On Thu, Mar 29, 2018 at 08:49:22AM +0800, Qu Wenruo wrote: > [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 <dste...@suse.cz> > Signed-off-by: Qu Wenruo <w...@suse.com> > --- > 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;
I'd rather fold this to the original patch as it's still in the devel queue and I don't see much point to add a buggy patch and fix separatelly. If you have a suggestion for a text to be put to changelog so at least we have some sort of documentation about the special case for delayed inode item reservation. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
