fuse: Trust kernel i_mtime only

Let the kernel maintain i_mtime locally:
 - clear S_NOCMTIME
 - implement i_op->update_time()
 - flush mtime on fsync and last close
 - update i_mtime explicitly on truncate and fallocate

Fuse inode flag FUSE_I_MTIME_DIRTY serves as indication that local i_mtime
should be flushed to the server eventually.

Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 374a8be014fd..1e6ad6d43051 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -119,6 +119,8 @@ enum {
 	FUSE_I_INIT_RDPLUS,
 	/** An operation changing file size is in progress  */
 	FUSE_I_SIZE_UNSTABLE,
+	/** i_mtime has been updated locally; a flush to userspace needed */
+	FUSE_I_MTIME_DIRTY,
 };
 
 struct fuse_conn;
@@ -876,7 +878,9 @@ long fuse_ioctl_common(struct file *file, unsigned int cmd,
 unsigned fuse_file_poll(struct file *file, poll_table *wait);
 int fuse_dev_release(struct inode *inode, struct file *file);
 
-void fuse_write_update_size(struct inode *inode, loff_t pos);
+bool fuse_write_update_size(struct inode *inode, loff_t pos);
+
+int fuse_flush_mtime(struct file *file, bool nofail);
 
 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
 		    struct file *file);