[patch 08/12] fuse: support BSD locking semantics

Miklos Szeredi
2007-10-02T15:54:38Z

[-- Attachment #1: fuse_flock.patch --]
[-- Type: text/plain, Size: 4013 bytes --]

From: Miklos Szeredi <mszeredi@suse.cz>

It is trivial to add support for flock(2) semantics to the existing
protocol, by setting the lock owner field to the file pointer, and
passing a new FUSE_LK_FLOCK flag with the locking request.

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

Index: linux/fs/fuse/file.c
===================================================================
--- linux.orig/fs/fuse/file.c 2007-09-25 21:19:14.000000000 +0200
+++ linux/fs/fuse/file.c 2007-09-25 21:19:14.000000000 +0200
@@ -699,7 +699,8 @@ static int convert_fuse_file_lock(const
}

static void fuse_lk_fill(struct fuse_req *req, struct file *file,
- const struct file_lock *fl, int opcode, pid_t pid)
+ const struct file_lock *fl, int opcode, pid_t pid,
+ int flock)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
@@ -712,6 +713,8 @@ static void fuse_lk_fill(struct fuse_req
arg->lk.end = fl->fl_end;
arg->lk.type = fl->fl_type;
arg->lk.pid = pid;
+ if (flock)
+ arg->lk_flags |= FUSE_LK_FLOCK;
req->in.h.opcode = opcode;
req->in.h.nodeid = get_node_id(inode);
req->in.numargs = 1;
@@ -731,7 +734,7 @@ static int fuse_getlk(struct file *file,
if (IS_ERR(req))
return PTR_ERR(req);

- fuse_lk_fill(req, file, fl, FUSE_GETLK, 0);
+ fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
req->out.numargs = 1;
req->out.args[0].size = sizeof(outarg);
req->out.args[0].value = &outarg;
@@ -744,7 +747,7 @@ static int fuse_getlk(struct file *file,
return err;
}

-static int fuse_setlk(struct file *file, struct file_lock *fl)
+static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct fuse_conn *fc = get_fuse_conn(inode);
@@ -761,7 +764,7 @@ static int fuse_setlk(struct file *file,
if (IS_ERR(req))
return PTR_ERR(req);

- fuse_lk_fill(req, file, fl, opcode, pid);
+ fuse_lk_fill(req, file, fl, opcode, pid, flock);
request_send(fc, req);
err = req->out.h.error;
/* locking is restartable */
@@ -787,11 +790,28 @@ static int fuse_file_lock(struct file *f
if (fc->no_lock)
err = posix_lock_file_wait(file, fl);
else
- err = fuse_setlk(file, fl);
+ err = fuse_setlk(file, fl, 0);
}
return err;
}

+static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ int err;
+
+ if (fc->no_lock) {
+ err = flock_lock_file_wait(file, fl);
+ } else {
+ /* emulate flock with POSIX locks */
+ fl->fl_owner = (fl_owner_t) file;
+ err = fuse_setlk(file, fl, 1);
+ }
+
+ return err;
+}
+
static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
{
struct inode *inode = mapping->host;
@@ -840,6 +860,7 @@ static const struct file_operations fuse
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
+ .flock = fuse_file_flock,
.splice_read = generic_file_splice_read,
};

@@ -852,6 +873,7 @@ static const struct file_operations fuse
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
+ .flock = fuse_file_flock,
/* no mmap and splice_read */
};

Index: linux/include/linux/fuse.h
===================================================================
--- linux.orig/include/linux/fuse.h 2007-09-25 21:19:14.000000000 +0200
+++ linux/include/linux/fuse.h 2007-09-25 21:19:14.000000000 +0200
@@ -13,6 +13,7 @@
*
* 7.9:
* - new fuse_getattr_in input argument of GETATTR
+ * - add lk_flags in fuse_lk_in
*/

#include <asm/types.h>
@@ -113,6 +114,11 @@ struct fuse_file_lock {
*/
#define FUSE_GETATTR_FH (1 << 0)

+/**
+ * Lock flags
+ */
+#define FUSE_LK_FLOCK (1 << 0)
+
enum fuse_opcode {
FUSE_LOOKUP = 1,
FUSE_FORGET = 2, /* no reply */
@@ -295,6 +301,8 @@ struct fuse_lk_in {
__u64 fh;
__u64 owner;
struct fuse_file_lock lk;
+ __u32 lk_flags;
+ __u32 padding;
};

struct fuse_lk_out {

--