[PATCH v5 6/7] fs: pass iocb to generic_write_sync

[Milosz Tanski]

From: Christoph Hellwig <hch@xxxxxx>

Clean up the generic_write_sync by just passing an iocb and a bytes
written / negative errno argument.  In addition to simplifying the
callers this also prepares for passing a per-operation O_DSYNC
flag.  Two callers didn't quite fit that scheme:

 - dio_complete didn't both to update ki_pos as we don't need it
   on a iocb that is about to be freed, so we had to add it. Additionally
   it also synced out written data in the error case, which has been
   changed to operate like the other callers.
 - gfs2 also used generic_write_sync to implement a crude version
   of fallocate.  It has been switched to use an open coded variant
   instead.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/block_dev.c     |  8 +-------
 fs/btrfs/file.c    |  7 ++-----
 fs/cifs/file.c     |  8 +-------
 fs/direct-io.c     |  8 ++------
 fs/ext4/file.c     |  8 +-------
 fs/gfs2/file.c     |  9 +++++++--
 fs/ntfs/file.c     |  8 ++------
 fs/udf/file.c      | 11 ++---------
 fs/xfs/xfs_file.c  |  8 +-------
 include/linux/fs.h |  8 +-------
 mm/filemap.c       | 30 ++++++++++++++++++++----------
 11 files changed, 40 insertions(+), 73 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index cc9d411..c529b1c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1568,18 +1568,12 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
  */
 ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-	struct file *file = iocb->ki_filp;
 	struct blk_plug plug;
 	ssize_t ret;
 
 	blk_start_plug(&plug);
 	ret = __generic_file_write_iter(iocb, from);
-	if (ret > 0) {
-		ssize_t err;
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	ret = generic_write_sync(iocb, ret);
 	blk_finish_plug(&plug);
 	return ret;
 }
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a18ceab..4f4a6f7 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1820,11 +1820,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
 	 */
 	BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
 	BTRFS_I(inode)->last_sub_trans = root->log_transid;
-	if (num_written > 0) {
-		err = generic_write_sync(file, pos, num_written);
-		if (err < 0)
-			num_written = err;
-	}
+
+	num_written = generic_write_sync(iocb, num_written);
 
 	if (sync)
 		atomic_dec(&BTRFS_I(inode)->sync_writers);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c485afa..32359de 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2706,13 +2706,7 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
 		rc = __generic_file_write_iter(iocb, from);
 		mutex_unlock(&inode->i_mutex);
 
-		if (rc > 0) {
-			ssize_t err;
-
-			err = generic_write_sync(file, iocb->ki_pos - rc, rc);
-			if (err < 0)
-				rc = err;
-		}
+		rc = generic_write_sync(iocb, rc);
 	} else {
 		mutex_unlock(&inode->i_mutex);
 	}
diff --git a/fs/direct-io.c b/fs/direct-io.c
index e181b6b..b72ac83 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -257,12 +257,8 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret,
 	inode_dio_done(dio->inode);
 	if (is_async) {
 		if (dio->rw & WRITE) {
-			int err;
-
-			err = generic_write_sync(dio->iocb->ki_filp, offset,
-						 transferred);
-			if (err < 0 && ret > 0)
-				ret = err;
+			dio->iocb->ki_pos = offset + transferred;
+			ret = generic_write_sync(dio->iocb, ret);
 		}
 
 		aio_complete(dio->iocb, ret, 0);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index aca7b24..79b000c 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -175,13 +175,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	ret = __generic_file_write_iter(iocb, from);
 	mutex_unlock(&inode->i_mutex);
 
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
+	ret = generic_write_sync(iocb, ret);
 	if (o_direct)
 		blk_finish_plug(&plug);
 
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 80dd44d..3fafeca 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -895,8 +895,13 @@ retry:
 		gfs2_quota_unlock(ip);
 	}
 
-	if (error == 0)
-		error = generic_write_sync(file, pos, count);
+	if (error)
+		goto out_unlock;
+
+	if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host)) {
+		error = vfs_fsync_range(file, pos, pos + count - 1,
+			       (file->f_flags & __O_SYNC) ? 0 : 1);
+	}
 	goto out_unlock;
 
 out_trans_fail:
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 643faa4..4f3d664 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -2127,12 +2127,8 @@ static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 	mutex_lock(&inode->i_mutex);
 	ret = ntfs_file_aio_write_nolock(iocb, iov, nr_segs, &iocb->ki_pos);
 	mutex_unlock(&inode->i_mutex);
-	if (ret > 0) {
-		int err = generic_write_sync(file, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
-	return ret;
+
+	return generic_write_sync(iocb, ret);
 }
 
 /**
diff --git a/fs/udf/file.c b/fs/udf/file.c
index bb15771..1cdabd0 100644
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -155,16 +155,9 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	retval = __generic_file_write_iter(iocb, from);
 	mutex_unlock(&inode->i_mutex);
 
-	if (retval > 0) {
-		ssize_t err;
-
+	if (retval > 0)
 		mark_inode_dirty(inode);
-		err = generic_write_sync(file, iocb->ki_pos - retval, retval);
-		if (err < 0)
-			retval = err;
-	}
-
-	return retval;
+	return generic_write_sync(iocb, retval);
 }
 
 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 0655915..a8cab66 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -792,14 +792,8 @@ xfs_file_write_iter(
 		ret = xfs_file_buffered_aio_write(iocb, from);
 
 	if (ret > 0) {
-		ssize_t err;
-
 		XFS_STATS_ADD(xs_write_bytes, ret);
-
-		/* Handle various SYNC-type writes */
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
+		ret = generic_write_sync(iocb, ret);
 	}
 	return ret;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index eaebd99..7d0e116 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2242,13 +2242,7 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
 			   int datasync);
 extern int vfs_fsync(struct file *file, int datasync);
-static inline int generic_write_sync(struct file *file, loff_t pos, loff_t count)
-{
-	if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
-		return 0;
-	return vfs_fsync_range(file, pos, pos + count - 1,
-			       (file->f_flags & __O_SYNC) ? 0 : 1);
-}
+extern int generic_write_sync(struct kiocb *iocb, loff_t count);
 extern void emergency_sync(void);
 extern void emergency_remount(void);
 #ifdef CONFIG_BLOCK
diff --git a/mm/filemap.c b/mm/filemap.c
index 09d3af3..6107058 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2664,6 +2664,24 @@ out:
 }
 EXPORT_SYMBOL(__generic_file_write_iter);
 
+int generic_write_sync(struct kiocb *iocb, loff_t count)
+{
+	struct file *file = iocb->ki_filp;
+
+	if (count > 0 &&
+	    ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))) {
+		bool fdatasync = !(file->f_flags & __O_SYNC);
+		ssize_t ret = 0;
+
+		ret = vfs_fsync_range(file, iocb->ki_pos - count,
+				iocb->ki_pos - 1, fdatasync);
+		if (ret < 0)
+			return ret;
+	}
+	return count;
+}
+EXPORT_SYMBOL(generic_write_sync);
+
 /**
  * generic_file_write_iter - write data to a file
  * @iocb:	IO state structure
@@ -2675,22 +2693,14 @@ EXPORT_SYMBOL(__generic_file_write_iter);
  */
 ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-	struct file *file = iocb->ki_filp;
-	struct inode *inode = file->f_mapping->host;
+	struct inode *inode = iocb->ki_filp->f_mapping->host;
 	ssize_t ret;
 
 	mutex_lock(&inode->i_mutex);
 	ret = __generic_file_write_iter(iocb, from);
 	mutex_unlock(&inode->i_mutex);
 
-	if (ret > 0) {
-		ssize_t err;
-
-		err = generic_write_sync(file, iocb->ki_pos - ret, ret);
-		if (err < 0)
-			ret = err;
-	}
-	return ret;
+	return generic_write_sync(iocb, ret);
 }
 EXPORT_SYMBOL(generic_file_write_iter);
 
-- 
1.9.1

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