aio: fix freeze protection of aio writes (70fe2f48) · Commits · 戴 / test

Currently we dropped freeze protection of aio writes just after IO was submitted. Thus aio write could be in flight while the filesystem was frozen and that could result in unexpected situation like aio completion wanting to convert extent type on frozen filesystem. Testcase from Dmitry triggering this is like: for ((i=0;i<60;i++));do fsfreeze -f /mnt ;sleep 1;fsfreeze -u /mnt;done & fio --bs=4k --ioengine=libaio --iodepth=128 --size=1g --direct=1 \ --runtime=60 --filename=/mnt/file --name=rand-write --rw=randwrite Fix the problem by dropping freeze protection only once IO is completed in aio_complete(). Reported-by:

Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by:

Jan Kara <jack@suse.cz> [hch: forward ported on top of various VFS and aio changes] Signed-off-by:

Christoph Hellwig <hch@lst.de> Signed-off-by:

Al Viro <viro@zeniv.linux.org.uk>

fs/aio.c

+18 −1

Original line number	Diff line number	Diff line
		@@ -1078,6 +1078,17 @@ static void aio_complete(struct kiocb *kiocb, long res, long res2)
		unsigned tail, pos, head;
		unsigned long flags;

		if (kiocb->ki_flags & IOCB_WRITE) {
		struct file *file = kiocb->ki_filp;

		/*
		* Tell lockdep we inherited freeze protection from submission
		* thread.
		*/
		__sb_writers_acquired(file_inode(file)->i_sb, SB_FREEZE_WRITE);
		file_end_write(file);
		}

		/*
		* Special case handling for sync iocbs:
		* - events go directly into the iocb for fast handling
		@@ -1473,9 +1484,15 @@ static ssize_t aio_write(struct kiocb req, struct iocb iocb, bool vectored,
		return ret;
		ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
		if (!ret) {
		req->ki_flags \|= IOCB_WRITE;
		file_start_write(file);
		ret = aio_ret(req, file->f_op->write_iter(req, &iter));
		file_end_write(file);
		/*
		* We release freeze protection in aio_complete(). Fool lockdep
		* by telling it the lock got released so that it doesn't
		* complain about held lock when we return to userspace.
		*/
		__sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
		}
		kfree(iovec);
		return ret;

include/linux/fs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -321,6 +321,7 @@ struct writeback_control;
		#define IOCB_HIPRI (1 << 3)
		#define IOCB_DSYNC (1 << 4)
		#define IOCB_SYNC (1 << 5)
		#define IOCB_WRITE (1 << 6)

		struct kiocb {
		struct file *ki_filp;

Admin message