fuse: support BSD locking semantics
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 6726378..471ea70 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -699,7 +699,8 @@
}
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
+ .flock = fuse_file_flock,
.splice_read = generic_file_splice_read,
};
@@ -852,6 +873,7 @@
.release = fuse_release,
.fsync = fuse_fsync,
.lock = fuse_file_lock,
+ .flock = fuse_file_flock,
/* no mmap and splice_read */
};