iomap: Allow forcing of waiting for running DIO in iomap_dio_rw()

Filesystems do not support doing IO as asynchronous in some cases. For
example in case of unaligned writes or in case file size needs to be
extended (e.g. for ext4). Instead of forcing filesystem to wait for AIO
in such cases, add argument to iomap_dio_rw() which makes the function
wait for IO completion. This also results in executing
iomap_dio_complete() inline in iomap_dio_rw() providing its return value
to the caller as for ordinary sync IO.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 997b326247e26c9432cb87e94688e716b0debd49..f0caee2b7c00004a9aa490eba7860ea887fdb642 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -732,7 +732,8 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to)
        if (ret)
                goto out_uninit;
 
-       ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL);
+       ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
+                          is_sync_kiocb(iocb));
 
        gfs2_glock_dq(&gh);
 out_uninit:
@@ -767,7 +768,8 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
        if (offset + len > i_size_read(&ip->i_inode))
                goto out;
 
-       ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL);
+       ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
+                          is_sync_kiocb(iocb));
 
 out:
        gfs2_glock_dq(&gh);

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 1fc28c2da2790fc6ed9d1f167b1f17d577223d88..da124cee1783fab256a50760bc4dff9a3a622c5c 100644 (file)
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -392,7 +392,8 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
  */
 ssize_t
 iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
-               const struct iomap_ops *ops, const struct iomap_dio_ops *dops)
+               const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
+               bool wait_for_completion)
 {
        struct address_space *mapping = iocb->ki_filp->f_mapping;
        struct inode *inode = file_inode(iocb->ki_filp);
@@ -400,7 +401,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
        loff_t pos = iocb->ki_pos, start = pos;
        loff_t end = iocb->ki_pos + count - 1, ret = 0;
        unsigned int flags = IOMAP_DIRECT;
-       bool wait_for_completion = is_sync_kiocb(iocb);
        struct blk_plug plug;
        struct iomap_dio *dio;
 
@@ -409,6 +409,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
        if (!count)
                return 0;
 
+       if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion))
+               return -EIO;
+
        dio = kmalloc(sizeof(*dio), GFP_KERNEL);
        if (!dio)
                return -ENOMEM;

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 1ffb179f35d23ab5ae3bb12d98106430f6381034..0739ba72a82ed21f7cd99eea6f86adaccbc9fed1 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -188,7 +188,7 @@ xfs_file_dio_aio_read(
        file_accessed(iocb->ki_filp);
 
        xfs_ilock(ip, XFS_IOLOCK_SHARED);
-       ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL);
+       ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL, is_sync_kiocb(iocb));
        xfs_iunlock(ip, XFS_IOLOCK_SHARED);
 
        return ret;
@@ -547,7 +547,8 @@ xfs_file_dio_aio_write(
        }
 
        trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
-       ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops);
+       ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops,
+                          is_sync_kiocb(iocb));
 
        /*
         * If unaligned, this is the only IO in-flight. If it has not yet

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 7aa5d61179361d3bbdd3e949645568160d25ae15..76b14cb729dc918b3de300de7aa969bdc1b93459 100644 (file)
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -195,7 +195,8 @@ struct iomap_dio_ops {
 };
 
 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
-               const struct iomap_ops *ops, const struct iomap_dio_ops *dops);
+               const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
+               bool wait_for_completion);
 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
 
 #ifdef CONFIG_SWAP