From: coreytesdahl <corey.tesdahl@hpe.com>
Date: Wed, 4 Dec 2024 22:37:06 +0000 (-0600)
Subject: LU-18791 lmv: report an overflowed nlink correctly
X-Git-Tag: 2.16.54~69
X-Git-Url: https://git.whamcloud.com/?a=commitdiff_plain;h=b968372d746012a868c742d75ac8062cc361a07a;p=fs%2Flustre-release.git

LU-18791 lmv: report an overflowed nlink correctly

inode nlink count should be set to 1 if any component
stripe in stripped dir has overflowed and been set to 1

HPE-bug-id: LUS-12747
Signed-off-by: Corey Tesdahl <corey.tesdahl@hpe.com>
Change-Id: I2a3b6f5bd846d11d768ee1979b7f11f0e7cf1c88
Signed-off-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58357
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
---

diff --git a/lustre/lmv/lmv_obd.c b/lustre/lmv/lmv_obd.c
index 9b7d205..2d34110 100644
--- a/lustre/lmv/lmv_obd.c
+++ b/lustre/lmv/lmv_obd.c
@@ -4215,6 +4215,7 @@ static int lmv_merge_attr(struct obd_export *exp,
 	const struct lmv_stripe_md *lsm = &lso->lso_lsm;
 	int rc;
 	int i;
+	int nlink_overflow = 0;
 
 	if (!lmv_dir_striped(lso))
 		return 0;
@@ -4237,11 +4238,12 @@ static int lmv_merge_attr(struct obd_export *exp,
 		       (s64)inode_get_ctime_sec(inode),
 		       (s64)inode_get_mtime_sec(inode));
 
-		/* for slave stripe, it needs to subtract nlink for . and .. */
-		if (i != 0)
-			attr->cat_nlink += inode->i_nlink - 2;
-		else
-			attr->cat_nlink = inode->i_nlink;
+		/* nlink==1 is a special value meaning nlink overflow
+		 * for directories on Ldiskfs.
+		 */
+		nlink_overflow |= (inode->i_nlink == 1);
+		/* not counting . and .. for each stripe */
+		attr->cat_nlink += inode->i_nlink - 2;
 
 		attr->cat_size += i_size_read(inode);
 		attr->cat_blocks += inode->i_blocks;
@@ -4255,6 +4257,14 @@ static int lmv_merge_attr(struct obd_export *exp,
 		if (attr->cat_mtime < inode_get_mtime_sec(inode))
 			attr->cat_mtime = inode_get_mtime_sec(inode);
 	}
+	if (nlink_overflow)
+		/* Indicate that nlink is not correct for a striped dir the
+		 * same way it is done in Ldiskfs by setting nlink = 1.
+		 */
+		attr->cat_nlink = 1;
+	else
+		/* add 2 for . and .. */
+		attr->cat_nlink += 2;
 	return 0;
 }
 
diff --git a/lustre/tests/sanity.sh b/lustre/tests/sanity.sh
index 9e21ed2..a6484aa 100755
--- a/lustre/tests/sanity.sh
+++ b/lustre/tests/sanity.sh
@@ -6247,7 +6247,7 @@ test_51b() {
 
 	# create files
 	createmany -d $dir/d $nrdirs || {
-		unlinkmany $dir/d $nrdirs
+		unlinkmany -d $dir/d $nrdirs
 		error "failed to create $nrdirs subdirs in MDT$mdtidx:$dir"
 	}
 
@@ -6284,6 +6284,39 @@ test_51b() {
 }
 run_test 51b "exceed 64k subdirectory nlink limit on create, verify unlink"
 
+test_51c() {
+	(( MDSCOUNT > 1 )) || skip "needs >= 2 MDTs"
+	local dir=$DIR/$tdir-c2
+	local nrdirs=$((65536 * 2 + 2000))
+	local mdtidx
+
+	trap cleanup_print_lfs_df EXIT
+
+	$LFS mkdir -c 2 -H fnv_1a_64 $dir
+	while read mtdidx rest; do
+		local mdtname=$FSNAME-MDT$(printf "%04x" $mdtidx)
+		local numfree=$(lctl get_param -n mdc.$mdtname*.filesfree)
+		local blkfree=$(lctl get_param -n mdc.$mdtname*.kbytesavail)
+
+		(( numfree < nrdirs / 2 || blkfree / $(fs_inode_ksize) < nrdirs / 2 )) &&
+			skip "not enough inodes or blocks for mdt$mdtidx"
+	done < <( $LFS getdirstripe $dir | awk '{ if ($2 ~ /\[0x.*:0x.*:0x.*\]/) {  print $1; } }' )
+
+	createmany -d $dir/d $nrdirs ||
+		error "failed to create $nrdirs subdirs in $dir"
+	# nlink for the striped dir should be either 1
+	# (ldiskfs, nlink is overflowed at least in one stripe)
+	# or $ndirs + 2
+	local nlinks=$(stat -c %h $dir)
+	(( nlinks == 1 || nlinks == nrdirs + 2 )) ||
+		error "Wrong nlink count of $nlinks"
+
+	unlinkmany -d $dir/d $nrdirs || error "Removal of the subdirs failed"
+	rmdir $dir || error "rmdir failed"
+	cleanup_print_lfs_df
+}
+run_test 51c "exceed 64k subdirectory count per dir stripe, verify nlink count"
+
 test_51d_sub() {
 	local stripecount=$1
 	local nfiles=$2