ocfs2: fix trans extend while flush truncate log

ocfs2: fix trans extend while flush truncate log

Orabug: 24759174

Every time,  ocfs2_extend_trans() included a credit for truncate log inode,
but as that inode had been managed by jbd2 running transaction first time,
it will not consume that credit until jbd2_journal_restart(). Since total
credits to extend always included the un-consumed ones, there will be more
and more un-consumed credit, at last jbd2_journal_restart() will fail due
to credit number over the half of max transction credit.

The following error was caught when unlink a large file with many extents.

[233096.013936] ------------[ cut here ]------------
[233096.018586] WARNING: CPU: 0 PID: 13626 at fs/jbd2/transaction.c:269 start_this_handle+0x4c3/0x510 [jbd2]()
[233096.028335] Modules linked in: ocfs2 nfsd lockd grace nfs_acl auth_rpcgss sunrpc autofs4 ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue configfs sd_mod sg ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i cxgb4 cxgb3i libcxgbi cxgb3 mdio ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ppdev xen_kbdfront xen_netfront fb_sys_fops sysimgblt sysfillrect syscopyarea parport_pc parport pcspkr i2c_piix4 i2c_core acpi_cpufreq ext4 jbd2 mbcache xen_blkfront floppy pata_acpi ata_generic ata_piix dm_mirror dm_region_hash dm_log dm_mod
[233096.081751] CPU: 0 PID: 13626 Comm: unlink Tainted: G        W       4.1.12-37.6.3.el6uek.x86_64 #2
[233096.088556] Hardware name: Xen HVM domU, BIOS 4.4.4OVM 02/11/2016
[233096.093125]  000000000000010d ffff88000018b768 ffffffff816bc5bc 000000000000010d
[233096.099082]  0000000000000000 ffff88000018b7a8 ffffffff81081475 ffff88000018b788
[233096.105038]  ffff88007a99a000 ffff88007b573390 00000000000000fb 0000000000000050
[233096.110540] Call Trace:
[233096.111893]  [<ffffffff816bc5bc>] dump_stack+0x48/0x5c
[233096.114637]  [<ffffffff81081475>] warn_slowpath_common+0x95/0xe0
[233096.117797]  [<ffffffff810814da>] warn_slowpath_null+0x1a/0x20
[233096.120984]  [<ffffffffa0080993>] start_this_handle+0x4c3/0x510 [jbd2]
[233096.124505]  [<ffffffffa0088f95>] ? __jbd2_log_start_commit+0xe5/0xf0 [jbd2]
[233096.128115]  [<ffffffff810c4eb3>] ? __wake_up+0x53/0x70
[233096.130924]  [<ffffffffa0080b41>] jbd2__journal_restart+0x161/0x1b0 [jbd2]
[233096.134523]  [<ffffffffa0080ba3>] jbd2_journal_restart+0x13/0x20 [jbd2]
[233096.137986]  [<ffffffffa06d1d94>] ocfs2_extend_trans+0x74/0x220 [ocfs2]
[233096.141407]  [<ffffffffa06d156a>] ? ocfs2_journal_dirty+0x3a/0x90 [ocfs2]
[233096.144921]  [<ffffffffa0692943>] ocfs2_replay_truncate_records+0x93/0x360 [ocfs2]
[233096.148819]  [<ffffffffa0697ace>] __ocfs2_flush_truncate_log+0x13e/0x3a0 [ocfs2]
[233096.152644]  [<ffffffffa0697304>] ? ocfs2_reserve_blocks_for_rec_trunc.clone.0+0x44/0x1f0 [ocfs2]
[233096.157310]  [<ffffffffa069f768>] ocfs2_remove_btree_range+0x458/0x7f0 [ocfs2]
[233096.161099]  [<ffffffffa0696777>] ? __ocfs2_find_path+0x187/0x2d0 [ocfs2]
[233096.164612]  [<ffffffffa06a2673>] ocfs2_commit_truncate+0x1b3/0x6f0 [ocfs2]
[233096.168204]  [<ffffffffa0744ac0>] ? ocfs2_xattr_tree_et_ops+0x60/0xfffffffffffe8c20 [ocfs2]
[233096.172539]  [<ffffffffa06d1a00>] ? ocfs2_journal_access_eb+0x20/0x20 [ocfs2]
[233096.176285]  [<ffffffff81202303>] ? __sb_end_write+0x33/0x70
[233096.179226]  [<ffffffffa06ca61d>] ocfs2_truncate_for_delete+0xbd/0x380 [ocfs2]
[233096.183009]  [<ffffffffa06ca294>] ? ocfs2_query_inode_wipe+0xf4/0x320 [ocfs2]
[233096.186738]  [<ffffffffa06caf76>] ocfs2_wipe_inode+0x136/0x6a0 [ocfs2]
[233096.190165]  [<ffffffffa06ca294>] ? ocfs2_query_inode_wipe+0xf4/0x320 [ocfs2]
[233096.193846]  [<ffffffffa06cb782>] ocfs2_delete_inode+0x2a2/0x3e0 [ocfs2]
[233096.197274]  [<ffffffff812298c9>] ? __inode_wait_for_writeback+0x69/0xc0
[233096.200736]  [<ffffffffa0732180>] ? __PRETTY_FUNCTION__.112282+0x20/0xffffffffffffb520 [ocfs2]
[233096.205146]  [<ffffffffa06cc298>] ocfs2_evict_inode+0x28/0x60 [ocfs2]
[233096.208462]  [<ffffffff8121b81b>] evict+0xab/0x1a0
[233096.211020]  [<ffffffffa0732180>] ? __PRETTY_FUNCTION__.112282+0x20/0xffffffffffffb520 [ocfs2]
[233096.215396]  [<ffffffff8121ba06>] iput_final+0xf6/0x190
[233096.218169]  [<ffffffff8121bb68>] iput+0xc8/0xe0
[233096.220586]  [<ffffffff8120f9b7>] do_unlinkat+0x1b7/0x310
[233096.223487]  [<ffffffff8106ae5b>] ? __do_page_fault+0x18b/0x480
[233096.226655]  [<ffffffff81126dbc>] ? __audit_syscall_entry+0xac/0x110
[233096.230009]  [<ffffffff810236cc>] ? do_audit_syscall_entry+0x6c/0x70
[233096.233346]  [<ffffffff81023823>] ? syscall_trace_enter_phase1+0x153/0x180
[233096.237103]  [<ffffffff8120fb26>] SyS_unlink+0x16/0x20
[233096.239800]  [<ffffffff816c122e>] system_call_fastpath+0x12/0x71
[233096.244346] ---[ end trace 28aa7410e69369cf ]---
[233096.247798] JBD2: unlink wants too many credits (251 > 128)

Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>