[PATCH] fuse: add POSIX file locking support
This patch adds POSIX file locking support to the fuse interface.
This implementation doesn't keep any locking state in kernel. Unlocking on
close() is handled by the FLUSH message, which now contains the lock owner id.
Mandatory locking is not supported. The filesystem may enfoce mandatory
locking in userspace if needed.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 13a7e8a..4128929 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -98,6 +98,14 @@
}
}
+static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ if (*flags & MS_MANDLOCK)
+ return -EINVAL;
+
+ return 0;
+}
+
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr)
{
if (S_ISREG(inode->i_mode) && i_size_read(inode) != attr->size)
@@ -409,6 +417,7 @@
.destroy_inode = fuse_destroy_inode,
.read_inode = fuse_read_inode,
.clear_inode = fuse_clear_inode,
+ .remount_fs = fuse_remount_fs,
.put_super = fuse_put_super,
.umount_begin = fuse_umount_begin,
.statfs = fuse_statfs,
@@ -428,8 +437,12 @@
ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
if (arg->flags & FUSE_ASYNC_READ)
fc->async_read = 1;
- } else
+ if (!(arg->flags & FUSE_POSIX_LOCKS))
+ fc->no_lock = 1;
+ } else {
ra_pages = fc->max_read / PAGE_CACHE_SIZE;
+ fc->no_lock = 1;
+ }
fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
fc->minor = arg->minor;
@@ -447,7 +460,7 @@
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;
+ arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);
@@ -479,6 +492,9 @@
struct fuse_req *init_req;
int err;
+ if (sb->s_flags & MS_MANDLOCK)
+ return -EINVAL;
+
if (!parse_fuse_opt((char *) data, &d))
return -EINVAL;