Hello everyone, The test below creates a sparse file and then fills a hole with O_DIRECT. As far as I can tell from reading generic_osync_inode, the filesystem metadata is only forced to disk if i_size changes during the file write. I've tested ext3, xfs and reiserfs and they all skip the commit when filling holes. I would argue that filling holes via O_DIRECT is supposed to commit the metadata required to find those file blocks later. At least on ext3, O_SYNC does force a commit on fill holes (haven't tested others). So, is the current behavior a bug or a feature? dd if=/dev/zero of=foo bs=1M seek=1 count=1 oflag=direct hexdump foo | head -n 2 0000000 62b1 ea2d 73e8 c64f f5ef 1af5 dd09 8ccd 0000010 75ec 9581 e0ea ae9b e28f b76d a700 4d5b dd if=/dev/urandom of=foo bs=4k count=1 conv=notrunc oflag=direct reboot -nf (after reboot) hexdump foo 0000000 0000 0000 0000 0000 0000 0000 0000 0000 * 0200000 -chris - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
