Re: Linux 2.4.30-rc3 md/ext3 problems

From: Marcelo Tosatti
Date: Tue Mar 29 2005 - 21:49:56 EST

On Tue, Mar 29, 2005 at 10:10:34AM +1000, Neil Brown wrote:
> On Monday March 28, vherva@xxxxxxxxxx wrote:
> > On Mon, Mar 28, 2005 at 10:34:05AM +0300, [Ville Herva] wrote:
> > >
> > > I just upgraded from linux-2.4.21 + vserser 0.17 to 2.4.30rc3 + vserver
> > > 1.2.10. The box has been running stable with 2.4.21 + vserver 0.17/0.16 for
> > > a few years (uptime before reboot was nearly 400 days.)
> > >
> > > The boot went fine, but after few hours I got
> > > Message from syslogd@box at Sun Mar 27 22:07:00 2005 ...
> > > kernel: journal commit I/O error
>
> I got that error on 2.4.30-rc1 a couple of times, and now cannot
> reproduce it :-(
> But if you got it too, then it wasn't just bad luck.
>
> The ext3 code in 2.4.30-rc does have a few more checks for IO errors
> which will cause the journal to be aborted and produce this error, so
> I suspect that change which caused the problem is a change in ext3.
> However that doesn't mean the bug is there.
>
> The extra code in ext3 seems to just check if buffer_uptodate is false
> after it has waited on a locked buffer, and triggers a journal abort
> if it isn't. This should be perfectly safe, and I cannot find any
> logic error near by. But nor can I find any errors that would cause a
> buffer returned from raid1 to not be uptodate (unless there really was
> an IO error).

Attached is the backout patch, for convenience.
# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
# 2005/03/29 18:49:25-03:00 marcelo@xxxxxxxxxx
# Cset exclude: hifumi.hisashi@xxxxxxxxxxxxx|ChangeSet|20050226095914|25750
#
# mm/filemap.c
# 2005/03/29 18:49:22-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# include/linux/jbd.h
# 2005/03/29 18:49:22-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# fs/jbd/transaction.c
# 2005/03/29 18:49:21-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# fs/jbd/journal.c
# 2005/03/29 18:49:21-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# fs/jbd/commit.c
# 2005/03/29 18:49:21-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# fs/ext3/super.c
# 2005/03/29 18:49:21-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
# fs/ext3/fsync.c
# 2005/03/29 18:49:21-03:00 marcelo@xxxxxxxxxx +0 -0
# Exclude
#
diff -Nru a/fs/ext3/fsync.c b/fs/ext3/fsync.c
--- a/fs/ext3/fsync.c 2005-03-29 18:50:56 -03:00
+++ b/fs/ext3/fsync.c 2005-03-29 18:50:56 -03:00
@@ -69,7 +69,7 @@
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)
ret |= fsync_inode_data_buffers(inode);

- ret |= ext3_force_commit(inode->i_sb);
+ ext3_force_commit(inode->i_sb);

return ret;
}
diff -Nru a/fs/ext3/super.c b/fs/ext3/super.c
--- a/fs/ext3/super.c 2005-03-29 18:50:56 -03:00
+++ b/fs/ext3/super.c 2005-03-29 18:50:56 -03:00
@@ -1608,13 +1608,12 @@

static int ext3_sync_fs(struct super_block *sb)
{
- int err;
tid_t target;

sb->s_dirt = 0;
target = log_start_commit(EXT3_SB(sb)->s_journal, NULL);
- err = log_wait_commit(EXT3_SB(sb)->s_journal, target);
- return err;
+ log_wait_commit(EXT3_SB(sb)->s_journal, target);
+ return 0;
}

/*
diff -Nru a/fs/jbd/commit.c b/fs/jbd/commit.c
--- a/fs/jbd/commit.c 2005-03-29 18:50:55 -03:00
+++ b/fs/jbd/commit.c 2005-03-29 18:50:55 -03:00
@@ -92,7 +92,7 @@
struct buffer_head *wbuf[64];
int bufs;
int flags;
- int err = 0;
+ int err;
unsigned long blocknr;
char *tagp = NULL;
journal_header_t *header;
@@ -299,8 +299,6 @@
spin_unlock(&journal_datalist_lock);
unlock_journal(journal);
wait_on_buffer(bh);
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
/* the journal_head may have been removed now */
lock_journal(journal);
goto write_out_data;
@@ -328,8 +326,6 @@
spin_unlock(&journal_datalist_lock);
unlock_journal(journal);
wait_on_buffer(bh);
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
lock_journal(journal);
spin_lock(&journal_datalist_lock);
continue; /* List may have changed */
@@ -355,9 +351,6 @@
}
spin_unlock(&journal_datalist_lock);

- if (err)
- __journal_abort_hard(journal);
-
/*
* If we found any dirty or locked buffers, then we should have
* looped back up to the write_out_data label. If there weren't
@@ -548,8 +541,6 @@
if (buffer_locked(bh)) {
unlock_journal(journal);
wait_on_buffer(bh);
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
lock_journal(journal);
goto wait_for_iobuf;
}
@@ -611,8 +602,6 @@
if (buffer_locked(bh)) {
unlock_journal(journal);
wait_on_buffer(bh);
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
lock_journal(journal);
goto wait_for_ctlbuf;
}
@@ -661,8 +650,6 @@
bh->b_end_io = journal_end_buffer_io_sync;
submit_bh(WRITE, bh);
wait_on_buffer(bh);
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
put_bh(bh); /* One for getblk() */
journal_unlock_journal_head(descriptor);
}
@@ -674,9 +661,6 @@

skip_commit: /* The journal should be unlocked by now. */

- if (err)
- __journal_abort_hard(journal);
-
/* Call any callbacks that had been registered for handles in this
* transaction. It is up to the callback to free any allocated
* memory.
diff -Nru a/fs/jbd/journal.c b/fs/jbd/journal.c
--- a/fs/jbd/journal.c 2005-03-29 18:50:55 -03:00
+++ b/fs/jbd/journal.c 2005-03-29 18:50:55 -03:00
@@ -582,10 +582,8 @@
* Wait for a specified commit to complete.
* The caller may not hold the journal lock.
*/
-int log_wait_commit (journal_t *journal, tid_t tid)
+void log_wait_commit (journal_t *journal, tid_t tid)
{
- int err = 0;
-
lock_kernel();
#ifdef CONFIG_JBD_DEBUG
lock_journal(journal);
@@ -602,12 +600,6 @@
sleep_on(&journal->j_wait_done_commit);
}
unlock_kernel();
-
- if (unlikely(is_journal_aborted(journal))) {
- printk(KERN_EMERG "journal commit I/O error\n");
- err = -EIO;
- }
- return err;
}

/*
@@ -1334,7 +1326,7 @@

/* Wait for the log commit to complete... */
if (transaction)
- err = log_wait_commit(journal, transaction->t_tid);
+ log_wait_commit(journal, transaction->t_tid);

/* ...and flush everything in the log out to disk. */
lock_journal(journal);
diff -Nru a/fs/jbd/transaction.c b/fs/jbd/transaction.c
--- a/fs/jbd/transaction.c 2005-03-29 18:50:55 -03:00
+++ b/fs/jbd/transaction.c 2005-03-29 18:50:55 -03:00
@@ -1484,7 +1484,7 @@
* to wait for the commit to complete.
*/
if (handle->h_sync && !(current->flags & PF_MEMALLOC))
- err = log_wait_commit(journal, tid);
+ log_wait_commit(journal, tid);
}
kfree(handle);
return err;
@@ -1509,7 +1509,7 @@
goto out;
}
handle->h_sync = 1;
- ret = journal_stop(handle);
+ journal_stop(handle);
out:
unlock_kernel();
return ret;
diff -Nru a/include/linux/jbd.h b/include/linux/jbd.h
--- a/include/linux/jbd.h 2005-03-29 18:50:55 -03:00
+++ b/include/linux/jbd.h 2005-03-29 18:50:55 -03:00
@@ -848,7 +848,7 @@

extern int log_space_left (journal_t *); /* Called with journal locked */
extern tid_t log_start_commit (journal_t *, transaction_t *);
-extern int log_wait_commit (journal_t *, tid_t);
+extern void log_wait_commit (journal_t *, tid_t);
extern int log_do_checkpoint (journal_t *, int);

extern void log_wait_for_space(journal_t *, int nblocks);
diff -Nru a/mm/filemap.c b/mm/filemap.c
--- a/mm/filemap.c 2005-03-29 18:50:55 -03:00
+++ b/mm/filemap.c 2005-03-29 18:50:55 -03:00
@@ -3261,12 +3261,7 @@
status = generic_osync_inode(inode, OSYNC_METADATA|OSYNC_DATA);
}

- /*
- * generic_osync_inode always returns 0 or negative value.
- * So 'status < written' is always true, and written should
- * be returned if status >= 0.
- */
- err = (status < 0) ? status : written;
+ err = written ? written : status;
out:

return err;