ext3: Use WRITE_SYNC for commits which are caused by fsync()

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>
Acked-by: Jan Kara <jack@suse.cz>

2 files changed, 17 insertions, 8 deletions

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 3fbffb1ea714..f8077b9c8981 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 e6a117431277..ed886e6db399 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);