[patch 07/12] fuse: add atomic open+truncate support

Miklos Szeredi
2007-10-02T15:53:25Z

[-- Attachment #1: fuse_atomic_open_truncate.patch --]
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From: Miklos Szeredi <mszeredi@suse.cz>

This patch allows fuse filesystems to implement open(..., O_TRUNC) as
a single request, instead of separate truncate and open requests.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---

Index: linux/fs/fuse/dir.c
===================================================================
--- linux.orig/fs/fuse/dir.c 2007-09-26 23:32:53.000000000 +0200
+++ linux/fs/fuse/dir.c 2007-09-27 00:41:38.000000000 +0200
@@ -1083,6 +1083,9 @@ static int fuse_do_setattr(struct dentry
return err;
}

+ if ((attr->ia_valid & ATTR_OPEN) && fc->atomic_o_trunc)
+ return 0;
+
if (attr->ia_valid & ATTR_SIZE) {
unsigned long limit;
if (IS_SWAPFILE(inode))
Index: linux/fs/fuse/file.c
===================================================================
--- linux.orig/fs/fuse/file.c 2007-09-26 23:32:53.000000000 +0200
+++ linux/fs/fuse/file.c 2007-09-27 00:41:41.000000000 +0200
@@ -28,7 +28,9 @@ static int fuse_send_open(struct inode *
return PTR_ERR(req);

memset(&inarg, 0, sizeof(inarg));
- inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
+ inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
+ if (!fc->atomic_o_trunc)
+ inarg.flags &= ~O_TRUNC;
req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h 2007-09-26 23:32:53.000000000 +0200
+++ linux/fs/fuse/fuse_i.h 2007-09-27 00:41:40.000000000 +0200
@@ -320,6 +320,9 @@ struct fuse_conn {
/** Do readpages asynchronously? Only set in INIT */
unsigned async_read : 1;

+ /** Do not send separate SETATTR request before open(O_TRUNC) */
+ unsigned atomic_o_trunc : 1;
+
/*
* The following bitfields are only for optimization purposes
* and hence races in setting them will not cause malfunction
Index: linux/fs/fuse/inode.c
===================================================================
--- linux.orig/fs/fuse/inode.c 2007-09-26 23:32:53.000000000 +0200
+++ linux/fs/fuse/inode.c 2007-09-27 00:41:40.000000000 +0200
@@ -548,6 +548,8 @@ static void process_init_reply(struct fu
fc->async_read = 1;
if (!(arg->flags & FUSE_POSIX_LOCKS))
fc->no_lock = 1;
+ if (arg->flags & FUSE_ATOMIC_O_TRUNC)
+ fc->atomic_o_trunc = 1;
} else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
fc->no_lock = 1;
@@ -570,7 +572,8 @@ static void fuse_send_init(struct fuse_c
arg->major = FUSE_KERNEL_VERSION;
arg->minor = FUSE_KERNEL_MINOR_VERSION;
arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
- arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_FILE_OPS;
+ arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_FILE_OPS |
+ FUSE_ATOMIC_O_TRUNC;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
Index: linux/include/linux/fuse.h
===================================================================
--- linux.orig/include/linux/fuse.h 2007-09-26 23:32:53.000000000 +0200
+++ linux/include/linux/fuse.h 2007-09-27 00:41:47.000000000 +0200
@@ -101,6 +101,7 @@ struct fuse_file_lock {
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
#define FUSE_FILE_OPS (1 << 2)
+#define FUSE_ATOMIC_O_TRUNC (1 << 3)

/**
* Release flags

--