This patch issues a flush in generic_file_fsync.
(Modern filesystems already do it)
-Behaviour can be reversed using /sys/devices/.../cache_type
-Filesystems can also call __generic_file_fsync with bool flush false
Suggested-by: Jan Kara <j...@suse.cz>
Suggested-by: Christoph Hellwig <h...@infradead.org>
Cc: Jan Kara <j...@suse.cz>
Cc: Christoph Hellwig <h...@infradead.org>
Cc: Alexander Viro <v...@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <ty...@mit.edu>
Cc: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Fabian Frederick <f...@skynet.be>
---
V3: __generic_file_fsync = no flush
V2: No flag
V1: First version with MS_BARRIER flag
fs/libfs.c | 36 +++++++++++++++++++++++++++++++++---
include/linux/fs.h | 1 +
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/fs/libfs.c b/fs/libfs.c
index a184424..4877906 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -3,6 +3,7 @@
* Library for filesystems writers.
*/
+#include <linux/blkdev.h>
#include <linux/export.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
@@ -923,16 +924,19 @@ struct dentry *generic_fh_to_parent(struct super_block
*sb, struct fid *fid,
EXPORT_SYMBOL_GPL(generic_fh_to_parent);
/**
- * generic_file_fsync - generic fsync implementation for simple filesystems
+ * __generic_file_fsync - generic fsync implementation for simple filesystems
+ *
* @file: file to synchronize
+ * @start: start offset in bytes
+ * @end: end offset in bytes (inclusive)
* @datasync: only synchronize essential metadata if true
*
* This is a generic implementation of the fsync method for simple
* filesystems which track all non-inode metadata in the buffers list
* hanging off the address_space structure.
*/
-int generic_file_fsync(struct file *file, loff_t start, loff_t end,
- int datasync)
+int __generic_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
{
struct inode *inode = file->f_mapping->host;
int err;
@@ -952,10 +956,36 @@ int generic_file_fsync(struct file *file, loff_t start,
loff_t end,
err = sync_inode_metadata(inode, 1);
if (ret == 0)
ret = err;
+
out:
mutex_unlock(&inode->i_mutex);
return ret;
}
+EXPORT_SYMBOL(__generic_file_fsync);
+
+/**
+ * generic_file_fsync - generic fsync implementation for simple filesystems
+ * with flush
+ * @file: file to synchronize
+ * @start: start offset in bytes
+ * @end: end offset in bytes (inclusive)
+ * @datasync: only synchronize essential metadata if true
+ *
+ */
+
+int generic_file_fsync(struct file *file, loff_t start, loff_t end,
+ int datasync)
+{
+ struct inode *inode = file->f_mapping->host;
+ int err;
+
+ err = __generic_file_fsync(file, start, end, datasync);
+ if (err)
+ return err;
+
+ return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
+
+}
EXPORT_SYMBOL(generic_file_fsync);
/**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8780312..c3f46e4 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2590,6 +2590,7 @@ extern ssize_t simple_read_from_buffer(void __user *to,
size_t count,
extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
const void __user *from, size_t count);
+extern int __generic_file_fsync(struct file *, loff_t, loff_t, int);
extern int generic_file_fsync(struct file *, loff_t, loff_t, int);
extern int generic_check_addressable(unsigned, u64);
--
1.8.4.5
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