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 ---
  14  fs/ext4/fsync.c |    4 ++++
  15  1 file changed, 4 insertions(+)
  16
  17 Index: linux-2.6.26-rc4/fs/ext4/fsync.c
  18 ===================================================================
  19 --- linux-2.6.26-rc4.orig/fs/ext4/fsync.c       2008-05-29 10:52:28.000000000 -0700
  20 +++ linux-2.6.26-rc4/fs/ext4/fsync.c    2008-05-29 10:52:37.000000000 -0700
  21 @@ -27,6 +27,7 @@
  22  #include <linux/sched.h>
  23  #include <linux/writeback.h>
  24  #include <linux/jbd2.h>
  25 +#include <linux/blkdev.h>
  26  #include "ext4.h"
  27  #include "ext4_jbd2.h"
  28
  29 @@ -45,6 +46,7 @@
  30  int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
  31  {
  32         struct inode *inode = dentry->d_inode;
  33 +       journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
  34         int ret = 0;
  35
  36         J_ASSERT(ext4_journal_current_handle() == NULL);
  37 @@ -85,6 +87,8 @@ int ext4_sync_file(struct file * file, s
  38                         .nr_to_write = 0, /* sys_fsync did this */
  39                 };
  40                 ret = sync_inode(inode, &wbc);
  41 +               if (journal && (journal->j_flags & JBD2_BARRIER))
  42 +                       blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
  43         }
  44  out:
  45         return ret;