add ftruncate() method

ChangeLog

@@ -1,15 +1,20 @@
 2005-10-26  Miklos Szeredi <miklos@szeredi.hu>
 
+	* Change kernel ABI version to 7.3
+
 	* Add ACCESS operation.  This is called from the access() system
 	call if 'default_permissions' mount option is not given, and is
 	not called on kernels 2.4.*
 
-	* Fix kernel module compile if kernel source and build directories
-	differ.  Report and initial patch by John Eastman
-
 	* Add atomic CREATE+OPEN operation.  This will only work with
 	2.6.15 (presumably) or later Linux kernels.
 
+	* Add ftruncate() method.  This will only work with 2.6.15
+	(presumably) or later Linux kernels.
+
+	* Fix kernel module compile if kernel source and build directories
+	differ.  Report and initial patch by John Eastman
+
 2005-10-18  Miklos Szeredi <miklos@szeredi.hu>
 
 	* lib: optimize buffer reallocation in fill_dir.

example/fusexmp_fh.c

@@ -204,6 +204,20 @@ static int xmp_truncate(const char *path, off_t size)
     return 0;
 }
 
+static int xmp_ftruncate(const char *path, off_t size,
+                         struct fuse_file_info *fi)
+{
+    int res;
+
+    (void) path;
+
+    res = ftruncate(fi->fh, size);
+    if(res == -1)
+        return -errno;
+
+    return 0;
+}
+
 static int xmp_utime(const char *path, struct utimbuf *buf)
 {
     int res;
@@ -354,6 +368,7 @@ static struct fuse_operations xmp_oper = {
     .chmod	= xmp_chmod,
     .chown	= xmp_chown,
     .truncate	= xmp_truncate,
+    .ftruncate	= xmp_ftruncate,
     .utime	= xmp_utime,
     .create	= xmp_create,
     .open	= xmp_open,

include/fuse.h

@@ -63,9 +63,9 @@ typedef int (*fuse_dirfil_t) (fuse_dirh_t h, const char *name, int type,
  *
  * All methods are optional, but some are essential for a useful
  * filesystem (e.g. getattr).  Open, flush, release, fsync, opendir,
- * releasedir, fsyncdir, access, create, init and destroy are special
+ * releasedir, fsyncdir, access, create, ftruncate, init and destroy
- * purpose methods, without which a full featured filesystem can still
+ * are special purpose methods, without which a full featured
- * be implemented.
+ * filesystem can still be implemented.
  */
 struct fuse_operations {
     /** Get file attributes.
@@ -324,6 +324,20 @@ struct fuse_operations {
      * Introduced in version 2.5
      */
     int (*create) (const char *, mode_t, struct fuse_file_info *);
+
+    /**
+     * Change the size of an open file
+     *
+     * This method is called instead of the truncate() method if the
+     * truncation was invoked from an ftruncate() system call.
+     *
+     * If this method is not implemented or under Linux kernel
+     * versions earlier than 2.6.15, the truncate() method will be
+     * called instead.
+     *
+     * Introduced in version 2.5
+     */
+    int (*ftruncate) (const char *, off_t, struct fuse_file_info *);
 };
 
 /** Extra context that may be needed by some filesystems

include/fuse_lowlevel.h

@@ -198,6 +198,13 @@ struct fuse_lowlevel_ops {
      * bitmask contain valid values.  Other members contain undefined
      * values.
      *
+     * If the setattr was invoked from the ftruncate() system call
+     * under Linux kernel versions 2.6.15 or later, the fi->fh will
+     * contain the value set by the open method or will be undefined
+     * if the open method didn't set any value.  Otherwise (not
+     * ftruncate call, or kernel version earlier than 2.6.15) the fi
+     * parameter will be NULL.
+     *
      * Valid replies:
      *   fuse_reply_attr()
      *   fuse_reply_err()
@@ -206,7 +213,10 @@ struct fuse_lowlevel_ops {
      * @param ino the inode number
      * @param attr the attributes
      * @param to_set bit mask of attributes which should be set
-     * @param fi for future use, currently always NULL
+     * @param fi file information, or NULL
+     *
+     * Changed in version 2.5:
+     *     file information filled in for ftruncate
      */
     void (*setattr) (fuse_req_t req, fuse_ino_t ino, struct stat *attr,
                     int to_set, struct fuse_file_info *fi);

kernel/dir.c

@@ -838,34 +838,36 @@ static int fuse_dir_fsync(struct file *file, struct dentry *de, int datasync)
 	return file ? fuse_fsync_common(file, de, datasync, 1) : 0;
 }
 
-static unsigned iattr_to_fattr(struct iattr *iattr, struct fuse_attr *fattr)
+static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
 {
 	unsigned ivalid = iattr->ia_valid;
-	unsigned fvalid = 0;
-
-	memset(fattr, 0, sizeof(*fattr));
 
 	if (ivalid & ATTR_MODE)
-		fvalid |= FATTR_MODE,   fattr->mode = iattr->ia_mode;
+		arg->valid |= FATTR_MODE,   arg->mode = iattr->ia_mode;
 	if (ivalid & ATTR_UID)
-		fvalid |= FATTR_UID,    fattr->uid = iattr->ia_uid;
+		arg->valid |= FATTR_UID,    arg->uid = iattr->ia_uid;
 	if (ivalid & ATTR_GID)
-		fvalid |= FATTR_GID,    fattr->gid = iattr->ia_gid;
+		arg->valid |= FATTR_GID,    arg->gid = iattr->ia_gid;
 	if (ivalid & ATTR_SIZE)
-		fvalid |= FATTR_SIZE,   fattr->size = iattr->ia_size;
+		arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
 	/* You can only _set_ these together (they may change by themselves) */
 	if ((ivalid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME)) {
-		fvalid |= FATTR_ATIME | FATTR_MTIME;
+		arg->valid |= FATTR_ATIME | FATTR_MTIME;
 #ifdef KERNEL_2_6
-		fattr->atime = iattr->ia_atime.tv_sec;
+		arg->atime = iattr->ia_atime.tv_sec;
-		fattr->mtime = iattr->ia_mtime.tv_sec;
+		arg->mtime = iattr->ia_mtime.tv_sec;
 #else
-		fattr->atime = iattr->ia_atime;
+		arg->atime = iattr->ia_atime;
-		fattr->mtime = iattr->ia_mtime;
+		arg->mtime = iattr->ia_mtime;
 #endif
 	}
-
+#ifdef ATTR_FILE
-	return fvalid;
+	if (ivalid & ATTR_FILE) {
+		struct fuse_file *ff = iattr->ia_file->private_data;
+		arg->valid |= FATTR_FH;
+		arg->fh = ff->fh;
+	}
+#endif
 }
 
 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
@@ -904,7 +906,7 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr)
 		return -EINTR;
 
 	memset(&inarg, 0, sizeof(inarg));
-	inarg.valid = iattr_to_fattr(attr, &inarg.attr);
+	iattr_to_fattr(attr, &inarg);
 	req->in.h.opcode = FUSE_SETATTR;
 	req->in.h.nodeid = get_node_id(inode);
 	req->inode = inode;

kernel/fuse_kernel.h

@@ -42,7 +42,7 @@
 #define FUSE_KERNEL_VERSION 7
 
 /** Minor version number of this interface */
-#define FUSE_KERNEL_MINOR_VERSION 2
+#define FUSE_KERNEL_MINOR_VERSION 3
 
 /** The node ID of the root inode */
 #define FUSE_ROOT_ID 1
@@ -89,6 +89,7 @@ struct fuse_kstatfs {
 #define FATTR_SIZE	(1 << 3)
 #define FATTR_ATIME	(1 << 4)
 #define FATTR_MTIME	(1 << 5)
+#define FATTR_FH	(1 << 6)
 
 /**
  * Flags returned by the OPEN request
@@ -182,7 +183,20 @@ struct fuse_link_in {
 struct fuse_setattr_in {
 	__u32	valid;
 	__u32	padding;
-	struct fuse_attr attr;
+	__u64	fh;
+	__u64	size;
+	__u64	unused1;
+	__u64	atime;
+	__u64	mtime;
+	__u64	unused2;
+	__u32	atimensec;
+	__u32	mtimensec;
+	__u32	unused3;
+	__u32	mode;
+	__u32	unused4;
+	__u32	uid;
+	__u32	gid;
+	__u32	unused5;
 };
 
 struct fuse_open_in {

lib/fuse.c

@@ -674,12 +674,15 @@ static int do_chown(struct fuse *f, const char *path, struct stat *attr,
     return err;
 }
 
-static int do_truncate(struct fuse *f, const char *path, struct stat *attr)
+static int do_truncate(struct fuse *f, const char *path, struct stat *attr,
+                       struct fuse_file_info *fi)
 {
     int err;
 
     err = -ENOSYS;
-    if (f->op.truncate)
+    if (fi && f->op.ftruncate)
+        err = f->op.ftruncate(path, attr->st_size, fi);
+    else if (f->op.truncate)
         err = f->op.truncate(path, attr->st_size);
 
     return err;
@@ -706,8 +709,6 @@ static void fuse_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
     char *path;
     int err;
 
-    (void) fi;
-
     err = -ENOENT;
     pthread_rwlock_rdlock(&f->tree_lock);
     path = get_path(f, ino);
@@ -720,7 +721,7 @@ static void fuse_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
             if (!err && (valid & (FUSE_SET_ATTR_UID | FUSE_SET_ATTR_GID)))
                 err = do_chown(f, path, attr, valid);
             if (!err && (valid & FUSE_SET_ATTR_SIZE))
-                err = do_truncate(f, path, attr);
+                err = do_truncate(f, path, attr, fi);
             if (!err && (valid & (FUSE_SET_ATTR_ATIME | FUSE_SET_ATTR_MTIME)) == (FUSE_SET_ATTR_ATIME | FUSE_SET_ATTR_MTIME))
                 err = do_utime(f, path, attr);
             if (!err)

lib/fuse_lowlevel.c

@@ -95,7 +95,7 @@ static void convert_stat(const struct stat *stbuf, struct fuse_attr *attr)
 #endif
 }
 
-static void convert_attr(const struct fuse_attr *attr, struct stat *stbuf)
+static void convert_attr(const struct fuse_setattr_in *attr, struct stat *stbuf)
 {
     stbuf->st_mode         = attr->mode;
     stbuf->st_uid          = attr->uid;
@@ -103,11 +103,9 @@ static void convert_attr(const struct fuse_attr *attr, struct stat *stbuf)
     stbuf->st_size         = attr->size;
     stbuf->st_atime        = attr->atime;
     stbuf->st_mtime        = attr->mtime;
-    stbuf->st_ctime        = attr->ctime;
 #ifdef HAVE_STRUCT_STAT_ST_ATIM
     stbuf->st_atim.tv_nsec = attr->atimensec;
     stbuf->st_mtim.tv_nsec = attr->mtimensec;
-    stbuf->st_ctim.tv_nsec = attr->ctimensec;
 #endif
 }
 
@@ -366,12 +364,20 @@ static void do_getattr(fuse_req_t req, fuse_ino_t nodeid)
 }
 
 static void do_setattr(fuse_req_t req, fuse_ino_t nodeid,
-                       struct fuse_setattr_in *arg, struct fuse_file_info *fi)
+                       struct fuse_setattr_in *arg)
 {
     if (req->f->op.setattr) {
+        struct fuse_file_info *fi = NULL;
+        struct fuse_file_info fi_store;
         struct stat stbuf;
         memset(&stbuf, 0, sizeof(stbuf));
-        convert_attr(&arg->attr, &stbuf);
+        convert_attr(arg, &stbuf);
+        if (arg->valid & FATTR_FH) {
+            arg->valid &= ~FATTR_FH;
+            memset(&fi_store, 0, sizeof(fi_store));
+            fi = &fi_store;
+            fi->fh = arg->fh;
+        }
         req->f->op.setattr(req, nodeid, &stbuf, arg->valid, fi);
     } else
         fuse_reply_err(req, ENOSYS);
@@ -754,7 +760,7 @@ static void fuse_ll_process(void *data, const char *buf, size_t len,
         break;
 
     case FUSE_SETATTR:
-        do_setattr(req, in->nodeid, (struct fuse_setattr_in *) inarg, NULL);
+        do_setattr(req, in->nodeid, (struct fuse_setattr_in *) inarg);
         break;
 
     case FUSE_READLINK: