On Wed, May 11, 2011 at 12:29:34AM +0200, Jan Kara wrote: > We should not allow file modification via mmap while the filesystem is > frozen. So block in ext4_page_mkwrite() while the filesystem is frozen. > > We have to check for frozen filesystem with the page marked dirty and under > page lock with which we then return from ext4_page_mkwrite(). Only that way we > cannot race with writeback done by freezing code - either we mark the page > dirty after the writeback has started, see freezing in progress and block, or > writeback will wait for our page lock which is released only when the fault is > done and then writeback will writeout and writeprotect the page again. This really should be done in (__)block_page_mkwrite. I'd also return VM_FAULT_RETRY instead of retrying inside the block_mkwrite handler in case you hit the race. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
