ext4_delalloc_setpageprivate_fix.patch

   1 ext4: delalloc setpageprivate fix (XXX fix comments, fold? in patch series?)
   2
   3 From: Mingming Cao <cmm@us.ibm.com>
   4
   5 On 16:46 Срд 20 Июн     , Mingming Cao wrote:
   6 > On Wed, 2007-06-20 at 12:15 +0400, Alex Tomas wrote:
   7 > > Mingming Cao wrote:
   8 > > > Hmm, PageMappedToDisk is probably not sufficient enough for pagesize!
   9 > > > =blocksize. Is that the reason we need page->private to pass the
  10 > > > request?
  11 > >
  12 > > PageMappedToDisk isn't enough in that case, definitely. bh is the way
  13 > > to track state of each block (this is what i'm implementing now), but
  14 > > I think current nobh version (per-page flags are used) is valuable.
  15 > >
  16 > > > That's good to know, thanks for the update. So probably above error case
  17 > > > handling will be addressed in the new version?
  18 > >
  19 > > well, you actually can move that SetPagePrivate() few lines above
  20 > > (Dmitriy already tested this).
  21 >
  22 > Like this?
  23 Of course not, we may set page private bit only if
  24 space was successfully reserved by ext4_wb_reserve_space_page().
  25 So patch looks like this:
  26
  27 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  28 Signed-off-by: Alex Tomas <alex@clusterfs.com>
  29
  30 ---
  31  fs/ext4/writeback.c |    6 +++---
  32  1 file changed, 3 insertions(+), 3 deletions(-)
  33
  34 Index: linux-2.6.23-rc2/fs/ext4/writeback.c
  35 ===================================================================
  36 --- linux-2.6.23-rc2.orig/fs/ext4/writeback.c   2007-08-06 22:19:08.000000000 -0700
  37 +++ linux-2.6.23-rc2/fs/ext4/writeback.c        2007-08-06 22:19:19.000000000 -0700
  38 @@ -918,9 +918,6 @@ int ext4_wb_commit_write(struct file *fi
  39         wb_debug("commit page %lu (%u-%u) for inode %lu\n",
  40                         page->index, from, to, inode->i_ino);
  41
  42 -       /* mark page private so that we get
  43 -        * called to invalidate/release page */
  44 -       SetPagePrivate(page);
  45
  46         if (!PageBooked(page) && !PageMappedToDisk(page)) {
  47                 /* ->prepare_write() observed that block for this
  48 @@ -932,6 +929,9 @@ int ext4_wb_commit_write(struct file *fi
  49                 if (err)
  50                         return err;
  51         }
  52 +       /* mark page private so that we get
  53 +        * called to invalidate/release page */
  54 +       SetPagePrivate(page);
  55
  56         /* ok. block for this page is allocated already or it has
  57          * been reserved succesfully. so, user may use it */