[PATCH] fuse: add bmap support

Add support for the BMAP operation for block device based filesystems.  This
is needed to support swap-files and lilo.

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/dir.c b/fs/fuse/dir.c
index 677f3ed..1cabdb2 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1024,6 +1024,8 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
        if (attr->ia_valid & ATTR_SIZE) {
                unsigned long limit;
                is_truncate = 1;
+               if (IS_SWAPFILE(inode))
+                       return -ETXTBSY;
                limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
                if (limit != RLIM_INFINITY && attr->ia_size > (loff_t) limit) {
                        send_sig(SIGXFSZ, current, 0);

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 763a50d..128f79c 100644 (file)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -754,6 +754,42 @@ static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
        return err;
 }
 
+static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
+{
+       struct inode *inode = mapping->host;
+       struct fuse_conn *fc = get_fuse_conn(inode);
+       struct fuse_req *req;
+       struct fuse_bmap_in inarg;
+       struct fuse_bmap_out outarg;
+       int err;
+
+       if (!inode->i_sb->s_bdev || fc->no_bmap)
+               return 0;
+
+       req = fuse_get_req(fc);
+       if (IS_ERR(req))
+               return 0;
+
+       memset(&inarg, 0, sizeof(inarg));
+       inarg.block = block;
+       inarg.blocksize = inode->i_sb->s_blocksize;
+       req->in.h.opcode = FUSE_BMAP;
+       req->in.h.nodeid = get_node_id(inode);
+       req->in.numargs = 1;
+       req->in.args[0].size = sizeof(inarg);
+       req->in.args[0].value = &inarg;
+       req->out.numargs = 1;
+       req->out.args[0].size = sizeof(outarg);
+       req->out.args[0].value = &outarg;
+       request_send(fc, req);
+       err = req->out.h.error;
+       fuse_put_request(fc, req);
+       if (err == -ENOSYS)
+               fc->no_bmap = 1;
+
+       return err ? 0 : outarg.block;
+}
+
 static const struct file_operations fuse_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = do_sync_read,
@@ -787,6 +823,7 @@ static const struct address_space_operations fuse_file_aops  = {
        .commit_write   = fuse_commit_write,
        .readpages      = fuse_readpages,
        .set_page_dirty = fuse_set_page_dirty,
+       .bmap           = fuse_bmap,
 };
 
 void fuse_init_file_inode(struct inode *inode)

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 91edb89..58d482d 100644 (file)
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -339,6 +339,9 @@ struct fuse_conn {
        /** Is interrupt not implemented by fs? */
        unsigned no_interrupt : 1;
 
+       /** Is bmap not implemented by fs? */
+       unsigned no_bmap : 1;
+
        /** The number of requests waiting for completion */
        atomic_t num_waiting;
 

diff --git a/include/linux/fuse.h b/include/linux/fuse.h
index 7633632..162a754 100644 (file)
--- a/include/linux/fuse.h
+++ b/include/linux/fuse.h
@@ -132,6 +132,7 @@ enum fuse_opcode {
        FUSE_ACCESS        = 34,
        FUSE_CREATE        = 35,
        FUSE_INTERRUPT     = 36,
+       FUSE_BMAP          = 37,
 };
 
 /* The read buffer is required to be at least 8k, but may be much larger */
@@ -302,6 +303,16 @@ struct fuse_interrupt_in {
        __u64   unique;
 };
 
+struct fuse_bmap_in {
+       __u64   block;
+       __u32   blocksize;
+       __u32   padding;
+};
+
+struct fuse_bmap_out {
+       __u64   block;
+};
+
 struct fuse_in_header {
        __u32   len;
        __u32   opcode;