iomap: split size and error for iomap_dio_rw ->end_io

Modify the calling convention for the iomap_dio_rw ->end_io() callback.
Rather than passing either dio->error or dio->size as the 'size' argument,
instead pass both the dio->error and the dio->size value separately.

In the instance that an error occurred during a write, we currently cannot
determine whether any blocks have been allocated beyond the current EOF and
data has subsequently been written to these blocks within the ->end_io()
callback. As a result, we cannot judge whether we should take the truncate
failed write path. Having both dio->error and dio->size will allow us to
perform such checks within this callback.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
[hch: minor cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 10517ce..2ccf1c6 100644 (file)
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -77,13 +77,10 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio)
        loff_t offset = iocb->ki_pos;
        ssize_t ret;
 
-       if (dio->end_io) {
-               ret = dio->end_io(iocb,
-                               dio->error ? dio->error : dio->size,
-                               dio->flags);
-       } else {
+       if (dio->end_io)
+               ret = dio->end_io(iocb, dio->size, dio->error, dio->flags);
+       else
                ret = dio->error;
-       }
 
        if (likely(!ret)) {
                ret = dio->size;

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 28101bb..7441129 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -369,21 +369,23 @@ static int
 xfs_dio_write_end_io(
        struct kiocb            *iocb,
        ssize_t                 size,
+       int                     error,
        unsigned                flags)
 {
        struct inode            *inode = file_inode(iocb->ki_filp);
        struct xfs_inode        *ip = XFS_I(inode);
        loff_t                  offset = iocb->ki_pos;
        unsigned int            nofs_flag;
-       int                     error = 0;
 
        trace_xfs_end_io_direct_write(ip, offset, size);
 
        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
                return -EIO;
 
-       if (size <= 0)
-               return size;
+       if (error)
+               return error;
+       if (!size)
+               return 0;
 
        /*
         * Capture amount written on completion as we can't reliably account

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index bc499ce..50bb746 100644 (file)
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -188,8 +188,8 @@ sector_t iomap_bmap(struct address_space *mapping, sector_t bno,
  */
 #define IOMAP_DIO_UNWRITTEN    (1 << 0)        /* covers unwritten extent(s) */
 #define IOMAP_DIO_COW          (1 << 1)        /* covers COW extent(s) */
-typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t ret,
-               unsigned flags);
+typedef int (iomap_dio_end_io_t)(struct kiocb *iocb, ssize_t size, int error,
+                                unsigned int flags);
 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
                const struct iomap_ops *ops, iomap_dio_end_io_t end_io);
 int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);