[PATCH v3 2/2] generic/486: adjust the max xattr size

["Luís Henriques" <lhenriques@suse.de>]

CephFS doesn't have a maximum xattr size.  Instead, it imposes a maximum
size for the full set of xattrs names+values, which by default is 64K.  And
since it reports 4M as the blocksize (the default ceph object size),
generic/486 will fail in ceph because the XATTR_SIZE_MAX value can't be used
in attr_replace_test.

The fix is to add a new argument to the test so that the max size can be
passed in instead of trying to auto-probe a value for it.

Signed-off-by: Luís Henriques <lhenriques@suse.de>
---
 src/attr_replace_test.c | 30 ++++++++++++++++++++++++++----
 tests/generic/486       | 11 ++++++++++-
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/attr_replace_test.c b/src/attr_replace_test.c
index cca8dcf8ff60..1218e7264c8f 100644
--- a/src/attr_replace_test.c
+++ b/src/attr_replace_test.c
@@ -20,19 +20,41 @@ exit(1); } while (0)
 fprintf(stderr, __VA_ARGS__); exit (1); \
 } while (0)
 
+void usage(char *progname)
+{
+	fail("usage: %s [-m max_attr_size] <file>\n", progname);
+}
+
 int main(int argc, char *argv[])
 {
 	int ret;
 	int fd;
+	int c;
 	char *path;
 	char *name = "user.world";
 	char *value;
 	struct stat sbuf;
 	size_t size = sizeof(value);
+	size_t maxsize = XATTR_SIZE_MAX;
+
+	while ((c = getopt(argc, argv, "m:")) != -1) {
+		char *endp;
+
+		switch (c) {
+		case 'm':
+			maxsize = strtoul(optarg, &endp, 0);
+			if (*endp || (maxsize > XATTR_SIZE_MAX))
+				fail("Invalid 'max_attr_size' value\n");
+			break;
+		default:
+			usage(argv[0]);
+		}
+	}
 
-	if (argc != 2)
-		fail("Usage: %s <file>\n", argv[0]);
-	path = argv[1];
+	if (optind == argc - 1)
+		path = argv[optind];
+	else
+		usage(argv[0]);
 
 	fd = open(path, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
 	if (fd < 0) die();
@@ -46,7 +68,7 @@ int main(int argc, char *argv[])
 	size = sbuf.st_blksize * 3 / 4;
 	if (!size)
 		fail("Invalid st_blksize(%ld)\n", sbuf.st_blksize);
-	size = MIN(size, XATTR_SIZE_MAX);
+	size = MIN(size, maxsize);
 	value = malloc(size);
 	if (!value)
 		fail("Failed to allocate memory\n");
diff --git a/tests/generic/486 b/tests/generic/486
index 7de198f93a71..7dbfcb9835d9 100755
--- a/tests/generic/486
+++ b/tests/generic/486
@@ -41,7 +41,16 @@ filter_attr_output() {
 		sed -e 's/has a [0-9]* byte value/has a NNNN byte value/g'
 }
 
-$here/src/attr_replace_test $SCRATCH_MNT/hello
+max_attr_size=65536
+
+# attr_replace_test can't easily auto-probe the attr size for ceph because:
+# - ceph imposes a maximum value for the total xattr names+values, and
+# - ceph reports the 'object size' in the block size, which is, by default, much
+#   larger than XATTR_SIZE_MAX (4M > 64k)
+# Hence, we need to provide it with a maximum size.
+[ "$FSTYP" = "ceph" ] && max_attr_size=65000
+
+$here/src/attr_replace_test -m $max_attr_size $SCRATCH_MNT/hello
 $ATTR_PROG -l $SCRATCH_MNT/hello >>$seqres.full 2>&1
 $ATTR_PROG -l $SCRATCH_MNT/hello | filter_attr_output