Hi Neil, I am reading following lines from "raid5.h" , not clear what they mean. If some DMA engines doesn't support what should we do ? * 1/ Parity check operations destroy the in cache version of the parity block, * so we prevent parity dependent operations like writes and compute_blocks * from starting while a check is in progress. Some dma engines can perform * the check without damaging the parity block, in these cases the parity * block is re-marked up to date (assuming the check was successful) and is * not re-read from disk. Regards, Marri -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Tirumala Reddy Marri Sent: Monday, July 20, 2009 10:39 AM To: linux-raid@xxxxxxxxxxxxxxx Subject: Question on RAID-5 rmw & rcw(read modify write & read construct write) Hi, I am trying to understand read-modify-write & read-construct-write as part of my HW accelerated RAID-5 driver debugging. How it is decided on stripe to be rmw/rcw ? Is this happen every time when application try to write to disks with bio of less than a chunk size ? I am seeing file system inconsistencies while raid-5 recovery is happening and writing data to /dev/md0 with ext3/ext2 installed and mounted on a directory. Thanks in advance, Marri -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
