On Fri, Jan 20, 2012 at 09:34:40PM +0100, Jan Kara wrote: > There are three entry points which dirty pages in a filesystem. mmap (handled > by block_page_mkwrite()), buffered write (handled by > __generic_file_aio_write()), and truncate (it can dirty last partial page - > handled inside each filesystem separately). Protect these places with > sb_start_write() and sb_end_write(). fallocate can also dirty pages, either during preallocation or hole punching. Hence if you are going to promote truncate to SB_FREEZE_WRITE protection then you need to promote everything else that can zero partial blocks as well. That also means that anything the has implemented XFS_IOC_ ioctl interfaces for prellocation and hole punching (xfs, ocfs2 and gfs2 IIRC) also needs to be protected in the same way. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
