ext4: 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>

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 62804e5..4ea7237 100644 (file)
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -367,6 +367,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
        int tag_bytes = journal_tag_bytes(journal);
        struct buffer_head *cbh = NULL; /* For transactional checksums */
        __u32 crc32_sum = ~0;
+       int write_op = WRITE;
 
        /*
         * First job: lock down the current transaction and wait for
@@ -401,6 +402,8 @@ void jbd2_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;
        stats.u.run.rs_wait = commit_transaction->t_max_wait;
        stats.u.run.rs_locked = jiffies;
        stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
@@ -680,7 +683,7 @@ 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();
                        stats.u.run.rs_blocks_logged += bufs;

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 28ce21d..996ffda 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1315,6 +1315,8 @@ int jbd2_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/jbd2.h b/include/linux/jbd2.h
index 4d248b3..8815a34 100644 (file)
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -648,6 +648,12 @@ 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;
+
        /*
         * For use by the filesystem to store fs-specific data
         * structures associated with the transaction