From aaeb9c8f6b579d943af4fc9e1575b2fc53f08296 Mon Sep 17 00:00:00 2001 From: Eric Ren Date: Tue, 10 Jan 2017 16:57:33 -0800 Subject: [PATCH] ocfs2: fix crash caused by stale lvb with fsdlm plugin commit e7ee2c089e94067d68475990bdeed211c8852917 upstream. The crash happens rather often when we reset some cluster nodes while nodes contend fiercely to do truncate and append. The crash backtrace is below: dlm: C21CBDA5E0774F4BA5A9D4F317717495: dlm_recover_grant 1 locks on 971 resources dlm: C21CBDA5E0774F4BA5A9D4F317717495: dlm_recover 9 generation 5 done: 4 ms ocfs2: Begin replay journal (node 318952601, slot 2) on device (253,18) ocfs2: End replay journal (node 318952601, slot 2) on device (253,18) ocfs2: Beginning quota recovery on device (253,18) for slot 2 ocfs2: Finishing quota recovery on device (253,18) for slot 2 (truncate,30154,1):ocfs2_truncate_file:470 ERROR: bug expression: le64_to_cpu(fe->i_size) != i_size_read(inode) (truncate,30154,1):ocfs2_truncate_file:470 ERROR: Inode 290321, inode i_size = 732 != di i_size = 937, i_flags = 0x1 ------------[ cut here ]------------ kernel BUG at /usr/src/linux/fs/ocfs2/file.c:470! invalid opcode: 0000 [#1] SMP Modules linked in: ocfs2_stack_user(OEN) ocfs2(OEN) ocfs2_nodemanager ocfs2_stackglue(OEN) quota_tree dlm(OEN) configfs fuse sd_mod iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi af_packet iscsi_ibft iscsi_boot_sysfs softdog xfs libcrc32c ppdev parport_pc pcspkr parport joydev virtio_balloon virtio_net i2c_piix4 acpi_cpufreq button processor ext4 crc16 jbd2 mbcache ata_generic cirrus virtio_blk ata_piix drm_kms_helper ahci syscopyarea libahci sysfillrect sysimgblt fb_sys_fops ttm floppy libata drm virtio_pci virtio_ring uhci_hcd virtio ehci_hcd usbcore serio_raw usb_common sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod autofs4 Supported: No, Unsupported modules are loaded CPU: 1 PID: 30154 Comm: truncate Tainted: G OE N 4.4.21-69-default #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20151112_172657-sheep25 04/01/2014 task: ffff88004ff6d240 ti: ffff880074e68000 task.ti: ffff880074e68000 RIP: 0010:[] [] ocfs2_truncate_file+0x640/0x6c0 [ocfs2] RSP: 0018:ffff880074e6bd50 EFLAGS: 00010282 RAX: 0000000000000074 RBX: 000000000000029e RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000246 RDI: 0000000000000246 RBP: ffff880074e6bda8 R08: 000000003675dc7a R09: ffffffff82013414 R10: 0000000000034c50 R11: 0000000000000000 R12: ffff88003aab3448 R13: 00000000000002dc R14: 0000000000046e11 R15: 0000000000000020 FS: 00007f839f965700(0000) GS:ffff88007fc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f839f97e000 CR3: 0000000036723000 CR4: 00000000000006e0 Call Trace: ocfs2_setattr+0x698/0xa90 [ocfs2] notify_change+0x1ae/0x380 do_truncate+0x5e/0x90 do_sys_ftruncate.constprop.11+0x108/0x160 entry_SYSCALL_64_fastpath+0x12/0x6d Code: 24 28 ba d6 01 00 00 48 c7 c6 30 43 62 a0 8b 41 2c 89 44 24 08 48 8b 41 20 48 c7 c1 78 a3 62 a0 48 89 04 24 31 c0 e8 a0 97 f9 ff <0f> 0b 3d 00 fe ff ff 0f 84 ab fd ff ff 83 f8 fc 0f 84 a2 fd ff RIP [] ocfs2_truncate_file+0x640/0x6c0 [ocfs2] It's because ocfs2_inode_lock() get us stale LVB in which the i_size is not equal to the disk i_size. We mistakenly trust the LVB because the underlaying fsdlm dlm_lock() doesn't set lkb_sbflags with DLM_SBF_VALNOTVALID properly for us. But, why? The current code tries to downconvert lock without DLM_LKF_VALBLK flag to tell o2cb don't update RSB's LVB if it's a PR->NULL conversion, even if the lock resource type needs LVB. This is not the right way for fsdlm. The fsdlm plugin behaves different on DLM_LKF_VALBLK, it depends on DLM_LKF_VALBLK to decide if we care about the LVB in the LKB. If DLM_LKF_VALBLK is not set, fsdlm will skip recovering RSB's LVB from this lkb and set the right DLM_SBF_VALNOTVALID appropriately when node failure happens. The following diagram briefly illustrates how this crash happens: RSB1 is inode metadata lock resource with LOCK_TYPE_USES_LVB; The 1st round: Node1 Node2 RSB1: PR RSB1(master): NULL->EX ocfs2_downconvert_lock(PR->NULL, set_lvb==0) ocfs2_dlm_lock(no DLM_LKF_VALBLK) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - dlm_lock(no DLM_LKF_VALBLK) convert_lock(overwrite lkb->lkb_exflags with no DLM_LKF_VALBLK) RSB1: NULL RSB1: EX reset Node2 dlm_recover_rsbs() recover_lvb() /* The LVB is not trustable if the node with EX fails and * no lock >= PR is left. We should set RSB_VALNOTVALID for RSB1. */ if(!(kb_exflags & DLM_LKF_VALBLK)) /* This means we miss the chance to return; * to invalid the LVB here. */ The 2nd round: Node 1 Node2 RSB1(become master from recovery) ocfs2_setattr() ocfs2_inode_lock(NULL->EX) /* dlm_lock() return the stale lvb without setting DLM_SBF_VALNOTVALID */ ocfs2_meta_lvb_is_trustable() return 1 /* so we don't refresh inode from disk */ ocfs2_truncate_file() mlog_bug_on_msg(disk isize != i_size_read(inode)) /* crash! */ The fix is quite straightforward. We keep to set DLM_LKF_VALBLK flag for dlm_lock() if the lock resource type needs LVB and the fsdlm plugin is uesed. Link: http://lkml.kernel.org/r/1481275846-6604-1-git-send-email-zren@suse.com Signed-off-by: Eric Ren Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/ocfs2/dlmglue.c | 10 ++++++++++ fs/ocfs2/stackglue.c | 6 ++++++ fs/ocfs2/stackglue.h | 3 +++ 3 files changed, 19 insertions(+) diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c index 6465317e47a6..9ab2acca5a84 100644 --- a/fs/ocfs2/dlmglue.c +++ b/fs/ocfs2/dlmglue.c @@ -3270,6 +3270,16 @@ static int ocfs2_downconvert_lock(struct ocfs2_super *osb, mlog(ML_BASTS, "lockres %s, level %d => %d\n", lockres->l_name, lockres->l_level, new_level); + /* + * On DLM_LKF_VALBLK, fsdlm behaves differently with o2cb. It always + * expects DLM_LKF_VALBLK being set if the LKB has LVB, so that + * we can recover correctly from node failure. Otherwise, we may get + * invalid LVB in LKB, but without DLM_SBF_VALNOTVALID being set. + */ + if (!ocfs2_is_o2cb_active() && + lockres->l_ops->flags & LOCK_TYPE_USES_LVB) + lvb = 1; + if (lvb) dlm_flags |= DLM_LKF_VALBLK; diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c index 39abf89697ed..88610b3cbc04 100644 --- a/fs/ocfs2/stackglue.c +++ b/fs/ocfs2/stackglue.c @@ -48,6 +48,12 @@ static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl"; */ static struct ocfs2_stack_plugin *active_stack; +inline int ocfs2_is_o2cb_active(void) +{ + return !strcmp(active_stack->sp_name, OCFS2_STACK_PLUGIN_O2CB); +} +EXPORT_SYMBOL_GPL(ocfs2_is_o2cb_active); + static struct ocfs2_stack_plugin *ocfs2_stack_lookup(const char *name) { struct ocfs2_stack_plugin *p; diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h index 1ec56fdb8d0d..fa49d8a1dc7b 100644 --- a/fs/ocfs2/stackglue.h +++ b/fs/ocfs2/stackglue.h @@ -289,4 +289,7 @@ void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_p int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin); void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin); +/* In ocfs2_downconvert_lock(), we need to know which stack we are using */ +int ocfs2_is_o2cb_active(void); + #endif /* STACKGLUE_H */ -- 2.39.2