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, 4 insertions, 7 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 3587554f45ef..849293c4f418 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -39,11 +39,10 @@
 /*
  * FIXME: remove all knowledge of the buffer layer from the core VM
  */
-#include <linux/buffer_head.h> /* for generic_osync_inode */
+#include <linux/buffer_head.h> /* for try_to_free_buffers */
 
 #include <asm/mman.h>
 
-
 /*
  * Shared mappings implemented 30.11.1994. It's not fully working yet,
  * though.
@@ -2477,8 +2476,7 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
                 unsigned long nr_segs, loff_t pos)
 {
         struct file *file = iocb->ki_filp;
-        struct address_space *mapping = file->f_mapping;
-        struct inode *inode = mapping->host;
+        struct inode *inode = file->f_mapping->host;
         ssize_t ret;
 
         BUG_ON(iocb->ki_pos != pos);
@@ -2487,11 +2485,10 @@ 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 || ret == -EIOCBQUEUED) &&
-            ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+        if (ret > 0 || ret == -EIOCBQUEUED) {
                 ssize_t err;
 
-                err = sync_page_range(inode, mapping, pos, ret);
+                err = generic_write_sync(file, pos, ret);
                 if (err < 0 && ret > 0)
                         ret = err;
         }