[BUG]
With latest qgroup metadata reservation patch applied, it's possible to
hit BUG_ON() when running btrfs/042:
------
run fstests btrfs/042 at 2018-03-28 12:14:26
BTRFS: device fsid cc876c27-bf31-44d6-bd6a-2c19b8c8e1b8 devid 1 transid 5 /dev/sdc1
BTRFS info (device sdc1): disk space caching is enabled
BTRFS info (device sdc1): has skinny extents
BTRFS info (device sdc1): flagging fs with big metadata feature
BTRFS info (device sdc1): creating UUID tree
BTRFS info (device sdc1): qgroup scan completed (inconsistency flag cleared)
------------[ cut here ]------------
kernel BUG at fs/btrfs/delayed-inode.c:1467!
invalid opcode: 0000 [#1] PREEMPT SMP PTI
CPU: 12 PID: 28830 Comm: xfs_io Tainted: G I 4.16.0-rc7-1.gab9e909-default+ #92
Hardware name: HP ProLiant DL380 G6, BIOS P62 10/01/2009
RIP: 0010:btrfs_insert_delayed_dir_index+0x230/0x240 [btrfs]
RSP: 0018:ffff9b4488777a30 EFLAGS: 00010282
RAX: 00000000ffffff86 RBX: ffff8f1bd86ee600 RCX: 0000000000000020
RDX: 000000000000000c RSI: 0000000000000004 RDI: ffff8f1bd3a830a8
RBP: ffff8f1bd86ee618 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: ffff8f1bd5cdf908
R13: 0000000000000004 R14: ffff8f1bc38f5680 R15: ffff8f1bc6364820
FS: 00007ffae04eb700(0000) GS:ffff8f1bdaa00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000626880 CR3: 00000001155b6000 CR4: 00000000000006e0
Call Trace:
? _raw_spin_unlock+0x24/0x40
btrfs_insert_dir_item+0x1a9/0x210 [btrfs]
btrfs_add_link+0xec/0x3d0 [btrfs]
btrfs_create+0x19c/0x1e0 [btrfs]
lookup_open+0x64c/0x720
? __wake_up_common_lock+0x51/0x90
? find_held_lock+0x3c/0xa0
path_openat+0x5ff/0xcf0
? sched_clock+0x5/0x10
? sched_clock_cpu+0xc/0xb0
do_filp_open+0x7e/0xd0
? _raw_spin_unlock+0x24/0x40
do_sys_open+0x116/0x1e0
do_syscall_64+0x6e/0x110
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7ffae00d3520
RSP: 002b:00007ffc0554bf48 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000004042 RCX: 00007ffae00d3520
RDX: 0000000000000180 RSI: 0000000000004042 RDI: 00007ffc0554d537
RBP: 0000000000000022 R08: 00007ffc0554c110 R09: 0000000000000001
R10: 0000000012ef9861 R11: 0000000000000246 R12: 00007ffadfe7220c
R13: 00007ffc0554c110 R14: 00007ffc0554d537 R15: 00007ffc0554c260
RIP: btrfs_insert_delayed_dir_index+0x230/0x240 [btrfs] RSP: ffff9b4488777a30
---[ end trace 88182a219a9080f6 ]---
------
Where the BUG_ON() is triggered by -EDQUOT.
[CAUSE]
btrfs_qgroup_reserve_meta_prealloc() is called in
btrfs_delayed_item_reserve_metadata(), however
btrfs_delayed_item_reserve_metadata() is just migrating reserved space
from current transaction to delayed_block_rsv, all metadata space is
already reserved when starting a new transaction.
And for all @trans passed into btrfs_delayed_item_reserve_metadata(),
they are all new transaction allocated by btrfs_start_transaction(), or
operation won't increase btrfs reserved metadata space (delete item,
like unlink).
So the extra btrfs_qgroup_reserve_meta_prealloc() call here could cause
unexpected -EDQUOT and hit BUG_ON() for its caller.
[FIX]
Fix it by just remove the btrfs_qgroup_reserve_meta_prealloc() call.
Reported-by: David Sterba <dsterba@xxxxxxx>
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
fs/btrfs/delayed-inode.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index f1bc110e229c..492af96d0e38 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -569,9 +569,6 @@ static int btrfs_delayed_item_reserve_metadata(struct btrfs_trans_handle *trans,
dst_rsv = &fs_info->delayed_block_rsv;
num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
- ret = btrfs_qgroup_reserve_meta_prealloc(root, num_bytes, true);
- if (ret < 0)
- return ret;
ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
if (!ret) {
--
2.16.2
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
