vfs: Introduce new helpers for syncing after writing to O_SYNC file or IS_SYNC inode

Introduce new function for generic inode syncing (vfs_fsync_range) and use
it from fsync() path. Introduce also new helper for syncing after a sync
write (generic_write_sync) using the generic function.

Use these new helpers for syncing from generic VFS functions. This makes
O_SYNC writes to block devices acquire i_mutex for syncing. If we really
care about this, we can make block_fsync() drop the i_mutex and reacquire
it before it returns.

CC: Evgeniy Polyakov <zbr@ioremap.net>
CC: ocfs2-devel@oss.oracle.com
CC: Joel Becker <joel.becker@oracle.com>
CC: Felix Blyakher <felixb@sgi.com>
CC: xfs@oss.sgi.com
CC: Anton Altaparmakov <aia21@cantab.net>
CC: linux-ntfs-dev@lists.sourceforge.net
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: linux-ext4@vger.kernel.org
CC: tytso@mit.edu
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 6 insertions, 16 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 73766d24f97b..819023733f8e 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -976,25 +976,15 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 
         if (ret > 0) {
                 unsigned long nr_pages;
+                int err;
 
-                *ppos += ret;
                 nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 
-                /*
-                 * If file or inode is SYNC and we actually wrote some data,
-                 * sync it.
-                 */
-                if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
-                        int err;
-
-                        mutex_lock(&inode->i_mutex);
-                        err = generic_osync_inode(inode, mapping,
-                                                  OSYNC_METADATA|OSYNC_DATA);
-                        mutex_unlock(&inode->i_mutex);
-
-                        if (err)
-                                ret = err;
-                }
+                err = generic_write_sync(out, *ppos, ret);
+                if (err)
+                        ret = err;
+                else
+                        *ppos += ret;
                 balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
         }