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Commit c18ceab0 authored by Wengang Wang's avatar Wengang Wang Committed by Linus Torvalds
Browse files

ocfs2: change ip_unaligned_aio to of type mutex from atomit_t 



There is a problem that waitqueue_active() may check stale data thus miss
a wakeup of threads waiting on ip_unaligned_aio.

The valid value of ip_unaligned_aio is only 0 and 1 so we can change it to
be of type mutex thus the above prolem is avoid.  Another benifit is that
mutex which works as FIFO is fairer than wake_up_all().

Signed-off-by: default avatarWengang Wang <wen.gang.wang@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 181a9a04

fs/ocfs2/aops.c

+1 −5
Original line number Diff line number Diff line
@@ -571,7 +571,6 @@ static void ocfs2_dio_end_io(struct kiocb *iocb, 
{

	struct inode *inode = file_inode(iocb->ki_filp);

	int level;

	wait_queue_head_t *wq = ocfs2_ioend_wq(inode);



	/* this io's submitter should not have unlocked this before we could */

	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
@@ -582,10 +581,7 @@ static void ocfs2_dio_end_io(struct kiocb *iocb, 
	if (ocfs2_iocb_is_unaligned_aio(iocb)) {

		ocfs2_iocb_clear_unaligned_aio(iocb);



		if (atomic_dec_and_test(&OCFS2_I(inode)->ip_unaligned_aio) &&

		    waitqueue_active(wq)) {

			wake_up_all(wq);

		}

		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);

	}



	ocfs2_iocb_clear_rw_locked(iocb);

fs/ocfs2/aops.h

+0 −5
Original line number Diff line number Diff line
@@ -102,9 +102,4 @@ enum ocfs2_iocb_lock_bits { 
#define ocfs2_iocb_is_unaligned_aio(iocb) \

	test_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)



#define OCFS2_IOEND_WQ_HASH_SZ	37

#define ocfs2_ioend_wq(v)   (&ocfs2__ioend_wq[((unsigned long)(v)) %\

					    OCFS2_IOEND_WQ_HASH_SZ])

extern wait_queue_head_t ocfs2__ioend_wq[OCFS2_IOEND_WQ_HASH_SZ];



#endif /* OCFS2_FILE_H */

fs/ocfs2/file.c

+3 −12
Original line number Diff line number Diff line
@@ -2061,13 +2061,6 @@ int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos, 
	return ret;

}



static void ocfs2_aiodio_wait(struct inode *inode)

{

	wait_queue_head_t *wq = ocfs2_ioend_wq(inode);



	wait_event(*wq, (atomic_read(&OCFS2_I(inode)->ip_unaligned_aio) == 0));

}



static int ocfs2_is_io_unaligned(struct inode *inode, size_t count, loff_t pos)

{

	int blockmask = inode->i_sb->s_blocksize - 1;
@@ -2345,10 +2338,8 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb, 
		 * Wait on previous unaligned aio to complete before

		 * proceeding.

		 */

		ocfs2_aiodio_wait(inode);



		/* Mark the iocb as needing a decrement in ocfs2_dio_end_io */

		atomic_inc(&OCFS2_I(inode)->ip_unaligned_aio);

		mutex_lock(&OCFS2_I(inode)->ip_unaligned_aio);

		/* Mark the iocb as needing an unlock in ocfs2_dio_end_io */

		ocfs2_iocb_set_unaligned_aio(iocb);

	}
@@ -2428,7 +2419,7 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb, 


	if (unaligned_dio) {

		ocfs2_iocb_clear_unaligned_aio(iocb);

		atomic_dec(&OCFS2_I(inode)->ip_unaligned_aio);

		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);

	}



out:

fs/ocfs2/inode.h

+1 −1
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ struct ocfs2_inode_info 
	struct rw_semaphore		ip_xattr_sem;



	/* Number of outstanding AIO's which are not page aligned */

	atomic_t			ip_unaligned_aio;

	struct mutex			ip_unaligned_aio;



	/* These fields are protected by ip_lock */

	spinlock_t			ip_lock;

fs/ocfs2/super.c

+2 −7
Original line number Diff line number Diff line
@@ -1612,14 +1612,9 @@ static int ocfs2_show_options(struct seq_file *s, struct dentry *root) 
	return 0;

}



wait_queue_head_t ocfs2__ioend_wq[OCFS2_IOEND_WQ_HASH_SZ];



static int __init ocfs2_init(void)

{

	int status, i;



	for (i = 0; i < OCFS2_IOEND_WQ_HASH_SZ; i++)

		init_waitqueue_head(&ocfs2__ioend_wq[i]);

	int status;



	status = init_ocfs2_uptodate_cache();

	if (status < 0)
@@ -1761,7 +1756,7 @@ static void ocfs2_inode_init_once(void *data) 
	ocfs2_extent_map_init(&oi->vfs_inode);

	INIT_LIST_HEAD(&oi->ip_io_markers);

	oi->ip_dir_start_lookup = 0;

	atomic_set(&oi->ip_unaligned_aio, 0);

	mutex_init(&oi->ip_unaligned_aio);

	init_rwsem(&oi->ip_alloc_sem);

	init_rwsem(&oi->ip_xattr_sem);

	mutex_init(&oi->ip_io_mutex);