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Denis V. Lunev
af28b65fae
qcow2_reopen_prepare() clears the dirty bit whenever the node is reopened read-only, with an unguarded header write. A read-only node can still be dirty, inherited from an earlier writable session, and it holds no BLK_PERM_WRITE to resolve that. A read-only to read-only reopen of a dirty image therefore fails outright: $ qemu-io -r -f qcow2 dirty.qcow2 <<< $'reopen -r\nquit' qemu-io: failed while preparing to reopen image 'dirty.qcow2' Where the file node below is writable the write is not refused early, and bdrv_co_write_req_prepare() aborts on its BLK_PERM_WRITE assertion instead. Clear it only for a node that is writable now, the predicate qcow2_do_open() already uses for the repair. bdrv_is_writable() also excludes an inactive node, whose header must not be touched either. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> CC: Kevin Wolf <kwolf@redhat.com> CC: Hanna Reitz <hreitz@redhat.com> CC: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com> Cc: qemu-stable@nongnu.org Message-ID: <20260824133729.1141990-2-den@openvz.org> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>