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xfs: split xfs_file_read_iter into buffered and direct I/O helpers 

Similar to what we did on the write side a while ago.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig 2016-07-20 11:35:42 +10:00 committed by Dave Chinner
parent cf810712cc
commit bbc5a740c4
1 changed files with 59 additions and 28 deletions
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87
fs/xfs/xfs_file.c
View File

@ -282,35 +282,33 @@ xfs_file_fsync(
}
STATIC ssize_t
xfs_file_read_iter(
xfs_file_dio_aio_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct address_space *mapping = iocb->ki_filp->f_mapping;
struct inode *inode = mapping->host;
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
size_t size = iov_iter_count(to);
size_t count = iov_iter_count(to);
struct xfs_buftarg *target;
ssize_t ret = 0;
loff_t pos = iocb->ki_pos;
XFS_STATS_INC(mp, xs_read_calls);
trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
if ((iocb->ki_flags & IOCB_DIRECT) && !IS_DAX(inode)) {
xfs_buftarg_t *target =
XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;
if (XFS_IS_REALTIME_INODE(ip))
target = ip->i_mount->m_rtdev_targp;
else
target = ip->i_mount->m_ddev_targp;
if (!IS_DAX(inode)) {
/* DIO must be aligned to device logical sector size */
if ((pos | size) & target->bt_logical_sectormask) {
if (pos == i_size_read(inode))
if ((iocb->ki_pos | count) & target->bt_logical_sectormask) {
if (iocb->ki_pos == i_size_read(inode))
return 0;
return -EINVAL;
}
}
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
/*
* Locking is a bit tricky here. If we take an exclusive lock for direct
* IO, we effectively serialise all new concurrent read IO to this file
@ -322,7 +320,7 @@ xfs_file_read_iter(
* serialisation.
*/
xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_mapping->nrpages) {
if (mapping->nrpages) {
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
@ -337,8 +335,8 @@ xfs_file_read_iter(
* flush and reduce the chances of repeated iolock cycles going
* forward.
*/
if (inode->i_mapping->nrpages) {
ret = filemap_write_and_wait(VFS_I(ip)->i_mapping);
if (mapping->nrpages) {
ret = filemap_write_and_wait(mapping);
if (ret) {
xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
return ret;
@ -349,23 +347,56 @@ xfs_file_read_iter(
* we fail to invalidate a page, but this should never
* happen on XFS. Warn if it does fail.
*/
ret = invalidate_inode_pages2(VFS_I(ip)->i_mapping);
ret = invalidate_inode_pages2(mapping);
WARN_ON_ONCE(ret);
ret = 0;
}
xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
}
if (iocb->ki_flags & IOCB_DIRECT)
trace_xfs_file_direct_read(ip, size, pos);
else
trace_xfs_file_buffered_read(ip, size, pos);
ret = generic_file_read_iter(iocb, to);
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
STATIC ssize_t
xfs_file_buffered_aio_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ssize_t ret;
trace_xfs_file_buffered_read(ip, iov_iter_count(to), iocb->ki_pos);
xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
ret = generic_file_read_iter(iocb, to);
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
STATIC ssize_t
xfs_file_read_iter(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_mount *mp = XFS_I(file_inode(iocb->ki_filp))->i_mount;
ssize_t ret = 0;
XFS_STATS_INC(mp, xs_read_calls);
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
if (iocb->ki_flags & IOCB_DIRECT)
ret = xfs_file_dio_aio_read(iocb, to);
else
ret = xfs_file_buffered_aio_read(iocb, to);
if (ret > 0)
XFS_STATS_ADD(mp, xs_read_bytes, ret);
xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
@ -747,7 +778,7 @@ xfs_file_dio_aio_write(
end = iocb->ki_pos + count - 1;
/*
* See xfs_file_read_iter() for why we do a full-file flush here.
* See xfs_file_dio_aio_read() for why we do a full-file flush here.
*/
if (mapping->nrpages) {
ret = filemap_write_and_wait(VFS_I(ip)->i_mapping);