re: [PATCH] Change ll_rw_block() calls in JBD
From: Zoltan Menyhart
Date: Thu May 18 2006 - 04:25:30 EST
We must be sure that the current data in buffer are sent to disk.
Hence we have to call ll_rw_block() with SWRITE.
Let's consider the following case:
while (commit_transaction->t_sync_datalist) {
...
// Assume a "bh" got locked before starting this loop
if (buffer_locked(bh)) {
...
__journal_temp_unlink_buffer(jh);
__journal_file_buffer(jh, commit_transaction, BJ_Locked);
} else ...
}
...
while (commit_transaction->t_locked_list) {
...
// Assume our "bh" is not locked any more
// Nothing has happened to this "bh", someone just wanted
// to look at it in a safe way
if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
__journal_unfile_buffer(jh);
jbd_unlock_bh_state(bh);
journal_remove_journal_head(bh);
put_bh(bh);
} else ...
}
I.e. having an already locked "bh", it is missed out from the log.
Regards,
Zoltan Menyhart
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