Merge pull request #61 from bgly/bduffyly/rename2

Add basic renameat2 syscall support

kmod/src/dir.c

@@ -1615,8 +1615,9 @@ static int verify_ancestors(struct super_block *sb, u64 p1, u64 p2,
  * from using parent/child locking orders as two groups can have both
  * parent and child relationships to each other.
  */
-static int scoutfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-			  struct inode *new_dir, struct dentry *new_dentry)
+static int scoutfs_rename_common(struct inode *old_dir,
+				 struct dentry *old_dentry, struct inode *new_dir,
+				 struct dentry *new_dentry, unsigned int flags)
 {
 	struct super_block *sb = old_dir->i_sb;
 	struct inode *old_inode = old_dentry->d_inode;
@@ -1688,6 +1689,11 @@ static int scoutfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (ret)
 		goto out_unlock;
 
+	if ((flags & RENAME_NOREPLACE) && (new_inode != NULL)) {
+		ret = -EEXIST;
+		goto out_unlock;
+	}
+
 	if (should_orphan(new_inode)) {
 		ret = scoutfs_lock_orphan(sb, SCOUTFS_LOCK_WRITE_ONLY, 0, scoutfs_ino(new_inode),
 					  &orph_lock);
@@ -1870,6 +1876,23 @@ out_unlock:
 	return ret;
 }
 
+static int scoutfs_rename(struct inode *old_dir,
+			  struct dentry *old_dentry, struct inode *new_dir,
+			  struct dentry *new_dentry)
+{
+	return scoutfs_rename_common(old_dir, old_dentry, new_dir, new_dentry, 0);
+}
+
+static int scoutfs_rename2(struct inode *old_dir,
+			  struct dentry *old_dentry, struct inode *new_dir,
+			  struct dentry *new_dentry, unsigned int flags)
+{
+	if (flags & ~RENAME_NOREPLACE)
+		return -EINVAL;
+
+	return scoutfs_rename_common(old_dir, old_dentry, new_dir, new_dentry, flags);
+}
+
 #ifdef KC_FMODE_KABI_ITERATE
 /* we only need this to set the iterate flag for kabi :/ */
 static int scoutfs_dir_open(struct inode *inode, struct file *file)
@@ -1960,6 +1983,7 @@ const struct inode_operations_wrapper scoutfs_dir_iops = {
 	.permission	= scoutfs_permission,
 	},
 	.tmpfile	= scoutfs_tmpfile,
+	.rename2	= scoutfs_rename2,
 };
 
 void scoutfs_dir_exit(void)

tests/.gitignore

@@ -1,5 +1,6 @@
 src/*.d
 src/createmany
+src/dumb_renameat2
 src/dumb_setxattr
 src/handle_cat
 src/bulk_create_paths

tests/Makefile

@@ -3,6 +3,7 @@ SHELL := /usr/bin/bash
 
 # each binary command is built from a single .c file
 BIN := src/createmany			\
+	src/dumb_renameat2		\
 	src/dumb_setxattr		\
 	src/handle_cat			\
 	src/bulk_create_paths		\

tests/golden/renameat2-noreplace

@@ -0,0 +1,2 @@
+=== renameat2 noreplace flag test
+=== run two asynchronous calls to renameat2 NOREPLACE

tests/golden/xfstests

@@ -9,6 +9,8 @@ generic/011
 generic/013
 generic/014
 generic/020
+generic/023
+generic/024
 generic/028
 generic/032
 generic/034
@@ -82,6 +84,7 @@ generic/016
 generic/018
 generic/021
 generic/022
+generic/025
 generic/026
 generic/031
 generic/033
@@ -93,6 +96,7 @@ generic/060
 generic/061
 generic/063
 generic/064
+generic/078
 generic/079
 generic/081
 generic/082
@@ -278,4 +282,4 @@ shared/004
 shared/032
 shared/051
 shared/289
-Passed all 73 tests
+Passed all 75 tests

tests/sequence

@@ -37,4 +37,5 @@ createmany-parallel-mounts.sh
 archive-light-cycle.sh
 block-stale-reads.sh
 inode-deletion.sh
+renameat2-noreplace.sh
 xfstests.sh

tests/src/dumb_renameat2.c

@@ -0,0 +1,93 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#ifndef RENAMEAT2_EXIST
+#include <unistd.h>
+#include <sys/syscall.h>
+
+#if !defined(SYS_renameat2) && defined(__x86_64__)
+#define SYS_renameat2 316			/* from arch/x86/entry/syscalls/syscall_64.tbl */
+#endif
+
+static int renameat2(int olddfd, const char *old_dir,
+		     int newdfd, const char *new_dir,
+		     unsigned int flags)
+{
+#ifdef SYS_renameat2
+	return syscall(SYS_renameat2, olddfd, old_dir, newdfd, new_dir, flags);
+#else
+	errno = ENOSYS;
+	return -1;
+#endif
+}
+#endif
+
+#ifndef RENAME_NOREPLACE
+#define RENAME_NOREPLACE	(1 << 0)	/* Don't overwrite newpath of rename */
+#endif
+#ifndef RENAME_EXCHANGE
+#define RENAME_EXCHANGE		(1 << 1)	/* Exchange oldpath and newpath */
+#endif
+#ifndef RENAME_WHITEOUT
+#define RENAME_WHITEOUT		(1 << 2)	/* Whiteout oldpath */
+#endif
+
+static void exit_usage(char **argv)
+{
+	fprintf(stderr,
+		"usage: %s [-n|-x|-w] old_path new_path\n"
+		"  -n  noreplace\n"
+		"  -x  exchange\n"
+		"  -w  whiteout\n", argv[0]);
+
+		exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	const char *old_path = NULL;
+	const char *new_path = NULL;
+	unsigned int flags = 0;
+	int ret;
+	int c;
+
+	for (c = 1; c < argc; c++) {
+		if (argv[c][0] == '-') {
+			switch (argv[c][1]) {
+				case 'n':
+					flags |= RENAME_NOREPLACE;
+					break;
+				case 'x':
+					flags |= RENAME_EXCHANGE;
+					break;
+				case 'w':
+					flags |= RENAME_WHITEOUT;
+					break;
+				default:
+					exit_usage(argv);
+			}
+		} else if (!old_path) {
+			old_path = argv[c];
+		} else if (!new_path) {
+			new_path = argv[c];
+		} else {
+			exit_usage(argv);
+		}
+	}
+
+	if (!old_path || !new_path) {
+		printf("specify the correct directory path\n");
+		errno = ENOENT;
+		return 1;
+	}
+
+	ret = renameat2(AT_FDCWD, old_path, AT_FDCWD, new_path, flags);
+	if (ret == -1) {
+		perror("Error");
+		return 1;
+	}
+
+	return 0;
+}

tests/tests/renameat2-noreplace.sh

@@ -0,0 +1,37 @@
+#
+# simple renameat2 NOREPLACE unit test
+#
+
+t_require_commands dumb_renameat2
+t_require_mounts 2
+
+echo "=== renameat2 noreplace flag test"
+
+# give each mount their own dir (lock group) to minimize create contention
+mkdir $T_M0/dir0
+mkdir $T_M1/dir1
+
+echo "=== run two asynchronous calls to renameat2 NOREPLACE"
+for i in $(seq 0 100); do
+        # prepare inputs in isolation
+        touch "$T_M0/dir0/old0"
+        touch "$T_M1/dir1/old1"
+
+        # race doing noreplace renames, both can't succeed
+        dumb_renameat2 -n "$T_M0/dir0/old0" "$T_M0/dir0/sharednew" 2> /dev/null &
+        pid0=$!
+        dumb_renameat2 -n "$T_M1/dir1/old1" "$T_M1/dir0/sharednew" 2> /dev/null &
+        pid1=$!
+
+        wait $pid0
+        rc0=$?
+        wait $pid1
+        rc1=$?
+
+        test "$rc0" == 0 -a "$rc1" == 0 && t_fail "both renames succeeded"
+
+        # blow away possible files for either race outcome
+        rm -f "$T_M0/dir0/old0" "$T_M1/dir1/old1" "$T_M0/dir0/sharednew" "$T_M1/dir1/sharednew"
+done
+
+t_pass

tests/tests/xfstests.sh

@@ -60,13 +60,9 @@ EOF
 
 cat << EOF > local.exclude
 generic/003	# missing atime update in buffered read
-generic/023	# renameat2 not implemented
-generic/024	# renameat2 not implemented
-generic/025	# renameat2 not implemented
 generic/029	# mmap missing
 generic/030	# mmap missing
 generic/075	# file content mismatch failures (fds, etc)
-generic/078	# renameat2 not implemented
 generic/080	# mmap missing
 generic/103	# enospc causes trans commit failures
 generic/105	# needs trigage: something about acls