ext4_delalloc_setpageprivate_fix.patch

   1 On 16:46 Срд 20 Июн     , Mingming Cao wrote:
   2 > On Wed, 2007-06-20 at 12:15 +0400, Alex Tomas wrote:
   3 > > Mingming Cao wrote:
   4 > > > Hmm, PageMappedToDisk is probably not sufficient enough for pagesize!
   5 > > > =blocksize. Is that the reason we need page->private to pass the
   6 > > > request?
   7 > >
   8 > > PageMappedToDisk isn't enough in that case, definitely. bh is the way
   9 > > to track state of each block (this is what i'm implementing now), but
  10 > > I think current nobh version (per-page flags are used) is valuable.
  11 > >
  12 > > > That's good to know, thanks for the update. So probably above error case
  13 > > > handling will be addressed in the new version?
  14 > >
  15 > > well, you actually can move that SetPagePrivate() few lines above
  16 > > (Dmitriy already tested this).
  17 >
  18 > Like this?
  19 Of course not, we may set page private bit only if
  20 space was successfully reserved by ext4_wb_reserve_space_page().
  21 So patch looks like this:
  22
  23 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  24
  25 diff --git a/fs/ext4/writeback.c b/fs/ext4/writeback.c
  26 index 3e669d6..84e5029 100644
  27 --- a/fs/ext4/writeback.c
  28 +++ b/fs/ext4/writeback.c
  29 @@ -904,9 +904,6 @@ int ext4_wb_commit_write(struct file *file, struct page *page,
  30         wb_debug("commit page %lu (%u-%u) for inode %lu\n",
  31                         page->index, from, to, inode->i_ino);
  32
  33 -       /* mark page private so that we get
  34 -        * called to invalidate/release page */
  35 -       SetPagePrivate(page);
  36
  37         if (!PageBooked(page) && !PageMappedToDisk(page)) {
  38                 /* ->prepare_write() observed that block for this
  39 @@ -918,6 +915,9 @@ int ext4_wb_commit_write(struct file *file, struct page *page,
  40                 if (err)
  41                         return err;
  42         }
  43 +       /* mark page private so that we get
  44 +        * called to invalidate/release page */
  45 +       SetPagePrivate(page);
  46
  47         /* ok. block for this page is allocated already or it has
  48          * been reserved succesfully. so, user may use it */