[PATCH 032/102] xfs: cleanup xfs_file_aio_write

Dave Chinner
2012-08-23T05:03:21Z

From: Christoph Hellwig <hch@infradead.org>

Upstream commit: d060646436233912178e6b9e3a7f30a41214220f

With all the size field updates out of the way xfs_file_aio_write can
be further simplified by pushing all iolock handling into
xfs_file_dio_aio_write and xfs_file_buffered_aio_write and using
the generic generic_write_sync helper for synchronous writes.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
---
fs/xfs/linux-2.6/xfs_file.c | 90 +++++++++++++++++++------------------------
1 file changed, 39 insertions(+), 51 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_file.c b/fs/xfs/linux-2.6/xfs_file.c
index b9e3101..d9f5f9f 100644
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -719,8 +719,7 @@ xfs_file_dio_aio_write(
const struct iovec *iovp,
unsigned long nr_segs,
loff_t pos,
- size_t ocount,
- int *iolock)
+ size_t ocount)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
@@ -730,10 +729,10 @@ xfs_file_dio_aio_write(
ssize_t ret = 0;
size_t count = ocount;
int unaligned_io = 0;
+ int iolock;
struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;

- *iolock = 0;
if ((pos & target->bt_smask) || (count & target->bt_smask))
return -XFS_ERROR(EINVAL);

@@ -748,31 +747,31 @@ xfs_file_dio_aio_write(
* EOF zeroing cases and fill out the new inode size as appropriate.
*/
if (unaligned_io || mapping->nrpages)
- *iolock = XFS_IOLOCK_EXCL;
+ iolock = XFS_IOLOCK_EXCL;
else
- *iolock = XFS_IOLOCK_SHARED;
- xfs_rw_ilock(ip, *iolock);
-
- ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
- if (ret)
- return ret;
+ iolock = XFS_IOLOCK_SHARED;
+ xfs_rw_ilock(ip, iolock);

/*
* Recheck if there are cached pages that need invalidate after we got
* the iolock to protect against other threads adding new pages while
* we were waiting for the iolock.
*/
- if (mapping->nrpages && *iolock == XFS_IOLOCK_SHARED) {
- xfs_rw_iunlock(ip, *iolock);
- *iolock = XFS_IOLOCK_EXCL;
- xfs_rw_ilock(ip, *iolock);
+ if (mapping->nrpages && iolock == XFS_IOLOCK_SHARED) {
+ xfs_rw_iunlock(ip, iolock);
+ iolock = XFS_IOLOCK_EXCL;
+ xfs_rw_ilock(ip, iolock);
}

+ ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
+ if (ret)
+ goto out;
+
if (mapping->nrpages) {
ret = -xfs_flushinval_pages(ip, (pos & PAGE_CACHE_MASK), -1,
FI_REMAPF_LOCKED);
if (ret)
- return ret;
+ goto out;
}

/*
@@ -781,15 +780,18 @@ xfs_file_dio_aio_write(
*/
if (unaligned_io)
xfs_ioend_wait(ip);
- else if (*iolock == XFS_IOLOCK_EXCL) {
+ else if (iolock == XFS_IOLOCK_EXCL) {
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
- *iolock = XFS_IOLOCK_SHARED;
+ iolock = XFS_IOLOCK_SHARED;
}

trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
ret = generic_file_direct_write(iocb, iovp,
&nr_segs, pos, &iocb->ki_pos, count, ocount);

+out:
+ xfs_rw_iunlock(ip, iolock);
+
/* No fallback to buffered IO on errors for XFS. */
ASSERT(ret < 0 || ret == count);
return ret;
@@ -801,8 +803,7 @@ xfs_file_buffered_aio_write(
const struct iovec *iovp,
unsigned long nr_segs,
loff_t pos,
- size_t ocount,
- int *iolock)
+ size_t ocount)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
@@ -810,14 +811,14 @@ xfs_file_buffered_aio_write(
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
int enospc = 0;
+ int iolock = XFS_IOLOCK_EXCL;
size_t count = ocount;

- *iolock = XFS_IOLOCK_EXCL;
- xfs_rw_ilock(ip, *iolock);
+ xfs_rw_ilock(ip, iolock);

- ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
+ ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
if (ret)
- return ret;
+ goto out;

/* We can write back this queue in page reclaim */
current->backing_dev_info = mapping->backing_dev_info;
@@ -831,13 +832,15 @@ write_retry:
* page locks and retry *once*
*/
if (ret == -ENOSPC && !enospc) {
- ret = -xfs_flush_pages(ip, 0, -1, 0, FI_NONE);
- if (ret)
- return ret;
enospc = 1;
- goto write_retry;
+ ret = -xfs_flush_pages(ip, 0, -1, 0, FI_NONE);
+ if (!ret)
+ goto write_retry;
}
+
current->backing_dev_info = NULL;
+out:
+ xfs_rw_iunlock(ip, iolock);
return ret;
}

@@ -853,7 +856,6 @@ xfs_file_aio_write(
struct inode *inode = mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
- int iolock;
size_t ocount = 0;

XFS_STATS_INC(xs_write_calls);
@@ -873,36 +875,22 @@ xfs_file_aio_write(
return -EIO;

if (unlikely(file->f_flags & O_DIRECT))
- ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
- ocount, &iolock);
+ ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos, ocount);
else
ret = xfs_file_buffered_aio_write(iocb, iovp, nr_segs, pos,
- ocount, &iolock);
-
- if (ret <= 0)
- goto out_unlock;
+ ocount);

- XFS_STATS_ADD(xs_write_bytes, ret);
+ if (ret > 0) {
+ ssize_t err;

- /* Handle various SYNC-type writes */
- if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
- loff_t end = pos + ret - 1;
- int error, error2;
-
- xfs_rw_iunlock(ip, iolock);
- error = filemap_write_and_wait_range(mapping, pos, end);
- xfs_rw_ilock(ip, iolock);
+ XFS_STATS_ADD(xs_write_bytes, ret);

- error2 = -xfs_file_fsync(file,
- (file->f_flags & __O_SYNC) ? 0 : 1);
- if (error)
- ret = error;
- else if (error2)
- ret = error2;
+ /* Handle various SYNC-type writes */
+ err = generic_write_sync(file, pos, ret);
+ if (err < 0)
+ ret = err;
}

-out_unlock:
- xfs_rw_iunlock(ip, iolock);
return ret;