piaojun
2019-Dec-19 14:15 UTC
[Ocfs2-devel] [PATCH v3] ocfs2: call journal flush to mark journal as empty after journal recovery when mount
On 2019/12/17 10:01, 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 at h3c.com> > --- > fs/ocfs2/journal.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c > index 1afe57f425a0..68ba354cf361 100644 > --- a/fs/ocfs2/journal.c > +++ b/fs/ocfs2/journal.c > @@ -1066,6 +1066,14 @@ 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) { > + jbd2_journal_lock_updates(journal->j_journal); > + status = jbd2_journal_flush(journal->j_journal);What if jbd2_journal_flush gets failed? The 's_sequence' and 's_start' won't be reset, and I wonder if the problem still remains. Thanks, Jun> + jbd2_journal_unlock_updates(journal->j_journal); > + if (status < 0) > + mlog_errno(status); > + } > + > status = ocfs2_journal_toggle_dirty(osb, 1, replayed); > if (status < 0) { > mlog_errno(status); >
Joseph Qi
2019-Dec-20 01:11 UTC
[Ocfs2-devel] [PATCH v3] ocfs2: call journal flush to mark journal as empty after journal recovery when mount
On 19/12/19 22:15, piaojun wrote:> > > On 2019/12/17 10:01, 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 at h3c.com> >> --- >> fs/ocfs2/journal.c | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c >> index 1afe57f425a0..68ba354cf361 100644 >> --- a/fs/ocfs2/journal.c >> +++ b/fs/ocfs2/journal.c >> @@ -1066,6 +1066,14 @@ 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) { >> + jbd2_journal_lock_updates(journal->j_journal); >> + status = jbd2_journal_flush(journal->j_journal); > > What if jbd2_journal_flush gets failed? The 's_sequence' and 's_start' > won't be reset, and I wonder if the problem still remains. >Yes, but we don't want this to fail the mount process, instead we just log an error and system administrator should know the result. Thanks, Joseph