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Date: Fri, 7 Jul 2017 23:27:58 +0200
From: Andreas Gruenbacher <agruenba@...hat.com>
To: Christoph Hellwig <hch@....de>
Cc: Andreas Gruenbacher <agruenba@...hat.com>, Jan Kara <jack@...e.cz>,
linux-fsdevel@...r.kernel.org, linux-xfs@...r.kernel.org,
linux-ext4@...r.kernel.org
Subject: Re: [PATCH 5/5] ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA
On Fri, Jun 30, 2017 at 1:51 PM, Andreas Gruenbacher <agruenba@...hat.com> wrote:
> On Thu, Jun 29, 2017 at 3:54 PM, Christoph Hellwig <hch@....de> wrote:
>> Switch to the iomap_seek_hole and iomap_seek_data helpers for
>> implementing lseek SEEK_HOLE / SEEK_DATA, and remove all the
>> code that isn't needed any more.
>>
>> Note that with this patch ext4 will now always depend on the iomap
>> code instead of only when CONFIG_DAX is enabled, and it requires
>> adding a call into the extent status tree for iomap_begin as well
>> to properly deal with delalloc extents.
>
> This breaks SEEK_HOLE / SEEK_DATA on filesystems with the inline_data feature.
>
> Also, ext4 no longer calls inode_lock or inode_lock_shared; that needs
> to be added back for consistency between reading i_size and walking
> the file extents.
Here are some possible fixes on top of this patch.
One problem with iomap is that is uses a sector number for the physical offset
instead of a byte offset which prevents iomap from being used for inline data
(ext4) / stuffed inodes (gfs2). If we convert that into a byte offset,
iomap_fiemap and iomap_seek_{hole,data} will just work for those kinds of files.
Andreas
Andreas Gruenbacher (3):
ext4: Add missing locking around iomap_seek_{hole,data}
iomap: Switch from blkno to physical offset
ext4: Add IOMAP_REPORT support for inline data
fs/buffer.c | 2 +-
fs/dax.c | 2 +-
fs/ext2/inode.c | 4 ++--
fs/ext4/ext4.h | 4 ++++
fs/ext4/file.c | 4 ++++
fs/ext4/inline.c | 33 +++++++++++++++++++++++++++++++++
fs/ext4/inode.c | 13 +++++++++----
fs/iomap.c | 14 ++++++++------
fs/nfsd/blocklayout.c | 4 ++--
fs/xfs/xfs_iomap.c | 6 +++---
include/linux/iomap.h | 5 +++--
11 files changed, 70 insertions(+), 21 deletions(-)
--
2.7.5
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