Support receiving file handle from kernel in GETATTR request; Allow operations with a NULL path argument, if the filesystem supports it

8 files changed, 206 insertions, 135 deletions

diff --git a/ChangeLog b/ChangeLog
index 5b45dcf..7149a07 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,11 @@
 
 	* Update kernel interface to 7.9
 
+	* Support receiving file handle from kernel in GETATTR request
+
+	* Allow operations with a NULL path argument, if the filesystem
+	supports it
+
 2008-02-03  Csaba Henk <csaba.henk@creo.hu>
 
 	* lib/mount_bsd.c:
diff --git a/example/fusexmp_fh.c b/example/fusexmp_fh.c
index 4949675..b86d3f6 100644
--- a/example/fusexmp_fh.c
+++ b/example/fusexmp_fh.c
@@ -484,6 +484,8 @@ static struct fuse_operations xmp_oper = {
 	.removexattr	= xmp_removexattr,
 #endif
 	.lock		= xmp_lock,
+
+	.flag_nullpath_ok = 1,
 };
 
 int main(int argc, char *argv[])
diff --git a/include/fuse.h b/include/fuse.h
index b7708c7..384a7b4 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -423,6 +423,20 @@ struct fuse_operations {
 	 * Introduced in version 2.6
 	 */
 	int (*bmap) (const char *, size_t blocksize, uint64_t *idx);
+
+	/**
+	 * Flag indicating, that the filesystem can accept a NULL path
+	 * as the first argument for the following operations:
+	 *
+	 * read, write, flush, release, fsync, readdir, releasedir,
+	 * fsyncdir, ftruncate, fgetattr and lock
+	 */
+	unsigned int flag_nullpath_ok : 1;
+
+	/**
+	 * Reserved flags, don't set
+	 */
+	unsigned int flag_reserved : 31;
 };
 
 /** Extra context that may be needed by some filesystems
diff --git a/include/fuse_common.h b/include/fuse_common.h
index 8d4ba2b..5f50d60 100644
--- a/include/fuse_common.h
+++ b/include/fuse_common.h
@@ -22,7 +22,7 @@
 #define FUSE_MAJOR_VERSION 2
 
 /** Minor version of FUSE library interface */
-#define FUSE_MINOR_VERSION 7
+#define FUSE_MINOR_VERSION 8
 
 #define FUSE_MAKE_VERSION(maj, min)  ((maj) * 10 + (min))
 #define FUSE_VERSION FUSE_MAKE_VERSION(FUSE_MAJOR_VERSION, FUSE_MINOR_VERSION)
diff --git a/lib/fuse.c b/lib/fuse.c
index 7bcbe76..a15b5c2 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -90,6 +90,7 @@ struct fuse {
 	struct fuse_config conf;
 	int intr_installed;
 	struct fuse_fs *fs;
+	int nullpath_ok;
 };
 
 struct lock {
@@ -764,7 +765,7 @@ int fuse_fs_fgetattr(struct fuse_fs *fs, const char *path, struct stat *buf,
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.fgetattr)
 		return fs->op.fgetattr(path, buf, fi);
-	else if (fs->op.getattr)
+	else if (path && fs->op.getattr)
 		return fs->op.getattr(path, buf);
 	else
 		return -ENOSYS;
@@ -992,7 +993,7 @@ int fuse_fs_ftruncate(struct fuse_fs *fs, const char *path, off_t size,
 	fuse_get_context()->private_data = fs->user_data;
 	if (fs->op.ftruncate)
 		return fs->op.ftruncate(path, size, fi);
-	else if (fs->op.truncate)
+	else if (path && fs->op.truncate)
 		return fs->op.truncate(path, size);
 	else
 		return -ENOSYS;
@@ -1409,16 +1410,18 @@ static void fuse_lib_getattr(fuse_req_t req, fuse_ino_t ino,
 	char *path;
 	int err;
 
-	(void) fi;
 	memset(&buf, 0, sizeof(buf));
 
 	err = -ENOENT;
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path != NULL) {
+	if (path != NULL || (fi && f->nullpath_ok)) {
 		struct fuse_intr_data d;
 		fuse_prepare_interrupt(f, req, &d);
-		err = fuse_fs_getattr(f->fs, path, &buf);
+		if (fi)
+			err = fuse_fs_fgetattr(f->fs, path, &buf, fi);
+		else
+			err = fuse_fs_getattr(f->fs, path, &buf);
 		fuse_finish_interrupt(f, req, &d);
 		free(path);
 	}
@@ -1774,7 +1777,7 @@ static void fuse_do_release(struct fuse *f, fuse_ino_t ino, const char *path,
 	struct node *node;
 	int unlink_hidden = 0;
 
-	fuse_fs_release(f->fs, path ? path : "-", fi);
+	fuse_fs_release(f->fs, (path || f->nullpath_ok) ? path : "-", fi);
 
 	pthread_mutex_lock(&f->lock);
 	node = get_node(f, ino);
@@ -1950,7 +1953,7 @@ static void fuse_lib_read(fuse_req_t req, fuse_ino_t ino, size_t size,
 	res = -ENOENT;
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path != NULL) {
+	if (path != NULL || f->nullpath_ok) {
 		struct fuse_intr_data d;
 		if (f->conf.debug)
 			fprintf(stderr, "READ[%llu] %lu bytes from %llu\n",
@@ -1987,7 +1990,7 @@ static void fuse_lib_write(fuse_req_t req, fuse_ino_t ino, const char *buf,
 	res = -ENOENT;
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path != NULL) {
+	if (path != NULL || f->nullpath_ok) {
 		struct fuse_intr_data d;
 		if (f->conf.debug)
 			fprintf(stderr, "WRITE%s[%llu] %lu bytes to %llu\n",
@@ -2024,7 +2027,7 @@ static void fuse_lib_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
 	err = -ENOENT;
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path != NULL) {
+	if (path != NULL || f->nullpath_ok) {
 		struct fuse_intr_data d;
 		if (f->conf.debug)
 			fprintf(stderr, "FSYNC[%llu]\n",
@@ -2251,7 +2254,7 @@ static void fuse_lib_releasedir(fuse_req_t req, fuse_ino_t ino,
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
 	fuse_prepare_interrupt(f, req, &d);
-	fuse_fs_releasedir(f->fs, path ? path : "-", &fi);
+	fuse_fs_releasedir(f->fs, (path || f->nullpath_ok) ? path : "-", &fi);
 	fuse_finish_interrupt(f, req, &d);
 	if (path)
 		free(path);
@@ -2644,7 +2647,7 @@ static void fuse_lib_flush(fuse_req_t req, fuse_ino_t ino,
 
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path && f->conf.debug)
+	if (f->conf.debug)
 		fprintf(stderr, "FLUSH[%llu]\n", (unsigned long long) fi->fh);
 	err = fuse_flush_common(f, req, ino, path, fi);
 	free(path);
@@ -2663,7 +2666,7 @@ static int fuse_lock_common(fuse_req_t req, fuse_ino_t ino,
 	err = -ENOENT;
 	pthread_rwlock_rdlock(&f->tree_lock);
 	path = get_path(f, ino);
-	if (path != NULL) {
+	if (path != NULL || f->nullpath_ok) {
 		struct fuse_intr_data d;
 		fuse_prepare_interrupt(f, req, &d);
 		err = fuse_fs_lock(f->fs, path, fi, cmd, lock);
@@ -3023,6 +3026,7 @@ static int fuse_push_module(struct fuse *f, const char *module,
 	}
 	newfs->m = m;
 	f->fs = newfs;
+	f->nullpath_ok = newfs->op.flag_nullpath_ok && f->nullpath_ok;
 	return 0;
 }
 
@@ -3072,6 +3076,7 @@ struct fuse *fuse_new_common(struct fuse_chan *ch, struct fuse_args *args,
 
 	fs->compat = compat;
 	f->fs = fs;
+	f->nullpath_ok = fs->op.flag_nullpath_ok;
 
 	/* Oh f**k, this is ugly! */
 	if (!fs->op.lock) {
@@ -3103,6 +3108,9 @@ struct fuse *fuse_new_common(struct fuse_chan *ch, struct fuse_args *args,
 		}
 	}
 
+	if (f->conf.debug)
+		fprintf(stderr, "nullpath_ok: %i\n", f->nullpath_ok);
+
 	if (!f->conf.ac_attr_timeout_set)
 		f->conf.ac_attr_timeout = f->conf.attr_timeout;
 
diff --git a/lib/fuse_lowlevel.c b/lib/fuse_lowlevel.c
index ed885fd..d1ef7b2 100644
--- a/lib/fuse_lowlevel.c
+++ b/lib/fuse_lowlevel.c
@@ -458,10 +458,22 @@ static void do_forget(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 
 static void do_getattr(fuse_req_t req, fuse_ino_t nodeid, const void *inarg)
 {
-	(void) inarg;
+	struct fuse_file_info *fip = NULL;
+	struct fuse_file_info fi;
+
+	if (req->f->conn.proto_minor >= 9) {
+		struct fuse_getattr_in *arg = (struct fuse_getattr_in *) inarg;
+
+		if (arg->getattr_flags & FUSE_GETATTR_FH) {
+			memset(&fi, 0, sizeof(fi));
+			fi.fh = arg->fh;
+			fi.fh_old = fi.fh;
+			fip = &fi;
+		}
+	}
 
 	if (req->f->op.getattr)
-		req->f->op.getattr(req, nodeid, NULL);
+		req->f->op.getattr(req, nodeid, fip);
 	else
 		fuse_reply_err(req, ENOSYS);
 }
diff --git a/lib/modules/iconv.c b/lib/modules/iconv.c
index c0e2b80..409cb66 100644
--- a/lib/modules/iconv.c
+++ b/lib/modules/iconv.c
@@ -42,17 +42,27 @@ static struct iconv *iconv_get(void)
 static int iconv_convpath(struct iconv *ic, const char *path, char **newpathp,
 			  int fromfs)
 {
-	size_t pathlen = strlen(path);
-	size_t newpathlen = pathlen * 4;
-	char *newpath = malloc(newpathlen + 1);
-	size_t plen = newpathlen;
-	char *p = newpath;
+	size_t pathlen;
+	size_t newpathlen;
+	char *newpath;
+	size_t plen;
+	char *p;
 	size_t res;
 	int err;
 
+	if (path == NULL) {
+		*newpathp = NULL;
+		return 0;
+	}
+
+	pathlen = strlen(path);
+	newpathlen = pathlen * 4;
+	newpath = malloc(newpathlen + 1);
 	if (!newpath)
 		return -ENOMEM;
 
+	plen = newpathlen;
+	p = newpath;
 	pthread_mutex_lock(&ic->lock);
 	do {
 		res = iconv(fromfs ? ic->fromfs : ic->tofs, (char **) &path,
@@ -607,6 +617,8 @@ static struct fuse_operations iconv_oper = {
 	.removexattr	= iconv_removexattr,
 	.lock		= iconv_lock,
 	.bmap		= iconv_bmap,
+
+	.flag_nullpath_ok = 1,
 };
 
 static struct fuse_opt iconv_opts[] = {
diff --git a/lib/modules/subdir.c b/lib/modules/subdir.c
index 6f7b187..3188d1f 100644
--- a/lib/modules/subdir.c
+++ b/lib/modules/subdir.c
@@ -27,11 +27,17 @@ static struct subdir *subdir_get(void)
 	return fuse_get_context()->private_data;
 }
 
-static char *subdir_addpath(struct subdir *d, const char *path)
+static int subdir_addpath(struct subdir *d, const char *path, char **newpathp)
 {
-	unsigned newlen = d->baselen + strlen(path);
-	char *newpath = malloc(newlen + 2);
-	if (newpath) {
+	char *newpath = NULL;
+
+	if (path != NULL) {
+		unsigned newlen = d->baselen + strlen(path);
+
+		newpath = malloc(newlen + 2);
+		if (!newpath)
+			return -ENOMEM;
+
 		if (path[0] == '/')
 			path++;
 		strcpy(newpath, d->base);
@@ -39,15 +45,17 @@ static char *subdir_addpath(struct subdir *d, const char *path)
 		if (!newpath[0])
 			strcpy(newpath, ".");
 	}
-	return newpath;
+	*newpathp = newpath;
+
+	return 0;
 }
 
 static int subdir_getattr(const char *path, struct stat *stbuf)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_getattr(d->next, newpath, stbuf);
 		free(newpath);
 	}
@@ -58,9 +66,9 @@ static int subdir_fgetattr(const char *path, struct stat *stbuf,
 			   struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_fgetattr(d->next, newpath, stbuf, fi);
 		free(newpath);
 	}
@@ -70,9 +78,9 @@ static int subdir_fgetattr(const char *path, struct stat *stbuf,
 static int subdir_access(const char *path, int mask)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_access(d->next, newpath, mask);
 		free(newpath);
 	}
@@ -146,9 +154,9 @@ static void transform_symlink(struct subdir *d, const char *path,
 static int subdir_readlink(const char *path, char *buf, size_t size)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_readlink(d->next, newpath, buf, size);
 		if (!err && d->rellinks)
 			transform_symlink(d, newpath, buf, size);
@@ -160,9 +168,9 @@ static int subdir_readlink(const char *path, char *buf, size_t size)
 static int subdir_opendir(const char *path, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_opendir(d->next, newpath, fi);
 		free(newpath);
 	}
@@ -174,9 +182,9 @@ static int subdir_readdir(const char *path, void *buf,
 			  struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_readdir(d->next, newpath, buf, filler, offset,
 				      fi);
 		free(newpath);
@@ -187,9 +195,9 @@ static int subdir_readdir(const char *path, void *buf,
 static int subdir_releasedir(const char *path, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_releasedir(d->next, newpath, fi);
 		free(newpath);
 	}
@@ -199,9 +207,9 @@ static int subdir_releasedir(const char *path, struct fuse_file_info *fi)
 static int subdir_mknod(const char *path, mode_t mode, dev_t rdev)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_mknod(d->next, newpath, mode, rdev);
 		free(newpath);
 	}
@@ -211,9 +219,9 @@ static int subdir_mknod(const char *path, mode_t mode, dev_t rdev)
 static int subdir_mkdir(const char *path, mode_t mode)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_mkdir(d->next, newpath, mode);
 		free(newpath);
 	}
@@ -223,9 +231,9 @@ static int subdir_mkdir(const char *path, mode_t mode)
 static int subdir_unlink(const char *path)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_unlink(d->next, newpath);
 		free(newpath);
 	}
@@ -235,9 +243,9 @@ static int subdir_unlink(const char *path)
 static int subdir_rmdir(const char *path)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_rmdir(d->next, newpath);
 		free(newpath);
 	}
@@ -247,9 +255,9 @@ static int subdir_rmdir(const char *path)
 static int subdir_symlink(const char *from, const char *path)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_symlink(d->next, from, newpath);
 		free(newpath);
 	}
@@ -259,35 +267,43 @@ static int subdir_symlink(const char *from, const char *path)
 static int subdir_rename(const char *from, const char *to)
 {
 	struct subdir *d = subdir_get();
-	char *newfrom = subdir_addpath(d, from);
-	char *newto = subdir_addpath(d, to);
-	int err = -ENOMEM;
-	if (newfrom && newto)
-		err = fuse_fs_rename(d->next, newfrom, newto);
-	free(newfrom);
-	free(newto);
+	char *newfrom;
+	char *newto;
+	int err = subdir_addpath(d, from, &newfrom);
+	if (!err) {
+		err = subdir_addpath(d, to, &newto);
+		if (!err) {
+			err = fuse_fs_rename(d->next, newfrom, newto);
+			free(newto);
+		}
+		free(newfrom);
+	}
 	return err;
 }
 
 static int subdir_link(const char *from, const char *to)
 {
 	struct subdir *d = subdir_get();
-	char *newfrom = subdir_addpath(d, from);
-	char *newto = subdir_addpath(d, to);
-	int err = -ENOMEM;
-	if (newfrom && newto)
-		err = fuse_fs_link(d->next, newfrom, newto);
-	free(newfrom);
-	free(newto);
+	char *newfrom;
+	char *newto;
+	int err = subdir_addpath(d, from, &newfrom);
+	if (!err) {
+		err = subdir_addpath(d, to, &newto);
+		if (!err) {
+			err = fuse_fs_link(d->next, newfrom, newto);
+			free(newto);
+		}
+		free(newfrom);
+	}
 	return err;
 }
 
 static int subdir_chmod(const char *path, mode_t mode)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_chmod(d->next, newpath, mode);
 		free(newpath);
 	}
@@ -297,9 +313,9 @@ static int subdir_chmod(const char *path, mode_t mode)
 static int subdir_chown(const char *path, uid_t uid, gid_t gid)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_chown(d->next, newpath, uid, gid);
 		free(newpath);
 	}
@@ -309,9 +325,9 @@ static int subdir_chown(const char *path, uid_t uid, gid_t gid)
 static int subdir_truncate(const char *path, off_t size)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_truncate(d->next, newpath, size);
 		free(newpath);
 	}
@@ -322,9 +338,9 @@ static int subdir_ftruncate(const char *path, off_t size,
 			    struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_ftruncate(d->next, newpath, size, fi);
 		free(newpath);
 	}
@@ -334,9 +350,9 @@ static int subdir_ftruncate(const char *path, off_t size,
 static int subdir_utimens(const char *path, const struct timespec ts[2])
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_utimens(d->next, newpath, ts);
 		free(newpath);
 	}
@@ -347,9 +363,9 @@ static int subdir_create(const char *path, mode_t mode,
 			 struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_create(d->next, newpath, mode, fi);
 		free(newpath);
 	}
@@ -359,9 +375,9 @@ static int subdir_create(const char *path, mode_t mode,
 static int subdir_open(const char *path, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_open(d->next, newpath, fi);
 		free(newpath);
 	}
@@ -372,9 +388,9 @@ static int subdir_read(const char *path, char *buf, size_t size, off_t offset,
 		       struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_read(d->next, newpath, buf, size, offset, fi);
 		free(newpath);
 	}
@@ -385,9 +401,9 @@ static int subdir_write(const char *path, const char *buf, size_t size,
 			off_t offset, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_write(d->next, newpath, buf, size, offset, fi);
 		free(newpath);
 	}
@@ -397,9 +413,9 @@ static int subdir_write(const char *path, const char *buf, size_t size,
 static int subdir_statfs(const char *path, struct statvfs *stbuf)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_statfs(d->next, newpath, stbuf);
 		free(newpath);
 	}
@@ -409,9 +425,9 @@ static int subdir_statfs(const char *path, struct statvfs *stbuf)
 static int subdir_flush(const char *path, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_flush(d->next, newpath, fi);
 		free(newpath);
 	}
@@ -421,9 +437,9 @@ static int subdir_flush(const char *path, struct fuse_file_info *fi)
 static int subdir_release(const char *path, struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_release(d->next, newpath, fi);
 		free(newpath);
 	}
@@ -434,9 +450,9 @@ static int subdir_fsync(const char *path, int isdatasync,
 			struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_fsync(d->next, newpath, isdatasync, fi);
 		free(newpath);
 	}
@@ -447,9 +463,9 @@ static int subdir_fsyncdir(const char *path, int isdatasync,
 			   struct fuse_file_info *fi)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_fsyncdir(d->next, newpath, isdatasync, fi);
 		free(newpath);
 	}
@@ -460,9 +476,9 @@ static int subdir_setxattr(const char *path, const char *name,
 			   const char *value, size_t size, int flags)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_setxattr(d->next, newpath, name, value, size,
 				       flags);
 		free(newpath);
@@ -474,9 +490,9 @@ static int subdir_getxattr(const char *path, const char *name, char *value,
 			   size_t size)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_getxattr(d->next, newpath, name, value, size);
 		free(newpath);
 	}
@@ -486,9 +502,9 @@ static int subdir_getxattr(const char *path, const char *name, char *value,
 static int subdir_listxattr(const char *path, char *list, size_t size)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_listxattr(d->next, newpath, list, size);
 		free(newpath);
 	}
@@ -498,9 +514,9 @@ static int subdir_listxattr(const char *path, char *list, size_t size)
 static int subdir_removexattr(const char *path, const char *name)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_removexattr(d->next, newpath, name);
 		free(newpath);
 	}
@@ -511,9 +527,9 @@ static int subdir_lock(const char *path, struct fuse_file_info *fi, int cmd,
 		       struct flock *lock)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_lock(d->next, newpath, fi, cmd, lock);
 		free(newpath);
 	}
@@ -523,9 +539,9 @@ static int subdir_lock(const char *path, struct fuse_file_info *fi, int cmd,
 static int subdir_bmap(const char *path, size_t blocksize, uint64_t *idx)
 {
 	struct subdir *d = subdir_get();
-	char *newpath = subdir_addpath(d, path);
-	int err = -ENOMEM;
-	if (newpath) {
+	char *newpath;
+	int err = subdir_addpath(d, path, &newpath);
+	if (!err) {
 		err = fuse_fs_bmap(d->next, newpath, blocksize, idx);
 		free(newpath);
 	}
@@ -584,6 +600,8 @@ static struct fuse_operations subdir_oper = {
 	.removexattr	= subdir_removexattr,
 	.lock		= subdir_lock,
 	.bmap		= subdir_bmap,
+
+	.flag_nullpath_ok = 1,
 };
 
 static struct fuse_opt subdir_opts[] = {