On Tue, 2012-03-27 at 22:14 +0200, Jan Kara wrote: > On Tue 27-03-12 16:29:58, Artem Bityutskiy wrote: > > On Thu, 2012-03-22 at 11:33 +0100, Jan Kara wrote: > > > Then we have ext4_mark_super_dirty() call from 4 places - I forgot about > > > these originally... I kind of miss their purpose. Originally they were used > > > so that we write total number of free blocks and inodes in the superblock > > > but when we do not maintain them in the journal mode I don't see a reason > > > to periodically sync them in no-journal mode. Ted, what is the purpose of > > > these calls? > > > > I do not understand what's the fundamental difference between journal > > and non-journal mode. Why when we do have the journal we do not mark the > > super-block as dirty in many places (e.g., in 'ext4_file_open()' - if we > > do have the journal, when do we make sure we save the mount point path > > change?). > We write it at least during ext4_put_super(). > > > May be it has something to do with behaving like the ext2 driver when > > mounting ext2-formatted media with the the ext4 driver? > I'm not really sure about this... > > > Jan, since Ted did not answer, may be you can figure out the reasons > > from this commit message, which actually introduced the > > 'ext4_mark_super_dirty()' function? > Anyway, attached are two patches which you can include in your series > and which should make your cleanups simpler. I amended the second patch: - ext4_journal_stop(sb); + ext4_journal_stop(sbi->s_sbh); Extensive testing with xfstests found a problem with these patches: [23500.238579] ------------[ cut here ]------------ [23500.238720] kernel BUG at fs/buffer.c:2871! [23500.238842] invalid opcode: 0000 [#1] SMP [23500.239279] CPU 11 [23500.239338] Modules linked in: [last unloaded: scsi_wait_scan] [23500.239442] [23500.239442] Pid: 15799, comm: fsstress Not tainted 3.3.0+ #43 Bochs Bochs [23500.239442] RIP: 0010:[<ffffffff811a9add>] [<ffffffff811a9add>] submit_bh+0x10d/0x120 [23500.239442] RSP: 0018:ffff880273a41b58 EFLAGS: 00010202 [23500.239442] RAX: 000000000004d025 RBX: ffff8802469e5a90 RCX: 0000000000000000 [23500.239442] RDX: ffff880273a41fd8 RSI: ffff8802469e5a90 RDI: 0000000000000211 [23500.239442] RBP: ffff880273a41b78 R08: ffff880409645d80 R09: 0000000000000001 [23500.239442] R10: 0000000000000001 R11: ffff880178439000 R12: 0000000000000211 [23500.239442] R13: ffff880273a41c34 R14: ffff8804059b7000 R15: ffff880273a41fd8 [23500.239442] FS: 00007fc8731e7700(0000) GS:ffff88041fd60000(0000) knlGS:0000000000000000 [23500.239442] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [23500.239442] CR2: 00007fc873082008 CR3: 000000012456a000 CR4: 00000000000006e0 [23500.239442] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [23500.239442] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [23500.239442] Process fsstress (pid: 15799, threadinfo ffff880273a40000, task ffff880150dd8000) [23500.239442] Stack: [23500.239442] ffff8804059b7000 ffff8802469e5a90 0000000000000211 ffff880273a41c34 [23500.239442] ffff880273a41b98 ffffffff811ab59d 0000000000000002 ffff8804059b7128 [23500.239442] ffff880273a41bf8 ffffffff8123be1d 0000000091827364 ffff88010e9a7e30 [23500.239442] Call Trace: [23500.239442] [<ffffffff811ab59d>] write_dirty_buffer+0x4d/0x80 [23500.239442] [<ffffffff8123be1d>] __flush_batch+0x4d/0xa0 [23500.239442] [<ffffffff8123c605>] jbd2_log_do_checkpoint+0xf5/0x4f0 [23500.239442] [<ffffffff8123ca89>] __jbd2_log_wait_for_space+0x89/0x190 [23500.239442] [<ffffffff81237a98>] start_this_handle+0x3a8/0x4e0 [23500.239442] [<ffffffff810799e0>] ? remove_wait_queue+0x50/0x50 [23500.239442] [<ffffffff81237c93>] jbd2__journal_start+0xc3/0x100 [23500.239442] [<ffffffff81237ce3>] jbd2_journal_start+0x13/0x20 [23500.239442] [<ffffffff8121743f>] ext4_journal_start_sb+0x7f/0x1d0 [23500.239442] [<ffffffff81224a24>] ? ext4_fallocate+0x1a4/0x530 [23500.239442] [<ffffffff811f64c5>] ? ext4_meta_trans_blocks+0xa5/0xb0 [23500.239442] [<ffffffff81224a24>] ext4_fallocate+0x1a4/0x530 [23500.239442] [<ffffffff8117a092>] do_fallocate+0xf2/0x160 [23500.239442] [<ffffffff8117a14b>] sys_fallocate+0x4b/0x70 [23500.239442] [<ffffffff815e6d69>] system_call_fastpath+0x16/0x1b [23500.239442] Code: ee 44 89 e7 e8 35 1f 0f 00 49 8b 5d 18 4c 89 ef e8 19 4e 00 00 48 83 c4 08 c1 e3 18 c1 fb 1f 83 e3 a1 89 d8 5b 41 5c 41 5d 5d c3 <0f> 0b 0f 0b 0f 0b 0f 0b 0f 0b 66 0f 1f 84 00 00 00 00 00 55 48 [23500.239442] RIP [<ffffffff811a9add>] submit_bh+0x10d/0x120 [23500.239442] RSP <ffff880273a41b58> [23500.261657] ---[ end trace 3db7a7a7ae953551 ]--- [23500.262131] ------------[ cut here ]------------ [23500.262577] WARNING: at kernel/exit.c:897 do_exit+0x55/0x870() [23500.263070] Hardware name: Bochs [23500.263467] Modules linked in: [last unloaded: scsi_wait_scan] [23500.264129] Pid: 15799, comm: fsstress Tainted: G D 3.3.0+ #43 [23500.264623] Call Trace: [23500.265066] [<ffffffff810572bf>] warn_slowpath_common+0x7f/0xc0 [23500.265542] [<ffffffff8105731a>] warn_slowpath_null+0x1a/0x20 [23500.266034] [<ffffffff8105b1c5>] do_exit+0x55/0x870 [23500.266482] [<ffffffff81058f6c>] ? kmsg_dump+0x5c/0xf0 [23500.266932] [<ffffffff815dfeac>] oops_end+0xac/0xf0 [23500.267418] [<ffffffff81017928>] die+0x58/0x90 [23500.267852] [<ffffffff815df7a4>] do_trap+0xc4/0x170 [23500.268343] [<ffffffff81014fa5>] do_invalid_op+0x95/0xb0 [23500.268803] [<ffffffff811a9add>] ? submit_bh+0x10d/0x120 [23500.269344] [<ffffffff81299db4>] ? drive_stat_acct+0x114/0x190 [23500.269825] [<ffffffff8129ec36>] ? blk_queue_bio+0x106/0x400 [23500.270324] [<ffffffff815e7f9b>] invalid_op+0x1b/0x20 [23500.270778] [<ffffffff811a9add>] ? submit_bh+0x10d/0x120 [23500.271263] [<ffffffff811a9ac7>] ? submit_bh+0xf7/0x120 [23500.271723] [<ffffffff811ab59d>] write_dirty_buffer+0x4d/0x80 [23500.272217] [<ffffffff8123be1d>] __flush_batch+0x4d/0xa0 [23500.272675] [<ffffffff8123c605>] jbd2_log_do_checkpoint+0xf5/0x4f0 [23500.273226] [<ffffffff8123ca89>] __jbd2_log_wait_for_space+0x89/0x190 [23500.273714] [<ffffffff81237a98>] start_this_handle+0x3a8/0x4e0 [23500.274213] [<ffffffff810799e0>] ? remove_wait_queue+0x50/0x50 [23500.274686] [<ffffffff81237c93>] jbd2__journal_start+0xc3/0x100 [23500.275193] [<ffffffff81237ce3>] jbd2_journal_start+0x13/0x20 [23500.275664] [<ffffffff8121743f>] ext4_journal_start_sb+0x7f/0x1d0 [23500.276166] [<ffffffff81224a24>] ? ext4_fallocate+0x1a4/0x530 [23500.276638] [<ffffffff811f64c5>] ? ext4_meta_trans_blocks+0xa5/0xb0 [23500.277186] [<ffffffff81224a24>] ext4_fallocate+0x1a4/0x530 [23500.277654] [<ffffffff8117a092>] do_fallocate+0xf2/0x160 [23500.278164] [<ffffffff8117a14b>] sys_fallocate+0x4b/0x70 [23500.278624] [<ffffffff815e6d69>] system_call_fastpath+0x16/0x1b [23500.279124] ---[ end trace 3db7a7a7ae953552 ]--- -- Best Regards, Artem Bityutskiy
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