Re: [PATCH, RFC -V2 4/4] ext4: Avoid group preallocation for closed files
From: Theodore Tso <tytso@mit.edu>
Date: 2009-08-21 02:45:46
On Thu, Aug 20, 2009 at 12:10:35PM +0530, Aneesh Kumar K.V wrote:
quoted
+ if ((size == isize) &&What is this check supposed to help us ?. This would also imply we disable prealloc only if we are allocating the last chunk in the file.
That was the idea, yes; the idea was to disable preallocation if the file is small enough that it could be written in a single call to ext4_da_writepages, or if we are allocating/writing the last chunk in a file. Otherwise, preallocation would be a good thing.
shouldn't it be !ext4_fs_is_busy(sbi) ?. Can you also write function documentation for ext4_fs_is_busy. I found in confusing that you are decrementing s_lock_busy if we are going to spin on spin_lock.
Um, oops. Yeah, good point. It should be !ext4_fs_is_busy(). I also
have the logic backwards in ext4_lock_group as well, so the two errors
mostly cancel each other out. I'll fix that in the patch.
- Ted