Re: [PATCH v4 0/9] xfs/iomap: fix non-atomic clone operation and don't update size when zeroing range post eof

[Christian Brauner]

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@xxxxxxxxxxxxxxx/
> > [2] https://lore.kernel.org/linux-ext4/9b0040ef-3d9d-6246-4bdd-82b9a8f55fa2@xxxxxxxxxxxxxxx/
> > [3] https://lore.kernel.org/linux-ext4/9c9f1831-a772-299b-072b-1c8116c3fb35@xxxxxxxxxxxxxxx/
> >
> > 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?