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Message-ID: <beae5aaf-eb90-4486-9430-3ac7c9d020b4@suse.de>
Date: Mon, 3 Jun 2024 08:35:54 +0200
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Subject: Re: [PATCH v6 06/11] filemap: cap PTE range to be created to allowed
 zero fill in folio_map_range()
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To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>, david@fromorbit.com,
 chandan.babu@oracle.com, akpm@linux-foundation.org, brauner@kernel.org,
 willy@infradead.org, djwong@kernel.org
Cc: linux-kernel@vger.kernel.org, john.g.garry@oracle.com,
 gost.dev@samsung.com, yang@os.amperecomputing.com, p.raghav@samsung.com,
 cl@os.amperecomputing.com, linux-xfs@vger.kernel.org, hch@lst.de,
 mcgrof@kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
References: <20240529134509.120826-1-kernel@pankajraghav.com>
 <20240529134509.120826-7-kernel@pankajraghav.com>
From: Hannes Reinecke <hare@suse.de>
In-Reply-To: <20240529134509.120826-7-kernel@pankajraghav.com>
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On 5/29/24 15:45, Pankaj Raghav (Samsung) wrote:
> From: Pankaj Raghav <p.raghav@samsung.com>
> 
> Usually the page cache does not extend beyond the size of the inode,
> therefore, no PTEs are created for folios that extend beyond the size.
> 
> But with LBS support, we might extend page cache beyond the size of the
> inode as we need to guarantee folios of minimum order. Cap the PTE range
> to be created for the page cache up to the max allowed zero-fill file
> end, which is aligned to the PAGE_SIZE.
> 
> An fstests test has been created to trigger this edge case [0].
> 
> [0] https://lore.kernel.org/fstests/20240415081054.1782715-1-mcgrof@kernel.org/
> 
> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> ---
>   mm/filemap.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
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