[PATCH v2 0/5] Tests for overlayfs immutable/append-only files

[PATCH v2 0/5] Tests for overlayfs immutable/append-only files

[Amir Goldstein]

Eryu,

Overlayfs never had full support for immutable/append-only files.
Whatever works is covered by generic/079 and overlay/030 tests.
Both tests cover only upper files and directories.
generic/079 is notrun on kernel < 5.10 and passes on >= 5.10.

This series improves the t_immutable test program and adds two new
tests.

overlay/075 tests immutable/append-only lower files and directories -
the test fails on upstream kernel.  Fixing this requires some VFS API
changes that Miklos has proposed [1].

overlay/076 is a "dangerous" test that triggers a deadlock.
The deadlock was fixed in master and in stable kernel v5.10.15.

Thanks,
Amir. 

Changes since v1:
- Split the dangerous test
- Document fix commit
- Fix Eryu's minor review comments on t_immutable

[1] https://lore.kernel.org/linux-fsdevel/20210203124112.1182614-1-mszeredi@redhat.com/

Amir Goldstein (5):
  overlay/030: Update comment w.r.t upstream kernel
  src/t_immutable: factor out some helpers
  src/t_immutable: Allow setting flags on existing files
  overlay: Test lost immutable/append-only flags on copy-up
  overlay: Regression test for deadlock on directory ioctl

 src/t_immutable.c     | 241 +++++++++++++++++++++---------------------
 tests/overlay/030     |   7 +-
 tests/overlay/075     |  92 ++++++++++++++++
 tests/overlay/075.out |  11 ++
 tests/overlay/076     |  66 ++++++++++++
 tests/overlay/076.out |   2 +
 tests/overlay/group   |   2 +
 7 files changed, 301 insertions(+), 120 deletions(-)
 create mode 100755 tests/overlay/075
 create mode 100644 tests/overlay/075.out
 create mode 100644 tests/overlay/076
 create mode 100644 tests/overlay/076.out

-- 
2.25.1

[PATCH v2 1/5] overlay/030: Update comment w.r.t upstream kernel

[Amir Goldstein]

commit 61536bed2149 ("ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR
ioctls for directories") makes the comment in test header inaccurate.
Fix the comment to include this information.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tests/overlay/030 | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tests/overlay/030 b/tests/overlay/030
index 3ef206b6..c461e502 100755
--- a/tests/overlay/030
+++ b/tests/overlay/030
@@ -8,8 +8,11 @@
 # and directories in an overlayfs upper directory.
 #
 # This test is similar and was derived from generic/079, but
-# the original test is _notrun on overlay mount because FS_IOC_GETFLAGS
-# FS_IOC_SETFLAGS ioctls fail on overlay directory inodes.
+# the original test is _notrun with FSTYP=overlay on kernel < v5.10
+# because prior to commit 61536bed2149 ("ovl: support [S|G]ETFLAGS
+# and FS[S|G]ETXATTR ioctls for directories"), t_immutable -c would
+# fail to prepare immutable/append-only directories on the overlay
+# mount path.
 #
 seq=`basename $0`
 seqres=$RESULT_DIR/$seq
-- 
2.25.1

[PATCH v2 2/5] src/t_immutable: factor out some helpers

[Amir Goldstein]

Reduce boilerplate code.
define _GNU_SOURCE needed for asprintf.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 src/t_immutable.c | 221 ++++++++++++++++++++++------------------------
 1 file changed, 104 insertions(+), 117 deletions(-)

diff --git a/src/t_immutable.c b/src/t_immutable.c
index 86c567ed..7431e75d 100644
--- a/src/t_immutable.c
+++ b/src/t_immutable.c
@@ -8,6 +8,9 @@
 
 #define TEST_UTIME
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -1895,13 +1898,66 @@ static int check_test_area(const char *dir)
      return 0;
 }
 
+static int create_dir(char **ppath, const char *fmt, const char *dir)
+{
+     const char *path;
+     struct stat st;
+
+     if (asprintf(ppath, fmt, dir) == -1) {
+	  return 1;
+     }
+     path = *ppath;
+     if (stat(path, &st) == 0) {
+	  fprintf(stderr, "%s: Test area directory %s must not exist for test area creation.\n",
+		  __progname, path);
+	  return 1;
+     }
+     if (mkdir(path, 0777) != 0) {
+	  fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
+	  return 1;
+     }
+     return 0;
+}
+
+static int create_file(char **ppath, const char *fmt, const char *dir)
+{
+     const char *path;
+     int fd;
+
+     if (asprintf(ppath, fmt, dir) == -1) {
+	  return 1;
+     }
+     path = *ppath;
+     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
+	  fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
+          return 1;
+     }
+     return fd;
+}
+
+static int create_xattrs(int fd)
+{
+     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
+	  if (errno != EOPNOTSUPP) {
+	       perror("setxattr");
+	       return 1;
+	  }
+     }
+     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
+	  if (errno != EOPNOTSUPP) {
+	       perror("setxattr");
+	       return 1;
+	  }
+     }
+     return 0;
+}
+
 static int create_test_area(const char *dir)
 {
      int fd;
      char *path;
      static const char *acl_u_text = "u::rw-,g::rw-,o::rw-,u:nobody:rw-,m::rw-";
      static const char *acl_u_text_d = "u::rwx,g::rwx,o::rwx,u:nobody:rwx,m::rwx";
-     struct stat st;
      static const char *immutable = "This is an immutable file.\nIts contents cannot be altered.\n";
      static const char *append_only = "This is an append-only file.\nIts contents cannot be altered.\n"
 	  "Data can only be appended.\n---\n";
@@ -1911,79 +1967,45 @@ static int create_test_area(const char *dir)
 	  return 1;
      }
 
-     if (stat(dir, &st) == 0) {
-	  fprintf(stderr, "%s: Test area directory %s must not exist for test area creation.\n",
-		  __progname, dir);
-	  return 1;
-     }
-
      umask(0000);
-     if (mkdir(dir, 0777) != 0) {
-	  fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, dir, strerror(errno));
+     if (create_dir(&path, "%s", dir)) {
 	  return 1;
      }
-
-     asprintf(&path, "%s/immutable.d", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
-          return 1;
-     }
-     free(path);
-
-     asprintf(&path, "%s/empty-immutable.d", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
-          return 1;
-     }
      free(path);
 
-     asprintf(&path, "%s/append-only.d", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
-          return 1;
+     if (create_dir(&path, "%s/append-only.d", dir)) {
+	  return 1;
      }
      free(path);
 
-     asprintf(&path, "%s/empty-append-only.d", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
-          return 1;
+     if (create_dir(&path, "%s/append-only.d/dir", dir)) {
+	  return 1;
      }
      free(path);
 
-     asprintf(&path, "%s/immutable.d/dir", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
+     if ((fd = create_file(&path, "%s/append-only.d/file", dir)) == -1) {
           return 1;
      }
+     close(fd);
      free(path);
 
-     asprintf(&path, "%s/append-only.d/dir", dir);
-     if (mkdir(path, 0777) != 0) {
-          fprintf(stderr, "%s: error creating directory %s: %s\n", __progname, path, strerror(errno));
-          return 1;
+     if (create_dir(&path, "%s/immutable.d", dir)) {
+	  return 1;
      }
      free(path);
 
-     asprintf(&path, "%s/append-only.d/file", dir);
-     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
-	  fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
-          return 1;
+     if (create_dir(&path, "%s/immutable.d/dir", dir)) {
+	  return 1;
      }
-     close(fd);
      free(path);
 
-     asprintf(&path, "%s/immutable.d/file", dir);
-     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
-          fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
+     if ((fd = create_file(&path, "%s/immutable.d/file", dir)) == -1) {
           return 1;
      }
      close(fd);
      free(path);
 
-     asprintf(&path, "%s/immutable.f", dir);
-     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
-          fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
+     if ((fd = create_file(&path, "%s/immutable.f", dir)) == -1) {
           return 1;
      }
      if (write(fd, immutable, strlen(immutable)) != strlen(immutable)) {
@@ -1994,17 +2016,8 @@ static int create_test_area(const char *dir)
 	  perror("acl");
 	  return 1;
      }
-     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
-     }
-     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
+     if (create_xattrs(fd)) {
+	  return 1;
      }
      if (fsetflag(path, fd, 1, 1)) {
           perror("fsetflag");
@@ -2014,8 +2027,7 @@ static int create_test_area(const char *dir)
      close(fd);
      free(path);
 
-     asprintf(&path, "%s/append-only.f", dir);
-     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
+     if ((fd = create_file(&path, "%s/append-only.f", dir)) == -1) {
           fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
           return 1;
      }
@@ -2027,17 +2039,8 @@ static int create_test_area(const char *dir)
           perror("acl");
           return 1;
      }
-     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
-     }
-     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
+     if (create_xattrs(fd)) {
+	  return 1;
      }
      if (fsetflag(path, fd, 1, 0)) {
           perror("fsetflag");
@@ -2056,17 +2059,8 @@ static int create_test_area(const char *dir)
           perror("acl");
           return 1;
      }
-     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
-     }
-     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
+     if (create_xattrs(fd)) {
+	  return 1;
      }
      if (fsetflag(path, fd, 1, 1)) {
           perror("fsetflag");
@@ -2076,7 +2070,9 @@ static int create_test_area(const char *dir)
      close(fd);
      free(path);
 
-     asprintf(&path, "%s/empty-immutable.d", dir);
+     if (create_dir(&path, "%s/empty-immutable.d", dir)) {
+	  return 1;
+     }
      if ((fd = open(path, O_RDONLY)) == -1) {
           fprintf(stderr, "%s: error opening %s: %s\n", __progname, path, strerror(errno));
           return 1;
@@ -2098,17 +2094,8 @@ static int create_test_area(const char *dir)
           perror("acl");
           return 1;
      }
-     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
-     }
-     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
-	  if (errno != EOPNOTSUPP) {
-	       perror("setxattr");
-	       return 1;
-	  }
+     if (create_xattrs(fd)) {
+	  return 1;
      }
      if (fsetflag(path, fd, 1, 0)) {
           perror("fsetflag");
@@ -2118,7 +2105,9 @@ static int create_test_area(const char *dir)
      close(fd);
      free(path);
 
-     asprintf(&path, "%s/empty-append-only.d", dir);
+     if (create_dir(&path, "%s/empty-append-only.d", dir)) {
+	  return 1;
+     }
      if ((fd = open(path, O_RDONLY)) == -1) {
           fprintf(stderr, "%s: error opening %s: %s\n", __progname, path, strerror(errno));
           return 1;
@@ -2242,6 +2231,7 @@ int main(int argc, char **argv)
 {
      int ret;
      int failed = 0;
+     int runtest = 1, create = 0, remove = 0;
 
 /* this arg parsing is gross, but who cares, its a test program */
 
@@ -2251,32 +2241,29 @@ int main(int argc, char **argv)
      }
 
      if (!strcmp(argv[1], "-c")) {
-	  if (argc == 3) {
-	       if ((ret = create_test_area(argv[argc-1])))
-		    return ret;
-	  } else {
-	       fprintf(stderr, "usage: t_immutable -c test_area_dir\n");
-	       return 1;
-	  }
+	  create = 1;
      } else if (!strcmp(argv[1], "-C")) {
-          if (argc == 3) {
-               return create_test_area(argv[argc-1]);
-          } else {
-               fprintf(stderr, "usage: t_immutable -C test_area_dir\n");
-               return 1;
-          }
+	  /* Prepare test area without running tests */
+	  create = 1;
+	  runtest = 0;
      } else if (!strcmp(argv[1], "-r")) {
-	  if (argc == 3)
-	       return remove_test_area(argv[argc-1]);
-	  else {
-	       fprintf(stderr, "usage: t_immutable -r test_area_dir\n");
-	       return 1;
-	  }
-     } else if (argc != 2) {
-	  fprintf(stderr, "usage: t_immutable [-c|-r] test_area_dir\n");
+	  remove = 1;
+     }
+
+     if (argc != 2 + (create | remove)) {
+	  fprintf(stderr, "usage: t_immutable [-C|-c|-r] test_area_dir\n");
 	  return 1;
      }
 
+     if (create) {
+	  ret = create_test_area(argv[argc-1]);
+	  if (ret || !runtest) {
+               return ret;
+	  }
+     } else if (remove) {
+	  return remove_test_area(argv[argc-1]);
+     }
+
      umask(0000);
 
      if (check_test_area(argv[argc-1]))
-- 
2.25.1

[PATCH v2 3/5] src/t_immutable: Allow setting flags on existing files

[Amir Goldstein]

For overlayfs tests we need to be able to setflags on existing
(lower) files.

t_immutable -C test_dir

Creates the test area and sets flags, but it also allows setting flags
on an existing test area.

t_immutable -R test_dir

Removes the flags from existing test area, but does not remove the files
in the test area.

To setup a test area with file without flags, need to run the -C and -R
commands.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 src/t_immutable.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/t_immutable.c b/src/t_immutable.c
index 7431e75d..0611e193 100644
--- a/src/t_immutable.c
+++ b/src/t_immutable.c
@@ -1898,6 +1898,8 @@ static int check_test_area(const char *dir)
      return 0;
 }
 
+static int allow_existing;
+
 static int create_dir(char **ppath, const char *fmt, const char *dir)
 {
      const char *path;
@@ -1908,6 +1910,9 @@ static int create_dir(char **ppath, const char *fmt, const char *dir)
      }
      path = *ppath;
      if (stat(path, &st) == 0) {
+	  if (allow_existing && S_ISDIR(st.st_mode)) {
+	       return 0;
+	  }
 	  fprintf(stderr, "%s: Test area directory %s must not exist for test area creation.\n",
 		  __progname, path);
 	  return 1;
@@ -1921,6 +1926,7 @@ static int create_dir(char **ppath, const char *fmt, const char *dir)
 
 static int create_file(char **ppath, const char *fmt, const char *dir)
 {
+     int flags = O_WRONLY|O_CREAT | (allow_existing ? 0 : O_EXCL);
      const char *path;
      int fd;
 
@@ -1928,7 +1934,7 @@ static int create_file(char **ppath, const char *fmt, const char *dir)
 	  return 1;
      }
      path = *ppath;
-     if ((fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0666)) == -1) {
+     if ((fd = open(path, flags, 0666)) == -1) {
 	  fprintf(stderr, "%s: error creating file %s: %s\n", __progname, path, strerror(errno));
           return 1;
      }
@@ -1937,13 +1943,15 @@ static int create_file(char **ppath, const char *fmt, const char *dir)
 
 static int create_xattrs(int fd)
 {
-     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
+     int flags = allow_existing ? 0 : XATTR_CREATE;
+
+     if (fsetxattr(fd, "trusted.test", "readonly", strlen("readonly"), flags) != 0) {
 	  if (errno != EOPNOTSUPP) {
 	       perror("setxattr");
 	       return 1;
 	  }
      }
-     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), XATTR_CREATE) != 0) {
+     if (fsetxattr(fd, "user.test", "readonly", strlen("readonly"), flags) != 0) {
 	  if (errno != EOPNOTSUPP) {
 	       perror("setxattr");
 	       return 1;
@@ -2214,6 +2222,10 @@ static int remove_test_area(const char *dir)
 	  return 1;
      }
 
+     if (allow_existing) {
+	     return 0;
+     }
+
      pid = fork();
      if (!pid) {
 	  execl("/bin/rm", "rm", "-rf", dir, NULL);
@@ -2236,7 +2248,7 @@ int main(int argc, char **argv)
 /* this arg parsing is gross, but who cares, its a test program */
 
      if (argc < 2) {
-	  fprintf(stderr, "usage: t_immutable [-C|-c|-r] test_area_dir\n");
+	  fprintf(stderr, "usage: t_immutable [-C|-c|-R|-r] test_area_dir\n");
 	  return 1;
      }
 
@@ -2246,18 +2258,24 @@ int main(int argc, char **argv)
 	  /* Prepare test area without running tests */
 	  create = 1;
 	  runtest = 0;
+	  /* With existing test area, only setflags */
+	  allow_existing = 1;
      } else if (!strcmp(argv[1], "-r")) {
 	  remove = 1;
+     } else if (!strcmp(argv[1], "-R")) {
+	  /* Cleanup flags on test area but leave the files */
+	  remove = 1;
+	  allow_existing = 1;
      }
 
      if (argc != 2 + (create | remove)) {
-	  fprintf(stderr, "usage: t_immutable [-C|-c|-r] test_area_dir\n");
+	  fprintf(stderr, "usage: t_immutable [-C|-c|-R|-r] test_area_dir\n");
 	  return 1;
      }
 
      if (create) {
 	  ret = create_test_area(argv[argc-1]);
-	  if (ret || !runtest) {
+	  if (ret || allow_existing || !runtest) {
                return ret;
 	  }
      } else if (remove) {
-- 
2.25.1

[PATCH v2 4/5] overlay: Test lost immutable/append-only flags on copy-up

[Amir Goldstein]

Chengguang Xu reported [1] that append-only flag is lost on copy-up.
I had noticed that for directories, immutable flag can also be lost on
copy up (when parent is copied up). That's an old overlayfs bug.

[1] https://lore.kernel.org/linux-unionfs/20201226104618.239739-1-cgxu519@mykernel.net/

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tests/overlay/075     | 92 +++++++++++++++++++++++++++++++++++++++++++
 tests/overlay/075.out | 11 ++++++
 tests/overlay/group   |  1 +
 3 files changed, 104 insertions(+)
 create mode 100755 tests/overlay/075
 create mode 100644 tests/overlay/075.out

diff --git a/tests/overlay/075 b/tests/overlay/075
new file mode 100755
index 00000000..5a6c3be0
--- /dev/null
+++ b/tests/overlay/075
@@ -0,0 +1,92 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 CTERA Networks. All Rights Reserved.
+#
+# FS QA Test No. 075
+#
+# Run the t_immutable test program for immutable/append-only files
+# and directories that exist in overlayfs lower layer.
+#
+# This test is similar and was derived from generic/079, but instead
+# of creating new files which are created in upper layer, prepare
+# the test area in lower layer before running the t_immutable test on
+# the overlayfs mount.
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+timmutable=$here/src/t_immutable
+lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
+upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	# -r will fail to remove test dirs, because we added subdirs
+	# we just need to remove the flags so use -R
+	$timmutable -R $upperdir/testdir &> /dev/null
+	$timmutable -R $lowerdir/testdir &> /dev/null
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+_supported_fs overlay
+
+_require_chattr ia
+_require_test_program "t_immutable"
+_require_scratch
+
+_scratch_mkfs
+
+# Preparing test area files in lower dir and check chattr support of base fs
+mkdir -p $lowerdir
+mkdir -p $upperdir
+$timmutable -C $lowerdir/testdir >$tmp.out 2>&1
+if grep -q -e 'Operation not supported' -e "Inappropriate ioctl" $tmp.out; then
+	_notrun "Setting immutable/append flag not supported"
+fi
+# Remove the immutable/append-only flags and create subdirs
+$timmutable -R $lowerdir/testdir >$tmp.out 2>&1
+for dir in $lowerdir/testdir/*.d; do
+	mkdir $dir/subdir
+done
+# Restore the immutable/append-only flags
+$timmutable -C $lowerdir/testdir >$tmp.out 2>&1
+
+_scratch_mount
+
+# Test immutability of files in overlay
+echo "Before directories copy up"
+$timmutable $SCRATCH_MNT/testdir 2>&1
+
+# Trigger copy-up of immutable/append-only dirs by touching their subdirs
+# inode flags are not copied-up, so immutable/append-only flags are lost
+for dir in $SCRATCH_MNT/testdir/*.d; do
+	touch $dir/subdir
+done
+
+# Trigger copy-up of append-only files by touching them
+# inode flags are not copied-up, so append-only flags are lost
+# touch on the immutable files is expected to fail, so immutable
+# flags will not be lost
+for file in $SCRATCH_MNT/testdir/*.f; do
+	touch $file > /dev/null 2>&1
+done
+
+# immutable/append-only flags still exist on the overlay in-core inode
+# After mount cycle, flags are forever lost
+_scratch_cycle_mount
+
+# Test immutability of files in overlay after directories copy-up
+echo "After directories copy up"
+$timmutable $SCRATCH_MNT/testdir 2>&1
+
+status=$?
+exit
diff --git a/tests/overlay/075.out b/tests/overlay/075.out
new file mode 100644
index 00000000..ab39c6b8
--- /dev/null
+++ b/tests/overlay/075.out
@@ -0,0 +1,11 @@
+QA output created by 075
+Before directories copy up
+testing immutable...PASS.
+testing append-only...PASS.
+testing immutable as non-root...PASS.
+testing append-only as non-root...PASS.
+After directories copy up
+testing immutable...PASS.
+testing append-only...PASS.
+testing immutable as non-root...PASS.
+testing append-only as non-root...PASS.
diff --git a/tests/overlay/group b/tests/overlay/group
index 047ea046..cfc75bb1 100644
--- a/tests/overlay/group
+++ b/tests/overlay/group
@@ -77,6 +77,7 @@
 072 auto quick copyup hardlink
 073 auto quick whiteout
 074 auto quick exportfs dangerous
+075 auto quick perms
 100 auto quick union samefs
 101 auto quick union nonsamefs
 102 auto quick union nonsamefs xino
-- 
2.25.1

[PATCH v2 5/5] overlay: Regression test for deadlock on directory ioctl

[Amir Goldstein]

Overlayfs added the ability to set inode flags (e.g. chattr +i) in
kernel 5.10 by commit 61536bed2149 ("ovl: support [S|G]ETFLAGS and
FS[S|G]ETXATTR ioctls for directories").
Icenowy Zheng reported [1] a regression in that commit that causes
a deadlock when setting inode flags on lower dir.

The regression was fixed by commit b854cc659dcb ("ovl: avoid deadlock
on directory ioctl") and applied to kernel 5.10.15.

[1] https://lore.kernel.org/linux-unionfs/20210101201230.768653-1-icenowy@aosc.io/

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 tests/overlay/076     | 66 +++++++++++++++++++++++++++++++++++++++++++
 tests/overlay/076.out |  2 ++
 tests/overlay/group   |  1 +
 3 files changed, 69 insertions(+)
 create mode 100644 tests/overlay/076
 create mode 100644 tests/overlay/076.out

diff --git a/tests/overlay/076 b/tests/overlay/076
new file mode 100644
index 00000000..07827c0b
--- /dev/null
+++ b/tests/overlay/076
@@ -0,0 +1,66 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2021 CTERA Networks. All Rights Reserved.
+#
+# FS QA Test 076
+#
+# Support for chattr on overlayfs directories was added in kernel v5.10
+# by commit 61536bed2149 ("ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR
+# ioctls for directories").  That commit introduced a deadlock.
+#
+# This is a regression test for the fix commit b854cc659dcb ("ovl: avoid
+# deadlock on directory ioctl")
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1        # failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+        cd /
+        $CHATTR_PROG -i $lowerdir/foo > /dev/null 2>&1
+        $CHATTR_PROG -i $upperdir/foo > /dev/null 2>&1
+        rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs overlay
+_require_scratch
+_require_chattr i
+
+# remove all files from previous runs
+_scratch_mkfs
+
+# prepare lower test file
+lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER
+upperdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER
+workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK
+mkdir -p $lowerdir
+mkdir $lowerdir/foo
+
+# mounting overlay
+_scratch_mount
+
+# Try to add the immutable attributes, it will invoke ioctl() on the directory
+# The ioctl will fail on kernel < 5.10, succeed on kernel >= 5.10.15 and hang
+# on kernel v5.10..v5.10.14.  Anything but hang is considered a test success.
+$CHATTR_PROG +i $SCRATCH_MNT/foo > /dev/null 2>&1
+
+$UMOUNT_PROG $SCRATCH_MNT
+
+# success, all done
+echo "Silence is golden"
+status=0
+exit
diff --git a/tests/overlay/076.out b/tests/overlay/076.out
new file mode 100644
index 00000000..248e095d
--- /dev/null
+++ b/tests/overlay/076.out
@@ -0,0 +1,2 @@
+QA output created by 076
+Silence is golden
diff --git a/tests/overlay/group b/tests/overlay/group
index cfc75bb1..ddc355e5 100644
--- a/tests/overlay/group
+++ b/tests/overlay/group
@@ -78,6 +78,7 @@
 073 auto quick whiteout
 074 auto quick exportfs dangerous
 075 auto quick perms
+076 auto quick perms dangerous
 100 auto quick union samefs
 101 auto quick union nonsamefs
 102 auto quick union nonsamefs xino
-- 
2.25.1