fuse: Turn writeback cache on
Introduce a bit kernel and userspace exchange between each-other on
the init stage and turn writeback on if the userspace want this and
mount option 'allow_wbcache' is present (controlled by fusermount).
Also add each writable file into per-inode write list and call the
generic_file_aio_write to make use of the Linux page cache engine.
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 2764330..d03a35d 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -224,6 +224,8 @@
spin_unlock(&fc->lock);
fuse_invalidate_attr(inode);
}
+ if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
+ fuse_link_write_file(file);
}
int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
@@ -1197,6 +1199,15 @@
struct iov_iter i;
loff_t endbyte = 0;
+ if (get_fuse_conn(inode)->writeback_cache) {
+ /* Update size (EOF optimization) and mode (SUID clearing) */
+ err = fuse_update_attributes(mapping->host, NULL, file, NULL);
+ if (err)
+ return err;
+
+ return generic_file_aio_write(iocb, iov, nr_segs, pos);
+ }
+
WARN_ON(iocb->ki_pos != pos);
ocount = 0;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1061b0d9..9ba1919 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -887,6 +887,8 @@
}
if (arg->flags & FUSE_ASYNC_DIO)
fc->async_dio = 1;
+ if (arg->flags & FUSE_WRITEBACK_CACHE)
+ fc->writeback_cache = 1;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
@@ -914,7 +916,8 @@
FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
FUSE_FLOCK_LOCKS | FUSE_IOCTL_DIR | FUSE_AUTO_INVAL_DATA |
- FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO;
+ FUSE_DO_READDIRPLUS | FUSE_READDIRPLUS_AUTO | FUSE_ASYNC_DIO |
+ FUSE_WRITEBACK_CACHE;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 60bb2f9..cf4750e 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -93,6 +93,9 @@
*
* 7.22
* - add FUSE_ASYNC_DIO
+ *
+ * 7.23
+ * - add FUSE_WRITEBACK_CACHE
*/
#ifndef _LINUX_FUSE_H
@@ -128,7 +131,7 @@
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 22
+#define FUSE_KERNEL_MINOR_VERSION 23
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
@@ -219,6 +222,7 @@
* FUSE_DO_READDIRPLUS: do READDIRPLUS (READDIR+LOOKUP in one)
* FUSE_READDIRPLUS_AUTO: adaptive readdirplus
* FUSE_ASYNC_DIO: asynchronous direct I/O submission
+ * FUSE_WRITEBACK_CACHE: use writeback cache for buffered writes
*/
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
@@ -236,6 +240,7 @@
#define FUSE_DO_READDIRPLUS (1 << 13)
#define FUSE_READDIRPLUS_AUTO (1 << 14)
#define FUSE_ASYNC_DIO (1 << 15)
+#define FUSE_WRITEBACK_CACHE (1 << 16)
/**
* CUSE INIT request/reply flags