Date: Thu, 18 Apr 2024 15:00:11 +0530
From: Chandan Babu R <chandanbabu@...nel.org>
To: Christian Brauner <brauner@...nel.org>
Cc: Zhang Yi <yi.zhang@...weicloud.com>, linux-xfs@...r.kernel.org,
 linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
 djwong@...nel.org, hch@...radead.org, david@...morbit.com, tytso@....edu,
 jack@...e.cz, yi.zhang@...wei.com, chengzhihao1@...wei.com,
 yukuai3@...wei.com
Subject: Re: [PATCH v4 0/9] xfs/iomap: fix non-atomic clone operation and
 don't update size when zeroing range post eof

On Wed, Apr 17, 2024 at 01:40:36 PM +0200, Christian Brauner wrote:
> On Wed, Apr 17, 2024 at 10:12:10AM +0530, Chandan Babu R wrote:
>> On Wed, Mar 20, 2024 at 07:05:39 PM +0800, Zhang Yi wrote:
>> > Changes since v3:
>> >  - Improve some git message comments and do some minor code cleanup, no
>> >    logic changes.
>> >
>> > Changes since v2:
>> >  - Merge the patch for dropping of xfs_convert_blocks() and the patch
>> >    for modifying xfs_bmapi_convert_delalloc().
>> >  - Reword the commit message of the second patch.
>> >
>> > Changes since v1:
>> >  - Make xfs_bmapi_convert_delalloc() to allocate the target offset and
>> >    drop the writeback helper xfs_convert_blocks().
>> >  - Don't use xfs_iomap_write_direct() to convert delalloc blocks for
>> >    zeroing posteof case, use xfs_bmapi_convert_delalloc() instead.
>> >  - Fix two off-by-one issues when converting delalloc blocks.
>> >  - Add a separate patch to drop the buffered write failure handle in
>> >    zeroing and unsharing.
>> >  - Add a comments do emphasize updating i_size should under folio lock.
>> >  - Make iomap_write_end() to return a boolean, and do some cleanups in
>> >    buffered write begin path.
>> >
>> > This patch series fix a problem of exposing zeroed data on xfs since the
>> > non-atomic clone operation. This problem was found while I was
>> > developing ext4 buffered IO iomap conversion (ext4 is relying on this
>> > fix [1]), the root cause of this problem and the discussion about the
>> > solution please see [2]. After fix the problem, iomap_zero_range()
>> > doesn't need to update i_size so that ext4 can use it to zero partial
>> > block, e.g. truncate eof block [3].
>> >
>> > [1] https://lore.kernel.org/linux-ext4/20240127015825.1608160-1-yi.zhang@huaweicloud.com/
>> > [2] https://lore.kernel.org/linux-ext4/9b0040ef-3d9d-6246-4bdd-82b9a8f55fa2@huaweicloud.com/
>> > [3] https://lore.kernel.org/linux-ext4/9c9f1831-a772-299b-072b-1c8116c3fb35@huaweicloud.com/
>> >
>> > Thanks,
>> > Yi.
>> >
>> > Zhang Yi (9):
>> >   xfs: match lock mode in xfs_buffered_write_iomap_begin()
>> >   xfs: make the seq argument to xfs_bmapi_convert_delalloc() optional
>> >   xfs: make xfs_bmapi_convert_delalloc() to allocate the target offset
>> >   xfs: convert delayed extents to unwritten when zeroing post eof blocks
>> >   iomap: drop the write failure handles when unsharing and zeroing
>> >   iomap: don't increase i_size if it's not a write operation
>> >   iomap: use a new variable to handle the written bytes in
>> >     iomap_write_iter()
>> >   iomap: make iomap_write_end() return a boolean
>> >   iomap: do some small logical cleanup in buffered write
>> >
>> 
>> Hi all,
>> 
>> I have picked up this patchset for inclusion into XFS' 6.10-rc1 patch
>> queue. Please let me know if there are any objections.
>
> It'd be nice if I could take the iomap patches into the vfs.iomap tree
> that you can then pull from if you depend on it.. There's already some
> cleanups in there. Sounds ok?

Yes, that works for me. I will pick only those patches that are specific to
XFS i.e. patches numbered 1 to 4.

-- 
Chandan

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