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[XFS] Delay direct I/O completion to a workqueue This is nessecary 

because aio+dio completions may happen from irq context but we need
process context for converting unwritten extents.  We also queue regular
direct I/O completions to workqueue for regularity, there's only one
queue_work call per syscall.

SGI-PV: 934766
SGI-Modid: xfs-linux:xfs-kern:196857a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
This commit is contained in:
Christoph Hellwig 2005-09-05 08:22:52 +10:00 committed by Nathan Scott
parent 65b3da3705
commit f09738638d
2 changed files with 48 additions and 29 deletions
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74
fs/xfs/linux-2.6/xfs_aops.c
View File

@ -126,7 +126,7 @@ xfs_destroy_ioend(
/*
* Issue transactions to convert a buffer range from unwritten
* to written extents (buffered IO).
* to written extents.
*/
STATIC void
xfs_end_bio_unwritten(
@ -191,29 +191,6 @@ linvfs_unwritten_done(
end_buffer_async_write(bh, uptodate);
}
/*
* Issue transactions to convert a buffer range from unwritten
* to written extents (direct IO).
*/
STATIC void
linvfs_unwritten_convert_direct(
struct kiocb *iocb,
loff_t offset,
ssize_t size,
void *private)
{
struct inode *inode = iocb->ki_filp->f_dentry->d_inode;
ASSERT(!private || inode == (struct inode *)private);
/* private indicates an unwritten extent lay beneath this IO */
if (private && size > 0) {
vnode_t *vp = LINVFS_GET_VP(inode);
int error;
VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
}
}
STATIC int
xfs_map_blocks(
struct inode *inode,
@ -1045,6 +1022,44 @@ linvfs_get_blocks_direct(
create, 1, BMAPI_WRITE|BMAPI_DIRECT);
}
STATIC void
linvfs_end_io_direct(
struct kiocb *iocb,
loff_t offset,
ssize_t size,
void *private)
{
xfs_ioend_t *ioend = iocb->private;
/*
* Non-NULL private data means we need to issue a transaction to
* convert a range from unwritten to written extents. This needs
* to happen from process contect but aio+dio I/O completion
* happens from irq context so we need to defer it to a workqueue.
* This is not nessecary for synchronous direct I/O, but we do
* it anyway to keep the code uniform and simpler.
*
* The core direct I/O code might be changed to always call the
* completion handler in the future, in which case all this can
* go away.
*/
if (private && size > 0) {
ioend->io_offset = offset;
ioend->io_size = size;
xfs_finish_ioend(ioend);
} else {
ASSERT(size >= 0);
xfs_destroy_ioend(ioend);
}
/*
* blockdev_direct_IO can return an error even afer the I/O
* completion handler was called. Thus we need to protect
* against double-freeing.
*/
iocb->private = NULL;
}
STATIC ssize_t
linvfs_direct_IO(
int rw,
@ -1059,16 +1074,23 @@ linvfs_direct_IO(
xfs_iomap_t iomap;
int maps = 1;
int error;
ssize_t ret;
VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error);
if (error)
return -error;
return blockdev_direct_IO_own_locking(rw, iocb, inode,
iocb->private = xfs_alloc_ioend(inode);
ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
iomap.iomap_target->pbr_bdev,
iov, offset, nr_segs,
linvfs_get_blocks_direct,
linvfs_unwritten_convert_direct);
linvfs_end_io_direct);
if (unlikely(ret <= 0 && iocb->private))
xfs_destroy_ioend(iocb->private);
return ret;
}

3
fs/xfs/linux-2.6/xfs_lrw.c
View File

@ -660,9 +660,6 @@ xfs_write(
(xip->i_d.di_flags & XFS_DIFLAG_REALTIME) ?
mp->m_rtdev_targp : mp->m_ddev_targp;
if (ioflags & IO_ISAIO)
return XFS_ERROR(-ENOSYS);
if ((pos & target->pbr_smask) || (count & target->pbr_smask))
return XFS_ERROR(-EINVAL);