[PATCH 11/11] xfs: cleanup xfs_file_aio_write

Christoph Hellwig
2011-12-18T20:01:34Z

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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>

---
fs/xfs/xfs_file.c | 82 ++++++++++++++++++++++++------------------------------
1 file changed, 37 insertions(+), 45 deletions(-)

Index: xfs/fs/xfs/xfs_file.c
===================================================================
--- xfs.orig/fs/xfs/xfs_file.c 2011-12-07 12:48:33.309903801 +0100
+++ xfs/fs/xfs/xfs_file.c 2011-12-07 12:48:48.546487926 +0100
@@ -724,8 +724,7 @@ 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;
@@ -735,10 +734,10 @@ 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);

@@ -753,31 +752,31 @@ 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);
+ 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);
+ ret = xfs_file_aio_write_checks(file, &pos, &count, &iolock);
if (ret)
- return 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;
}

/*
@@ -786,15 +785,18 @@ xfs_file_dio_aio_write(
*/
if (unaligned_io)
inode_dio_wait(inode);
- 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;
@@ -806,8 +808,7 @@ 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;
@@ -815,14 +816,14 @@ 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;
@@ -836,13 +837,15 @@ 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;
}

@@ -858,7 +861,6 @@ 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);
@@ -878,32 +880,22 @@ 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);
+ ocount);

- if (ret <= 0)
- goto out_unlock;
+ if (ret > 0) {
+ ssize_t err;

- XFS_STATS_ADD(xs_write_bytes, ret);
+ XFS_STATS_ADD(xs_write_bytes, ret);

- /* Handle various SYNC-type writes */
- if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
- loff_t end = pos + ret - 1;
- int error;
-
- xfs_rw_iunlock(ip, iolock);
- error = xfs_file_fsync(file, pos, end,
- (file->f_flags & __O_SYNC) ? 0 : 1);
- xfs_rw_ilock(ip, iolock);
- if (error)
- ret = error;
+ /* 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;
}