From cd4caef54f63b6a0d26a90d879f378b7fe3d4862 Mon Sep 17 00:00:00 2001
From: "John L. Hammond" <jhammond@whamcloud.com>
Date: Wed, 7 Apr 2021 14:11:25 -0500
Subject: [PATCH] LU-14583 llapi: handle symlinks in llapi_file_get_stripe()

In llapi_file_get_stripe(), if the IOC_MDC_GETFILESTRIPE ioctl handler
returns -ENOTTY or -ENODATA then try to resolve any symlinks in the
path and try again.

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: Ic046d6ef77d8342d47336144e3066cab3a940a96
Reviewed-on: https://review.whamcloud.com/43229
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---
 lustre/tests/sanity.sh      | 31 +++++++++++++++++++++++++++++++
 lustre/utils/liblustreapi.c | 27 ++++++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index 2bc8ed7..dc731af 100755
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -3319,6 +3319,37 @@ test_27P() {
 }
 run_test 27P "basic ops on foreign dir of foreign_symlink type"
 
+test_27Q() {
+	rm -f $TMP/$tfile $TMP/$tfile.loop $TMP/$tfile.none $TMP/$tfile.broken
+
+	test_mkdir $DIR/$tdir-1
+	test_mkdir $DIR/$tdir-2
+
+	echo 'It is what it is' > $DIR/$tdir-1/$tfile
+	lov_getstripe_old $DIR/$tdir-1/$tfile || error "$DIR/$tdir-1/$tfile: rc = $?"
+
+	ln -s $DIR/$tdir-1/$tfile $DIR/$tdir-2/$tfile
+	lov_getstripe_old $DIR/$tdir-2/$tfile || error "$DIR/$tdir-2/$tfile: rc = $?"
+
+	ln -s $DIR/$tdir-1/$tfile $TMP/$tfile
+	lov_getstripe_old $TMP/$tfile || error "$TMP/$tfile: rc = $?"
+
+	# Create some bad symlinks and ensure that we don't loop
+	# forever or something. These should return ELOOP (40) and
+	# ENOENT (2) but I don't want to test for that because there's
+	# always some weirdo architecture that needs to ruin
+	# everything by defining these error numbers differently.
+
+	ln -s $TMP/$tfile.loop $TMP/$tfile.loop
+	lov_getstripe_old $TMP/$tfile.loop && error "$TMP/$tfile.loop: rc = $?"
+
+	ln -s $TMP/$tfile.none $TMP/$tfile.broken
+	lov_getstripe_old $TMP/$tfile.broken && error "$TMP/$tfile.broken: rc = $?"
+
+	return 0
+}
+run_test 27Q "llapi_file_get_stripe() works on symlinks"
+
 # createtest also checks that device nodes are created and
 # then visible correctly (#2091)
 test_28() { # bug 2091
diff --git a/lustre/utils/liblustreapi.c b/lustre/utils/liblustreapi.c
index 2d29c35..14263ac 100644
--- a/lustre/utils/liblustreapi.c
+++ b/lustre/utils/liblustreapi.c
@@ -4051,7 +4051,7 @@ static void llapi_lov_dump_user_lmm(struct find_param *param, char *path,
 	}
 }
 
-int llapi_file_get_stripe(const char *path, struct lov_user_md *lum)
+static int llapi_file_get_stripe1(const char *path, struct lov_user_md *lum)
 {
 	const char *fname;
 	char *dname;
@@ -4093,6 +4093,31 @@ out_free:
 	return rc;
 }
 
+int llapi_file_get_stripe(const char *path, struct lov_user_md *lum)
+{
+	char *canon_path = NULL;
+	int rc, rc2;
+
+	rc = llapi_file_get_stripe1(path, lum);
+	if (!(rc == -ENOTTY || rc == -ENODATA))
+		goto out;
+
+	/* Handle failure due to symlinks by dereferencing path manually. */
+	canon_path = canonicalize_file_name(path);
+	if (canon_path == NULL)
+		goto out; /* Keep original rc. */
+
+	rc2 = llapi_file_get_stripe1(canon_path, lum);
+	if (rc2 < 0)
+		goto out; /* Keep original rc. */
+
+	rc = 0;
+out:
+	free(canon_path);
+
+	return rc;
+}
+
 int llapi_file_lookup(int dirfd, const char *name)
 {
 	struct obd_ioctl_data data = { 0 };
-- 
1.8.3.1