ext4-call-blkdev_issue_flush-on-fsync.patch

   1 ext4: call blkdev_issue_flush on fsync
   2
   3 From: Eric Sandeen <sandeen@redhat.com>
   4
   5 To ensure that bits are truly on-disk after an fsync,
   6 we should call blkdev_issue_flush if barriers are supported.
   7
   8 Inspired by an old thread on barriers, by reiserfs & xfs
   9 which do the same, and by a patch SuSE ships with their kernel
  10
  11 Signed-off-by: Eric Sandeen <sandeen@redhat.com>
  12 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  13 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  14 ---
  15  fs/ext4/fsync.c |    4 ++++
  16  1 file changed, 4 insertions(+)
  17
  18 Index: linux-2.6.26-rc6/fs/ext4/fsync.c
  19 ===================================================================
  20 --- linux-2.6.26-rc6.orig/fs/ext4/fsync.c       2008-06-17 10:43:18.000000000 -0700
  21 +++ linux-2.6.26-rc6/fs/ext4/fsync.c    2008-06-17 10:43:32.000000000 -0700
  22 @@ -27,6 +27,7 @@
  23  #include <linux/sched.h>
  24  #include <linux/writeback.h>
  25  #include <linux/jbd2.h>
  26 +#include <linux/blkdev.h>
  27  #include "ext4.h"
  28  #include "ext4_jbd2.h"
  29
  30 @@ -45,6 +46,7 @@
  31  int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
  32  {
  33         struct inode *inode = dentry->d_inode;
  34 +       journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
  35         int ret = 0;
  36
  37         J_ASSERT(ext4_journal_current_handle() == NULL);
  38 @@ -85,6 +87,8 @@ int ext4_sync_file(struct file * file, s
  39                         .nr_to_write = 0, /* sys_fsync did this */
  40                 };
  41                 ret = sync_inode(inode, &wbc);
  42 +               if (journal && (journal->j_flags & JBD2_BARRIER))
  43 +                       blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
  44         }
  45  out:
  46         return ret;