-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/4/2014 1:39 PM, Goffredo Baroncelli wrote: > LVM snapshots are a problem for the btrfs devices management. BTRFS > assumes that each device have an unique 'device UUID'. A LVM > snapshot breaks this assumption. > > This causes a lot of problems if some btrfs device are > snapshotted: - the set of devices for a btrfs multi-volume > filesystem may be mixed (i.e. some NON snapshotted device with some > snapshotted devices) - /proc/mount may returns a wrong device. > > In the mailing list some posts reported these incidents. > > This patch allows btrfs to skip LVM snapshot during the device scan > phase. > > But if you need to consider a LVM snapshot you can set the > environment variable BTRFS_SKIP_LVM_SNAPSHOT to "no". In this case > the old behavior is applied. > > To check if a device is a LVM snapshot, it is checked the 'udev' > device property 'DM_UDEV_LOW_PRIORITY_FLAG' . If it is set to 1, > the device has to be skipped. > > As consequence, btrfs now depends also by the libudev.
Rather than modify btrfs device scan to link to libudev and ignore the caller when commanded to scan a snapshot, wouldn't it be simpler/better to just fix the udev rule to not *call* btrfs device scan on the snapshot? -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) iQEcBAEBAgAGBQJUhcQyAAoJENRVrw2cjl5R1YAIAJlCine4apKnM+01Tw6JpofZ 447+FVizi5SjdgkcjcREyU5zu1pa7ioOTdExF1v1irN1xMUrRBL/RJcRjjnjkvjB dP8JU0x52MEvQABzQP9ANWJnkMqUJ0j+ryPn+3B7wLP/RtAnIn2P9Vh1EhiLkZ9N TdxZIPtPROWPTFBl9ONTBghOHjWYEtcDMkuTS6ZhwLh5c1LE8d3A9c68ez++oSGz TbS51ITFZCEUyF7E/r/xWHhrYagoRM+xdYqVACpi5eY8rFKl3oH4R96gBK8hNdiN AIOilSsNFscXiflORMAaRquW/7tUolfNt+3TfzTYmaVnK4Hv5h0wiJjiKJhNgDY= =HlmL -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
