linux-kernel - [PATCH 4.19 105/191] udf: Fix free space reporting for metadata and virtual partitions

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Message-Id: <20200221072303.549580099@linuxfoundation.org>
Date:   Fri, 21 Feb 2020 08:41:18 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Pali Rohár <pali.rohar@...il.com>,
        Jan Kara <jack@...e.cz>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 105/191] udf: Fix free space reporting for metadata and virtual partitions

From: Jan Kara <jack@...e.cz>

[ Upstream commit a4a8b99ec819ca60b49dc582a4287ef03411f117 ]

Free space on filesystems with metadata or virtual partition maps
currently gets misreported. This is because these partitions are just
remapped onto underlying real partitions from which keep track of free
blocks. Take this remapping into account when counting free blocks as
well.

Reviewed-by: Pali Rohár <pali.rohar@...il.com>
Reported-by: Pali Rohár <pali.rohar@...il.com>
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/udf/super.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/udf/super.c b/fs/udf/super.c
index 6fd0f14e9dd22..1676a175cd7a8 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -2469,17 +2469,29 @@ static unsigned int udf_count_free_table(struct super_block *sb,
 static unsigned int udf_count_free(struct super_block *sb)
 {
 	unsigned int accum = 0;
-	struct udf_sb_info *sbi;
+	struct udf_sb_info *sbi = UDF_SB(sb);
 	struct udf_part_map *map;
+	unsigned int part = sbi->s_partition;
+	int ptype = sbi->s_partmaps[part].s_partition_type;
+
+	if (ptype == UDF_METADATA_MAP25) {
+		part = sbi->s_partmaps[part].s_type_specific.s_metadata.
+							s_phys_partition_ref;
+	} else if (ptype == UDF_VIRTUAL_MAP15 || ptype == UDF_VIRTUAL_MAP20) {
+		/*
+		 * Filesystems with VAT are append-only and we cannot write to
+ 		 * them. Let's just report 0 here.
+		 */
+		return 0;
+	}
 
-	sbi = UDF_SB(sb);
 	if (sbi->s_lvid_bh) {
 		struct logicalVolIntegrityDesc *lvid =
 			(struct logicalVolIntegrityDesc *)
 			sbi->s_lvid_bh->b_data;
-		if (le32_to_cpu(lvid->numOfPartitions) > sbi->s_partition) {
+		if (le32_to_cpu(lvid->numOfPartitions) > part) {
 			accum = le32_to_cpu(
-					lvid->freeSpaceTable[sbi->s_partition]);
+					lvid->freeSpaceTable[part]);
 			if (accum == 0xFFFFFFFF)
 				accum = 0;
 		}
@@ -2488,7 +2500,7 @@ static unsigned int udf_count_free(struct super_block *sb)
 	if (accum)
 		return accum;
 
-	map = &sbi->s_partmaps[sbi->s_partition];
+	map = &sbi->s_partmaps[part];
 	if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
 		accum += udf_count_free_bitmap(sb,
 					       map->s_uspace.s_bitmap);
-- 
2.20.1