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corruption bug in cmirror. 'dm_bit' is only ever used as a boolean operation within LVM, but it can return a range of values. If the bit is set, a power of 2 is returned. If the bit is unset, 0 is returned. 'log_test_bit' (a function in the cluster mirror log daemon code) has switched to using the dm bit operations in rhel6. There are two places in the daemon code where 'log_test_bit' is not used merely as a boolean, but rather the return value is used as the return value for the log functions 'is_clean' and 'in_sync' - having assumed that 'dm_bit' was returning 0 or 1 only. One place the 'in_sync' function is utilized is in 'dm_rh_get_state' - a function that informs the mirroring code how to treat I/O and which devices to read/write from. 'dm_rh_get_state' was checking if the return value of 'in_sync' was 1 to determine if the region was DM_RH_CLEAN. Since 'dm_bit' (and by extension 'log_test_bit' and 'in_sync') was returning powers of 2, DM_RH_CLEAN was rarely being reported as it should have been. Thinking the region was out-of-sync, the mirroring code would write only to the primary device. When the primary device was failed, all of those writes were lost - leaving the entire mirror corrupted.
This tree contains the LVM2 and device-mapper tools and libraries. For more information about LVM2 read the changelog in the WHATS_NEW file. Installation instructions are in INSTALL. There is no warranty - see COPYING and COPYING.LIB. Tarballs are available from: ftp://sources.redhat.com/pub/lvm2/ To access the CVS tree use: cvs -d :pserver:cvs@sources.redhat.com:/cvs/lvm2 login CVS password: cvs cvs -d :pserver:cvs@sources.redhat.com:/cvs/lvm2 co LVM2 Mailing list for general discussion related to LVM2: linux-lvm@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm Mailing list for LVM2 development, patches and commits: lvm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/linux-lvm Mailing list for device-mapper development, including kernel patches and multipath-tools: dm-devel@redhat.com Subscribe from https://www.redhat.com/mailman/listinfo/dm-devel