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See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 34126C0041 X-Stat-Signature: 3xoqeztue4btqzfmwt9yx83d5ginq5az X-HE-Tag: 1738851264-424052 X-HE-Meta: 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 apWiIb3Q 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Feb 04, 2025 at 02:00:23PM +1030, Qu Wenruo wrote: > [BUG] > It is a long known bug that VM image on btrfs can lead to data csum > mismatch, if the qemu is using direct-io for the image (this is commonly > known as cache mode none). > > [CAUSE] > Inside the VM, if the fs is EXT4 or XFS, or even NTFS from Windows, the > fs is allowed to dirty/modify the folio even the folio is under > writeback (as long as the address space doesn't have AS_STABLE_WRITES > flag inherited from the block device). Btw, can you add an xfstests that reproduces this by modifying pages under direct I/O? That would be really helpful to verify the code when we want to turn back on real direct I/O eventually when the VM is fixed to prevent the modifications.