Messages in this thread | | | From | Likai <> | Subject | Re: [Ocfs2-devel] [PATCH v2] ocfs2: call journal flush to mark journal as empty after journal recovery when mount | Date | Tue, 17 Dec 2019 01:38:17 +0000 |
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On 2019/12/16 21:36, Joseph Qi wrote: > > On 19/12/16 20:12, Likai wrote: >> On 2019/12/16 18:02, Joseph Qi wrote: >>> On 19/12/12 14:00, Kai Li wrote: >>>> If journal is dirty when mount, it will be replayed but jbd2 sb >>>> log tail cannot be updated to mark a new start because >>>> journal->j_flag has already been set with JBD2_ABORT first >>>> in journal_init_common. When a new transaction is committed, it >>>> will be recored in block 1 first(journal->j_tail is set to 1 in >>>> journal_reset).If emergency restart happens again before journal >>>> super block is updated unfortunately, the new recorded trans will >>>> not be replayed in the next mount. >>>> >>>> The following steps describe this procedure in detail. >>>> 1. mount and touch some files >>>> 2. these transactions are committed to journal area but not checkpointed >>>> 3. emergency restart >>>> 4. mount again and its journals are replayed >>>> 5. journal super block's first s_start is 1, but its s_seq is not updated >>>> 6. touch a new file and its trans is committed but not checkpointed >>>> 7. emergency restart again >>>> 8. mount and journal is dirty, but trans committed in 6 will not be >>>> replayed. >>>> >>>> This exception happens easily when this lun is used by only one node. If it >>>> is used by multi-nodes, other node will replay its journal and its >>>> journal super block will be updated after recovery like what this patch >>>> does. >>>> >>>> ocfs2_recover_node->ocfs2_replay_journal. >>>> >>>> The following jbd2 journal can be generated by touching a new file after >>>> journal is replayed, and seq 15 is the first valid commit, but first seq >>>> is 13 in journal super block. >>>> logdump: >>>> Block 0: Journal Superblock >>>> Seq: 0 Type: 4 (JBD2_SUPERBLOCK_V2) >>>> Blocksize: 4096 Total Blocks: 32768 First Block: 1 >>>> First Commit ID: 13 Start Log Blknum: 1 >>>> Error: 0 >>>> Feature Compat: 0 >>>> Feature Incompat: 2 block64 >>>> Feature RO compat: 0 >>>> Journal UUID: 4ED3822C54294467A4F8E87D2BA4BC36 >>>> FS Share Cnt: 1 Dynamic Superblk Blknum: 0 >>>> Per Txn Block Limit Journal: 0 Data: 0 >>>> >>>> Block 1: Journal Commit Block >>>> Seq: 14 Type: 2 (JBD2_COMMIT_BLOCK) >>>> >>>> Block 2: Journal Descriptor >>>> Seq: 15 Type: 1 (JBD2_DESCRIPTOR_BLOCK) >>>> No. Blocknum Flags >>>> 0. 587 none >>>> UUID: 00000000000000000000000000000000 >>>> 1. 8257792 JBD2_FLAG_SAME_UUID >>>> 2. 619 JBD2_FLAG_SAME_UUID >>>> 3. 24772864 JBD2_FLAG_SAME_UUID >>>> 4. 8257802 JBD2_FLAG_SAME_UUID >>>> 5. 513 JBD2_FLAG_SAME_UUID JBD2_FLAG_LAST_TAG >>>> ... >>>> Block 7: Inode >>>> Inode: 8257802 Mode: 0640 Generation: 57157641 (0x3682809) >>>> FS Generation: 2839773110 (0xa9437fb6) >>>> CRC32: 00000000 ECC: 0000 >>>> Type: Regular Attr: 0x0 Flags: Valid >>>> Dynamic Features: (0x1) InlineData >>>> User: 0 (root) Group: 0 (root) Size: 7 >>>> Links: 1 Clusters: 0 >>>> ctime: 0x5de5d870 0x11104c61 -- Tue Dec 3 11:37:20.286280801 2019 >>>> atime: 0x5de5d870 0x113181a1 -- Tue Dec 3 11:37:20.288457121 2019 >>>> mtime: 0x5de5d870 0x11104c61 -- Tue Dec 3 11:37:20.286280801 2019 >>>> dtime: 0x0 -- Thu Jan 1 08:00:00 1970 >>>> ... >>>> Block 9: Journal Commit Block >>>> Seq: 15 Type: 2 (JBD2_COMMIT_BLOCK) >>>> >>>> The following is jouranl recovery log when recovering the upper jbd2 >>>> journal when mount again. >>>> syslog: >>>> [ 2265.648622] ocfs2: File system on device (252,1) was not unmounted cleanly, recovering it. >>>> [ 2265.649695] fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 0 >>>> [ 2265.650407] fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 1 >>>> [ 2265.650409] fs/jbd2/recovery.c:(do_one_pass, 449): Starting recovery pass 2 >>>> [ 2265.650410] fs/jbd2/recovery.c:(jbd2_journal_recover, 278): JBD2: recovery, exit status 0, recovered transactions 13 to 13 >>>> >>>> Due to first commit seq 13 recorded in journal super is not consistent >>>> with the value recorded in block 1(seq is 14), journal recovery will be >>>> terminated before seq 15 even though it is an unbroken commit, inode >>>> 8257802 is a new file and it will be lost. >>>> >>>> Signed-off-by: Kai Li <li.kai4@h3c.com> >>>> --- >>>> fs/ocfs2/journal.c | 9 +++++++++ >>>> 1 file changed, 9 insertions(+) >>>> >>>> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c >>>> index 1afe57f425a0..5c7a489f47b0 100644 >>>> --- a/fs/ocfs2/journal.c >>>> +++ b/fs/ocfs2/journal.c >>>> @@ -1066,6 +1066,15 @@ int ocfs2_journal_load(struct ocfs2_journal *journal, int local, int replayed) >>>> >>>> ocfs2_clear_journal_error(osb->sb, journal->j_journal, osb->slot_num); >>>> >>>> + if (replayed) { >>>> + mlog(ML_NOTICE, "journal recovery complete"); >>> I don't think this log is appropriate, or we can change it to something like: >>> "Journal is dirty, wipe it first"? >>> >>> Thanks, >>> Joseph >> This log is not used to interpret journal flush's purpose and calling >> journal flush to make jbd2 super block become normal should be a >> requisite operation internally, >> maybe a mark should be better I think if necessary. >> In addition, ocfs2 prints a log like 'ocfs2: File system on device (%s) >> was not unmounted cleanly, recovering it' before, >> and journal has already been replayed in >> jbd2_journal_load->jbd2_journal_recover, this log just means that it is >> done here. >> So I don't think it is inappropriate, could you think abort my proposal >> again? >> > Not really, just think that this log has no actual meaning. > Or we can simply remove it. > > Thanks, > Joseph > Ok, simply remove it, any other suggestions?
Thanks
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