Ocfs2 devel - Nov 2015 - [PATCH 1/4] ocfs2: fix ip_unaligned_aio deadlock with dio work queue

In the current implementation of unaligned aio+dio, lock order behave as follow:

in user process context:
  -> call io_submit()
    -> get i_mutex
		<== window1
      -> get ip_unaligned_aio
        -> submit direct io to block device
    -> release i_mutex
  -> io_submit() return

in dio work queue context(the work queue is created in __blockdev_direct_IO):
  -> release ip_unaligned_aio
		<== window2
    -> get i_mutex
      -> clear unwritten flag & change i_size
    -> release i_mutex

There is a limitation to the thread number of dio work queue. 256 at default.
If all 256 thread are in the above 'window2' stage, and there is a user
process
in the 'window1' stage, the system will became deadlock. Since the user
process
hold i_mutex to wait ip_unaligned_aio lock, while there is a direct bio hold
ip_unaligned_aio mutex who is waiting for a dio work queue thread to be
schedule. But all the dio work queue thread is waiting for i_mutex lock in
'window2'.

This case only happened in a test which send a large number(more than 256) of
aio at one io_submit() call.

My design is to remove ip_unaligned_aio lock. Change it to a sync io instead.
Just like ip_unaligned_aio lock, serialize the unaligned aio dio.

Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
---
 fs/ocfs2/aops.c  |    6 ------
 fs/ocfs2/aops.h  |    7 -------
 fs/ocfs2/file.c  |   27 +++++++++------------------
 fs/ocfs2/inode.h |    3 ---
 fs/ocfs2/super.c |    1 -
 5 files changed, 9 insertions(+), 35 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 4bb9921..cc604a2 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2388,12 +2388,6 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
 	/* this io's submitter should not have unlocked this before we could */
 	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
 
-	if (ocfs2_iocb_is_unaligned_aio(iocb)) {
-		ocfs2_iocb_clear_unaligned_aio(iocb);
-
-		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
-	}
-
 	if (private)
 		ocfs2_dio_end_io_write(inode, private, offset, bytes);
 
diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
index d06b80f..7fc1189 100644
--- a/fs/ocfs2/aops.h
+++ b/fs/ocfs2/aops.h
@@ -93,11 +93,4 @@ enum ocfs2_iocb_lock_bits {
 #define ocfs2_iocb_rw_locked_level(iocb) \
 	test_bit(OCFS2_IOCB_RW_LOCK_LEVEL, (unsigned long *)&iocb->private)
 
-#define ocfs2_iocb_set_unaligned_aio(iocb) \
-	set_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)
-#define ocfs2_iocb_clear_unaligned_aio(iocb) \
-	clear_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)
-#define ocfs2_iocb_is_unaligned_aio(iocb) \
-	test_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)
-
 #endif /* OCFS2_FILE_H */
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 05346fb..6ab91cd 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2170,7 +2170,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 	int full_coherency = !(osb->s_mount_opt &
 			       OCFS2_MOUNT_COHERENCY_BUFFERED);
-	int unaligned_dio = 0;
+	void *saved_ki_complete = NULL;
 	int append_write = ((iocb->ki_pos + count) > 			i_size_read(inode) ? 1 :
0);
 
@@ -2233,17 +2233,12 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 		goto out;
 	}
 
-	if (direct_io && !is_sync_kiocb(iocb))
-		unaligned_dio = ocfs2_is_io_unaligned(inode, count, iocb->ki_pos);
-
-	if (unaligned_dio) {
+	if (direct_io && !is_sync_kiocb(iocb) &&
+	    ocfs2_is_io_unaligned(inode, count, iocb->ki_pos)) {
 		/*
-		 * Wait on previous unaligned aio to complete before
-		 * proceeding.
+		 * Make it a sync io if it's an 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);
+		saved_ki_complete = xchg(&iocb->ki_complete, NULL);
 	}
 
 	/* communicate with ocfs2_dio_end_io */
@@ -2264,11 +2259,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 	 */
 	if ((written == -EIOCBQUEUED) || (!ocfs2_iocb_is_rw_locked(iocb))) {
 		rw_level = -1;
-		unaligned_dio = 0;
 	}
 
 	if (unlikely(written <= 0))
-		goto no_sync;
+		goto out;
 
 	if (((file->f_flags & O_DSYNC) && !direct_io) ||
 	    IS_SYNC(inode)) {
@@ -2290,13 +2284,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 						      iocb->ki_pos - 1);
 	}
 
-no_sync:
-	if (unaligned_dio && ocfs2_iocb_is_unaligned_aio(iocb)) {
-		ocfs2_iocb_clear_unaligned_aio(iocb);
-		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
-	}
-
 out:
+	if (saved_ki_complete)
+		xchg(&iocb->ki_complete, saved_ki_complete);
+
 	if (rw_level != -1)
 		ocfs2_rw_unlock(inode, rw_level);
 
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 0c22ddd..6e0633e 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -43,9 +43,6 @@ struct ocfs2_inode_info
 	/* protects extended attribute changes on this inode */
 	struct rw_semaphore		ip_xattr_sem;
 
-	/* Number of outstanding AIO's which are not page aligned */
-	struct mutex			ip_unaligned_aio;
-
 	/* These fields are protected by ip_lock */
 	spinlock_t			ip_lock;
 	u32				ip_open_count;
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index c70a80b..3fd171f 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1723,7 +1723,6 @@ static void ocfs2_inode_init_once(void *data)
 	INIT_LIST_HEAD(&oi->ip_io_markers);
 	INIT_LIST_HEAD(&oi->ip_unwritten_list);
 	oi->ip_dir_start_lookup = 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);
-- 
1.7.1

Take ip_alloc_sem to prevent concurrent access to extent tree, which may cause
the extent tree in an unstable state.

Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
---
 fs/ocfs2/aops.c |   23 +++++++++++++++++------
 1 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index cc604a2..d571509 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2151,6 +2151,7 @@ static int ocfs2_dio_get_block(struct inode *inode,
sector_t iblock,
 			       struct buffer_head *bh_result, int create)
 {
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 	struct ocfs2_write_ctxt *wc;
 	struct ocfs2_write_cluster_desc *desc = NULL;
 	struct ocfs2_dio_write_ctxt *dwc = NULL;
@@ -2166,9 +2167,12 @@ static int ocfs2_dio_get_block(struct inode *inode,
sector_t iblock,
 	mlog(0, "get block of %lu at %llu:%u req %u\n",
 			inode->i_ino, pos, len, total_len);
 
+	down_read(&oi->ip_alloc_sem);
 	/* This is the fast path for re-write. */
 	ret = ocfs2_get_block(inode, iblock, bh_result, create);
 
+	up_read(&oi->ip_alloc_sem);
+
 	if (buffer_mapped(bh_result) &&
 	    !buffer_new(bh_result) &&
 	    ret == 0)
@@ -2206,6 +2210,8 @@ static int ocfs2_dio_get_block(struct inode *inode,
sector_t iblock,
 		goto out;
 	}
 
+	down_write(&oi->ip_alloc_sem);
+
 	if (first_get_block) {
 		if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
 			ret = ocfs2_zero_tail(inode, di_bh, pos);
@@ -2259,6 +2265,7 @@ static int ocfs2_dio_get_block(struct inode *inode,
sector_t iblock,
 	BUG_ON(ret != len);
 	ret = 0;
 unlock:
+	up_write(&oi->ip_alloc_sem);
 	ocfs2_inode_unlock(inode, 1);
 	brelse(di_bh);
 out:
@@ -2275,6 +2282,7 @@ static void ocfs2_dio_end_io_write(struct inode *inode,
 	struct ocfs2_cached_dealloc_ctxt dealloc;
 	struct ocfs2_extent_tree et;
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
 	struct ocfs2_unwritten_extent *ue = NULL;
 	struct buffer_head *di_bh = NULL;
 	struct ocfs2_dinode *di;
@@ -2293,12 +2301,6 @@ static void ocfs2_dio_end_io_write(struct inode *inode,
 	    !dwc->dw_orphaned)
 		goto out;
 
-	ret = ocfs2_inode_lock(inode, &di_bh, 1);
-	if (ret < 0) {
-		mlog_errno(ret);
-		goto out;
-	}
-
 	/* ocfs2_file_write_iter will get i_mutex, so we need not lock if we
 	 * are in that context. */
 	if (dwc->dw_writer_pid != task_pid_nr(current)) {
@@ -2306,6 +2308,14 @@ static void ocfs2_dio_end_io_write(struct inode *inode,
 		locked = 1;
 	}
 
+	ret = ocfs2_inode_lock(inode, &di_bh, 1);
+	if (ret < 0) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	down_write(&oi->ip_alloc_sem);
+
 	/* Delete orphan before acquire i_mutex. */
 	if (dwc->dw_orphaned) {
 		BUG_ON(dwc->dw_writer_pid != task_pid_nr(current));
@@ -2359,6 +2369,7 @@ static void ocfs2_dio_end_io_write(struct inode *inode,
 commit:
 	ocfs2_commit_trans(osb, handle);
 unlock:
+	up_write(&oi->ip_alloc_sem);
 	ocfs2_inode_unlock(inode, 1);
 	brelse(di_bh);
 out:
-- 
1.7.1

When doing append direct write in an already allocated cluster, and fast path
in ocfs2_dio_get_block() is triggered, function ocfs2_dio_end_io_write() will
be skipped as there is no context allocated. So disk file size will not be
changed as it should be.
The solution is to skip fast path when we are about to change file size.

Fixes: af1310367f41 ("ocfs2: fix sparse file & data ordering issue in
direct io.")
Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
---
 fs/ocfs2/aops.c |   27 +++++++++++++++++----------
 1 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index d571509..f33cfe4 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2167,19 +2167,26 @@ static int ocfs2_dio_get_block(struct inode *inode,
sector_t iblock,
 	mlog(0, "get block of %lu at %llu:%u req %u\n",
 			inode->i_ino, pos, len, total_len);
 
-	down_read(&oi->ip_alloc_sem);
-	/* This is the fast path for re-write. */
-	ret = ocfs2_get_block(inode, iblock, bh_result, create);
+	/*
+	 * Because we need to change file size in ocfs2_dio_end_io_write(), or
+	 * we may need to add it to orphan dir. So can not fall to fast path
+	 * while file size will be changed.
+	 */
+	if (pos + total_len <= i_size_read(inode)) {
+		down_read(&oi->ip_alloc_sem);
+		/* This is the fast path for re-write. */
+		ret = ocfs2_get_block(inode, iblock, bh_result, create);
 
-	up_read(&oi->ip_alloc_sem);
+		up_read(&oi->ip_alloc_sem);
 
-	if (buffer_mapped(bh_result) &&
-	    !buffer_new(bh_result) &&
-	    ret == 0)
-		goto out;
+		if (buffer_mapped(bh_result) &&
+		    !buffer_new(bh_result) &&
+		    ret == 0)
+			goto out;
 
-	/* Clear state set by ocfs2_get_block. */
-	bh_result->b_state = 0;
+		/* Clear state set by ocfs2_get_block. */
+		bh_result->b_state = 0;
+	}
 
 	dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
 	if (unlikely(dwc == NULL)) {
-- 
1.7.1

Should call ocfs2_free_alloc_context() to free meta_ac & data_ac before
calling
ocfs2_run_deallocs(). Because ocfs2_run_deallocs() will acquire the system
inode's i_mutex hold by meta_ac. So try to release the lock before
ocfs2_run_deallocs().

Fixes: af1310367f41 ("ocfs2: fix sparse file & data ordering issue in
direct io.")
Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
---
 fs/ocfs2/aops.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index f33cfe4..182f754 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2341,6 +2341,10 @@ static void ocfs2_dio_end_io_write(struct inode *inode,
 
 	ret = ocfs2_lock_allocators(inode, &et, 0, dwc->dw_zero_count*2,
 				    &data_ac, &meta_ac);
+	if (ret) {
+		mlog_errno(ret);
+		goto unlock;
+	}
 
 	credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list);
 
@@ -2380,14 +2384,14 @@ unlock:
 	ocfs2_inode_unlock(inode, 1);
 	brelse(di_bh);
 out:
-	ocfs2_run_deallocs(osb, &dealloc);
-	if (locked)
-		mutex_unlock(&inode->i_mutex);
-	ocfs2_dio_free_write_ctx(inode, dwc);
 	if (data_ac)
 		ocfs2_free_alloc_context(data_ac);
 	if (meta_ac)
 		ocfs2_free_alloc_context(meta_ac);
+	ocfs2_run_deallocs(osb, &dealloc);
+	if (locked)
+		mutex_unlock(&inode->i_mutex);
+	ocfs2_dio_free_write_ctx(inode, dwc);
 }
 
 /*
-- 
1.7.1

On Fri, 20 Nov 2015 16:23:16 +0800 Ryan Ding <ryan.ding at oracle.com>
wrote:
> In the current implementation of unaligned aio+dio, lock order behave as
follow:
> 
> in user process context:
>   -> call io_submit()
>     -> get i_mutex
> 		<== window1
>       -> get ip_unaligned_aio
>         -> submit direct io to block device
>     -> release i_mutex
>   -> io_submit() return
> 
> in dio work queue context(the work queue is created in
__blockdev_direct_IO):
>   -> release ip_unaligned_aio
> 		<== window2
>     -> get i_mutex
>       -> clear unwritten flag & change i_size
>     -> release i_mutex
> 
> There is a limitation to the thread number of dio work queue. 256 at
default.
> If all 256 thread are in the above 'window2' stage, and there is a
user process
> in the 'window1' stage, the system will became deadlock. Since the
user process
> hold i_mutex to wait ip_unaligned_aio lock, while there is a direct bio
hold
> ip_unaligned_aio mutex who is waiting for a dio work queue thread to be
> schedule. But all the dio work queue thread is waiting for i_mutex lock in
> 'window2'.
> 
> This case only happened in a test which send a large number(more than 256)
of
> aio at one io_submit() call.
> 
> My design is to remove ip_unaligned_aio lock. Change it to a sync io
instead.
> Just like ip_unaligned_aio lock, serialize the unaligned aio dio.
So this patch series is a bunch of fixes against your previous patch series:

ocfs2-add-ocfs2_write_type_t-type-to-identify-the-caller-of-write.patch
ocfs2-use-c_new-to-indicate-newly-allocated-extents.patch
ocfs2-test-target-page-before-change-it.patch
ocfs2-do-not-change-i_size-in-write_end-for-direct-io.patch
ocfs2-return-the-physical-address-in-ocfs2_write_cluster.patch
ocfs2-record-unwritten-extents-when-populate-write-desc.patch
ocfs2-fix-sparse-file-data-ordering-issue-in-direct-io.patch
ocfs2-code-clean-up-for-direct-io.patch

correct?

Those patches are languishing a bit, awaiting review/ack.  I'll send
everything out for a round of review soon...

Hi Ryan,

On 11/20/2015 04:23 PM, Ryan Ding wrote:
> In the current implementation of unaligned aio+dio, lock order behave as
follow:
> 
> in user process context:
>   -> call io_submit()
>     -> get i_mutex
> 		<== window1
>       -> get ip_unaligned_aio
>         -> submit direct io to block device
>     -> release i_mutex
>   -> io_submit() return
> 
> in dio work queue context(the work queue is created in
__blockdev_direct_IO):
>   -> release ip_unaligned_aio
> 		<== window2
>     -> get i_mutex
>       -> clear unwritten flag & change i_size
>     -> release i_mutex
> 
> There is a limitation to the thread number of dio work queue. 256 at
default.
> If all 256 thread are in the above 'window2' stage, and there is a
user process
> in the 'window1' stage, the system will became deadlock. Since the
user process
> hold i_mutex to wait ip_unaligned_aio lock, while there is a direct bio
hold
> ip_unaligned_aio mutex who is waiting for a dio work queue thread to be
> schedule. But all the dio work queue thread is waiting for i_mutex lock in
> 'window2'.
> 
> This case only happened in a test which send a large number(more than 256)
of
> aio at one io_submit() call.
> 
> My design is to remove ip_unaligned_aio lock. Change it to a sync io
instead.
> Just like ip_unaligned_aio lock, serialize the unaligned aio dio.
> 
> Signed-off-by: Ryan Ding <ryan.ding at oracle.com>
> ---
>  fs/ocfs2/aops.c  |    6 ------
>  fs/ocfs2/aops.h  |    7 -------
>  fs/ocfs2/file.c  |   27 +++++++++------------------
>  fs/ocfs2/inode.h |    3 ---
>  fs/ocfs2/super.c |    1 -
>  5 files changed, 9 insertions(+), 35 deletions(-)
> 
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index 4bb9921..cc604a2 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -2388,12 +2388,6 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
>  	/* this io's submitter should not have unlocked this before we could
*/
>  	BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
>  
> -	if (ocfs2_iocb_is_unaligned_aio(iocb)) {
> -		ocfs2_iocb_clear_unaligned_aio(iocb);
> -
> -		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
> -	}
> -
>  	if (private)
>  		ocfs2_dio_end_io_write(inode, private, offset, bytes);
>  
> diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
> index d06b80f..7fc1189 100644
> --- a/fs/ocfs2/aops.h
> +++ b/fs/ocfs2/aops.h
> @@ -93,11 +93,4 @@ enum ocfs2_iocb_lock_bits {
>  #define ocfs2_iocb_rw_locked_level(iocb) \
>  	test_bit(OCFS2_IOCB_RW_LOCK_LEVEL, (unsigned long
*)&iocb->private)
>  
> -#define ocfs2_iocb_set_unaligned_aio(iocb) \
> -	set_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)
> -#define ocfs2_iocb_clear_unaligned_aio(iocb) \
> -	clear_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long
*)&iocb->private)
> -#define ocfs2_iocb_is_unaligned_aio(iocb) \
> -	test_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private)
> -
OCFS2_IOCB_UNALIGNED_IO is useless now. Please remove its definition.

Other looks good.
Reviewed-by: Junxiao Bi <junxiao.bi at oracle.com>

>  #endif /* OCFS2_FILE_H */
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 05346fb..6ab91cd 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -2170,7 +2170,7 @@ static ssize_t ocfs2_file_write_iter(struct kiocb
*iocb,
>  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>  	int full_coherency = !(osb->s_mount_opt &
>  			       OCFS2_MOUNT_COHERENCY_BUFFERED);
> -	int unaligned_dio = 0;
> +	void *saved_ki_complete = NULL;
>  	int append_write = ((iocb->ki_pos + count) >>  		
i_size_read(inode) ? 1 : 0);
>  
> @@ -2233,17 +2233,12 @@ static ssize_t ocfs2_file_write_iter(struct kiocb
*iocb,
>  		goto out;
>  	}
>  
> -	if (direct_io && !is_sync_kiocb(iocb))
> -		unaligned_dio = ocfs2_is_io_unaligned(inode, count, iocb->ki_pos);
> -
> -	if (unaligned_dio) {
> +	if (direct_io && !is_sync_kiocb(iocb) &&
> +	    ocfs2_is_io_unaligned(inode, count, iocb->ki_pos)) {
>  		/*
> -		 * Wait on previous unaligned aio to complete before
> -		 * proceeding.
> +		 * Make it a sync io if it's an 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);
> +		saved_ki_complete = xchg(&iocb->ki_complete, NULL);
>  	}
>  
>  	/* communicate with ocfs2_dio_end_io */
> @@ -2264,11 +2259,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb
*iocb,
>  	 */
>  	if ((written == -EIOCBQUEUED) || (!ocfs2_iocb_is_rw_locked(iocb))) {
>  		rw_level = -1;
> -		unaligned_dio = 0;
>  	}
>  
>  	if (unlikely(written <= 0))
> -		goto no_sync;
> +		goto out;
>  
>  	if (((file->f_flags & O_DSYNC) && !direct_io) ||
>  	    IS_SYNC(inode)) {
> @@ -2290,13 +2284,10 @@ static ssize_t ocfs2_file_write_iter(struct kiocb
*iocb,
>  						      iocb->ki_pos - 1);
>  	}
>  
> -no_sync:
> -	if (unaligned_dio && ocfs2_iocb_is_unaligned_aio(iocb)) {
> -		ocfs2_iocb_clear_unaligned_aio(iocb);
> -		mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio);
> -	}
> -
>  out:
> +	if (saved_ki_complete)
> +		xchg(&iocb->ki_complete, saved_ki_complete);
> +
>  	if (rw_level != -1)
>  		ocfs2_rw_unlock(inode, rw_level);
>  
> diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
> index 0c22ddd..6e0633e 100644
> --- a/fs/ocfs2/inode.h
> +++ b/fs/ocfs2/inode.h
> @@ -43,9 +43,6 @@ struct ocfs2_inode_info
>  	/* protects extended attribute changes on this inode */
>  	struct rw_semaphore		ip_xattr_sem;
>  
> -	/* Number of outstanding AIO's which are not page aligned */
> -	struct mutex			ip_unaligned_aio;
> -
>  	/* These fields are protected by ip_lock */
>  	spinlock_t			ip_lock;
>  	u32				ip_open_count;
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index c70a80b..3fd171f 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -1723,7 +1723,6 @@ static void ocfs2_inode_init_once(void *data)
>  	INIT_LIST_HEAD(&oi->ip_io_markers);
>  	INIT_LIST_HEAD(&oi->ip_unwritten_list);
>  	oi->ip_dir_start_lookup = 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);
>