[PATCH 2/3] ext3: Use WRITE_SYNC for commits which are caused by fsync()

Theodore Ts'o
2009-03-27T20:26:04Z

If a commit is triggered by fsync(), set a flag indicating the journal
blocks associated with the transaction should be flushed out using
WRITE_SYNC.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
fs/jbd/commit.c | 23 +++++++++++++++--------
fs/jbd/transaction.c | 2 ++
include/linux/jbd.h | 5 +++++
3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 3fbffb1..f8077b9 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -20,6 +20,7 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
+#include <linux/bio.h>

/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -171,14 +172,15 @@ static int journal_write_commit_record(journal_t *journal,
return (ret == -EIO);
}

-static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
+static void journal_do_submit_data(struct buffer_head **wbuf, int bufs,
+ int write_op)
{
int i;

for (i = 0; i < bufs; i++) {
wbuf[i]->b_end_io = end_buffer_write_sync;
/* We use-up our safety reference in submit_bh() */
- submit_bh(WRITE, wbuf[i]);
+ submit_bh(write_op, wbuf[i]);
}
}

@@ -186,7 +188,8 @@ static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
* Submit all the data buffers to disk
*/
static int journal_submit_data_buffers(journal_t *journal,
- transaction_t *commit_transaction)
+ transaction_t *commit_transaction,
+ int write_op)
{
struct journal_head *jh;
struct buffer_head *bh;
@@ -225,7 +228,7 @@ write_out_data:
BUFFER_TRACE(bh, "needs blocking lock");
spin_unlock(&journal->j_list_lock);
/* Write out all data to prevent deadlocks */
- journal_do_submit_data(wbuf, bufs);
+ journal_do_submit_data(wbuf, bufs, write_op);
bufs = 0;
lock_buffer(bh);
spin_lock(&journal->j_list_lock);
@@ -256,7 +259,7 @@ write_out_data:
jbd_unlock_bh_state(bh);
if (bufs == journal->j_wbufsize) {
spin_unlock(&journal->j_list_lock);
- journal_do_submit_data(wbuf, bufs);
+ journal_do_submit_data(wbuf, bufs, write_op);
bufs = 0;
goto write_out_data;
}
@@ -286,7 +289,7 @@ write_out_data:
}
}
spin_unlock(&journal->j_list_lock);
- journal_do_submit_data(wbuf, bufs);
+ journal_do_submit_data(wbuf, bufs, write_op);

return err;
}
@@ -315,6 +318,7 @@ void journal_commit_transaction(journal_t *journal)
int first_tag = 0;
int tag_flag;
int i;
+ int write_op = WRITE;

/*
* First job: lock down the current transaction and wait for
@@ -347,6 +351,8 @@ void journal_commit_transaction(journal_t *journal)
spin_lock(&journal->j_state_lock);
commit_transaction->t_state = T_LOCKED;

+ if (commit_transaction->t_synchronous_commit)
+ write_op = WRITE_SYNC;
spin_lock(&commit_transaction->t_handle_lock);
while (commit_transaction->t_updates) {
DEFINE_WAIT(wait);
@@ -431,7 +437,8 @@ void journal_commit_transaction(journal_t *journal)
* Now start flushing things to disk, in the order they appear
* on the transaction lists. Data blocks go first.
*/
- err = journal_submit_data_buffers(journal, commit_transaction);
+ err = journal_submit_data_buffers(journal, commit_transaction,
+ write_op);

/*
* Wait for all previously submitted IO to complete.
@@ -660,7 +667,7 @@ start_journal_io:
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
bh->b_end_io = journal_end_buffer_io_sync;
- submit_bh(WRITE, bh);
+ submit_bh(write_op, bh);
}
cond_resched();

diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index e6a1174..ed886e6 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -1440,6 +1440,8 @@ int journal_stop(handle_t *handle)
}
}

+ if (handle->h_sync)
+ transaction->t_synchronous_commit = 1;
current->journal_info = NULL;
spin_lock(&journal->j_state_lock);
spin_lock(&transaction->t_handle_lock);
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index 64246dc..2c69431 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -552,6 +552,11 @@ struct transaction_s
*/
int t_handle_count;

+ /*
+ * This transaction is being forced and some process is
+ * waiting for it to finish.
+ */
+ int t_synchronous_commit:1;
};

/**
--
1.5.6.3