| Message ID | 1423635852-23258-1-git-send-email-forrestl@synology.com (mailing list archive) |
|---|---|
| State | Under Review |
| Headers | show |
On Wed, Feb 11, 2015 at 1:24 AM, Forrest Liu <forrestl@synology.com> wrote: > Removing large amount of block group in a transaction may encounters > BUG_ON() in btrfs_orphan_add(). That is because > btrfs_orphan_reserve_metadata() > will grab metadata reservation from transaction handle, and > btrfs_delete_unused_bgs() didn't reserve metadata for trnasaction > handle when > delete unused block group. > > The problem can be reproduce by following script > > mntpath=/btrfs > loopdev=/dev/loop0 > filepath=/home/forrest/image > > umount $mntpath > losetup -d $loopdev > truncate --size 1000g $filepath > losetup $loopdev $filepath > mkfs.btrfs -f $loopdev > mount $loopdev $mntpath > > for j in `seq 1 1 1000`; do > fallocate -l 1g $mntpath/$j > done > # wait cleaner thread remove unused block group > sleep 300 > > The call trace that results from the BUG_ON() is: > > [ 613.093084] ------------[ cut here ]------------ > [ 613.097928] kernel BUG at fs/btrfs/inode.c:3142! This should fix a hard to trigger bug we've seen in production here. I was on a different (wrong) track for explaining it, so your timing is excellent. Thanks. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a684086..63b974f 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9611,7 +9611,8 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) * Want to do this before we do anything else so we can recover * properly if we fail to join the transaction. */ - trans = btrfs_join_transaction(root); + /* 1 for btrfs_orphan_reserve_metadata() */ + trans = btrfs_start_transaction(root, 1); if (IS_ERR(trans)) { btrfs_set_block_group_rw(root, block_group); ret = PTR_ERR(trans);
Removing large amount of block group in a transaction may encounters BUG_ON() in btrfs_orphan_add(). That is because btrfs_orphan_reserve_metadata() will grab metadata reservation from transaction handle, and btrfs_delete_unused_bgs() didn't reserve metadata for trnasaction handle when delete unused block group. The problem can be reproduce by following script mntpath=/btrfs loopdev=/dev/loop0 filepath=/home/forrest/image umount $mntpath losetup -d $loopdev truncate --size 1000g $filepath losetup $loopdev $filepath mkfs.btrfs -f $loopdev mount $loopdev $mntpath for j in `seq 1 1 1000`; do fallocate -l 1g $mntpath/$j done # wait cleaner thread remove unused block group sleep 300 The call trace that results from the BUG_ON() is: [ 613.093084] ------------[ cut here ]------------ [ 613.097928] kernel BUG at fs/btrfs/inode.c:3142! [ 613.105855] invalid opcode: 0000 [#1] SMP [ 613.112702] Modules linked in: coretemp(E) crc32_pclmul(E) ghash_clmulni_intel(E) aesni_intel(E) snd_ens1371(E) snd_ac97_codec(E) aes_x86_64(E) lrw(E) gf128mul(E) glue_helper(E) ppdev(E) ac97_bus(E) ablk_helper(E) gameport(E) cryptd(E) snd_rawmidi(E) snd_seq_device(E) snd_pcm(E) vmw_balloon(E) snd_timer(E) snd(E) soundcore(E) serio_raw(E) vmwgfx(E) ttm(E) drm_kms_helper(E) drm(E) vmw_vmci(E) parport_pc(E) shpchp(E) i2c_piix4(E) mac_hid(E) lp(E) parport(E) btrfs(E) xor(E) raid6_pq(E) hid_generic(E) usbhid(E) hid(E) psmouse(E) ahci(E) libahci(E) e1000(E) mptspi(E) mptscsih(E) mptbase(E) floppy(E) vmw_pvscsi(E) vmxnet3(E) [ 613.144196] CPU: 0 PID: 1480 Comm: btrfs-cleaner Tainted: G E 3.19.0-rc7-custom #2 [ 613.148501] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 [ 613.152694] task: ffff880035cdb1a0 ti: ffff880039cf4000 task.ti: ffff880039cf4000 [ 613.154969] RIP: 0010:[<ffffffffa01441c2>] [<ffffffffa01441c2>] btrfs_orphan_add+0x1d2/0x1e0 [btrfs] [ 613.157780] RSP: 0018:ffff880039cf7c48 EFLAGS: 00010286 [ 613.159560] RAX: 00000000ffffffe4 RBX: ffff88003bd981a0 RCX: ffff88003c9e4000 [ 613.161904] RDX: 0000000000002244 RSI: 0000000000040000 RDI: ffff88003c9e4138 [ 613.164264] RBP: ffff880039cf7c88 R08: 000060ffc0000850 R09: 0000000000000000 [ 613.166507] R10: ffff88003bc4b7a0 R11: ffffea0000eb6740 R12: ffff88003c9c0000 [ 613.168681] R13: ffff88003c102160 R14: ffff88003c9c0458 R15: 0000000000000001 [ 613.170932] FS: 0000000000000000(0000) GS:ffff88003f600000(0000) knlGS:0000000000000000 [ 613.173316] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 613.175227] CR2: 00007f6343537000 CR3: 0000000036329000 CR4: 00000000000407f0 [ 613.177554] Stack: [ 613.178712] ffff880039cf7c88 ffffffffa0182a54 ffff88003c9e4b04 ffff88003c9c7800 [ 613.181297] ffff88003bc4b7a0 ffff88003bd981a0 ffff88003c8db200 ffff88003c2fcc60 [ 613.183782] ffff880039cf7d18 ffffffffa012da97 ffff88003bc4b7a4 ffff88003bc4b7a0 [ 613.186171] Call Trace: [ 613.187493] [<ffffffffa0182a54>] ? lookup_free_space_inode+0x44/0x100 [btrfs] [ 613.189801] [<ffffffffa012da97>] btrfs_remove_block_group+0x137/0x740 [btrfs] [ 613.192126] [<ffffffffa0166912>] btrfs_remove_chunk+0x672/0x780 [btrfs] [ 613.194267] [<ffffffffa012e2ff>] btrfs_delete_unused_bgs+0x25f/0x280 [btrfs] [ 613.196567] [<ffffffffa0135e4c>] cleaner_kthread+0x12c/0x190 [btrfs] [ 613.198687] [<ffffffffa0135d20>] ? check_leaf+0x350/0x350 [btrfs] [ 613.200758] [<ffffffff8108f232>] kthread+0xd2/0xf0 [ 613.202616] [<ffffffff8108f160>] ? kthread_create_on_node+0x180/0x180 [ 613.204738] [<ffffffff8175dabc>] ret_from_fork+0x7c/0xb0 [ 613.206652] [<ffffffff8108f160>] ? kthread_create_on_node+0x180/0x180 [ 613.208741] Code: ff ff 0f 1f 80 00 00 00 00 89 45 c8 3e 80 63 80 fd 48 89 df e8 d0 23 fe ff 8b 45 c8 e9 14 ff ff ff b8 f4 ff ff ff e9 12 ff ff ff <0f> 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 [ 613.216562] RIP [<ffffffffa01441c2>] btrfs_orphan_add+0x1d2/0x1e0 [btrfs] [ 613.218828] RSP <ffff880039cf7c48> [ 613.220382] ---[ end trace 71073106deb8a457 ]--- This patch replace btrfs_join_transaction() with btrfs_start_transaction() in btrfs_delete_unused_bgs() to revent BUG_ON() in btrfs_orphan_add() Signed-off-by: Forrest Liu <forrestl@synology.com> --- V2: add reproducing step and call trace in commit message V3: fix a typo: becuase, in commit message fs/btrfs/extent-tree.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)