From: Nikolaus Rath <Nikolaus@rath.org>
Date: Thu, 25 May 2017 20:12:06 +0000 (-0700)
Subject: Document RENAME_EXCHANGE and RENAME_NOREPLACE flags.
X-Git-Tag: fuse-3.1.0~25
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=6ac254c00fc6026fd462b7b93aaa9dc4aa676f69;p=qemu-gpiodev%2Flibfuse.git

Document RENAME_EXCHANGE and RENAME_NOREPLACE flags.
---

diff --git a/ChangeLog.rst b/ChangeLog.rst
index 3bf56b7..560ad98 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -3,6 +3,10 @@ Unreleased Changes
 
 * `fuse_main()` / `fuse_remove_signal_handlers()`: do not reset
   `SIGPIPE` handler to `SIG_DFL` it was not set by us.
+* Documented the `RENAME_EXCHANGE` and `RENAME_NOREPLACE` flags that
+  may be passed to the `rename` handler of both the high- and
+  low-level API. Filesystem authors are strongly encouraged to check
+  that these flags are handled correctly.
 
 libfuse 3.0.2 (2017-05-24)
 ==========================
diff --git a/include/fuse.h b/include/fuse.h
index 754303f..0c5741f 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -339,8 +339,16 @@ struct fuse_operations {
 	/** Create a symbolic link */
 	int (*symlink) (const char *, const char *);
 
-	/** Rename a file */
-	int (*rename) (const char *, const char *, unsigned int);
+	/** Rename a file
+	 *
+	 * *flags* may be `RENAME_EXCHANGE` or `RENAME_NOREPLACE`. If
+	 * RENAME_NOREPLACE is specified, the filesystem must not
+	 * overwrite *newname* if it exists and return an error
+	 * instead. If `RENAME_EXCHANGE` is specified, the filesystem
+	 * must atomically exchange the two files, i.e. both must
+	 * exist and neither may be deleted.
+	 */
+	int (*rename) (const char *, const char *, unsigned int flags);
 
 	/** Create a hard link to a file */
 	int (*link) (const char *, const char *);
diff --git a/include/fuse_lowlevel.h b/include/fuse_lowlevel.h
index 987b24d..fd8bc1a 100644
--- a/include/fuse_lowlevel.h
+++ b/include/fuse_lowlevel.h
@@ -408,6 +408,13 @@ struct fuse_lowlevel_ops {
 	 * future bmap requests will fail with EINVAL without being
 	 * send to the filesystem process.
 	 *
+	 * *flags* may be `RENAME_EXCHANGE` or `RENAME_NOREPLACE`. If
+	 * RENAME_NOREPLACE is specified, the filesystem must not
+	 * overwrite *newname* if it exists and return an error
+	 * instead. If `RENAME_EXCHANGE` is specified, the filesystem
+	 * must atomically exchange the two files, i.e. both must
+	 * exist and neither may be deleted.
+	 *
 	 * Valid replies:
 	 *   fuse_reply_err
 	 *