Add statx support

This commit adds libfuse support for FUSE_STATX requests on
linux distributions.

Currently, statx is only supported on linux. To make the interface a
ergonomic as possible (eg using native 'struct statx' vs 'struct
fuse_statx'), this implementation gates the 'struct statx' changes
by #ifdef linux.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>

2 files changed, 52 insertions, 1 deletions

diff --git a/include/fuse.h b/include/fuse.h
index b990043..06feacb 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -33,6 +33,9 @@ extern "C" {
  * Basic FUSE API					       *
  * ----------------------------------------------------------- */
 
+/* Forward declaration */
+struct statx;
+
 /** Handle for a FUSE filesystem */
 struct fuse;
 
@@ -850,6 +853,19 @@ struct fuse_operations {
 	 * Find next data or hole after the specified offset
 	 */
 	off_t (*lseek) (const char *, off_t off, int whence, struct fuse_file_info *);
+
+#ifdef HAVE_STATX
+	/**
+	 * Get extended file attributes.
+	 *
+	 * fi may be NULL.
+	 *
+	 * If path is NULL, then the AT_EMPTY_PATH bit in flags will be
+	 * already set.
+	 */
+	int (*statx)(const char *path, int flags, int mask, struct statx *stxbuf,
+		     struct fuse_file_info *fi);
+#endif
 };
 
 /** Extra context that may be needed by some filesystems
@@ -1344,6 +1360,8 @@ ssize_t fuse_fs_copy_file_range(struct fuse_fs *fs, const char *path_in,
 				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);
+int fuse_fs_statx(struct fuse_fs *fs, const char *path, int flags, int mask,
+		  struct statx *stxbuf, 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 75e084d..844ee71 100644
--- a/include/fuse_lowlevel.h
+++ b/include/fuse_lowlevel.h
@@ -49,6 +49,9 @@ typedef uint64_t fuse_ino_t;
 /** Request pointer type */
 typedef struct fuse_req *fuse_req_t;
 
+/* Forward declaration */
+struct statx;
+
 /**
  * Session
  *
@@ -1303,7 +1306,6 @@ struct fuse_lowlevel_ops {
 	void (*lseek) (fuse_req_t req, fuse_ino_t ino, off_t off, int whence,
 		       struct fuse_file_info *fi);
 
-
 	/**
 	 * Create a tempfile
 	 * 
@@ -1325,6 +1327,23 @@ struct fuse_lowlevel_ops {
 	void (*tmpfile) (fuse_req_t req, fuse_ino_t parent,
 			mode_t mode, struct fuse_file_info *fi);
 
+#ifdef HAVE_STATX
+	/**
+	 * Get extended file attributes.
+	 *
+	 * Valid replies:
+	 *   fuse_reply_statx
+	 *   fuse_reply_err
+	 *
+	 * @param req request handle
+	 * @param ino the inode number
+	 * @param flags bitmask of requested flags
+	 * @param mask bitmask of requested fields
+	 * @param fi file information (may be NULL)
+	 */
+	void (*statx)(fuse_req_t req, fuse_ino_t ino, int flags, int mask,
+		      struct fuse_file_info *fi);
+#endif
 };
 
 /**
@@ -1705,6 +1724,20 @@ int fuse_reply_poll(fuse_req_t req, unsigned revents);
  */
 int fuse_reply_lseek(fuse_req_t req, off_t off);
 
+/**
+ * Reply with extended file attributes.
+ *
+ * Possible requests:
+ *   statx
+ *
+ * @param req request handle
+ * @param flags statx flags
+ * @param statx the attributes
+ * @param attr_timeout	validity timeout (in seconds) for the attributes
+ * @return zero for success, -errno for failure to send reply
+ */
+int fuse_reply_statx(fuse_req_t req, int flags, struct statx *statx, double attr_timeout);
+
 /* ----------------------------------------------------------- *
  * Notification						       *
  * ----------------------------------------------------------- */