb_workfn+0xd7/0x650
[<0>] process_one_work+0x236/0x560
[<0>] worker_thread+0x55/0x3c0
[<0>] kthread+0x13a/0x150
[<0>] ret_from_fork+0x1f/0x30
This is because we got an error while COWing a block, specifically here
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
}
[16402.241552] BTRFS: Transaction aborted (error -2)
[16402.242362] WARNING: CPU: 1 PID: 2563188 at fs/btrfs/ctree.c:1074 __btrfs_cow_block+0x376/0x540
[16402.249469] CPU: 1 PID: 2563188 Comm: fsstress Not tainted 5.9.0-rc6+ #8
[16402.249936] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
[16402.250525] RIP: 0010:__btrfs_cow_block+0x376/0x540
[16402.252417] RSP: 0018:ffff9cca40e578b0 EFLAGS: 00010282
[16402.252787] RAX: 0000000000000025 RBX: 0000000000000002 RCX: ffff9132bbd19388
[16402.253278] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9132bbd19380
[16402.254063] RBP: ffff9132b41a49c0 R08: 0000000000000000 R09: 0000000000000000
[16402.254887] R10: 0000000000000000 R11: ffff91324758b080 R12: ffff91326ef17ce0
[16402.255694] R13: ffff91325fc0f000 R14: ffff91326ef176b0 R15: ffff9132815e2000
[16402.256321] FS: 00007f542c6d7b80(0000) GS:ffff9132bbd00000(0000) knlGS:0000000000000000
[16402.256973] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[16402.257374] CR2: 00007f127b83f250 CR3: 0000000133480002 CR4: 0000000000370ee0
[16402.257867] Call Trace:
[16402.258072] btrfs_cow_block+0x109/0x230
[16402.258356] btrfs_search_slot+0x530/0x9d0
[16402.258655] btrfs_lookup_file_extent+0x37/0x40
[16402.259155] __btrfs_drop_extents+0x13c/0xd60
[16402.259628] ? btrfs_block_rsv_migrate+0x4f/0xb0
[16402.259949] btrfs_replace_file_extents+0x190/0x820
[16402.260873] btrfs_clone+0x9ae/0xc00
[16402.261139] btrfs_extent_same_range+0x66/0x90
[16402.261771] btrfs_remap_file_range+0x353/0x3b1
[16402.262333] vfs_dedupe_file_range_one.part.0+0xd5/0x140
[16402.262821] vfs_dedupe_file_range+0x189/0x220
[16402.263150] do_vfs_ioctl+0x552/0x700
[16402.263662] __x64_sys_ioctl+0x62/0xb0
[16402.264023] do_syscall_64+0x33/0x40
[16402.264364] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[16402.264862] RIP: 0033:0x7f542c7d15cb
[16402.266901] RSP: 002b:00007ffd35944ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[16402.267627] RAX: ffffffffffffffda RBX: 00000000009d1968 RCX: 00007f542c7d15cb
[16402.268298] RDX: 00000000009d2490 RSI: 00000000c0189436 RDI: 0000000000000003
[16402.268958] RBP: 00000000009d2520 R08: 0000000000000036 R09: 00000000009d2e64
[16402.269726] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
[16402.270659] R13: 000000000001f000 R14: 00000000009d1970 R15: 00000000009d2e80
[16402.271498] irq event stamp: 0
[16402.271846] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[16402.272497] hardirqs last disabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0
[16402.273343] softirqs last enabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0
[16402.273905] softirqs last disabled at (0): [<0000000000000000>] 0x0
[16402.274338] ---[ end trace 737874a5a41a8236 ]---
[16402.274669] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.276179] BTRFS info (device dm-9): forced readonly
[16402.277046] BTRFS: error (device dm-9) in btrfs_replace_file_extents:2723: errno=-2 No such entry
[16402.278744] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.279968] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.280582] BTRFS info (device dm-9): balance: ended with status: -30
The problem here is that as soon as we allocate the new block it is
locked and marked dirty in the btree inode. This means that we could
attempt to writeback this block and need to lock the extent buffer.
However we're not unlocking it here and thus we deadlock.
Fix this by unlocking the cow block if we have any errors inside of
__btrfs_cow_block, and also free it so we do not leak it.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a165093739c4..113da62dc17f 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1064,6 +1064,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, ret);
return ret;
}
@@ -1071,6 +1073,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, ret);
return ret;
}
@@ -1103,6 +1107,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (last_ref) {
ret = tree_mod_log_free_eb(buf);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, ret);
return ret;
}
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: FAILED: patch "[PATCH] btrfs: cleanup cow block on error" failed to apply to 4.4-stable tree
2020-11-03 13:57 FAILED: patch "[PATCH] btrfs: cleanup cow block on error" failed to apply to 4.4-stable tree gregkh
@ 2020-12-01 17:11 ` Sudip Mukherjee
2020-12-10 12:50 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: Sudip Mukherjee @ 2020-12-01 17:11 UTC (permalink / raw)
To: gregkh; +Cc: josef, dsterba, fdmanana, stable
[-- Attachment #1: Type: text/plain, Size: 367 bytes --]
Hi Greg,
On Tue, Nov 03, 2020 at 02:57:24PM +0100, gregkh@linuxfoundation.org wrote:
>
> The patch below does not apply to the 4.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
Here is the backport.
--
Regards
Sudip
[-- Attachment #2: 0001-btrfs-cleanup-cow-block-on-error.patch --]
[-- Type: text/x-diff, Size: 6539 bytes --]
From e9bc6c9aaf654f91bda1cd5742a875a3307908d5 Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 29 Sep 2020 08:53:54 -0400
Subject: [PATCH] btrfs: cleanup cow block on error
commit 572c83acdcdafeb04e70aa46be1fa539310be20c upstream
In fstest btrfs/064 a transaction abort in __btrfs_cow_block could lead
to a system lockup. It gets stuck trying to write back inodes, and the
write back thread was trying to lock an extent buffer:
$ cat /proc/2143497/stack
[<0>] __btrfs_tree_lock+0x108/0x250
[<0>] lock_extent_buffer_for_io+0x35e/0x3a0
[<0>] btree_write_cache_pages+0x15a/0x3b0
[<0>] do_writepages+0x28/0xb0
[<0>] __writeback_single_inode+0x54/0x5c0
[<0>] writeback_sb_inodes+0x1e8/0x510
[<0>] wb_writeback+0xcc/0x440
[<0>] wb_workfn+0xd7/0x650
[<0>] process_one_work+0x236/0x560
[<0>] worker_thread+0x55/0x3c0
[<0>] kthread+0x13a/0x150
[<0>] ret_from_fork+0x1f/0x30
This is because we got an error while COWing a block, specifically here
if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
}
[16402.241552] BTRFS: Transaction aborted (error -2)
[16402.242362] WARNING: CPU: 1 PID: 2563188 at fs/btrfs/ctree.c:1074 __btrfs_cow_block+0x376/0x540
[16402.249469] CPU: 1 PID: 2563188 Comm: fsstress Not tainted 5.9.0-rc6+ #8
[16402.249936] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
[16402.250525] RIP: 0010:__btrfs_cow_block+0x376/0x540
[16402.252417] RSP: 0018:ffff9cca40e578b0 EFLAGS: 00010282
[16402.252787] RAX: 0000000000000025 RBX: 0000000000000002 RCX: ffff9132bbd19388
[16402.253278] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9132bbd19380
[16402.254063] RBP: ffff9132b41a49c0 R08: 0000000000000000 R09: 0000000000000000
[16402.254887] R10: 0000000000000000 R11: ffff91324758b080 R12: ffff91326ef17ce0
[16402.255694] R13: ffff91325fc0f000 R14: ffff91326ef176b0 R15: ffff9132815e2000
[16402.256321] FS: 00007f542c6d7b80(0000) GS:ffff9132bbd00000(0000) knlGS:0000000000000000
[16402.256973] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[16402.257374] CR2: 00007f127b83f250 CR3: 0000000133480002 CR4: 0000000000370ee0
[16402.257867] Call Trace:
[16402.258072] btrfs_cow_block+0x109/0x230
[16402.258356] btrfs_search_slot+0x530/0x9d0
[16402.258655] btrfs_lookup_file_extent+0x37/0x40
[16402.259155] __btrfs_drop_extents+0x13c/0xd60
[16402.259628] ? btrfs_block_rsv_migrate+0x4f/0xb0
[16402.259949] btrfs_replace_file_extents+0x190/0x820
[16402.260873] btrfs_clone+0x9ae/0xc00
[16402.261139] btrfs_extent_same_range+0x66/0x90
[16402.261771] btrfs_remap_file_range+0x353/0x3b1
[16402.262333] vfs_dedupe_file_range_one.part.0+0xd5/0x140
[16402.262821] vfs_dedupe_file_range+0x189/0x220
[16402.263150] do_vfs_ioctl+0x552/0x700
[16402.263662] __x64_sys_ioctl+0x62/0xb0
[16402.264023] do_syscall_64+0x33/0x40
[16402.264364] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[16402.264862] RIP: 0033:0x7f542c7d15cb
[16402.266901] RSP: 002b:00007ffd35944ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[16402.267627] RAX: ffffffffffffffda RBX: 00000000009d1968 RCX: 00007f542c7d15cb
[16402.268298] RDX: 00000000009d2490 RSI: 00000000c0189436 RDI: 0000000000000003
[16402.268958] RBP: 00000000009d2520 R08: 0000000000000036 R09: 00000000009d2e64
[16402.269726] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
[16402.270659] R13: 000000000001f000 R14: 00000000009d1970 R15: 00000000009d2e80
[16402.271498] irq event stamp: 0
[16402.271846] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[16402.272497] hardirqs last disabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0
[16402.273343] softirqs last enabled at (0): [<ffffffff910dbf59>] copy_process+0x6b9/0x1ba0
[16402.273905] softirqs last disabled at (0): [<0000000000000000>] 0x0
[16402.274338] ---[ end trace 737874a5a41a8236 ]---
[16402.274669] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.276179] BTRFS info (device dm-9): forced readonly
[16402.277046] BTRFS: error (device dm-9) in btrfs_replace_file_extents:2723: errno=-2 No such entry
[16402.278744] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.279968] BTRFS: error (device dm-9) in __btrfs_cow_block:1074: errno=-2 No such entry
[16402.280582] BTRFS info (device dm-9): balance: ended with status: -30
The problem here is that as soon as we allocate the new block it is
locked and marked dirty in the btree inode. This means that we could
attempt to writeback this block and need to lock the extent buffer.
However we're not unlocking it here and thus we deadlock.
Fix this by unlocking the cow block if we have any errors inside of
__btrfs_cow_block, and also free it so we do not leak it.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[sudip: use old btrfs_abort_transaction()]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
fs/btrfs/ctree.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 3fa0515d7685..85b64475d808 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1129,6 +1129,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, root, ret);
return ret;
}
@@ -1136,6 +1138,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, root, ret);
return ret;
}
@@ -1174,6 +1178,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if (last_ref) {
ret = tree_mod_log_free_eb(root->fs_info, buf);
if (ret) {
+ btrfs_tree_unlock(cow);
+ free_extent_buffer(cow);
btrfs_abort_transaction(trans, root, ret);
return ret;
}
--
2.11.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: FAILED: patch "[PATCH] btrfs: cleanup cow block on error" failed to apply to 4.4-stable tree
2020-12-01 17:11 ` Sudip Mukherjee
@ 2020-12-10 12:50 ` Greg KH
0 siblings, 0 replies; 3+ messages in thread
From: Greg KH @ 2020-12-10 12:50 UTC (permalink / raw)
To: Sudip Mukherjee; +Cc: josef, dsterba, fdmanana, stable
On Tue, Dec 01, 2020 at 05:11:13PM +0000, Sudip Mukherjee wrote:
> Hi Greg,
>
> On Tue, Nov 03, 2020 at 02:57:24PM +0100, gregkh@linuxfoundation.org wrote:
> >
> > The patch below does not apply to the 4.4-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
>
> Here is the backport.
Now applied, thanks.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-12-10 12:50 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2020-11-03 13:57 FAILED: patch "[PATCH] btrfs: cleanup cow block on error" failed to apply to 4.4-stable tree gregkh
2020-12-01 17:11 ` Sudip Mukherjee
2020-12-10 12:50 ` Greg KH
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