From: Christoph Hellwig <hch@lst.de>
To: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: glaubitz@physik.fu-berlin.de, frank.li@vivo.com, hch@lst.de,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
vdubeyko@coreweave.com, willy@infradead.org, brauner@kernel.org,
djwong@kernel.org
Subject: Re: [PATCH v4 3/7] hfsplus: take the bitmap page lock for allocate/free
Date: Fri, 18 Sep 2026 15:30:26 +0200 [thread overview]
Message-ID: <20260918133026.GC18107@lst.de> (raw)
In-Reply-To: <20260914233941.2966421-4-slava@dubeyko.com>
On Mon, Sep 14, 2026 at 04:39:37PM -0700, Viacheslav Dubeyko wrote:
> The hfsplus_block_allocate() and hfsplus_block_free() kmap
> the allocation bitmap's pages and modify their bits in place
> under sbi->alloc_mutex, but without holding the page lock.
> That leaves the read-modify-write of the bitmap bits
> unprotected against a concurrent writeback of the same page,
> which can read a partially-updated bitmap word or race with
> the dirty-bit update.
Looks good:
Reviewed-by: Christoph Hellwig <hch@lst.de>
> + lock_page(page);
> + folio_wait_writeback(page_folio(page));
> pptr = kmap_local_page(page);
Although this really begs for a folio conversion rather sooner than
later.
next prev parent reply other threads:[~2026-09-18 13:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 23:39 [PATCH v4 0/7] hfsplus: convert regular file I/O to iomap-based operations Viacheslav Dubeyko
2026-09-14 23:39 ` [PATCH v4 1/7] hfs/hfsplus: exchange hardcoded number of extents on named constants Viacheslav Dubeyko
2026-09-18 13:28 ` Christoph Hellwig
2026-09-14 23:39 ` [PATCH v4 2/7] hfsplus: rework hfsplus_get_block() logic Viacheslav Dubeyko
2026-09-15 2:34 ` Darrick J. Wong
2026-09-15 18:34 ` Viacheslav Dubeyko
2026-09-18 13:29 ` Christoph Hellwig
2026-09-14 23:39 ` [PATCH v4 3/7] hfsplus: take the bitmap page lock for allocate/free Viacheslav Dubeyko
2026-09-18 13:30 ` Christoph Hellwig [this message]
2026-09-14 23:39 ` [PATCH v4 4/7] hfsplus: add iomap operations for regular file data Viacheslav Dubeyko
2026-09-18 13:36 ` Christoph Hellwig
2026-09-23 23:19 ` Viacheslav Dubeyko
2026-09-14 23:39 ` [PATCH v4 5/7] hfsplus: move file related operations to file.c Viacheslav Dubeyko
2026-09-15 2:22 ` Darrick J. Wong
2026-09-18 13:31 ` Christoph Hellwig
2026-09-14 23:39 ` [PATCH v4 6/7] hfsplus: introduce iomap-based file_operations Viacheslav Dubeyko
2026-09-18 13:39 ` Christoph Hellwig
2026-09-25 0:07 ` Viacheslav Dubeyko
2026-09-25 7:15 ` Christoph Hellwig
2026-09-14 23:39 ` [PATCH v4 7/7] hfsplus: switch address_space_operations on iomap-based support Viacheslav Dubeyko
2026-09-15 2:21 ` Darrick J. Wong
2026-09-15 18:37 ` Viacheslav Dubeyko
2026-09-18 13:57 ` Christoph Hellwig
2026-09-25 22:35 ` Viacheslav Dubeyko
2026-09-28 5:36 ` Christoph Hellwig
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