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From: Theodore Tso <tytso@mit.edu>
To: Andreas Dilger <adilger@sun.com>
Cc: linux-ext4@vger.kernel.org, aneesh.kumar@linux.vnet.ibm.com
Subject: Re: [PATCH, RFC] ext4: Automatically allocate delay allocated blocks on close
Date: Tue, 24 Feb 2009 08:21:03 -0500	[thread overview]
Message-ID: <20090224132103.GC1362@mit.edu> (raw)
In-Reply-To: <20090224101344.GN3199@webber.adilger.int>

On Tue, Feb 24, 2009 at 03:13:44AM -0700, Andreas Dilger wrote:
> On Feb 24, 2009  00:05 -0500, Theodore Ts'o wrote:
> > When closing a file that had been previously truncated, force any
> > delay allocated blocks that to be allocated so that if the filesystem
> > is mounted with data=ordered, the data blocks will be pushed out to
> > disk along with the journal commit.  Many application programs expect
> > this, so we do this to avoid zero length files if the system crashes
> > unexpectedly.
> 
> Should this only be done with "truncate-to-zero" operations, or any
> truncate?  Some applications may do extending truncates in order to
> trigger file preallocation ala Windows, and we don't necessarily want
> to punish all of the IO for those files.

Agreed, we should only do this on a truncate-to-zero.  I'll fix up the
patch to only set EXT4_STATE_DA_ALLOC_CLOSE on truncate if
inode->i_size is 0.

							- Ted

  reply	other threads:[~2009-02-24 13:21 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-24  5:05 [PATCH, RFC] Clean up of delalloc code and map-on-close/rename fixes Theodore Ts'o
2009-02-24  5:05 ` [PATCH, RFC] ext4: Simplify delalloc implementation by removing mpd.get_block Theodore Ts'o
2009-02-24  5:05   ` [PATCH, RFC] ext4: Save stack space by removing fake buffer heads Theodore Ts'o
2009-02-24  5:05     ` [PATCH, RFC] ext4: Simplify delalloc code by removing mpage_da_writepages() Theodore Ts'o
2009-02-24  5:05       ` [PATCH, RFC] ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl Theodore Ts'o
2009-02-24  5:05         ` [PATCH, RFC] ext4: Automatically allocate delay allocated blocks on close Theodore Ts'o
2009-02-24  5:05           ` [PATCH, RFC] ext4: Automatically allocate delay allocated blocks on rename Theodore Ts'o
2009-02-24 10:13           ` [PATCH, RFC] ext4: Automatically allocate delay allocated blocks on close Andreas Dilger
2009-02-24 13:21             ` Theodore Tso [this message]
2009-02-24  9:38         ` [PATCH, RFC] ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl Aneesh Kumar K.V
2009-02-24 13:14           ` Theodore Tso
2009-02-24 10:11         ` Andreas Dilger
2009-02-24 13:16           ` Theodore Tso
2009-03-11 22:41         ` Eric Sandeen
2009-03-12  5:29           ` Aneesh Kumar K.V
2009-03-12 16:32             ` Eric Sandeen
2009-03-12 20:04               ` Theodore Tso
2009-03-12 20:05                 ` Eric Sandeen

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