Jeff Moyer <jmoyer@xxxxxxxxxx> writes:
> Hi, Dave,
>
> Thanks for the review!
>
>> or better still, factor xfs_file_fsync() so that it calls a helper
>> that doesn't wait for data IO completion, and call that helper here
>> too. The semantics of fsync/fdatasync are too complex to have to
>> implement and maintain in multiple locations....
>
> I definitely agree with consolidating things. However, there are four
> blocking calls in xfs_file_fsync (filemap_write_and_wait_range,
> xfs_blkdev_issue_flush, _xfs_log_force_lsn, and another call to
> xfs_blkdev_issue_flush). How would you propose to make that
> non-blocking given that those steps have to happen in sequence?
OK, so re-reading your mail, I think you meant to just factor out
everything except the filemap_write_and_wait_range. Here are a couple
of patches which do that. Also, since we're not worried about blocking
in the endio processing, just making things synchronous makes the code a
lot simpler. Let me know what you think of the attached two patches
(which I've already run through xfstests).
Thanks!
Jeff
xfs: factor out everything but the filemap_write_and_wait from xfs_file_fsync
Hi,
Fsyncing is tricky business, so factor out the bits of the xfs_file_fsync
function that can be used from the I/O post-processing path.
Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 54a67dd..e63030f 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -153,25 +153,18 @@ xfs_dir_fsync(
return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
}
+/*
+ * Returns 0 on success, -errno on failure.
+ */
STATIC int
-xfs_file_fsync(
- struct file *file,
- loff_t start,
- loff_t end,
+do_xfs_file_fsync(
+ struct xfs_inode *ip,
+ struct xfs_mount *mp,
int datasync)
{
- struct inode *inode = file->f_mapping->host;
- struct xfs_inode *ip = XFS_I(inode);
- struct xfs_mount *mp = ip->i_mount;
- int error = 0;
int log_flushed = 0;
xfs_lsn_t lsn = 0;
-
- trace_xfs_file_fsync(ip);
-
- error = filemap_write_and_wait_range(inode->i_mapping, start, end);
- if (error)
- return error;
+ int error = 0;
if (XFS_FORCED_SHUTDOWN(mp))
return -XFS_ERROR(EIO);
@@ -223,6 +216,27 @@ xfs_file_fsync(
return -error;
}
+STATIC int
+xfs_file_fsync(
+ struct file *file,
+ loff_t start,
+ loff_t end,
+ int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ int error = 0;
+
+ trace_xfs_file_fsync(ip);
+
+ error = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (error)
+ return error;
+
+ return do_xfs_file_fsync(ip, mp, datasync);
+}
+
STATIC ssize_t
xfs_file_aio_read(
struct kiocb *iocb,
xfs: honor the O_SYNC flag for aysnchronous direct I/O requests
Hi,
If a file is opened with O_SYNC|O_DIRECT, the drive cache does not get
flushed after the write completion for AIOs. This patch attempts to fix
that problem by marking an I/O as requiring a cache flush in endio
processing, and then issuing the cache flush after any unwritten extent
conversion is done.
Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 0dbb9e7..5c71d25 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -39,6 +39,8 @@
#include <linux/pagevec.h>
#include <linux/writeback.h>
+extern int do_xfs_file_fsync(struct xfs_inode *, struct xfs_mount *, int);
+
void
xfs_count_page_state(
struct page *page,
@@ -170,6 +172,24 @@ xfs_setfilesize(
}
/*
+ * In the case of synchronous, AIO, O_DIRECT writes, we need to flush
+ * the disk cache when the I/O is complete.
+ */
+STATIC bool
+xfs_ioend_needs_cache_flush(
+ struct xfs_ioend *ioend)
+{
+ struct xfs_inode *ip = XFS_I(ioend->io_inode);
+ struct xfs_mount *mp = ip->i_mount;
+
+ if (!(mp->m_flags & XFS_MOUNT_BARRIER))
+ return false;
+
+ return (IS_SYNC(ioend->io_inode) ||
+ (ioend->io_iocb->ki_filp->f_flags & O_DSYNC));
+}
+
+/*
* Schedule IO completion handling on the final put of an ioend.
*
* If there is no work to do we might as well call it a day and free the
@@ -186,11 +206,30 @@ xfs_finish_ioend(
queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
else if (ioend->io_append_trans)
queue_work(mp->m_data_workqueue, &ioend->io_work);
+ else if (ioend->io_needs_fsync)
+ queue_work(mp->m_aio_blkdev_flush_wq, &ioend->io_work);
else
xfs_destroy_ioend(ioend);
}
}
+STATIC int
+xfs_ioend_force_cache_flush(
+ xfs_ioend_t *ioend)
+{
+ struct xfs_inode *ip = XFS_I(ioend->io_inode);
+ struct xfs_mount *mp = ip->i_mount;
+ int err = 0;
+ int datasync;
+
+ datasync = !IS_SYNC(ioend->io_inode) &&
+ !(ioend->io_iocb->ki_filp->f_flags & __O_SYNC);
+ err = do_xfs_file_fsync(ip, mp, datasync);
+ xfs_destroy_ioend(ioend);
+ /* do_xfs_file_fsync returns -errno. our caller expects positive. */
+ return -err;
+}
+
/*
* IO write completion.
*/
@@ -238,12 +277,22 @@ xfs_end_io(
error = xfs_setfilesize(ioend);
if (error)
ioend->io_error = -error;
+ } else if (ioend->io_needs_fsync) {
+ error = xfs_ioend_force_cache_flush(ioend);
+ if (error && ioend->io_result > 0)
+ ioend->io_error = -error;
+ ioend->io_needs_fsync = 0;
} else {
ASSERT(!xfs_ioend_is_append(ioend));
}
done:
- xfs_destroy_ioend(ioend);
+ /* the honoring of O_SYNC has to be done last */
+ if (ioend->io_needs_fsync) {
+ atomic_inc(&ioend->io_remaining);
+ xfs_finish_ioend(ioend);
+ } else
+ xfs_destroy_ioend(ioend);
}
/*
@@ -280,6 +329,7 @@ xfs_alloc_ioend(
atomic_set(&ioend->io_remaining, 1);
ioend->io_isasync = 0;
ioend->io_isdirect = 0;
+ ioend->io_needs_fsync = 0;
ioend->io_error = 0;
ioend->io_list = NULL;
ioend->io_type = type;
@@ -1324,6 +1374,8 @@ xfs_end_io_direct_write(
if (is_async) {
ioend->io_isasync = 1;
+ if (xfs_ioend_needs_cache_flush(ioend))
+ ioend->io_needs_fsync = 1;
xfs_finish_ioend(ioend);
} else {
xfs_finish_ioend_sync(ioend);
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index 84eafbc..f0ec42a 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -47,6 +47,7 @@ typedef struct xfs_ioend {
atomic_t io_remaining; /* hold count */
unsigned int io_isasync : 1; /* needs aio_complete */
unsigned int io_isdirect : 1;/* direct I/O */
+ unsigned int io_needs_fsync : 1; /* aio+dio+o_sync */
struct inode *io_inode; /* file being written to */
struct buffer_head *io_buffer_head;/* buffer linked list head */
struct buffer_head *io_buffer_tail;/* buffer linked list tail */
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index e63030f..9c1b5e8 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -156,7 +156,7 @@ xfs_dir_fsync(
/*
* Returns 0 on success, -errno on failure.
*/
-STATIC int
+int
do_xfs_file_fsync(
struct xfs_inode *ip,
struct xfs_mount *mp,
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 9eba738..4d85234 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -214,6 +214,7 @@ typedef struct xfs_mount {
struct workqueue_struct *m_data_workqueue;
struct workqueue_struct *m_unwritten_workqueue;
+ struct workqueue_struct *m_aio_blkdev_flush_wq;
} xfs_mount_t;
/*
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index dab9a5f..5543223 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -773,8 +773,15 @@ xfs_init_mount_workqueues(
if (!mp->m_unwritten_workqueue)
goto out_destroy_data_iodone_queue;
+ mp->m_aio_blkdev_flush_wq = alloc_workqueue("xfs-aio-blkdev-flush/%s",
+ WQ_MEM_RECLAIM, 0, mp->m_fsname);
+ if (!mp->m_aio_blkdev_flush_wq)
+ goto out_destroy_unwritten_queue;
+
return 0;
+out_destroy_unwritten_queue:
+ destroy_workqueue(mp->m_unwritten_workqueue);
out_destroy_data_iodone_queue:
destroy_workqueue(mp->m_data_workqueue);
out:
@@ -785,6 +792,7 @@ STATIC void
xfs_destroy_mount_workqueues(
struct xfs_mount *mp)
{
+ destroy_workqueue(mp->m_aio_blkdev_flush_wq);
destroy_workqueue(mp->m_data_workqueue);
destroy_workqueue(mp->m_unwritten_workqueue);
}
