[PATCH 08/11] fs/ntfs3: reserve a compression unit in maxbytes_sparse

[Konstantin Komarov]

With 32-bit clusters, the maximum size of a sparse file was computed
as the largest offset addressable by a 32-bit VCN.

Reserve one compression unit below the limit so the rounded-up VCN
still fits.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
---
 fs/ntfs3/super.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c
index cf67d34568d8..0c347085cb85 100644
--- a/fs/ntfs3/super.c
+++ b/fs/ntfs3/super.c
@@ -1235,8 +1235,13 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 	sbi->maxbytes_sparse = MAX_LFS_FILESIZE;
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 #else
-	/* Maximum size for sparse file. */
-	sbi->maxbytes_sparse = (1ull << (cluster_bits + 32)) - 1;
+	/* 
+	 * Maximum size for sparse file:
+	 * 16 aligned up clusters should fit in 32 bits.
+	 * xfstest 308 on sparse file.
+	 */
+	sbi->maxbytes_sparse = (1ull << (cluster_bits + 32)) - 1 -
+			       (sbi->cluster_size << NTFS_LZNT_CUNIT);
 	sb->s_maxbytes = 0xFFFFFFFFull << cluster_bits;
 #endif
 
-- 
2.43.0