vfs: Remove syncing from generic_file_direct_write() and generic_file_buffered_write()

generic_file_direct_write() and generic_file_buffered_write() called
generic_osync_inode() if it was called on O_SYNC file or IS_SYNC inode. But
this is superfluous since generic_file_aio_write() does the syncing as well.
Also XFS and OCFS2 which call these functions directly handle syncing
themselves. So let's have a single place where syncing happens:
generic_file_aio_write().

We slightly change the behavior by syncing only the range of file to which the
write happened for buffered writes but that should be all that is required.

CC: ocfs2-devel@oss.oracle.com
CC: Joel Becker <joel.becker@oracle.com>
CC: Felix Blyakher <felixb@sgi.com>
CC: xfs@oss.sgi.com
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 6 insertions, 29 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 554a396d85e2..f863e1d7e227 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2187,20 +2187,7 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
                 }
                 *ppos = end;
         }
-
-        /*
-         * Sync the fs metadata but not the minor inode changes and
-         * of course not the data as we did direct DMA for the IO.
-         * i_mutex is held, which protects generic_osync_inode() from
-         * livelocking.  AIO O_DIRECT ops attempt to sync metadata here.
-         */
 out:
-        if ((written >= 0 || written == -EIOCBQUEUED) &&
-            ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
-                int err = generic_osync_inode(inode, mapping, OSYNC_METADATA);
-                if (err < 0)
-                        written = err;
-        }
         return written;
 }
 EXPORT_SYMBOL(generic_file_direct_write);
@@ -2332,8 +2319,6 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
 {
         struct file *file = iocb->ki_filp;
         struct address_space *mapping = file->f_mapping;
-        const struct address_space_operations *a_ops = mapping->a_ops;
-        struct inode *inode = mapping->host;
         ssize_t status;
         struct iov_iter i;
 
@@ -2343,16 +2328,6 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
         if (likely(status >= 0)) {
                 written += status;
                 *ppos = pos + status;
-
-                /*
-                 * For now, when the user asks for O_SYNC, we'll actually give
-                 * O_DSYNC
-                 */
-                if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
-                        if (!a_ops->writepage || !is_sync_kiocb(iocb))
-                                status = generic_osync_inode(inode, mapping,
-                                                OSYNC_METADATA|OSYNC_DATA);
-                }
         }
         
         /*
@@ -2514,11 +2489,12 @@ ssize_t generic_file_aio_write_nolock(struct kiocb *iocb,
 
         ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
 
-        if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+        if ((ret > 0 || ret == -EIOCBQUEUED) &&
+            ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
                 ssize_t err;
 
                 err = sync_page_range_nolock(inode, mapping, pos, ret);
-                if (err < 0)
+                if (err < 0 && ret > 0)
                         ret = err;
         }
         return ret;
@@ -2550,11 +2526,12 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
         ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
         mutex_unlock(&inode->i_mutex);
 
-        if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+        if ((ret > 0 || ret == -EIOCBQUEUED) &&
+            ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
                 ssize_t err;
 
                 err = sync_page_range(inode, mapping, pos, ret);
-                if (err < 0)
+                if (err < 0 && ret > 0)
                         ret = err;
         }
         return ret;