cleanup-ext4_sync_parent

   1 ext4: cleanup ext4_sync_parent()
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 A condition !hlist_empty(&inode->i_dentry) is always true for open file.
   6 Just remove it. Also ext4_sync_parent() could use some explanation why
   7 races with rmdir() are not an issue - add a comment explaining that.
   8
   9 Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
  10 Signed-off-by: Jan Kara <jack@suse.cz>
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/ext4/fsync.c | 9 ++++++++-
  14  1 file changed, 8 insertions(+), 1 deletion(-)
  15
  16 diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
  17 index 5c43725..88effb1 100644
  18 --- a/fs/ext4/fsync.c
  19 +++ b/fs/ext4/fsync.c
  20 @@ -61,6 +61,13 @@ static int ext4_sync_parent(struct inode *inode)
  21                         break;
  22                 iput(inode);
  23                 inode = next;
  24 +               /*
  25 +                * The directory inode may have gone through rmdir by now. But
  26 +                * the inode itself and its blocks are still allocated (we hold
  27 +                * a reference to the inode so it didn't go through
  28 +                * ext4_evict_inode()) and so we are safe to flush metadata
  29 +                * blocks and the inode.
  30 +                */
  31                 ret = sync_mapping_buffers(inode->i_mapping);
  32                 if (ret)
  33                         break;
  34 @@ -107,7 +114,7 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
  35
  36         if (!journal) {
  37                 ret = __generic_file_fsync(file, start, end, datasync);
  38 -               if (!ret && !hlist_empty(&inode->i_dentry))
  39 +               if (!ret)
  40                         ret = ext4_sync_parent(inode);
  41                 if (test_opt(inode->i_sb, BARRIER))
  42                         goto issue_flush;