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From: sashiko-bot@kernel.org
To: "Daejun Park" <daejun7.park@samsung.com>
Cc: tytso@mit.edu, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] ext4: don't report delalloc data as a hole on indirect-mapped inodes
Date: Wed, 26 Aug 2026 05:34:26 +0000	[thread overview]
Message-ID: <20260826053427.796C71F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260826052446epcms2p5a415be5fbfe23b8a32786f0ae6d05aea@epcms2p5>

> When a plain lookup finds no block, ext4_ind_map_blocks() sizes the hole
> it reports by counting the empty subtrees under 'partial' in the on-disk
> indirect tree.  That count knows nothing about delayed allocation, so a
> range holding delalloc data that has not been written back yet is
> reported as a plain hole.  The extent-mapped path does not have this
> problem: ext4_ext_determine_insert_hole() trims the hole it found at the
> first delayed extent before returning it.
> 
> ext4_map_blocks() consults the extent status tree before it calls into
> the mapping layer, so a query that starts exactly on the delayed block
> still finds it.  A query that starts earlier does not, because the hole
> reported for the earlier block already spans the delayed one.  On a
> 4k-block filesystem, lseek(SEEK_DATA) from offset 0 on a file whose only
> data block is at logical block N and is still dirty returns:
> 
> [ ... ]
> Fixes: facab4d9711e ("ext4: return hole from ext4_map_blocks()")
> Reported-by: Alexander Monakov <amonakov@ispras.ru>
> Closes: https://lore.kernel.org/linux-ext4/594c17d9-c00f-e485-96fb-cedf27ce3aa3@ispras.ru/
> Cc: stable@vger.kernel.org
> Signed-off-by: Daejun Park <daejun7.park@samsung.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260826052446epcms2p5a415be5fbfe23b8a32786f0ae6d05aea@epcms2p5?part=1


  reply	other threads:[~2026-08-26  5:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20260826052446epcms2p5a415be5fbfe23b8a32786f0ae6d05aea@epcms2p5>
2026-08-26  5:24 ` [PATCH] ext4: don't report delalloc data as a hole on indirect-mapped inodes Daejun Park
2026-08-26  5:34   ` sashiko-bot [this message]
2026-08-26 16:55   ` Jan Kara

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