Re: Many warnings on 2.6.29 from your sync_single_inode warning

[Nick Piggin <npiggin@suse.de>]

On Tue, May 26, 2009 at 11:06:21AM -0700, Stephen Hemminger wrote:
> The WARN_ON you introduced in     
>  fs: new inode i_state corruption fix
>     
> Triggers every time during our regression test. The regression test runs
> on a VM under VMWare. Any ideas?

Thanks. Adding linux-fsdevel.

I guess you're mounting with -osync or -odirsync, or opening with O_SYNC?

I think it's a false positive. The filesystem code syncs the inode to disk
just after creating it but before doing an unlock_new_inode on it to
clear I_NEW. I believe this should not result in any race, because it is
called by the guy who has created the inode and he never clears I_NEW. The
race came about when pdflush would be able to perform writeout in this
window, and non-atomic updates of i_state would race with the creator when
they are messing with i_state (without inode_lock held, because inode is
new).

We could add some convoluted checks to try to allow for this, but I think
we might as well just rip out the checks...

Would anyone prefer me to try to keep them? If not, I'll send a patch to
rip them out.


> 
> May 26 02:20:59 vyatta ntpd[2792]: ntpd 4.2.4p6@1.1549-o Tue Mar 10 02:08:20 UTC 2009 (1)
> 
> May 26 02:20:59 vyatta ntpd[2793]: Warning: the "dynamic" keyword has been obsoleted and will be removed in the next release 
> 
> May 26 02:20:59 vyatta last message repeated 3 times
> 
> May 25 19:21:55 vyatta kernel: [   99.490294] ------------[ cut here ]------------
> 
> May 25 19:21:55 vyatta kernel: [   99.490314] WARNING: at fs/fs-writeback.c:292 __writeback_single_inode+0x150/0x35f()
> 
> May 25 19:21:55 vyatta kernel: [   99.490349] Hardware name: VMware Virtual Platform
> 
> May 25 19:21:55 vyatta kernel: [   99.490386] Modules linked in: iptable_nat ip6table_filter iptable_filter ip6table_raw ip6_tables xt_NOTRACK iptable_raw ip_tables x_tables nf_nat_pptp nf_conntrack_pptp nf_conntrack_proto_gre nf_nat_h323 nf_conntrack_h323 nf_nat_sip nf_conntrack_sip nf_nat_proto_gre nf_nat_tftp nf_nat_ftp nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack_tftp nf_conntrack_ftp nf_conntrack ipv6 md_mod parport_pc parport container psmouse serio_raw pcspkr i2c_piix4 i2c_core button shpchp pci_hotplug intel_agp ac agpgart evdev vfat fat ext2 mbcache battery squashfs loop unionfs nls_utf8 isofs nls_base zlib_inflate sg sr_mod cdrom floppy mptspi mptscsih mptbase scsi_transport_spi pcnet32 mii ata_piix pata_acpi ata_generic libata scsi_mod thermal processor fan thermal_sys
 
> 
> May 25 19:21:55 vyatta kernel: [   99.490713] Pid: 3483, comm: mkdir Not tainted 2.6.29-1-586-vyatta #1
> 
> May 25 19:21:55 vyatta kernel: [   99.490755] Call Trace:
> 
> May 25 19:21:55 vyatta kernel: [   99.491060]  [<c0122288>] warn_slowpath+0x80/0xb6
> 
> May 25 19:21:55 vyatta kernel: [   99.491093]  [<c02d8a8d>] schedule+0x688/0x6f3
> 
> May 25 19:21:55 vyatta kernel: [   99.491103]  [<c0137eea>] getnstimeofday+0x51/0xd7
> 
> May 25 19:21:55 vyatta kernel: [   99.491111]  [<c01343ad>] ktime_get_ts+0x22/0x49
> 
> May 25 19:21:55 vyatta kernel: [   99.491119]  [<c0152d90>] delayacct_end+0x70/0x77
> 
> May 25 19:21:55 vyatta kernel: [   99.491123]  [<c0152de8>] __delayacct_blkio_end+0x2f/0x32
> 
> May 25 19:21:55 vyatta kernel: [   99.491127]  [<c02d8b63>] io_schedule+0x6b/0x87
> 
> May 25 19:21:55 vyatta kernel: [   99.491131]  [<c02d8e69>] __wait_on_bit+0x50/0x58
> 
> May 25 19:21:55 vyatta kernel: [   99.491142]  [<c015abb8>] sync_page+0x0/0x36
> 
> May 25 19:21:55 vyatta kernel: [   99.491148]  [<c019020c>] __writeback_single_inode+0x150/0x35f
> 
> May 25 19:21:55 vyatta kernel: [   99.491152]  [<c01317dd>] wake_bit_function+0x0/0x3c
> 
> May 25 19:21:55 vyatta kernel: [   99.491157]  [<c015fa39>] write_one_page+0xa3/0xb8
> 
> May 25 19:21:55 vyatta kernel: [   99.491161]  [<c0190434>] sync_inode+0x19/0x23
> 
> May 25 19:21:55 vyatta kernel: [   99.491562]  [<d09bdfe4>] ext2_sync_inode+0x26/0x2c [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.491577]  [<d09bca65>] ext2_make_empty+0x165/0x17b [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.491589]  [<d09bfc8a>] ext2_mkdir+0x9c/0x105 [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.491607]  [<c0183231>] vfs_mkdir+0x51/0x95
> 
> May 25 19:21:55 vyatta kernel: [   99.491613]  [<c01842e8>] sys_mkdirat+0x97/0xd0
> 
> May 25 19:21:55 vyatta kernel: [   99.491621]  [<c016d78b>] remove_vma+0x3e/0x43
> 
> May 25 19:21:55 vyatta kernel: [   99.491625]  [<c016e351>] do_munmap+0x1ed/0x207
> 
> May 25 19:21:55 vyatta kernel: [   99.491633]  [<c0184330>] sys_mkdir+0xf/0x13
> 
> May 25 19:21:55 vyatta kernel: [   99.491638]  [<c0102f12>] syscall_call+0x7/0xb
> 
> May 25 19:21:55 vyatta kernel: [   99.491746] ---[ end trace 70fa05fb7550612c ]---
> 
> May 25 19:21:55 vyatta kernel: [   99.513627] ------------[ cut here ]------------
> 
> May 25 19:21:55 vyatta kernel: [   99.513633] WARNING: at fs/fs-writeback.c:317 __writeback_single_inode+0x202/0x35f()
> 
> May 25 19:21:55 vyatta kernel: [   99.513636] Hardware name: VMware Virtual Platform
> 
> May 25 19:21:55 vyatta kernel: [   99.513638] Modules linked in: iptable_nat ip6table_filter iptable_filter ip6table_raw ip6_tables xt_NOTRACK iptable_raw ip_tables x_tables nf_nat_pptp nf_conntrack_pptp nf_conntrack_proto_gre nf_nat_h323 nf_conntrack_h323 nf_nat_sip nf_conntrack_sip nf_nat_proto_gre nf_nat_tftp nf_nat_ftp nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack_tftp nf_conntrack_ftp nf_conntrack ipv6 md_mod parport_pc parport container psmouse serio_raw pcspkr i2c_piix4 i2c_core button shpchp pci_hotplug intel_agp ac agpgart evdev vfat fat ext2 mbcache battery squashfs loop unionfs nls_utf8 isofs nls_base zlib_inflate sg sr_mod cdrom floppy mptspi mptscsih mptbase scsi_transport_spi pcnet32 mii ata_piix pata_acpi ata_generic libata scsi_mod thermal processor fan thermal_sys
 
> 
> May 25 19:21:55 vyatta kernel: [   99.513784] Pid: 3483, comm: mkdir Tainted: G        W  2.6.29-1-586-vyatta #1
> 
> May 25 19:21:55 vyatta kernel: [   99.513788] Call Trace:
> 
> May 25 19:21:55 vyatta kernel: [   99.513794]  [<c0122288>] warn_slowpath+0x80/0xb6
> 
> May 25 19:21:55 vyatta kernel: [   99.513799]  [<c015a7a6>] find_get_pages_tag+0x35/0xd5
> 
> May 25 19:21:55 vyatta kernel: [   99.513805]  [<c02d8b63>] io_schedule+0x6b/0x87
> 
> May 25 19:21:55 vyatta kernel: [   99.513810]  [<c0161053>] pagevec_lookup_tag+0x1b/0x22
> 
> May 25 19:21:55 vyatta kernel: [   99.513814]  [<c015b4ac>] wait_on_page_writeback_range+0x9d/0xde
> 
> May 25 19:21:55 vyatta kernel: [   99.513819]  [<c0194e37>] __wait_on_buffer+0x16/0x18
> 
> May 25 19:21:55 vyatta kernel: [   99.513827]  [<c01951e3>] sync_dirty_buffer+0x54/0x87
> 
> May 25 19:21:55 vyatta kernel: [   99.513841]  [<d09be355>] ext2_update_inode+0x28a/0x2c4 [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.513846]  [<c01902be>] __writeback_single_inode+0x202/0x35f
> 
> May 25 19:21:55 vyatta kernel: [   99.513851]  [<c015fa39>] write_one_page+0xa3/0xb8
> 
> May 25 19:21:55 vyatta kernel: [   99.513855]  [<c0190434>] sync_inode+0x19/0x23
> 
> May 25 19:21:55 vyatta kernel: [   99.513867]  [<d09bdfe4>] ext2_sync_inode+0x26/0x2c [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.513879]  [<d09bca65>] ext2_make_empty+0x165/0x17b [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.513890]  [<d09bfc8a>] ext2_mkdir+0x9c/0x105 [ext2]
> 
> May 25 19:21:55 vyatta kernel: [   99.513897]  [<c0183231>] vfs_mkdir+0x51/0x95
> 
> May 25 19:21:55 vyatta kernel: [   99.513901]  [<c01842e8>] sys_mkdirat+0x97/0xd0
> 
> May 25 19:21:55 vyatta kernel: [   99.513905]  [<c016d78b>] remove_vma+0x3e/0x43
> 
> May 25 19:21:55 vyatta kernel: [   99.513909]  [<c016e351>] do_munmap+0x1ed/0x207
> 
> May 25 19:21:55 vyatta kernel: [   99.513914]  [<c0184330>] sys_mkdir+0xf/0x13
> 
> May 25 19:21:55 vyatta kernel: [   99.513918]  [<c0102f12>] syscall_call+0x7/0xb
> 
> May 25 19:21:55 vyatta kernel: [   99.513921] ---[ end trace 70fa05fb7550612d ]---