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>

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 3fbffb1..f8077b9 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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;
 };
 
 /**