Implement lseek operation (#457)

2 files changed, 40 insertions, 0 deletions

diff --git a/include/fuse.h b/include/fuse.h
index 2d2291c..883f6e5 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -776,6 +776,11 @@ struct fuse_operations {
 				    off_t offset_in, const char *path_out,
 				    struct fuse_file_info *fi_out,
 				    off_t offset_out, size_t size, int flags);
+
+	/**
+	 * Find next data or hole after the specified offset
+	 */
+	off_t (*lseek) (const char *, off_t off, int whence, struct fuse_file_info *);
 };
 
 /** Extra context that may be needed by some filesystems
@@ -1197,6 +1202,8 @@ ssize_t fuse_fs_copy_file_range(struct fuse_fs *fs, const char *path_in,
 				const char *path_out,
 				struct fuse_file_info *fi_out, off_t off_out,
 				size_t len, int flags);
+off_t fuse_fs_lseek(struct fuse_fs *fs, const char *path, off_t off, int whence,
+		    struct fuse_file_info *fi);
 void fuse_fs_init(struct fuse_fs *fs, struct fuse_conn_info *conn,
 		struct fuse_config *cfg);
 void fuse_fs_destroy(struct fuse_fs *fs);
diff --git a/include/fuse_lowlevel.h b/include/fuse_lowlevel.h
index 2073460..18c6363 100644
--- a/include/fuse_lowlevel.h
+++ b/include/fuse_lowlevel.h
@@ -1218,6 +1218,27 @@ struct fuse_lowlevel_ops {
 				 fuse_ino_t ino_out, off_t off_out,
 				 struct fuse_file_info *fi_out, size_t len,
 				 int flags);
+
+	/**
+	 * Find next data or hole after the specified offset
+	 *
+	 * If this request is answered with an error code of ENOSYS, this is
+	 * treated as a permanent failure, i.e. all future lseek() requests will
+	 * fail with the same error code without being send to the filesystem
+	 * process.
+	 *
+	 * Valid replies:
+	 *   fuse_reply_lseek
+	 *   fuse_reply_err
+	 *
+	 * @param req request handle
+	 * @param ino the inode number
+	 * @param off offset to start search from
+	 * @param whence either SEEK_DATA or SEEK_HOLE
+	 * @param fi file information
+	 */
+	void (*lseek) (fuse_req_t req, fuse_ino_t ino, off_t off, int whence,
+		       struct fuse_file_info *fi);
 };
 
 /**
@@ -1569,6 +1590,18 @@ int fuse_reply_ioctl_iov(fuse_req_t req, int result, const struct iovec *iov,
  */
 int fuse_reply_poll(fuse_req_t req, unsigned revents);
 
+/**
+ * Reply with offset
+ *
+ * Possible requests:
+ *   lseek
+ *
+ * @param req request handle
+ * @param off offset of next data or hole
+ * @return zero for success, -errno for failure to send reply
+ */
+int fuse_reply_lseek(fuse_req_t req, off_t off);
+
 /* ----------------------------------------------------------- *
  * Notification						       *
  * ----------------------------------------------------------- */