Re: [PATCH 11/11] xfs: cleanup xfs_file_aio_write

Ben Myers
2012-01-17T20:42:22Z

On Sun, Dec 18, 2011 at 03:00:14PM -0500, Christoph Hellwig wrote:
> 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>

Looks good!
Reviewed-by: Ben Myers <bpm@sgi.com>

> ---
> 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;
> }
>
>
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